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  #16  
Old June 30th, 2020, 14:42
1990JEEPXJ's Avatar
1990JEEPXJ 1990JEEPXJ is offline
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Re: Piston rings

Quote:
Originally Posted by tjmotter View Post
I hate it when others try to spend my money but I have to say that at this point you should seriously consider doing it right and pulling that block for some machining. You are already signed up to replace the bearings and rings. It is really going to suck if you put it all back together and find that you have to redo everything.



Based on what it sound like you have done, you are already on the hook for new:


- rings
- main bearings
- rod bearings
- gaskets
- rear main seal
- head bolts
- possibly main bolts (like head bolts, these are "torque to yield" and should probably be replaced if removed)


You are probably getting close to (or over) $300 in parts with this list alone. Adding pistons, ($100 at SummitRacing), cam bearings ($35), timing chain ($54), lifters ($66), and harmonic balancer ($52 - yours "might" have another 100K in it depending on a number of factors). This adds another $300 in parts and, oh yeah, if the engine doesn't hold up you are going to pay another $300 for the "re-do" on all the stuff you bought the first time.


Machining is going to cost you about $125 for a bore and hone, $80 to install the new pistons, $50 for a good clean and possibly another $120 for any crankshaft work.
Which I get all that. But it ran pretty good and quiet. No knocking or ticking or anything. Itís got a new timing chain already and had good oil pressure. So Iím not going to bother with the mains. Plus the added inconvenience of removing the motor itself. If the pistons are good, which they appear to be, Iím not going to replace those either. Iím not looking for this to last another 100k. Just looking to restore some compression and give it a quick refresh. If I were to to a rebuild I would just rebuild another motor out of the Jeep and just do a swap all together.
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  #17  
Old July 1st, 2020, 06:04
CJR CJR is offline
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Re: Piston rings

I'm a little confused with your statements:
1. "I also had a ton of blowby and was low on power."
2. "But it ran pretty good and quiet."
3. "I already tried the gumout on the rings to no avail".
4. "If the pistons are good, which they appear to be, Iím not going to replace those either."

Apparently, the Gumout spray trick didn't free-up the stuck-closed piston rings and eliminate the "ton of blowby" or improve power. So please explain how you know the pistons or rings are OK/not broken without pulling the pistons from the engine and examining them?

Best regards,
CJR
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  #18  
Old July 1st, 2020, 11:30
1990JEEPXJ's Avatar
1990JEEPXJ 1990JEEPXJ is offline
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Re: Piston rings

The skirts and tops look good as well as the bores. If there were a broken ring or piston would it not be pretty obvious visually on the bore? Can it not run quietly and simply be worn out?
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  #19  
Old July 1st, 2020, 14:52
CJR CJR is offline
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Re: Piston rings

The answer to your question is NO. If the piston lands between the piston ring grooves are broken, the oil would blowby the broken lands and all you'd hear would be a quiet clicking noise. The cylinder bores would look fine. Once the piston lands break, the piston rings can't seal on their sides and the combustion chamber pressure blows the oil through the broken land area. When piston rings break, the bores are typically scored and you can see the scoring. In my view, unless you have Superman's x-ray vision, the pistons need to be pulled and inspected visually.

Best regards,

CJR
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  #20  
Old July 1st, 2020, 15:12
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1990JEEPXJ 1990JEEPXJ is offline
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Re: Piston rings

Which is exactly what my plan is
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