General Tech Engine Teardown on the Way

I'm starting a new thread about my burning of oil on my totally rebuilt TR4A engine. I just borrowed a camera scope and dropped it down each piston.

The pistons are all clean and shiny around the edges of the sleeves. That can only mean one thing as I see it. I installed all scraper rings incorrectly. All four.

Defective or incorrect set of rings--not likely.

I distinctly recall carefully assembling those rings and following the written instructions. How I could ever have actually overlapped those tabs escapes me, but I did have some things going on back then, and I suppose I could have goofed up really bad.

Anyway, out come all pistons. what a joy this will be. But I love it.

Any advice? Go back to my regular day job? Never touch a friend's car? Wear a disguise?

Did I hurt the engine? I've put about 2200 miles on this rebuild running around burning oil. What do I check other than the the rod bearings?

Peace.

My advice? Lighten up! As mistakes go, that's not bad at all. Consider it a learning experience. As the old saying goes: Good judgement comes from experience. Experience comes from bad judgement!

The good news is, you don't have to pull the engine again. Just pop the head and pan off, take care of the rings, and put it back together. If you've got a gasket set on hand and the rings are OK, you could have it running again by Monday.

I doubt the excess oil hurt anything. Check out the pistons for any signs of preignition damage (oil has a very low octane), and the cylinder walls for scuffing or scoring; but I think they'll be fine. I would probably double-check the ring gaps at several places in the bores, just to be sure they are still straight, but again they should be fine.

I've been following this thread with interest as a friend of mine has a TR4 with a recently rebuilt engine and it has the same smoke symptoms as described. I'm not sure what brand of rings were used in the rebuild. Having never done a piston ring install myself I was wondering how the oil scraper rings could move to an overlap if they have been compressed by a piston ring compressor?....and how would you even know if they were overlapped once they were installed?

karls59tr said:

I've been following this thread with interest as a friend of mine has a TR4 with a recently rebuilt engine and it has the same smoke symptoms as described. I'm not sure what brand of rings were used in the rebuild. Having never done a piston ring install myself I was wondering how the oil scraper rings could move to an overlap if they have been compressed by a piston ring compressor?....and how would you even know if they were overlapped once they were installed?

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Unless I misunderstand, there are at least two possible scenarios possible. The first, which would seem to apply in KVH's case, is that the second compression ring, sometimes called a scraper, is often made with a very slight bevel which should be installed with the bevel oriented so that the max diameter faces the bottom. Oil control scrapers may also be beveled, and thus directional, but I don't think the cast rings for Triumph were (although there are may different ring designs available).
The more common oil control rings are the three piece, which I think Karl might be referring to. Those are the ones that tend to overlap (I made that mistake myself, only once so far though).
Tom

What was done to your head for the rebuild?

KVH said:

...How I could ever have actually overlapped those tabs escapes me...

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I hope that is what happened as it is not too big a job to check and fix.

As I recall from the last time when I used those rings I would have the springy thing correctly placed (butted end to end with two colors showing) but by the time I got the other two oil rings on, the darn thing would sometimes have an overlap and I would have to start over.

Once all three oil ring pieces are correctly in place I do not think the spring compressor would undo the work.

I'm going to step out on a limb so please be nice. I'm completely lost here. First off, I don't understand what "The pistons are all clean and shiny around the edges of the sleeves" means. Does KVH mean the outside circumference of the piston crowns is shiny clean, as in washed clean? Maybe the oil is diluted with gas? The best fit pistons rings can't control that. It is my understanding that the top 2 rings are for compression only. And they can be installed upside down and the gaps can be lined up so as to lower compression and cause some oil burning but in theory, there shouldn't be much oil above the third, or three piece rings. That three piece set up is there to control, or scrape the lubricating band of oil that splashes through the holes or slots in the piston for cylinder lubrication. Are the top two rings gapped and spaced correctly? A compression test should help diagnose that. I agree with Geo. I don't think you can mess up the the three piece rings and still drop the piston down the hole. The gaps would come into play here, too, but the same mistake on all four? I would be looking for something that would affect all four cylinders at the same time like overly thin oil.

I may have missed something from the previous thread BUT before i started a tear down of the innards I would take a serious look (figuratively) at the valve guides and valve seals. Depending on who and how the head was reconditioned could be the determining factor.

Agreed. Also look at the plugs. Oil entering through the intake valve guides tends to brown stain only the portion of the ceramic insulator adjacent to the intake guide.

FWIW, which may not be much, I recently followed the advice of others on this forum and did not use the Grant brand rings that currently are supplied with TR3/4 piston kits and I replaced them with Hastings brand rings. Others said that while some have had success with Grant, many more experienced high oil consumption. I have had good results with the Hastings brand I installed.
Andy

I personally wouldn't tear any engine down without running compression and leakdown tests. If compression and leakdown are decent, then it is not rings.

I am still wondering the condition of the head...?

Regarding the confusion on the "overlap" and presence or not of compression, the oil ring has a first-on piece that looks like the middle layer of a corrurgated box. The end corrugations are each painted a different color and both colors must be in view when the top and bottom scraper rings are installed over this piece. One color showing would indicate overlap of the corrugations and the affected ring apparently won't work, no matter what the compression.
Bob

I've torn it down. Head will be off in the morning. I eliminated all other possibilities already. The head was done by the best guy around. A pro beyond question. New guides and valves. Seats are all fine. Leak down test passed. But the piston chambers are wet with oil and the edges are washed out because oil is being sucked up past the scraper ring. My compression rings were identical, had no bevel, and no up or down. County piston, sleeve and ring set. I'll check those rings, though, and be sure they weren't defective. As for the scraper, I too am concerned they hopped when I put that compressor on. I'll get to the bottom of this. The best minds around town are all telling me it's the scraper ring arrangement--or defective scraper rings.

I had a brand new crate motor that smoked like a banshee. Even after a shop disassembled it, they swore it was rings. Rebuilt it for me with honed cylinders and fresh rings...and it still smoked like the devil!

It turned out being the crankcase vent to the intake. I had neglected to install the baffling...so it was sucking oil out of the valve cover. Even the "pros" missed it.

I will be surprised if your rings are bad. It's possible, but there are so many other things that can cause oil burn. Overlapping the oil ring spacer would make it tricky to install the pistons. Did you have difficulty, or did they slip right in?

We await the verdict. Seeing the time on your post...

Today, 02:34 AM

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... I think it will be much later today. Good luck buddy.

Geo--You know what kind of hours I keep. I would've had that head off last night at around 1:30, but I couldn't muscle it off. It kept catching on the studs. I'll have it off here shortly.

CJD said:

I had a brand new crate motor that smoked like a banshee. Even after a shop disassembled it, they swore it was rings. Rebuilt it for me with honed cylinders and fresh rings...and it still smoked like the devil!

It turned out being the crankcase vent to the intake. I had neglected to install the baffling...so it was sucking oil out of the valve cover. Even the "pros" missed it.

I will be surprised if your rings are bad. It's possible, but there are so many other things that can cause oil burn. Overlapping the oil ring spacer would make it tricky to install the pistons. Did you have difficulty, or did they slip right in?

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Not sure what you mean by the "baffling"...could you explain?

CJD said:

I had a brand new crate motor that smoked like a banshee. Even after a shop disassembled it, they swore it was rings. Rebuilt it for me with honed cylinders and fresh rings...and it still smoked like the devil!

It turned out being the crankcase vent to the intake. I had neglected to install the baffling...so it was sucking oil out of the valve cover.

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I've had that too, but as you say, SMOKE and lots of it in that scenario.
But I don't recall KVH saying there was an overwhelming amount of smoke, such that you'd get with a similar crankcase ventilation "malfunction".
There's been more than a few who have had trouble with the Grant butted oil control expander/spacer ring.
Here's how one fairly well known pro dealt with it...about the middle of this page:
https://www.triumphexp.com/phorum/read.php?2,1250004,1252755#msg-1252755

KVH said:

...I'll have it off here shortly.

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Inquiring minds want to know - what did you find?

I've learned a lot, and the photos tell it all. Here's the verdict: Those scraper rings hopped into an overlap and I missed it on all four pistons. That explains why such a mundane "of course" issue is treated with special instructions. I just didn't realize that when you put the upper and lower holding rail/rings on you "must" be so darn careful to avoid allowing the scraper to hop and overlap the adjacent ridge.

I'm very willing to admit my foibles, but to help others avoid this in the future, let me just point out that I tried two test runs on each removed piston and, without fail, those scraper rings hopped over again. The only way I could get it correct was to hold the scraper ring down with my thumb as I installed the upper and lower holder rail/rings. Seriously--every time.

Then, to make matters worse, take a look at those compression rings. I swear I had those gaps close to 90 degrees apart. That means that my ring compressor moved them. All four of my pistons show the two compression rings moved. I'm going to look into a better compressor. Or, maybe I should've oiled up the pistons more so that the rings were more stuck in place by the oil/goop. I'll need to figure that one out.

In the photos below, the correct scraper "butt up" is shown in the last picture.

Anyway, that's it. All human error. I did a terrible job on those scrapers. It's all over the internet that you must avoid overlapping those scrapers. I might've had Fox News on in the background when I was doing all this last year.