reusing piston rings ?

[blazer2007]

I had the thread on "could carbon knock be my problem" on a stock L-48 350 which was rebuilt and has maybe 8000 miles on it. The knocking occurred in the driveway so was never driven with the knocking . The orange paint on the engine is barely dirty. All pistons cleaned up good and cylinder bores are nice and still have the crosshatch. I will put new bearings in but was wondering if I should reuse the rings. They are all packaged up for each piston so the rings are matched for each piston and cylinder. My thought for reusing them is that pistons and rings are broke in to those cylinders just like a good pair of shoes. I have no problem with buying new rings but with my weird way of thinking I thought it would be a good choice, thanks.

[Tom]

Why wouldn't you re-use them is the better question.

[blazer2007]

Boy that was a turn around. I thought I was going to get a bunch of "don,t be cheap ,buy new ones " LOL.

[A1971Blazer]

I sold a Jeep once to some friends and shortly afterward it started knocking
I felt bad so I offered to fix it for parts cost only
Turns out, the back piston skirt was broken off.
I bought a new piston and rod assembly from Chrysler....took some 400 sandpaper and "scuffed" the cylinder wall and the edges of the rings...
put it back together and it was still running strong when they sold it...

[crazy longhorn]

My thoughts...why would you re use the rings? They are cheap, to replace? Why not? Longhorn

[MySons68C20]

Originally Posted by blazer2007

I had the thread on "could carbon knock be my problem" on a stock L-48 350 which was rebuilt and has maybe 8000 miles on it. The knocking occurred in the driveway so was never driven with the knocking . The orange paint on the engine is barely dirty. All pistons cleaned up good and cylinder bores are nice and still have the crosshatch. I will put new bearings in but was wondering if I should reuse the rings. They are all packaged up for each piston so the rings are matched for each piston and cylinder. My thought for reusing them is that pistons and rings are broke in to those cylinders just like a good pair of shoes. I have no problem with buying new rings but with my weird way of thinking I thought it would be a good choice, thanks.

You kept them in order so run em! My .02

[crazy longhorn]

Bull****! hone the block, & replace the rings.IMHO,there is no point to reuse rings or bearings.....longhorn

[AussieinNC]

I would hone the cylinders, measure the skirt clearance and ensure within spec,
make absolutely sure the small end pin is not called out in any of the pistons.

New rings should be installed....the old ones will have taken a set and are now heat cycled many times....

End gaps MUST be checked

[vince1]

I bought a 750 Norton from my brother and on his last ride he blew the top off a piston. .020 over higher compression pistons and no break in, it smoked a bit. I took it all apart and reassembled it after finding nothing wrong and back to running the heck out of it. By the end of the first summer it no longer smoked and I never did know why it did that.

I wouldn't hesitate to reuse the stuff except that there could be a bit more of a possibility that a ring could break if it had ever been stressed during the removal reinstallation process. I probably would have reused the bearings too. Heck, I reused bearings in a 3.2 Rambler engine with 120k miles on it when new were unobtainable at the time. The guy that redid the head told me it would be better than using -.002" that were available.

[blazer2007]

Originally Posted by crazy longhorn

Bull****! hone the block, & replace the rings.IMHO,there is no point to reuse rings or bearings.....longhorn

I don,t see the need to hone as I can see all the cross hatch from the machine shop 8000 miles ago and was bored .30 over. I don,t mind buying new rings but thought the old ones would be seated nice . Engine was never driven hard and just in town, probably why the carbon knock

[blazer2007]

Originally Posted by AussieinNC

I would hone the cylinders, measure the skirt clearance and ensure within spec,
make absolutely sure the small end pin is not called out in any of the pistons.

New rings should be installed....the old ones will have taken a set and are now heat cycled many times....

End gaps MUST be checked

what do you mean , the old ones have taken a set. Do you mean they have been subject to the heat from break in and running and now are abit brittle and won,t like the rings being taken off and put back on again ?

[geezer#99]

Put the top rings in and check the gap.
Then decide.
I’ll betcha you could back a trailer thru the wide gap you’ll find.

[AussieinNC]

As geezer suggested....measure everything while its easy and out of the engine....

I still dont believe carbon build up would cause a knock you could hear at idle...I would be double checking the small end and piston pin bore sizes....

I had a six cylinder a long time ago that had a distinct knock at idle...turned out the piston pin had galled the indies of the piston bore when assembled...it was only when I pulled the pins out and measured the bores etc that I found it.

The used rings have been through multiple heat cycles and are usually run hardened after 1000 miles or so....8000 miles...way too many cycles....new rings are cheap insurance...but make sure the end gaps are perfect.

Also check the ring land clearance with the ring that will be used in that ring land and piston.

[garyd1961]

I've never seen rings reused but I have seen several motors tore down with new pistons and rings installed, no honing and reuse old bearings. Warranty work, company not paying for anything except the defective parts.

[blazer2007]

Originally Posted by geezer#99

Put the top rings in and check the gap.
Then decide.
I’ll betcha you could back a trailer thru the wide gap you’ll find.

Will do that but I,m sure now I will put new rings in. It was just a thought while I was drinking. LOL

[blazer2007]

Originally Posted by AussieinNC

As geezer suggested....measure everything while its easy and out of the engine....

I still dont believe carbon build up would cause a knock you could hear at idle...I would be double checking the small end and piston pin bore sizes....

I had a six cylinder a long time ago that had a distinct knock at idle...turned out the piston pin had galled the indies of the piston bore when assembled...it was only when I pulled the pins out and measured the bores etc that I found it.

The used rings have been through multiple heat cycles and are usually run hardened after 1000 miles or so....8000 miles...way too many cycles....new rings are cheap insurance...but make sure the end gaps are perfect.

Also check the ring land clearance with the ring that will be used in that ring land and piston.

Read my post and you will see the pics of the carbon. It started just twice for a short period of time over a year or more . This time it stayed

[blazer2007]

Again thanks for the help. I will put new rings in but I will check old ring Geezer just cause I,m curious

[blazer2007]

Looks like Longhorn was right , I was told to hone just maybe 4-5 passes to deglaze the cylinder and get the a new crosshatch to help the rings to seat. I thought Longhorn was meaning to do a vigorous honing which I thought was not needed

[crazy longhorn]

Originally Posted by blazer2007

Looks like Longhorn was right , I was told to hone just maybe 4-5 passes to deglaze the cylinder and get the a new crosshatch to help the rings to seat. I thought Longhorn was meaning to do a vigorous honing which I thought was not needed

I should have expanded more (glaze buster) That said, I feel that Geezer, & many other guys had it figured....I agree with all longhorn