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Piston rings

Got the number 1 piston out. Had to use a ridge reamer to be able to get it out. Piston itself looks pretty good. The oil rings were carboned up a bit but there was no obvious issue. The bearings on the top side are definitely worn, which makes sense since that’s the side that sees all of the combustion pressure. I have new clevite bearings ready to go in as the crank looks good. Again, this is a mild rebuild and is by no means the best way to achieve factory reliability but I think it’ll work out fine

My question is, I bought new sealed power rings. The oil rings are self explanatory. Now for the other rings the upper and lower have a slight difference. The upper ring on the factory setup has a beveled edge on the inside facing towards the top of the piston. The lower ring appears to not have any bevel or rounded edges. The new rings have the same beveled edge on one edge but the dot on the ring indicating the top would have the beveled edge down, opposite the factory set up. Should I mimic the rings as they were from the factory or go by the rings indicator marks? Or would it even make much difference?
 
I would do what Sealed Power instructions say.
 
1990JEEPXJ,

A couple of questions about your statement; "The oil rings were carboned up a bit but there was no obvious issue".

1. Was the "carboned oil-ring" stuck in the piston-groove?
2. Or, did the "carboned oil-ring move freely in the piston-groove.

If No.1, there are not enough oil-drainback holes in the piston's oil ring groove. The oil backs-up around the oil-ring and then carbons-up the oil-ring. In time, the o-rings get stuck closed with lots of blow-by and power loss. I have found this to be a chronic problem with many new piston designs. When I pull pistons and have many stuck oil rings, I typically add more holes in the piston's oil ring grooves to increase oil-drainback to the crankcase.

If No. 2, this typically indicates there is sufficient oil drain-back through the piston's oil-ring groove and back into the crankcase.

Best regards,

CJR
 
Finally got around to getting all the pistons out. Had to use a ridge reamer on #1 and #2. All of the rod bearings look to have the same wear. I must have not been changing the oil enough. Some of the oil rings had carbon build up on them and there was also some build up in some of the ring grooves. So I scraped all of the carbon out of the grooves and threw new rings in.

All of the cylinders also got dingle ball honed and looked good prior to doing so. I had also pulled every lifter and looked at them. They weren’t dished or scarred or anything so I threw them back in.

Here’s the rod bearings
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And here’s the bores after refinishing
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So I went to go throw in the new rod bearings and noticed a difference. The relief cut into the factory bearings appears to help with giving the oil a way to escape around the rod bolt. I’m assuming it matters that the new ones do not have this relief but I wanted to be sure before throwing them in.


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They are not critical, it was to add additional oil the piston bore/piston skirt. The Scat rods do not even have that relief cut.
 
Got all of the pistons back in with the new bearings. Next will be the head but I’m not sure if I just want to clean it up and throw it on or send it out to give it a good once over for any issues.
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At a minimum I would send out be checked.
 
Probably will since there were a few blocked coolant passages and I’d like to have those cleared out. Plus it is GREASY.
 
Had the head looked at and cleaned up. Had to be decked .005 but was overall in good shape. Threw new valve seals in it just because.

Got the head back on and decided to play it safe and go with new head bolts. One thing I noticed when I put the rockers back on was that I forgot to account for the .005 that was removed and its effect on pushrod length. .005 was too much and there was always preload on the valve springs so I ordered some .005 shims for under the rocker assemblies.

Then threw the intake and exhaust manifolds back on.


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Congrats! I see that you went with ARP bolts. They make the absolute best bolts on the market and are the only ones I trust to re-use. In fact, they are the only ones I am aware of that are specifically designed to be re-used.


FWIW, last year I found a broken ARP head bolt on the floor of my garage from my project car. The beefed up SBF 302 I built for my '65 Shelby Cobra replica makes a ton of power so I decided early to only use the best parts available. To be fair, it wasn't ARP's fault that the bolt broke. Seems the dowels installed in my block to align the heads were the wrong ones (machine shop error that I should have caught) and one of them slipped out allowing the head to shift (probably when I dropped the engine/tranny in). Regardless, one call to ARP and the next thing I knew, Fedex was at my door with a new set of head bolts and a box to return the old ones so that they could run some tests to understand what happened. AMAZING customer service!!
 
Congrats! I see that you went with ARP bolts. They make the absolute best bolts on the market and are the only ones I trust to re-use. In fact, they are the only ones I am aware of that are specifically designed to be re-used.


FWIW, last year I found a broken ARP head bolt on the floor of my garage from my project car. The beefed up SBF 302 I built for my '65 Shelby Cobra replica makes a ton of power so I decided early to only use the best parts available. To be fair, it wasn't ARP's fault that the bolt broke. Seems the dowels installed in my block to align the heads were the wrong ones (machine shop error that I should have caught) and one of them slipped out allowing the head to shift (probably when I dropped the engine/tranny in). Regardless, one call to ARP and the next thing I knew, Fedex was at my door with a new set of head bolts and a box to return the old ones so that they could run some tests to understand what happened. AMAZING customer service!!


Yeah it was either re-use the stock bolts or go ARP. Was worth the small cost to me


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Got a little more done and decided to use some 1/4-20 studs for the valve cover.

Been having a rough time trying to get the injectors back in. Had new o-rings but they’re slightly thicker but I couldn’t even get the old ones back in. Ended up messing one up so I ordered new injectors just to be safe. Any tricks? Yes I tried lubing the o-rings

Also got the battery hooked back up and cranked the Jeep for a few seconds and it didn’t build oil pressure. So instead of ticking messing up the bearings, I pulled the distributor and made my own priming rod out of some 1/2” all thread. Was actually super easy. Got oil up to the rockers so at least that is taken care of. Got the 0.005 shims in to put under the rockers and am just waiting for the injectors to try and fire it.

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Got it up and running with new injectors. Fired right up and ran great. Took it out for a desert trip as well and didn’t take it easy. Did some dunes and what not. Didn’t skip a beat.

Best part is that I have zero blow by. I used to have a DIY catch can that would get ounces of oil every few weeks. Not a drop this time. No oil in the intake either. Guess the rings got seated well

And as per usual, I couldn’t get the pan to seal perfectly so it still drips a little oil. I’ll do an oil change soon and I have a few strong magnets on the drain plug to catch any debris.


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Got it up and running with new injectors. Fired right up and ran great. Took it out for a desert trip as well and didn’t take it easy. Did some dunes and what not. Didn’t skip a beat.

Best part is that I have zero blow by. I used to have a DIY catch can that would get ounces of oil every few weeks. Not a drop this time. No oil in the intake either. Guess the rings got seated well

And as per usual, I couldn’t get the pan to seal perfectly so it still drips a little oil. I’ll do an oil change soon and I have a few strong magnets on the drain plug to catch any debris.


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FWIW, I have had good success on getting a seal on the pan by using these one piece Felpro gaskets.



https://www.summitracing.com/parts/fel-os34308r


They ship with 4 alignment "snap ups" which makes it a lot easier. The process I use is


1) squeeze a small bit of RTV into the mating gap at each corner of the crankshaft drops.
2) install the snap up adapters and use them to align/hold the gasket in place
3) I then put a small dab of rtv on each corner and at least one small dab around the middle of each side
4) Next, I install the pan bolts and tighten them up to hold the gasket in place. At this point I also remove the snap ups and install the bolts to hold the gasket tight around the areas where the crank clearance is
5) I let the whole thing sit like this for about an hour to let the RTV firm up which holds the gasket in place.
6) Finally, I remove the 10 bolts I temporarily installed, reinstall the 4 snap ups, apply a small dab of RTV to the gasket at the corners of the crank clearance areas and push the pan up onto the snap ups.


Once the pan is hanging from the snap ups, I start installing the side bolts and finally, I remove the snap ups and install the end cap bolts.


This approach has worked well for me on a number of different engines and in the case of my XJ, has been tight and dry since I did this 5 years ago.


HTH
Todd
 
That’s what I was thinking. Ill have to do that next time. The snap ups are nice but still let the gasket hang away from the block.
 
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