CarTalk.com Blogs Car Info Our Show Deals Mechanics Files Vehicle Donation

Reuse of old piston ring?

Is it ok to reuse an old piston ring, compression #2, if it measures the same gap and has the same relaxed dimension, as a brand new one? They both gap within specs.

One of the new ones broke as it was being put into the cylinder. The old one doesn’t seem worn at all & still fits snug (is springy) in the cylinder. It’s for a 2000 Toyota Camry engine 5SFE (155,000 miles)being rebuilt because the rod bearing seized. Crank was turned & rods were reconditioned. Block has been cleaned and honed.

If the piston is clean and the ring fits snugly in its groove but has no binding it is “likely” that it is OK to re-use it. Will no one sell a ring set for one piston? That would be best, but you knew that already, obviously.

If you are thinking of reusing the old one, why? Just buy one. It sure would bite if you put the engine together and that cylinder had low compression. Pay for a ring set now or pay much more later.

I’m w/ meaneyedcatz

I’m not a fan of something like this at all but for a DIY deal it could be workable, although it’s a tossup about how well it could work. You should keep in mind that piston rings can also lose their spring tension due to heat and miles and it can be near impossible to determine how much spring tension there is in that ring.

If you insist on reusing it then try to make a rough guesstimate anyway as to how much tension there is by squeezing the ring between a thumb and forefinger at a point about 90 degrees away from the ring gap on each side. If it feels like it has a decent enough amount of spring on it then this could be feasible in some way.
And make sure the rings are right side up.

I can understand your point here because I’m sure those rings are pricy when compared to a set for an old Chevy 350.

Use it. No one will ever know. That ring is the LEAST of your worries…

Use it. No one will ever know…gee, what integrity. Are you a professional tech or an arm chair mechanic?

I’m just saying in the overall scheme of things it won’t make any difference.

Rebuilding disposable consumer products is seldom a worthwhile endeavor in any case…It’s STILL a 2000 Camry with 155,000 miles on it…One piston ring won’t make any difference, especially using old pistons and not re-boring the cylinders…

It’s a cast iron ring and due to it’s heat cycling over those 155,000 miles I wonder how prone it is to developing something like micro cracks when it’s removed from the old piston and installed on a new piston. What the heck, I went and bought a complete set for that one ring. End of my problem, but the question is still out there if somebody wants to share.

Why did the new one break? Is there any quality concern over the new set or just bad luck?

Mmmmmm… The Quality is good. “Somebody” didn’t have the ring compression tool squared up on the piston, which also means the tool couldn’t sit square on the cylinder. When the new piston was being installed, that ring’s gap happened to be where the tool was off the block just enough to let the ring pop out and …the rest is history.
FYI: new oil and water pumps; new timing belt set; new pistons, rings, bearings, seals and gaskets. Reground crank. Pressure tested head with a valve job and checked for flatness. The block was cleaned and measured at the machine shop. A hone was all that was needed and the ring gaps verify it.
The car is a “very” clean LE. My wife is involved with the rebuild (lucky me… Really!). She and I had a small discussion about that #2 ring. Another set was bought because of concerns that the old one might have lost tension and not seat.
Pre-98 5SFE’s are famous for piling on the miles while the 2000’s are famous for committing “Sludge suicide”, which is my only concern. As insurance I’m installing a oil cooler from a '95 5SFE and will run a cooler thermostat. (Oops, is that legal??? What I ment to say was, I wonder if installing a oil cooler from a '95 5SFE and a colder thermostat will help with the sludge problem). Probably switch to a synthetic after the break-in.

Well now that we know the WHOLE STORY, I would indeed buy another set of rings just so I could sleep at night…List the short set on e-bay, maybe you are not alone…

Cooler thermostat?? No. That will make the sludge problem worse. It’s not a heat problem, it’s a moisture collecting in the crankcase problem…

Keep with the OEM temp thermostat. The ECM will not like the cooler thermostat, and your gas mileage will suffer, as the computer thinks the engine still needs to warm up. Dino oil will be fine as long as you change the oil frequently, like every 3,000 to 4,000. Most of the problems with sludge was due to people extending the oil changes. Synthetic oil will allow for extended oil changes and help prevent the sludge problems. I always like Castrol GTX for dino oil at 4,000 mile change intervals and Syntec for synthetic at 7,500 mile change intervals. I don’t like to push it further than that myself.

Very good advice. Thanks for the information.