look closely at the connecting rods one edge of the main bearing are is beveled noticeably more than the other that beveled side faces away from the rod its paired with because it matches the slight radiased bevel of the crank journal
many builder class pistons are designed to go in, in either orientation ,and have both the valve notches and piston pin offset that are identical but most performance pistons have a dot or an F stamped on the crown indicating the side facing the front of the engine, naturally the rod big end bevels face the crank counter weights on each pair and the non-beveled big end faces the matched rod
think carefully about both the initial cost and the structural strength of the engine block you select, the OEM blocks used in production car engines will RARELY accept a .030 plus over bore with out having one or more cylinders having marginally thin bore walls, this results in inadequate bore to ring sealing if its in the wrong area and promotes stress cracks. A .060 over bore in a SBC is rather commonly pushing that bore wall thickness up to or over a reasonable limit so you need to sonic and magnetically check the block for cracks and wall thickness.
you could easily dump $500-$1500 into machine work on a block that won,t last more than a few months under high stress if its not carefully checked PRIOR to the machine work being done.
https://www.amazon.com/dp/B06VXC1FPL/ref=nav_timeline_asin?_encoding=UTF8&psc=1
a set of quick release tools for late model gm fuel lines and a/c line disconnects. ACETOLENE TORCH ADJUSTABLE LENGTH PUSHROD ADJUSTABLE POINTER , adjustable stand,for dial indicator assorted pliers/vise grips air compressor air ratchet Allen wrenches 200 amp ARC WELDER ASK QUESTIONS ASSORTED.
garage.grumpysperformance.comOk youve just installed your crankshaft in the engine block, with new main bearings and everything's well coated with assembly lube,and oil, and youve torqued down the main caps to spec. in at least three stages, and then gone back and rechecked the studs or bolts per the manufacturers.
garage.grumpysperformance.com
I was asked a few times after the last video about Piston Ring ring gap orientation aka "Clocking" so here's a video that should help out you first time engi.
www.youtube.com
Your first time filing piston rings can be tricky until you get the hang of it. Today, Jay walks us through the process of how he files the rings in our race.
www.youtube.com
read the links don,t skip them, youll likely save a great deal of cash and time knowing whats involved
it should be rather obvious that youll need to know the exact distance the piston deck sits at TDC ,above or below the block deck surface and the valve notch recess or pop-up dome volume of the piston to do accurate quench or compression calculations
http://www.harborfreight.com/1-inch-tra . r-623.html
ARP rod bolts are set up to use a stretch gauge with both ends of the bolt pre-machined for the gauge the bolt packaging from ARP,comes with the correct length the bolts are supposed to reach under the correct pre-load tension, in the instructions OR its available on their web site
most guys are familiar with use of a torque wrench to tighten rod bolts to the correct preload, but while this gets you very close its not as precise as a rod bolt stretch gauge,
having consistent clamp loads are mandatory for proper assembly
notice how the rod bolts come close to the cam bearings and cam lobes, as the pistons reach top dead canter in the bores, this clearance must be individually checked and should be no less than about .060 (generally you cam use a LARGE plastic tie-wrap
https://www.amazon.com/BuyCableTies. D=41U9CtmwOuL&preST=_SY300_QL70_&dpSrc=detail
placed between the cam lobe and connecting rod bolts or connecting rod shoulder areas to check clearances as the soft tie-wrap will not damage the cam lobe while you verify clearances)you must install the timing set and index the cam correctly to get a valid clearance , as the cam lobes rotate and at some point they can be incorrectly indexed too hit the rods, while they would not if correctly timed.
if you wonder why I suggest using SCAT (H) beam style cap screw connecting rods vs stock or most (I) beam designs this picture should show the increased cam to connecting rod clearance.
don,t assume anything! when you assemble the connecting rods and pistons there is ALWAYS some minor differences in dimensions,in piston pin height and rod length, VERIFY QUENCH DISTANCE TO THE BLOCK DECK, so youll want too, try to match the slightly shorter rods to the pistons with taller pin locations so the average quench distances is a bit more consistent
one factor to keep in mind is that rods typically have a side that rides against its matched companion and a side thats BEVELED for clearance on the crank journals radias EXAMPLE
notice the top rods non-beveled side that faces the matching rod is up, but on the lower rod the the beveled side that faces the crank counter weight is up on the lower rod
BTW I recommend THIS TYPE of piston ring compressor (below)as the type in the video can and occasionally does allow the rings to pop out and jam, or break far more frequently .
the picture lacks detail, but the interior of the compressors tapered, you tighten to a slide fit on the piston diam. and the rings compress fully as they are entering the cylinder entrance and only expand after entering the bore.
BTW when you go to buy a ring compressor. this type works far better than the others
if you find the rotating assembly is more difficult to rotate than you expected, you may want to verify some clearance issues that get over looked at times,
theres also some, other potential issues,
theres a slight potential for the piston wrist pins too not rotate effortlessly in the piston pin bores ,
that may add to the difficulty in rotating the assembly in the block.
the piston rings must have vertical and back clearance in the piston ring grooves
Piston Ring Groove Clearance
Pistons are grooved to fit rings that seal the cylinder’s compression and allow for lubrication of the cylinder walls. Piston rings come in a set. There are two compression rings. The top ring is affected by the most cylinder compression pressures. The second compression ring reinforces the top ring. The third ring down is the oil ring. It controls lubrication between the piston and cylinder bore.
Place the new ring into the top piston groove, and then place a feeler gauge into the gap between the new ring and the upper land. Move around the pistons groove and obtain a few measurements. Compare this reading to specifications. If this reading is too much and the gap is too large, the piston must be replaced. The top ring takes the most compression. This causes the ring to slap against and wear the lands in the piston groove.
and of course the pistons must have the correct piston too bore clearance. and connecting rod can only be installed facing one direction
youll be surprised at how much easier they slide into the bore if you BOTH pull/guide and push the pistons into the cylinders rather than just beat them in with a hammer handle, it takes some practice but a few taps to get them moving with a fist, while pulling and guiding the rod into its journal is usually all that necessary with a well oiled piston and that type of ring compressor.
IVE dunked my piston/ring assembly's in a can of MARVEL MYSTERY OIL just before installation with a ring compressor and have never seen the slightest indication of problems either on ring sealing getting the rings broken in, or on tearing the engines down later for inspections
KEEP IN MIND
be sure you, measure EACH bore and EACH piston,
(CORRECTLY with the proper tools in the way the tool and piston manufacturers suggested)
and number them on an engine build sheet indicating the bore and piston diam.
from large to smallest on each and install them on each cylinder to get the most consistent piston to bore clearance's
yes the difference may only be a few ten thousands if the bores are machined correctly, but you'll get the best results , most consistent lubrication, best durability and less heat build up that might result in detonation issues that way. its the little things that add up to making a good durable engine assembly,
BTW check rod orientation, so the beveled sides don't fact the adjacent rods, and check the bearing clearances with plasti guage
ok first some facts (1)cylinders will not be honed to true round as they will be in use with out the use of a deck plate to simulate and duplicate the bolt clamp stress on the cylinder walls, bores in blocks without a head or deck plate with the bolts or studs torqued to spec are not nearly the.
garage.grumpysperformance.com
So I decided to buy a couple of worthless old 283s to learn how to build engines. If I acquire the appropriate skills, I'm going to build a torquey 383 out of the anemic '77 350 in my C30. It tows cars, but it doesn't exactly set the road on fire, if you know what I mean. Anyway, I bought two.
garage.grumpysperformance.com
YES YOU NEED TO READ THRU THE LINKS THAT'S WHAT THEY ARE THERE FOR. AND THERE'S A GREAT DEAL OF USEFUL INFO IN THOSE LINKS, don,t get over whelmed, make a list and test adjust correct or replace each problem, and check it off the list then move to the next issue, its a finite list and theres.
garage.grumpysperformance.com
look closely at the connecting rods one edge of the main bearing are is beveled noticeably more than the other that beveled side faces away from the rod its paired with because it matches the slight radiased bevel of the crank journal many builder class pistons are designed to go in, in either.
garage.grumpysperformance.com
any ring compressor design you use regardless ,of the design MUST have its lower surface kept firmly in contact with the block surface and parallel to the bore to allow the rings to smoothly transition from the inner surface of the compressor to the blocks bore, and IDEALLY the compressor internal diameter will be marginally smaller in internal diameter that the cylinder bore the pistons sliding into from it!
http://www.engineprofessional.com/TB/EPQ410_10-18.pdf
when in doubt call the PISTON manufacturer and ASK!
naturally youll measure the bearing journals
one factor to keep in mind is that rods typically have a side that rides against its matched companion and a side thats BEVELED for clearance on the crank journals radias EXAMPLE
notice the top rods non-beveled side that faces the matching rod is up, but on the lower rod the the beveled side that faces the crank counter weight is up on the lower rod
rod-grinding
bearings AND connecting rods have an inner facing side and outer side the inner side facing the matching rod has far less edge clearance because they don,t need the radias that is required for the edge of the crank journals
notice the top rods non-beveled side that faces the matching rod is up, but on the lower rod the the beveled side that faces the crank counter weight is up on the lower rod
notice how one side of the bearing holding section has a radias (left)(GOES TOWARD CRANK COUNTER WEIGHT) but the opposite sides flush (right) (FACES MATCHED ROD)
ok lets look at a few things, first , if you look closely at your connecting rods you'll see that one side has considerably more bevel ground on the inner edge of the connecting rod around the bearing than the other side does, to side with that bevel ground on it is to provide clearance for the radius ground onto the crankshaft where the crank throw meets the counterweights like you mentioned, that side of course goes out away from the other rod, to side with far less pronounced bevel is the side where the two connecting rods meet, and ride against each other during normal engine operation normal clearance there is in the area of six to 15 thousands of an inch. When the two connecting rods are correctly torque in place and a feeler gauge is fitted between them to check the maximum clearance.
Now a small block Chevrolet the valve placement or valve layout is in this order on a normal head, E I I E E I I E , the letter (E) of course representing exhaust and the letter (I) of course representing intake your Pistons will have to be inserted into the cylinders matching that layout, this will mean there will be two left and two right Pistons on each cylinder bank, if there is a dome on the Pistons it will go towards the outside of the block, when the machine shop installed the Pistons on the connecting rods, they should have been set up with four of the Pistons set up with the exhaust valve notch on the Pistons facing towards the bevel on the connecting rods and four of the Pistons set out live the intake valve side of the Pistons facing that bevel, lets look at the first two cylinders, cylinder number one is the front left forward facing forward look at the diagram per cylinder layout any
on that Piston both the bevel for the Crank Journal that provides bearing clearance and the exhaust valve notch would be towards the front of the engine, but on the next cylinder number two, on the opposite side of the engine. That Piston would have the bevel on the connecting rod facing the rear of the engine, but the exhaust valve notch would be facing the front of the engine, now let's look at cylinders three and four, cylinder number three, would have the bevel on the rod of course facing forward but the exhaust valve notch facing the rear of the engine, on cylinder number four you would have the bevel on the connecting rod facing towards the rear of the engine, and the exhaust valve notch facing towards the rear of the engine, now let's look at cylinders 5 and 6 cylinder number five, bevel forward exhaust forward, cylinder number six exhaust forward but bevel towards the rear for cylinders number 7 & 8 on cylinder number seven, exhaust out notch towards the rear, bearing bevel towards the front of the engine on cylinder number eight bearing bevel towards the rear of the engine and exhaust out towards the rear of the engine
keep in mind that some non- standard head / port layouts can potentially change the piston notch layout
you¢ll also need to make sure youe piston ring end gap is correct, that the piston rings have the correct side facing upwards that the bearings are installed with the correct clearance, and coated with assembly lubricant, that the piston to cylinder block deck clearance is correct ,that your quench distances are correct, and that after you degree in the cam that the piston to valve Clearance is correct. Youll also need to be careful that you don,t hit the connecting rod or rod bolts to the crank journals potentially causing any damage during the installation, and its normal to oil the rings and piston with a lite machine oil during the installation.
Ive personally found that the piston ring compressors that work best are this type,
this type is far easier to line up to the block surface at a slight angle that allows the rings to partly pop out from under its lower edge just as the rings leave the lower edge of the compressor and enter the cylinders bore, now Im not saying you can,t do it, just that its far easier to do it correctly with this type of ring compressor.IVE dunked my piston/ring assembly's in a can of MARVEL MYSTERY OIL just before installation with a ring compressor and have never seen the slightest indication of problems either on ring sealing getting the rings broken in, or on tearing the engines down later for inspections
always protect the connecting rod journals from getting scratched during the rod assembly process, a 18" long section of 3/8" or 7/16" inside diam. rubber fuel line can be pushed over rod bolts , after being looped 180 degrees around the rod journal on the crank, if the rod bolts extend down from the rod or a 18" section of 7/16" fuel line with a u shaped section of 5/16" thread rod that's 24" long, bent in the center over a 2.5" section of pipe so the ends remain parallel and even in length can be used as a handy tool so that 3" of the thread rod extends from each end, you then cover all but the last 1" on each end with plastic electrical tape and place the ends thru the rod bolt holes, and thread on a nylon washer and a nut finger tight, can be used as a tool to draw into place a rod on the rod journal if you use cap-screw rod designs
basic rod bearing assembly
1. Clean the bearing surface of all the connecting rods and connecting rod caps and closely inspect them, in an ideal world they have both the upper and lower should be engraved or stamped so, they can,t get mixed.
2. Clean upper connecting rod bearing and lubricate the bearing face with clean engine oil and moly assembly lube.
3. Clean lower connecting rod bearing and lubricate the bearing face with clean engine oil and moly assembly lube..
NOTE: Align the tabs on the connecting rod bearings with the tab grooves in the connecting rod.
4. Install upper connecting rod bearing in connecting rod, so the bevel on the bearing matches the bevel on the rod and tabs align.
5. Pull the connecting rod and piston assembly into position against the crankshaft. using both a ring compressor, and a rod guide after verifying the ring gap and ring side clearance, ring indexing and the rings are installed with the proper side facing upwards
6. Install lower connecting rod bearing in connecting rod cap.
7. Install bearing cap in position on connecting rod. Ensure that the identification numbers you previously are stamped on the same side, of the rod and rod caps.
8. If you have Type A connecting rods, install two bolts and two nuts. If you have Type B connecting rods, install two bolts. The torque is very important. verify the correct torque, in this section of the site,and with the connecting rod manufacturer
9. Repeat Steps 1 through 8 for the remaining connecting rod bearings.
THIS BEAM STYLE TORQUE WRENCH IS THE TYPE TORQUE WRENCH YOU WANT TO CHECK ROTATIONAL RESISTANCE
as to the rotational smoothness, be aware that, all assembly lubes and oil on blocks bore the rings ride over and all bearing surfaces, coated with oil and assembly lube provide a surface shear tension that must be broken before the crank turns,
so its not un-usually for the rotating assembly after the pistons and rings are installed, too require lets say 35 ft lbs to get the assembly too start too spin ,but only 15-26 ft lbs to keep in rotating , (low tension rings provide less drag) you can generally call the piston ring manufacturers and they should know approximately what torque reading on the crank snout,a socket and a torque wrench will require to have the engine assembly rotate with their rings installed.
a crank snout, turning socket,but if that short block assembly,takes over 35-40 lbs to start it rotating once its assembled without cylinder heads attached, you've got serious issues, like cam lobe to connecting roods hitting or a connecting rod facing the wrong way on the crank journal, or the wrong size bearings, or the crank journals not the right size, badly polished or not round
read thru these related threads, posted below, youll find a good deal of info, on installing pistons and rings.
I've bought some time ago a set of used forged SRP pistons. Today i was cleaning them and I also did some measuring. Pistons are SRP part nr. 138084 - 0.020" overbore: Here is what I've got: 1. 4.0153 2. 4.0152 3. 4.0152 4. 4.0148 5. 4.0151 6. 4.0164 7. 4.0156 8. 4.0153 I've measured at .5".
garage.grumpysperformance.com\" how do you measure piston dome volume" I just bought a 454 from a yard sale, the seller has no clue as to the pistons used" https://www.summitracing.com/newsandevents/calcsandtools/compression-calculator http://www.grumpysperformance.com/cop2.png.
garage.grumpysperformance.comaaoil.co.uk
these tools come in various ring sizes ,(but the various piston diameters are not as critical as ring width, it should be obvious that you MUST USE the tool that places the drilled gas port at the correct place in the upper ring groove roof and you damn sure better not drill deeper than the rear edge of the ring groove or youll destroy the piston
while these professional ring filing tools ,(LINKED BELOW) would be great to have on hand,
during your engine assembly
, the price makes owning one as a hobbyist unlikely
early in this thread theres pictures and links to the manual piston ring filers
and if your very careful you can use a cut-off wheel on a dremel tool
yes as always theres cheap,functional, and theres expensive precision ring filers
if you have oil ring expanders with the plastic bits,they are there to prevent you from over lapping the ends of the oil ring expander, theres some oil ring expander s that are vertical ,some horizontal, but all have the ends butt , none over-lap
ideally the pressure above the piston gets behind the top compression ring and increases the force holding the ring face to the bore surface, noticabl;y more than the ring tension alone can do.
BTW GAPLESS PISTON RINGS HAVE TWO PIECES THAT EACH MUST BE GAPPED < THE IDEA IS THAT THE TWO GAPS IN THE SET ARE ON OPOSIRE SIDES OF THE PISTON GROOVE
your going to need decent feeler gauges
here is where you, or your machine shop can screw things up on ring to bore seal, you need to have the cylinders bored and honed to the correct size specified by the manufacturer of the pistons,after MEASURING THE PISTONS to verify their size per the piston manufacturers instructions, then gap the rings per the ring manufacturers instructions, when you hone the bores,get and use block deck hone plates, during the hone process , keep in kind you want to use the same (STUDS OR BOLTS) the machine shop used and the same torque settings they used when the cylinders were honed with deck plates or the distortion of the bore and ring seal won,t be identical (exactly round)or ideal, keep in mind the piston side clearance must match what the piston manufacturer states.
Ive used several sets of total seal gapless rings in several engine builds over the years, they usually have a slightly better leak down test result , but I can,t really see and measurable power or durability increase
youll need the info in this link, ABOVE and its sub links ALSO
now I work mostly on BBC engines and I built a custom ring square tool , out of cheap and easy to find PVC plumbing pipe adapters, (look at the pictures, rick posted,)remember it does not need to be a perfect bore diam. match too square the rings , but of course it must fit down the bore, too use when gapping rings,and on the big block engines you can build and use a custom tool like this without reducing the diam., but Rick went the extra step and built a very similar tool for his SBC projects engine
measure carefully as the piston groove depth and back clearance must match the rings you use or youll have major problems
The stock ring filer just had too much end play in the shaft that holds the abrasive disk. So I stopped
by the local bearing supply and picked up a couple of bushings. If I wanted to wait it might have been
easier to buy a metric size bushing, but they weren't in stock so I bought the fractional size. The only
thing wrong is both the OD and ID were not correct. So I reamed the hole in the aluminum frame to accept
the larger OD of the bushing and turned the shaft on a lathe to fit the ID of the bushing.
I used JB weld to make the bushings permanent so I left it sticking out far enough to keep the shaft from moving to
the left and the locating pin would keep it from moving to the right. Since I turned the OD of the shaft down, I
had to drill and tap the 5mm x .8 metric threads, moving it closer to the centerline so it would intersect the
groove again.
There is NO end play now, much nicer .
Stock Ring Filer
The pin was moved closer to the centerline of the abrasive wheel shaft.
Finished Ring Filer
Edit on 11/09/2011
I wanted to see if theory and reality were close when it comes to the gap needed on the left stop pin of the ring filer to correct the angle filed on the ring end such that they would be parallel. I knew I couldn't do the math, but I could use Microsoft Visio and let it do the math for me.
I did the drawing to scale so that I could move the ring over until it's CENTER-LINE lined up with the right side of the grinding wheel while also touching the RIGHT stop pin, then measure the gap. I did this for two bore sizes so I could see how much difference the bore made. I used a 4" bore and a 4.5" bore for this test. The difference was only 0.005", hardly worth taking into consideration.
The LEFT STOP PIN needs to be 0.35" to 0.36" in diameter or you could replace it with a pin of 11/32"(0.35437") or 23/64"(.3593"). Dowel pins don't seem to come in those sizes, the only thing I've found so far is "Drill Rod" which would be hard to cut. Or you could do as Grumpy has suggested above and slip some copper tubing over the 1/4" stop pin that is already there.
You can purchase the drill rod for $5-7$ for a 3 foot length from Fastenall.
http://www.fastenal.com/web/search/prod . evyx&Nty=0
http://www.fastenal.com/web/search/prod . evyw&Nty=0
BTW
if your un-aware, most rings have a DOT on the upper surface to indicate which side goes up , if they don,t the inner edge is sometimes beveled, or stepped and the wider gap or stepped recess faces up to allow high pressure gasses , from the combustion chamber to push it outwards
this type (ABOVE) handles many applications but the cheap versions are a P.I.T.A. to work with
BTW when you go to buy a ring compressor. this type(ABOVE & BELOW) works far better than the others, but its specific to a very limited range in bore size applications
Proform 66766 $31
#525 is a 220grit hard stone & pretty coarse.
It is what I consider a "production rebuilder finish" & not what I would finish any bore with especially a performance one but it will work with cast iron or chrome
#625 is a 280grit hard stone & mid range suited to moly rings
400-500 grit stones are sometimes used after a 280 grit hone to just prep the surface briefly before final clean-up and moly ring install
BTW when you go to buy a ring compressor. this type works far better than the others
related info, threads and sub-links, you should read carefully
remember to dip the piston and rings in high quality oil just prior too or before assembly I,ve used MARVEL MYSTERY OIL FOR DECADES
this style ring compressor below has a nasty habit of not keeping the rings evenly compressed and not seating evenly on the block , Ive used them but the type above is much easier to use
[paste:font size="3"]
The contact pressure also produces a friction between the bearing back and the housing surface which contradicts the friction generated by the journal rotating in the bearing (ML). The torque of the friction force formed between the bearing back and the housing MH prevents the bearing from shifting in the housing.
High performance bearings working at heavy loads, high rotation speeds and increased temperatures should be installed with a higher contact pressure. This provides better heat transfer and secures the bearing more tightly in the housing.
[paste:font size="3"]crush height.
Crush height is the difference between the outside circumferential length of a half bearing (one half shell) and half of the housing circumference [1] measured at a certain press load.
Fig.2 illustrates a device for measuring crush height.
The tested bearing is installed in the gauge block and pressed with a predetermined force F. The force is proportional to the cross-section area of the bearing wall.
The optimal value for crush height is dependent on the bearing diameter, housing material (modulus of elasticity and thermal expansion), housing dimensions and stricture (rigidity), and temperature.
[paste:font size="3"]
However the calculation results did not take into account a temperature increase. The crush height is measured at a normal ambient temperature, but the bearing together with its housing heat up during bearing operation. If bearing and housing are made of materials with different coefficients of thermal expansion, the effective crush height (interference) will be different from that measured at room temperature.
The most significant difference between the thermal expansions of the bearing and housing is realized when the housing is made of aluminum.
Fig.4 shows the effect of temperature on the contact pressure of the bearing (CR 807XPN) in an aluminum housing.
The graph shows that the required level of contact pressure in the heated aluminum housing may be achieved only if the crush height is not less than 0.009”.
Another factor affecting contact pressure is the rigidity of the bearing housing, determined by the housing dimensions and shape. Fig.5 presents the calculation results of the effect of the housing diameter on the contact pressure of the bearing in housings made of three different materials. The calculations are made for crush height ch = 0.005”.
The graph shows that the steel housing provides the required contact pressure even at a diameter as low as 1.25 of the bearing diameter. The contact pressure 1500 psi in a titanium housing is achieved at its diameter greater than 1.4 of the bearing diameter. The diameter of an aluminum housing should be at least 1.75 of the bearing diameter.
A tighter contact between bearing and housing may also be obtained by an increase of the thickness of the bearing steel back.
The effect of bearing thickness on contact pressure is shown in Fig.6.
The required minimum value of 1500 psi pressure in a steel housing is achieved with a bearing whose steel back is thicker than 0.047”, whereas the bearing back thickness in an aluminum housing should be at least 0.077” and 0.057” in titanium housing.
Thus, the design of crush height in a high performance bearing should take into account not only severe operating conditions (heavy load and high rotation speed), but also the housing parameters (material, shape, dimensions), bearing dimensions and the ambient working temperature.
However, there are limits to the minimum amount of crush height as well as the maximum amount of crush height. When a bearing with excessive crush height is installed and tightened in the housing, the material in the region of the parting line exerts an inward displacement which reduces the gap between the journal and the bearing surfaces in this area. The change of bearing profile at the parting line region results in the formation of peak oil film pressure, which may cause fatigue of the bearing material [3].
A bearing affected with fatigue cracks in the area of crush relief is shown in Fig.7.
The compression stress in the bearing was 72,300 psi which is greater than the maximum value of 65,000 psi.
[paste:font size="3"]regime of hydrodynamic lubrication [4]. The value of hydrodynamic friction torque developed using King high performance bearing CR 807XPN was calculated assuming the use of 15W50 oil, and a wide range of rotation speeds, oil clearances and eccentricity.
The calculations were performed using software developed by King Engine Bearings. This software is capable of calculating loads, friction forces, minimum oil film thickness, oil temperature rise, energy loss, oil flow rate and other thermodynamic, dynamic and hydrodynamic parameters for each bearing of an engine at any angular position of the crankshaft.
The maximum value of hydrodynamic friction torque ML resulted in a value of approximately 2 ft*lb.
The torque MH required to spin the bearing in the housing is about 100 ft*lb (corresponds to the contact pressure of 2630 psi).
Thus the safety factor is about 50 - sufficiently large enough to prevent spinning. Even if lubrication turned to mixed regime, the journal friction torque will be much lower than the torque keeping the bearing from spinning in the housing.
general rule for N/A engines is ring gaps should be between, .0040--.0045 per inch of bore dia.
displacement = bore x bore x stroke x 8 x .7854
1/2 stroke + rod length+piston pin compression height,
should roughly equal block deck height ,
Connecting Rods sold by SCAT Crankshafts, the leader in high-performance engine components for over 50 years.
www.scatcrankshafts.com
Molnar BBC rods. Big selection of H beam big block Chevy connecting rods. Standard, stroker, turbo, power adder, power adder plus and small journal.
molnarrods.com9.8 Short deck
Aftermarket block
Bore. Stroke. Rod. Displacement
4.5. 4. 6.385/6.535. 509
4.5. 4.25. 6.135/6.535 540
4.5. 4.5. 6.135. 572
4.56. 4.25. 6.385 555
4.6. 4.25. 6.385. 565
Tall deck 10.2
4.5. 4.25. 6.535. 540
4.5. 4.5. 6.535. 572
4.5. 4.75. 6.7. 604
4.56. 4.25. 6.535. 555
4.6. 4.5. 6.535. 598
plus or minus a few thousandths,
minor adjustments in compression,
due to head gasket thickness and what the piston deck height is are common
common BB CHEVY piston compression heights are
1.270"
1.395"
1.520"
1.645"
1.765"
remember the blocks deck height, minus the piston pin height minus 1/2 the crank stroke will equal the required connecting rod length
OR
the blocks deck height, minus the connecting rod length, minus 1/2 the crank stroke. will equal the required piston pin height
example
a 4" bore like a 350 x .004--.0045 = .016-.018 ring gap
heres a chart and links to tools for reference
you naturally take the time and effort to use clean components and tools during assembly and try to work in a reasonably dry and well lighted location with the engine up on an engine stand,and frequent use of lint free wipes, soaked in marvel mystery oil helps, as it keeps the metal surfaces from rusting or collecting crud, Ive generally found that if your cover the engine with a large plastic bag and duct tape, when your not actually working on it, its not been a factor worth worrying much about, in a reasonably clean shop with no open doors to let in wind carried debris.
heres some pictures I found on the web that may help
CHECKING TRUST BEARING CLEARANCE
when building a 383 stroker ,you need to check rod to cam and rod to block clearances, you should have not problem grinding .080 or so clearance on the lower bore wall edge with zero chance of getting into the water jacket passages or water jacket at the area of the yellow paint indicated in that picture, most people forget to check that area
obviously youll want to check all 8 cylinders and remove the cam and clean carefully before re-installing the cam.
AUTOMOTIVE
ENGINE ASSEMBLY: THE BOTTOM END
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By user666 / July 23, 2018
We’ll get into the actual meat and potatoes of engine assembly: measuring main bearing clearances, measuring rod bearing clearances and checking crankshaft thrust dimensions. In the process, the crankshaft will be installed, the main bearing caps will be torqued and the bottom end will be readied for reciprocating component (rod, wrist pin and piston) installation.
Sounds complex, but the truth is there’s nothing fancy here except persnickety measurements, attention to cleanliness and plenty of patience. Bottom line: If you can muster up the persistence for detail, you can handle the job. It’s that simple. Here’s how it’s done.
Measuring the mains
The first step is to measure the crankshaft main bearing journal diameters. This is best accomplished on your workbench. We use a micrometer to check the dimensions in an “around the clock” pattern on each journal. What that means is that we check each of the main journals in multiple locations.
To properly use a micrometer, slowly tighten the spin wheel until the mic contact points meet the crank journal. Spin the bottom thumbwheel (ratchet stop) until you feel three clicks on the micrometer as it contacts the journal (keeping in mind you don’t want to scratch the journal surface either). Double-check to ensure that the mic contact points are touching the journal evenly (not cocked to one side). Lock the micrometer and check the reading. Record each reading as you go around the journal. In essence, you’re accomplishing two things: You’re checking for crankshaft main journal out of round (if the readings from different points differ) and you’re also checking the outside diameter of the crankshaft journal.
Follow the same steps around each main bearing journal and record each set of figures for each journal. On a typical modern V8, you’ll have five bearing journals to measure on the crankshaft.
There are two different times you can measure rod journal dimensions: right after you’ve finished checking the mains or later, once the crank is installed in the engine. If you’re confident the crank was properly machined, you can save those steps for later (which is what we’re doing here). If you’re not so confident regarding the crank accuracy, it’s best to measure it now. That way, if the dimensions are off you don’t have to go any further on the engine assembly job.
Finally, when using a micrometer, keep in mind that heat has an effect on readings. Never carry a mic around in your pocket and don’t hold it for excessive amounts of time. Additionally, when storing the micrometer, be sure the measuring contact points are left open so that temperature variations do not stress the instrument.
Next up, each main bearing has to be installed, and the assembled diameter has to be checked. The bearings should be cleaned and dry. We start at the front and work our way backward, beginning with main bearing number one (bearing caps are usually numbered and marked with an arrow facing forward). The idea here is to install the bearing, torque the bearing cap and measure the inside diameter of the bearing bore with the bearing installed. More detail below.
Install the main bearings
To install the main bearing, you’ll note there are tangs on the bearing insert (in the old days, they were sometimes called bearing “shells”). Most engines also have an oil hole in the block that coincides with the upper bearing insert. This oil hole links the main bearing to the main bearing supply machined within the cylinder block. Only one-half of the bearing set (inserts) per main journal cap will be equipped with an oil hole. It’s essential you get them right (hole in the bearing coinciding with the hole in the cylinder block-machined bearing web).
Begin the installation with the tang side of the bearing insert. Install in the block and then push the opposite edge into the main bearing bore. Repeat the process in the accompanying main bearing cap. Be sure the bearing is fully seated. You’ll note there is a small amount of bearing insert extending past the main cap as well as past the cylinder block bearing bore. This is the bearing “crush.” When the main bearing cap bolts are torqued in place, the bearing “crushes” into the outside of the bore. This ensures the bearing does not spin or turn during engine operation. At this time, you only need to install bearings on the number one main.
In most engines, the main bearing caps are numbered (the exception is usually the thrust bearing cap since it’s far different than any of the other bearing caps). Additionally, many main caps have an arrow that points forward: It goes toward the front of the engine. This arrangement places all of the bearing tangs on one side.
Oil the threads for the main cap bolts. We generally use good old-fashioned SAE 30 conventional (non-synthetic) for this purpose. Install the front cap (with bearing inserts in place). Thread the bolts in by hand and then using a soft face hammer (dead blow plastic or brass), seat the cap against the block. Torque the cap bolts to the factory-recommended specification. Generally, we use three equal steps (for example, 25, 50 and 75 foot-pounds), alternating between the bolts in each of the steps. On four bolt main caps, we start on the inner caps first then work outward. This tends to tighten the bearing cap evenly.
Check the clearances
Using an inside micrometer or dial bore gauge, measure the bearing inside diameter. Much like the crankshaft, we tend to measure the bearings (within the bore) in several different locations. Subtract the crankshaft outside diameter (measured previously) for journal number one from the bearing bore diameter. That resulting figure is the bearing clearance. Check the figure against manufacturer specifications. If the bearings are out of spec, you’ll have to juggle bearing halves (you can buy slightly under- and oversize bearings for popular engines) to come up with the appropriate clearance figures.
Repeat the entire process for all of the main bearings and caps. Once complete, remove all of the caps. Keep each cap and bearing intact. Leave the lower bearings in the cylinder block.
Installing the crankshaft
Depending upon the engine you have, it can be equipped with either a one-piece or two-piece rear main seal. No matter what format, it must be installed next. In either case, install the seal so that the lip faces inward (toward the engine). Clean the seal groove with a shot of brake cleaner and a fresh shop towel. The groove must be clean and oil free for the sealant to work properly. Apply a small amount of RTV silicone sealer on the seal groove in both the cylinder block and the main cap. Wipe up any excess (a wet finger works perfectly). Install the bottom half of the seal, or in the case of a one-piece seal, gently tap into place over the crankshaft (you can use a seal driver, but most seals easily tap on).
Apply motor oil (the same SAE 30 oil works) to the main bearings. Alternatively, you can use engine assembly lube (shown in the photo). It sticks with more tenacity than oil, providing more protection during the initial startup. Apply a small amount of engine oil or assembly lube to the main seal lip. Lower the crankshaft into place.
Reinstall the number one cap and the thrust bearing cap only. Seat the caps (using a soft face hammer). Install the bolts by hand, but don’t tighten.
Checking thrust clearance
Using a soft face hammer (plastic dead blow or brass), tap the crank nose (moving the crankshaft rearward). Install a dial indicator to read on the crank flange or nose of the engine. Using a large (clean) screwdriver or pry bar, move the crankshaft backward. Zero the gauge on the dial indicator. Pry the crankshaft forward and check the reading. Record the measurement. Next, torque the caps to specs and repeat the process. Compare the measurements. If the second reading is less than the first, there’s a chance the rear main cap shifted and the thrust surfaces are misaligned. Shift the cap and recheck. By the way, this doesn’t regularly occur, but if it does, you might have to check and shift the rear main cap a couple of times to get it right. Compare your final thrust clearance figure to the manufacturer specifications. Finally, install the balance of the caps (and bearings) and torque to specifications.
Checking the rod clearances
Beginning at the front of the engine, use your micrometer to check the overall diameter of each of the connecting rod journals on the crankshaft. The process is exactly the same as we used to check the main bearing clearances. Check each journal in multiple locations and record those figures.
You can now check the rod bearing clearances. Use the same process we used for the main bearing caps: Install the bearings with the tabs aligned. You can match the numbers on the rods or check to ensure the chamfers are all on the same side and install the caps. The bearings (and caps) are aligned tang to tang (not offset). Using engine oil as the lubricant, torque the cap bolts to the recommended figure and measure the bearing ID with a bore gauge.
Subtract the journal diameter from each of those figures to determine the clearance. Repeat the process for all of the connecting rods. Like the case with the main bearings, if the clearances are out of spec, you can often correct the dimensions by juggling bearing inserts.
Once all of the rod clearances have been checked, you can loosen the rod bearing cap hardware, but don’t completely disassemble. You need to keep the rods and their respective bearings in order. Wrap the engine in the plastic storage bag. You’re done with this segment.
In the next part of our series, we’ll show you how to file-fit piston rings to each cylinder, how to assemble rods onto pistons, and, ultimately, how to install all of the pistons and rods in the engine short block.
Tools used for this part of the assembly:
To use it, loosen the bolts of bearing cap number one. Remove the bolts along with the cap (and bearing). Wipe all traces of oil from the crankshaft and bearing surfaces (we use a paper towel).
Next, tear off a short piece of Plastigage (it’s sold in a long, thin paper envelope). Place a section of Plastigage on the center of the crankshaft journal, oriented front to back or diagonally.
Install the bearing cap and bolts. Torque to specifications, then loosen the bolts once more and remove the cap. You’ll find the Plastigage has crushed on the crankshaft journal.
Using the envelope the Plastigage was packaged in, you’ll find a scale on one end. Compare the scale to the crushed Plastigage on the bearing journal. This is the clearance figure. If the clearances are within specifications, you can move forward: Clean the journal (it wipes off with a towel soaked in brake cleaner) and repeat the process for all bearing journals. You can also use the same format for checking connecting rod bearing clearances.
The first step in determining bearing clearances is to measure the crankshaft main journal diameter. Here we’re using an outside micrometer to get the measurement. The article text offers details on how it’s done and tips on using a mic. Check all crankshaft main bearings and record your figures.
Next, install the main bearing insert for journal number one in the cylinder block. Note the orientation. The oil hole in the bearing half aligns with the oil hole in the main bearing.
The matching bearing insert for the main cap is installed next. Because of the need for bearing crush, the insert will seem marginally too big, and a minute portion of the insert will protrude past the edge of the cap (the same applies to the insert in the block).
Install the cap and torque the main bearing cap to specs. Typically, we begin with the inside bolts and work outward. In addition, it’s best to use three steps on each of the fasteners in order to “sneak up” on the final torque figure.
With the bearing installed in the cap and the fasteners torqued to specifications, you can measure the main bearing inside diameter. Here, we’re using a B&B Performance dial bore gauge for the measurement. Subtracting the crankshaft journal figure from this measurement provides the bearing clearance. Record all measurements and repeat this process for all bearings except the rear main.
Before measuring the rear main bearing inside diameter, install the oil pump and torque to specifications. The reason is there is always the chance for some distortion of the cap once a heavy oil pump is installed. Here, a huge Titan G-Rotor oil pump is installed and torqued to specs.
Once you’ve checked all of the main clearances (and they’re all within specification), you can install the crankshaft. You can use conventional engine oil for the installation or assembly lube. Apply a light coating to the lower main bearing halves.
Next, the rear main seal is installed. With a one-piece seal such as this, it must be slipped over the rear of the crank prior to lowering the crankshaft into the block. The article text offers more detailed info, but in this photo you can see the installed seal.
With all of the lower bearing inserts in place, you can gently lower the crank into the main bearing saddles. You can reinstall the rear main bearing and cap along with the first (front) bearing cap.
Checking the crankshaft thrust dimension is next. You’ll need a dial indicator setup to read front-to-rear movement on the crankshaft. Depending on how you choose to perform the job, the dial indicator can be set up on the nose of the crank or on the rear flange. For this job, we have access to the flange on the engine stand (it needs to be tapped with a hammer), so we set the dial indicator up on the nose. The text offers details on how this job is accomplished.
All of the main bearing cap bolts (or studs) can be torqued in place. We use a half-inch drive torque wrench for the job, and while we have three other torque wrenches in our tool collection, this long handle one makes torquing large numbers easy. What’s with the blue line on the outer row of bolts? It’s used to note which caps have been fully torqued. That way you can’t forget if you’re called away. We always double-check them.
Measuring the rod bearing clearances is next. Here, the number one and two rod journals on the crankshaft are measured using a micrometer. Much like the main journal measurements, it’s a good idea to check in multiple places around the journal. This determines if the journal is in fact round. Repeat the process on all of the bearing journals and record the measurements.
At this point, the connecting rod bearings can be installed. Note the chamfer on the bearing is designed to match the chamfer on the connecting rod. You’ll also note the bearing tangs are next to one another. If the connecting rod (and cap) is unmarked, this orientation ensures the cap is installed correctly. When assembling the engine, the chamfer faces the large fillet radius on the crankshaft.
With the bearing installed and the cap correctly oriented, you can torque the connecting rod fasteners to specification. In this case, the GM Performance Parts connecting rods mandated 30W oil as the lubricant during tightening. Sneak up on the final figure just as you did with the main bearing caps.
Here, we’re using our B&B Performance dial bore gauge to determine the inside diameter of the rod bearing (installed within the connecting rod). Once this figure is determined for each connecting rod, subtract the crankshaft rod journal dimension to determine the oil clearance. FYI, the best way to measure bores such as this is by way of a dial bore gauge.
