Help needed, what would cause a 327, after heads intake and carb are replaced, to blow off rings on 4 of the cylinders? The engine smoked once it started. Once the engine was torn down there was damaged to a piston and a scorned cylinder also. Any thoughts on what caused this. The engine was stored for some time prior to being reassembled. Was a perfect running motor before being stored. Was oiled and turned while being stored.

Gutz66

What did the cylinder walls look like? How was the engine oiled? Was it misted into the chambers/cylinders?

Sounds like the motor hydrauliced,That is turned over with fluid in the cylinders. Is this a possibility??

I have not seen the motor since its demise. I sold this engine and the new owner has had it for about 2 yrs, I gave him the heads, intake and carb which were good. The engine was put back together by him and a friend. Once they started it this happened with the rings. I explained to him that the motor was fine when I pulled it. I took the heads off and stored it on an engine stand and occasionally put oil on the pistons and turned it over. He did tell me that he had compression of 125 in all but one which was 115. That tells me that the rings were fine when he checked it before he fired it. I am curious to know if he could have messed the timning up by accident. The cam and lifters only had about 1000 miles on them. I am not trying to get out of being responsible but I feel I sold him a decent motor. I know many a stories of experienced engine builders that made goofy mistakes while setting an engine up. I am guessing that they missed something or had something out of whack. I am hoping someone here can give me some insight as to what may have happened. I dont want a bad name in selling parts to fellow car nuts.

Thanks Gutz

You would have to put a fair amount of oil in there and I mean a lot. Unless this guy poured a quart in the cylinder ...in effect filling the cylinder I would not suspect esoteric causes like a hydraulic lock of the cylinder. I had a 454 which was pulling oil out of the crank case because of a bad intake manifold seal. When I pulled the heads there was about a shot glass of oil on each piston top...several ounces. The engine fired a ran just fine before teardown with no symptoms of a hydraulic lock.

Let's not get to technical with hydraulic locking of the motor. Something likely screwed up while it was sitting ...stuck ring or moisture or whatever OR something went wrong during assembly. Usually something very basic is at issue. I would look at those kind of things long and hard before suspecting a hydraulic lock.

How much ring ridge does it have ? A high milage grandma car that never went over 2500 rpm in its life. Grandson gets it & now its never under 6000 rpm. Rings go bye bye.

Did he replace the rings? If so and he used a cheapie ring compressor, he may have cracked them going in, EASY to do with a junk compressor. It's kind of weird that 4 of the eight cylinders wound up broken, don't you think?

Were they random, all on one bank?

Plus he's had it for 2 years. I don't think even Re-builds a under warranty that long...

sorry, i have been on the road and have not been able to get to the computer. the engine did not have any cylinder wear at all. i have owned this motor since 1987. i know that the condition of the engine was excellent prior to my selling it. i really feel that an improper reassembling of the engine is the problem here. i am just not sure what they did to cause this. he did tell me that he thought that 2 cyl. on each side had ring problems but he was not possitive on which ones they were. it sounds like they were ajoining. also not know what was done as far as care for the engine while he stored it makes this difficult to figure out. my guess is that the timing or valve train was out of whack when they tried to start it, causing some sort of explosion in the chambers. i was told that there was no damage to the top of the pistons. any thoughts????

Gutz

There is an explosion in the chamber every time the cylinder fires, it normal and called the compression stroke. Not to sound smart, but I don't see how even if the timing is 180 out that would cause damage That happens often.
A cylinder can only produce X amount of compression , unless off couse it is filled with something,,,,AKA gas,oil, ...etc and cause hydurlicing.

You really didn't answer my questions so I can't make an educated guess.....sorry.

Did he replace the rings, and is he hassling you about getting money back?

What he told me was that he tore it down and was taking it to a shop for a rebuild. I was only guessing a backfire of some sort may have caused enough pressure to blow the rings. It very well may be that he had the engine sitting and he never oiled it and it may have developed a ridge of rust or the rings were froze and when he cranked it over it broke the rings. He is not hassling me but he did call and explained to me the money he paid and now he has to get a rebuild. I don't plan on refunding him due to the two yrs. he has had the engine. Hard to tell how it was taken care of. Also he did tell me that the compression readings, 7 at 125 and 1 at 115. Does not sound like ring damage when he took the readings.

You say he's had it for two years.. How long has the engine been in use? For the entire 2 years, or did he just get it put together and installed?

One thing to consider-what is the compression ratio of the engine? If it is at 10:1 or above, or even if the vehicle he put the motor in had bad gas, it is possible that he was experiencing detonation and popped the rings on one half of the motor.

If you do a search under my user name on the Camaros.net site (sister site to this one) you will see that I had this exact same situation happen to my 383 last year. At the time the engine had less than 5,000 miles on a complete rebuild. I got ahold of some bad gas and all it took was one episode of hot-rodding it on the way home one night and the motor suddenly lost power and would not idle. On tear down I found that 4 cylinders-all on the same side of the motor-had broken rings and broken ring lands from the detonation. For the record, I could not hear the detonation when it was happening. Prior to this happening the car was running perfectly. Then I got into the gas one time and went through the gears up to 3rd gear flooring it each time.. Then when I pushed in the clutch to coast the motor stalled, and was toast after that one incident.

Could be that this guy installed it, had bad gas, or simply compression too high for pump gas, and detonation killed the engine. If he did not pull the pistons for some reason (new rings installed) and simply put the heads and intake back on, this would be my guess as to what happened.

Regardless, YOU are not responsible for anything that happened to the motor once the money changed hands. The buyer did a compression test, and accepted the results, and paid you the money. End of story.