Stuck Rings, Sticky rings, anyone heard of or experienced this??
Hasn't come up as a specific TR issue here before -- but certainly possible on any Otto cycle engine. What is your symptom? Is the TR in question a GQ?
There is 2 cylinders with 15% less compression the wet test brought them up to even. The diagnosis was a stuck ring?
Otto cycle engine = a four-stroke gasoline engine -- see: http://en.wikipedia.org/wiki/Four-stroke_engine (and you should get 20 lashes with a wet spark plug wire for not knowing who Nicolas Otto was ) GQ = Garage Queen (a little used car that's spent a lot of time in storage) Could be stuck rings, but could also be scored cylinder walls (artifically adding a lot of oil into the cylinder would "fix" either of those problems in a compression test). If this was part of a PPI and I was the Buyer, I wouldn't just say OK and assume the problem will go away -- I'd ask the Seller to drive it for a while (maybe with some Zmax or equivalent) and demonstrate that the problem goes away -- JMO.
Thanks Steve, I thought about asking the seller put a few miles on it and then recheck the compression.
Its either a stuck ring, or mechanical failure, nothing inbetween. So you can either tear it apart and fix it, drive it as is until it demands more attention, or, if it is really a stuck ring, try and unstick it. Being as there is absolutely no way, short of disassembling the engine, to determine the cause. So logic would dictate to try unsticking it. What have you to lose? There are 100's of ideas how to go about it, but the majority involve marvel mystery oil down the plug hole and let it sit a week or two. Another popular method is light oil with a good dose of MMO and drive it easy for 50 miles or so and dump it. I personally have had outstanding results using gunk motor flush, and following the instructions on the can in concert with the above methods. Just remember that if you fill up any cylinder with oil and screw the plug back in, to disconnect the battery so it cant be turned over. It WILL hydrolock.
Will the rings unstick with just normal usage? Or does some specific intervention need to occur? Motor oil flushes seem like a risky proposition... all that loose material/sludge has to go somewhere... oil galley, anyone?
Did you by any chance do a leakdown test or just a cranking compression? I was attempting to buy a 1987 which had exactly this issue - two cylinders were only about 95 psi, and leakdown was over 20. There was a notion that squirting some oil in there after driving it 30 minutes would bring numbers up; it did not. So, we suggested owner drive it for a month or two and retest. Unfortunately, he broke the transmission while driving it and that car went out the window. I later developed the theory that most low compression numbers equate to probably crud around the valves more than the rings.
You could always use a borescope to check the condition of the bores. We use several at my shop to determine bore condition on long deep bores. You would take out the sparkplug and review. We use a very high quality scope made by Olympus. There are several reasonably priced scopes, but I'm not sure they would give a quality image for review. John
Doesn't the term 'Stuck Rings', mean that the rings are not free to rotate, ie, stuck to the grooves? Don't recall for sure. Anyway, if something like this is a possibility, sounds like lots of carbon buildup. Something to try may be a fuel additive... don't think it would hurt. Here's a link to a recent discussion on the subject: http://www.ferrarichat.com/forum/showthread.php?t=225576&highlight=fuel+additives
Question - Does anybody know of a legitimate case where compression was really down, rings were suspect, and this cured itself by either just driving it, or putting in some additive and then driving it? I mean with before and after compression and leakdown tests?
This was a situation with a car I bought a couple years back. (not a TR, but A Ferrari with limited activity). Car was not driven much in several years less than 1000miles. Started regularly (say every couple weeks, month) but not driven much other than around the parking lot, and stored again. PPI on the car showed compression low, and I was about to bag the deal. Tim Stanford in Florida recommended that we put Marvel Mystery Oil (now there's a name for you) in the gas, and in the oil sump, and drive the car several hundred miles. Upon retest, the compression was back to normal, and the car was fine thereafter and continues to be. Rings were 'stuck' and driving it proved to 'unstick' them.
After squirting some oil in the cylinder the compression cameup to normal,this would indicate aring problem valves are fine.
Seafoam is also a product that claims to un-stick rings and clean carbon out... it has a great reputation in the marine industry for seldom used marine engines. http://www.seafoamsales.com/motorTuneUpTechGas.htm
Are you saying that sticky rings are common in marine engines?? Have you had experience with thi product and sticky ring problems?
ACEA A5/B5 oil does a good job in cleaning up deposits. It is for extended oil change intervals and it is expensive.
My Dad was a trained mechanic, and I remember him having and using Marvel Mystery Oil 50yrs ago when I was just a kid Although I think he just used it as a penetrant or lube. Never recall him putting it in gas or the sump. But I know some have done that... it is a good product and seems to be useful for many things
