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Can I reuse my Moly piston rings?

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rang-a-stang View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote rang-a-stang Quote  Post ReplyReply Direct Link To This Post Topic: Can I reuse my Moly piston rings?
    Posted: Nov/20/2020 at 8:00pm
My 401 block is at the machinist from low oil pressure. My moly rings have about 8,000 miles on them and my compression was good before I opened up the motor. Wiseco forged pistons/rings, 9.5:1, daily driver. 

Machine shop is cleaning the block and then is going to hone it. Is there any reason I could not just stick the same piston down the same hole with the same rings (after some cleaning)?
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Post Options Post Options   Thanks (0) Thanks(0)   Quote WesternRed Quote  Post ReplyReply Direct Link To This Post Posted: Nov/20/2020 at 8:13pm
If you are going to hone then maybe new rings on the old pistons  would be the go, rings are not very expensive.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote JGRANTAMX Quote  Post ReplyReply Direct Link To This Post Posted: Nov/20/2020 at 8:37pm
 Rings wear into the cylinder similar to bearings on the crankshaft, low mileage rings could be put back if they were oriented exactly the same as before in each cylinder without honing, rings are not intended to be run in more than once so time for a new set. I have a new set of the Wiseco flat top pistons they use thin rings that cost more.

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Post Options Post Options   Thanks (3) Thanks(3)   Quote mixed up Quote  Post ReplyReply Direct Link To This Post Posted: Nov/20/2020 at 11:07pm
for the cost of the rings and a piece of mind why reuse them
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Post Options Post Options   Thanks (0) Thanks(0)   Quote PROSTOCKTOM Quote  Post ReplyReply Direct Link To This Post Posted: Nov/21/2020 at 12:11am
I would never put a set back in a block after they have been removed with 8,000 miles on  them. Rings work because of tension and they are heat cycled to fit that bore. Once you pull them out of a bore they would never obtain the same level of seal they had when first installed. Run a hone through it, toss out the old rings, and go buy a new set. You'll be glad you did.

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Post Options Post Options   Thanks (0) Thanks(0)   Quote Boris Badanov Quote  Post ReplyReply Direct Link To This Post Posted: Nov/21/2020 at 8:00am
Best to replace them.
Why risk pulling it down again...
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Hurst390 Quote  Post ReplyReply Direct Link To This Post Posted: Nov/21/2020 at 8:36am
Originally posted by rang-a-stang rang-a-stang wrote:

My 401 block is at the machinist from low oil pressure. My moly rings have about 8,000 miles on them and my compression was good before I opened up the motor. Wiseco forged pistons/rings, 9.5:1, daily driver. 

Machine shop is cleaning the block and then is going to hone it. Is there any reason I could not just stick the same piston down the same hole with the same rings (after some cleaning)?
If it hasn't overheated and ring gaps are close to good AND the moly isn't chipped,I have re-used after running a ball hone through. Quick up and down and not super fast on the drill speed. I've never a problem in a scenario like yours. Done it several times. The ball hone finish is the key to a quick moly ring seal.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Hurst390 Quote  Post ReplyReply Direct Link To This Post Posted: Nov/21/2020 at 8:50am
I have a 360 in a street car. It was a reman engine that had sat outside for a bit. 2 cylinders had some pitting. I cleaned it up the best I could with a rigid hone and re assembled it with new gaskets. Re-using all the bearings and rings. I drive it to work daily and has yet to use a drop of oil in the last 2 years.
I don't recommend everyone to be a caveman builder but it works for me.
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rang-a-stang View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote rang-a-stang Quote  Post ReplyReply Direct Link To This Post Posted: Nov/21/2020 at 9:37pm
New moly rings are $150 (including shipping and tax) and won't get here for 2 weeks. If they were much cheaper and I could get them quickly I would do it for sure but I just don't think I have the $$ and don't want to wait to save up. When I had it bored from the first rebuild (8k miles ago), they used torque plates so I feel a little better about throwing them in. 

It sounds like it is not ideal to reuse them but it also sounds like it is not a death sentence, either. Maybe if the machine shop takes another couple weeks, I'll order some rings. 
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Post Options Post Options   Thanks (0) Thanks(0)   Quote JGRANTAMX Quote  Post ReplyReply Direct Link To This Post Posted: Nov/22/2020 at 7:33am
 Decades ago when I was learning engines I freshened up a 307 SBC after about 2K Mi. it was still burning a considerable amount of oil embarrassing blue smoke, frustrated I pulled it out took it apart while doing that I sketched where the ring gaps were in the cylinders, I thought somehow I got a bum set of rings. It was determined the hone stones I used was too fine for the the ring set I used the machine shop I consulted said it a was called a "wet set of rings" and to put them back and they would run in I did it took awhile but it did stop burning oil, I learned that one the hard way. It can be done however where your cylinders were honed I wouldn't do it, what is the rush? When you fire it up do you want in your mind "I hope these rings are going to be good?" Better safe than sorry!




Edited by JGRANTAMX - Nov/22/2020 at 7:41am
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