My Cam Research for the Experts Eye

used carefully, and with some experience,
a dremel tool cut-off wheel can do a decent job at cutting ring end gaps
read thru these related threads, posted below, youll find a good deal of info, on installing pistons and rings.

yodam.jpg


61iWToi3-+L._AC_SL1364_.jpg

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related threads with very useful info














 
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Awesome - thanks.
I'll be going through every link.
Yes I've got a dremel and a light touch. I've considered setting it up for the rings. I'll post progress on what path this goes.
 
It's just too easy to grind them, if anything it maybe too easy so manual is all you will need. If you want to upgrade the ring grinder, maybe a stop you can set would be very nice. I would have preferred a smoother stone so I could sneak up on the correct gap, I did get one too big. If you have something with 6-10 power magnification it will be useful when it come to inspecting the filed ends and how well you knocked the burrs off.
Rick I read thru your entire filing process in your engine thread. Very enlightening about the location of the stops and the (non)centering of the grinding wheel. I do have a set of eye loupes that provide excellent magnification.
I also found info posted by Grumpy on real world allowable gap, which is significantly larger than the average .004/in of bore. But the reasoning behind that larger allowable gap makes sense.
My hope is that the new rings will fit without any filing and this may be a real possibility. They should be delivered sometime tomorrow.
 
My rings arrived today and I did some measuring.

A recheck of the honed bores (nominal .030 over) resulted in a diameter of 2.2798. That's setting my (calibrated) mic to 4.28, aligning bore gauge to that dimension, then checking each bore. Negative delta was .0002 to .00025.

I assigned each ring to a cylinder and measured gap of all top and middle rings. Oil rings were just spot checked and had plenty of gap. Oil ring spacer fit fine onto piston, so my focus is on top and middle rings.

Mahle specs .004/bore inch as a min gap. If I multiply 4.2798 times .004 I get min gap of .017, virtually same as 4.28 in bore. This is for all compression rings, no difference noted by Mahle between top and middle rings.

Top ring gaps measured two @ .017, the rest @ .018
Middle ring gaps measured one @ .018, the rest at .019.

Now looking at this info from Grumpy:
for most of my 40 years of engine build experience most builders gapped the top rings for a
Normally aspirated
.0045 per inch of bore top
.004-.0045 per inch of bore second (slightly tighter end gap on the second ring)
because the second ring was not exposed to the same intense heat so it needed less gap to prevent the ring ends from touching as the heat expanded the rings and lowered the resulting end gap, remember that .0045 per inch of bore results in about a .019-.020 " end gap on the rings of a 427-454 bbc with its 4.25" bore

lately thats changed to

.0045 per inch of bore top

.005-.0055 per inch of bore for the second ring second

Using .0045 for top ring, I get 4.28 x .0045 = .019 gap
Using .005 for middle ring, I get 4.28 x .005 = .021 gap

Thinking of heat expansion, I think its feasible to use the .019 and .020-.021 gap numbers. Do you agree?
 
yes you'll be ok going that route as long as your not using a performance booster, like nitrous or a supercharger, that increases cylinder heat, significantly




significantly
ringinm.png
 
No adders, thanks Grumpy.

Edit - so I've been considering what to do on a ring grinder and decided to go this route. I can fab a pinned steady rest for the rings to ensure they are fixed parallel to the blade and are secured from moving. Very affordable and then I'll use later for my saw blades!
 
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I'll go back and measure crankshaft journals and mains/rods bores with mic/borescope again but I went ahead and checked the mains with plastigage. I'll do the same with the rods. They all look very even and consistent in width across the journal - the numbers on them are just using a set of calipers to measure the width of the plastigage, look to be .0017 to .0018.

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I went back and tried to find any info on the first build and found a note I had made stating that mains were set up at .0015, rods at .015 to .002. That seems tight but there was never a problem and all journals looked very good at disassembly.

One other thing related to the repeat torquing of the main studs that was mentioned in a post above. I noticed that first time everything torqued down ok, but just a bit stiff. I could definitely feel a "smoother" tightening after this third round of torquing the ARP main studs (110 ft/lb). I will do the same for the new SCAT rods (7/16 ARP bolts).

Slowly getting to assembly of the short block...:)
 
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I went back and tried to find any info on the first build and found a note I had made stating that mains were set up at .0015, rods at .015 to .002. That seems tight but there was never a problem and all journals looked very good at disassembly.
Nothing wrong with .0015 to .002, well unless you plan to turn the engine up to higher rpm's consistantly. I think you will find that OEM clearances are in that lower range.
 
Nothing wrong with .0015 to .002, well unless you plan to turn the engine up to higher rpm's consistantly. I think you will find that OEM clearances are in that lower range.
Yes, I'm satisfied with the clearances. Even though I'll measure with more precise tools, I like plastigage as a check. There's a reason its still used after 40 years! Lots of engines have been built just using it alone.

I also got to thinking that the crush may be higher now that I'm using ARP studs instead of oem bolts? 2 bolt main bolt spec is 95 ft lbs. The ARP studs are spec'd at 110 ft lbs. That's an additional 15 ft lbs squeezing those bearings.

Edit....Grumpy info
Note: clamping forces will change when installing new studs. Check the main bearing housing bores for proper size and out of round condition. In most cases align honing the mains with the new studs properly torqued will be necessary to ensure proper fit and clamping forces.

Looks like there's my answer. The block was align honed and I included the new ARP studs with it to the shop. It must have been pretty straight, there was only very light machining showing in a few spots. Definitely not align bored. My measure of crank to cam center lines confirmed this.
I think also as with new bolts/studs, that first torquing produces initial stretch, so I believe that after cycling tightening a few times the torque reading is more accurate. But I'm thinking of getting a stretch gauge for the rod bolts and also using my dial indicator for the main studs at final assembly. It may not show accurate stretch in the studs, more as an experiment to see how final torque might change the indicator reading.

A primary driver for my decision to install new scat rods was noticing that at disassembly, #2 rod bolts were below torque. So the stock 3/8 bolts had stretched. No damage to bearing so I assumed this was recent. Considering the zillions of rotational cycles, heat and loading the stock bolts have been through, I decided on new ARP bolts. But it was only a few bucks more to get the new scat rods that came with 7/16 ARP bolts so that's what I did. Shop checked and sized the rod journals too.
 
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I finished checking rod bearing clearances. I measured with tools and then did a final check with plastigage. All of them are at .0018 which didn't surprise me as far as uniformity - all rod bores were the same and all crank journals were the same.
I'm satisfied with all the clearances, so that leaves getting the ring gaps adjusted.
But I'm now ready to do a deep clean on the block and get it painted, ready to start some assembly :thumbsup: !

I also bought 2 felpro rear main seals, as I've looked at different info on rubber vs silicone seals.
FP 2904 - silicone
FP BS400961 - rubber

Questions -
1. What rear main seal (material) do you use?
2. There seems to be a lot of opinions on whether or not to offset the seal parting line from the main cap line. What do you do?

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READ THE LINK AND LOOK AT SUB LINKED INFO:like:
this may help.. yes I generally offset two piece rear seals about 1/4"-3/8"
22qa.jpg

don't forget to lube the rear seal to crank contact surface liberally with assembly lube
read link
 
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Don't forget to put a smidge of sealer on the back side of the seal, between the seal
and block. Also it don't hurt to put some between the rear main cap to block
mating surfaces. I think the graphic below pretty much covers it !

RearMainSeal_2378.jpg
.
 
I also bought 2 felpro rear main seals, as I've looked at different info on rubber vs silicone seals.
FP 2904 - silicone
FP BS400961 - rubber
I would be interested to know the difference myself. Normally one would think that the silicone seal would
be better, but I would like to know what Fel-Pro says. Have you tried calling their tech support line.


Technical Information
Need help installing a product? Want to know the specifications for a part? Call the Technical Line for
the product support you need to get the job done.

1.800.325.8886
Monday – Thursday: 7:30 a.m. – 4:30 p.m. (CST)
Friday: 7:30 a.m. – 4:00 p.m. (CST)
.
 
Thanks for the info!
I'll follow up.
Minor brainstorm - the seal that was in the engine was still working well. It was a felpro, I'll see if there's a part number on it out of curiosity.
I always save everything I've removed until the new stuff is completely installed and working.
 
If you have time, it would be interesting to see how another engine compares. These numbers
are only the crankshaft (all bearings), rod bearings, pistons and rings installed in sequence.


TorqueToTurnCrank.jpg

For exactly how I performed the above procedure click on the link below.

.
 
If you have time, it would be interesting to see how another engine compares. These numbers
are only the crankshaft (all bearings), rod bearings, pistons and rings installed in sequence.
Absolutely!
Will be interesting to see the results. I've got a beam type ft lb torque wrench that I use for measuring rotational resistance and an in lb gauge type torque wrench that I use on rear axle and steering gear rotational measurement.
I'll use your procedure so baseline methodology remains constant. It won't be right away but I've included this in my assembly checklist.
I'll be using permatex assembly lube so I'll check your info on what you used. I picked the permatex from Grumpy link info and because I wanted something that would "stick" well since I expect some time between initial assembly and first fire. But not sure if that stickiness may affect rotational readings to any noticeable amount.
Edit... looks like you used Clevite assembly lube. I think what I may do is use the Permatex but do a couple of tests mixing in a bit of MMO.
 
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