I tried to repair an engine with a broken piston ring by simply replacing the ring with a stock ring but it broke again. What would be the cause of this - a worn and tapered bore?
Rings will put up with SOME taper as they go up and down. I think something else is at work here. What sort of engine was this? What condition were the piston’s ring grooves in? Carboned up? Did you scrape the groove out? Was there sufficient end gap for the ring to expand? Did you do anything other than replace a ring while you were in there?
To be honest, this happened to a freind a long time ago and I am just trying to educate myself. This hasn’t happen to me (yet)and I don’t know all the particulars of the piston. However my car, a 1998 Chevy Cavalier has a 2.2 L. engine with almost 200,000 miles on it. If this does happen to me when say it has 250,000 miles on it, I was wondering how little I could do to repair it such as dropping the piston out the bottom without pulling the engine. It sounds like I would have to really rebuild the engine then or at least take measurements of the cylinder?
Cav: It really pays to be up front on boards such as this. You did not have the problem and cannot give specific info to questions such as Mg McAnick asked. you’re now asking about a hypethetical problem which you might encounter when your engine has 250K on it.
On a 2.2, I would not drop the piston out the bottom, I would pull the head, ream the ridge at the top of the cylinder, and pull it out the top. In the case of the broken ring that your friend had, if it was the correct ring and it was installed properly (as MG McAnick said, scrape out the ring land, check end-gap) I would guess that there was damage to that piston’s ring land which caused the ring to seat improperly.
If you do get to 250k and find that you need a ring job, places like http://www.northernautoparts.com sell re-ring kits for a few hundred dollars, and on a 2.2, you could probably do it with the block in place.
It sounds to me like someone inexperienced was doing this repair and forced a piston with new rings back into a ridged cylinder, thereby breaking the new ring instantly.
It’s also possible that the original ring was broken by whoever attempted to force the piston/rings out past a cylinder ridge and broken rings had nothing to do with the original problem, or perceived problem.
If someone does not know how to use a ridge reamer, inside micrometers, etc. then they have no business messing with it; and pistons will only come out the top - unless the engine is blowing up.
Poppypaul, your comment is based on the assumption that the guy will never log back in.
He doesn’t need to provide more information for you to tell him what the cause(s) of piston ring failure is/are. What really pays is if trolls like you log out rather than spam insults about how others use their free speech.
Are you serious ? This is a 12 year old thread and maybe you are the Troll.
All these answers are weird…
First one, The bore was tapered from the manufacturer and so your ring broke so your new ring broke too.
Second one, Guy just spamming, not even answering question.
Third one, alright, sure, that’s possible. It’s not a bad theory. but it doesn’t explain why the first ring broke. Half a theory isn’t a good theory…and rings wear out over time, das why dat one broked also isn’t a good theory, what about the other rings?
Fourth one, wrong. The ridge is the original size of the bore, so putting a stock ring back into it wouldn’t damage anything. It’s definitely improper to remove a piston through the top without cutting the ridge, but it’s also improper to cut the ridge with piston inside the bore, so…all your insults at this guy are probably wrong. You will never get a piston out the top. He’s here tryna get experience and you’re spamming nonsense and insults.
Sixth answer, 12 year old thread doesn’t matter, Volvo…the guy didn’t get his answer. So…looks like you’re the troll.
The simple fact of the matter is that the engine has been neglected…poor oiling caused your bad ring, and clogged your oiling system which broke your new ring…either by simply riding on it instead of oil or by, sure, being in an out-of-spec bore wherebeit too small a ring or a crooked bore.
@Cake_Jragen , Your comment is based on the assumption that Poppypaul WILL log back in, he hasn’t been here in 10 years.
Now who is the troll ?
You really think he’s still worrying about a hypothetical broken piston ring after 12 years.
I have no concern what his intentions are…frankly it’s none of our business.
The guy asked a question…questions are to be answered. You’ve made the mistake of assuming hypothetical questions are rhetorical…it’s not a common mistake.
“This is the first time Cake_Jragen has posted — let’s welcome them to our community!”
Kinda hard to do here, he comes in guns blazing…
You’ve made the mistake of assuming he actually had a broken ring.
And since he hasn’t logged on in 12 years Id say your point is moot.
I can’t speak for anyone else but I’d like for the complainee to explain to me why my more than a decade old answer was “weird”.
Any installed ring can break, ridge or no ridge, if care is not used.
Mustangman is correct of course and in case you don’t believe him here’s what Engine Builder Mag had to say about it; cut and pasted below.
Good Bore Geometry
The second major goal of boring and honing is to achieve the best possible bore geometry. This refers to the roundness, straightness and form or shape of the bore (cylindricity). You want the bores to be as round as possible, with no taper top to bottom, and true to the crankshaft centerline and deck surfaces on the block.
I know of what I’m talking about. It can be very easy to break a ring during installation with the installer being none the wiser. Extreme care must be used (meaning to gently tap the piston into place) to avoid breakage.
You are incorrect. NO engine manufacturer tapers the cylinder bore.That is exactly why during an engine build the bores are miked at 3 places (top, middle, and bottom) to assure there IS no taper.
I fail to see where anyone here is being irrational.