Engine Ring Failure

failure

#1

I own a 2000 Golf GTI 2.o Liter. I recently had the rings replaced and they only lasted 1,500 miles. The rings are becoming week and not maintaining thier originally size and strength. The car has not overheated. The mechanis tells me the compression is 225. Any information would be appreciated.


#2

There’s something wrong here. NOBODY disassembles an engine solely to replace rings without totally overhauling the engine. Rings also don’t fail after 1500 miles because they are “weak”.

Compression pressure of 225 PSI is pretty high…almost too high, even. Are you sure you’re not being fed an endless stream of BS by whoever is doing all of this work?

Start at the beginning, tell us what was wrong with the car initially, why it needed rings, and what it’s doing now to make you think the rings are weakening. Not a lot to go on from your initial post.


#3

Huh? How can anyone tell that the rings are “becoming weak and not maintaining their original size and strength?” This sounds extremely bogus to me.


#4

Ok-From the start. My son was driving the car back to college on I85. He notices lots of smoke coming from the tailpipe as he was going down the highway. Immediatly pulls over and calls dad. The car did not overheat, just lots of smoke. I have the car towed to a volks mechanic. He does a initial assessment and identifies one cylinder with very low compression. So - one of the rings in the cylinder with low compression has no strength - he showed to me and it just had no strength very flimsy. Cylinder walls were ok. His reccomendation: Replace head gasket, one set of rings (all 4 cylinders), one set rod bearings, 8 valve guide seals, oil filter, used oil cooler, oiler cooler seal, ngk plugs, valve cover gasket and cam shaft seal. I picked up the car and put about a hundred miles on the engine varing my speed - normal driving conditions. We return the car to my son in Virginia - drove great going up there, I varied my speed, pulled over let the engine cool down a couple of times, checked the oil (over 1,500 miles we added 3 qtrs). My son had the oil changed at 1,500 miles. The oil recommended by the mechanic is 20W50 Castrol. The car never overheated, actually ran cool. Returning to Georgia he got about 25 miles from home and noticed the same smoke coming from the tail pipe. I went and bought a tow strap and pulled to the mechanic shop. I could not afford another 150 towing bill. LOL The mechanic tells me that the rings have lost there strength again.


#5

That engine runs a very high cr, so 225 sounds right for new rings. Which begs the question, why do you think there’s something wrong ?


#6

ah…that missing snippet of information.


#7

None of what you’re stating here sounds plausible and that includes this alleged compression of 225.
You’re either omitting a lot of detail here and/or there’s a lot of misunderstanding.

Rings means the cylinder head was off. This means a valve job should have been done. Crank bearings should have been replaced at the very least.
If the rings have failed then how does one have this alleged 225 compression (which I assume is PSI).


#8

(son talking)

Also, as soon as I saw the smoke come out of the tailpipe I noticed a loss of power. After the work was done on the engine the car was getting very good gas mileage(around 35 mpg) however I had to add a lot of oil to it during the first 1500 miles.


#9

I’m looking at the reciept from the mechanic. Cylinder head was off and a valve job was done.


#10

When I got to the car there was a lot of smoke coming from the tailpipe, but it sounded great.


#11

The cylinder compression (225) that is given is way too high and to be honest, I do not understand that at all. With a gasoline engine MAXIMUM compression should be at about 200 PSI and even then one will find very few cars that will approach that. Compression readings of 210 and above would cause problems and one way I can think of that this 225 would be obtained is if the cylinder head was shaved WAY too much.

I’m still at a loss as to why the rings are failed if the compression is 225. What is occurring; blow-by, smoking, oil in the air cleaner housing, etc. ?
It is possible to have good compression and oil consumption if the oil wiper rings have a problem due to installation, distorted cylinder bore, etc.

Rings can be a problem for any one of several reasons. If the engine block was not bored to an overize then an improper honing job can cause ring problems. With high mileage the cylinders will develop an egg and taper shape to them. In this case honing will not work well because one is installing a perfectly round ring into an oval cylinder.
Improper cleaning of the piston ring lands (grooves) on the old piston, failure to set the ring end gap, ring side play, imroper ring orientation, etc. can all lead to ring problems.

Hope some of that helps. And that 225 thing is downright weird. I worked for VW for a long time, performed more compression tests than I could even start to remember, and have never seen a reading approach 225. About 180-185 was the norm even on near new vehicles.
(Another possible cause of such a high reading could possibly be a camshaft that is not properly aligned with the marks)


#12

Thank you for taking the time to reply. I think at this point I should get the car back from this guy and attempt to find a better mechanic. In Atlanta that may not be to hard. When I intially talked to this guy he said that he had twenty five years of experience. I’m no mechanic, but the information you provided above sounds realistic. I’m supposed to pick up the car on Wednesday - he said he found a new set of rings from another state. I do not think there is much I can do. Thanks again - Don


#13

From my vantage point one cannot know exactly what the problem is; however, bad rings it is not. Bad job of cleaning out the ring lands, installing the rings upside down (yes that is possible), or a bad job of honing the cylinders. Hopefully they did hone the cylinders.

There’s a bit of technique involved in a proper hone job and considering the fact this engine used 3 quarts of oil in 1500 miles after this repair tells me something was not done properly or there is a cylinder bore problem rather than something being wrong with those rings.
(That 225 thing really throws me. I don’t understand that at all.)


#14

I guess there is no real way for me to know if the job is done correctly. We will pick up the car on Wednesday or Thursday. I guess monitor the oil consumption, confirm compression and wait to see if it to happens again. If we do have the same thing happen again-I will try to locate a different shop. At that point, would you recommend having the cylinders bored instead of honed?


#15

When it comes to boring cylinders this means a total, by the book, engine overhaul because an auto machine shop must do this with a boring machine. The engine has to come out, be completely stripped, vatted and bored, etc.

It sounds like this job was what I would call an “engine in car, minor overhaul” type of thing. This kind of thing is always a bit dicy to do. With the cylinder head off the cylinders should be inspected with a bore gauge and if the specs are far enough out of range I would not even consider putting it back together because honing is not going to straighten any of that out.


#16

The 225 psi compression reading is probably valid for the 2001 2.0 Liter. Hard to understand it I know but that engine has a very high cr and is derived from a VW diesel block that originally had a compression reading of 500psi…I know, I know sounds far fetched but it’s true.

I can’t lay my hands on a suitable reference but I think the ‘run in’ reading should be somewhere around 195 - 215psi.

However that engine does also suffer with high oil consumption, 1 quart of oil per 1000 miles is nothing unusual.

Funnily enough, VW did have a batch of engines where the rings were installed upside down, the rings managed to totally glaze the bores before failing. Correct remedy was to fit new rings the correct way up and glazebust the bores before piston installation.

There are a few references kicking around and VW did issue a tech bulletin : http://www.myvwlemon.com/ubb/Forum4/HTML/000078.html

If the OP’s car is one of the inverted ring engines and the shop fitted the new rings the same way up as the original, several terms spring to mind.


#17

Thank you for the info. I will bring this to the attention of the mechanic. Maybe there is hope…


#18

np.

By the way, a little further investigation reveals that the upside down piston ring problem was limited to cylinder #2, though I haven’t been able to determine why that is the case. However a batch of rings had their labels stamped upside down, so there’s the root cause.

You mention you had a low compression on 1 cylinder, but don’t state which one. It wasn’t number 2 by any chance was it ?


#19

When I talk to the mechanic this week I will find out which cylinder and post a reply.


#20

To add to Scudder’s idea, I’ve seen what happens when rings are installed updside down. The rings are designed to “scrape” oil in one particular direction (down back into the crankcase). If you put the rings on upside down they will actually scrape oil up into the combustion chamber where it burns and the car consumes a lot of oil, even on a totally fresh rebuild. I saw it down to a brand new, very high-performance chevy engine build and the brand new 500 hp engine was using over a Quart per 500 miles :frowning:

Anyway, not certain that’s what happened to the OP’s car, but it is possible and does cause very high oil consumption (but not generally a loss of power).