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TR2/3/3A need an educational lesson about piston rings

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2billydavies

2billydavies

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hi everyone, me again!
question for you: recently took out the pistons in my 58' tr3a. putting a new set in with everything. I was wondering about the oil rings on all 4 pistons.
The pistons I took out all have multiple-piece oil rings. first layer was some sort of thin metal ring that went underneath a 3-piece ring. When I took them off, all three pieces to the rings came apart and then I took out the small thin metal piece. The oil ring was 4 pieces total for each piston.

The new rings i put in were a one-piece oil ring. ever see this before? this is my first tear down i've done down to the pistons, so i've never seen this type before. are these multiple-piece oil rings just old, from back in the day and the newer ones are all one piece?

I'm just wondering... thought it was odd, but i'm guessing maybe just newer technology, or whatever. Thanks to anyone who can answer this... for my own personal knowledge!
I can post a pic or two if need if my description doesn't do it...

thanks!
Billy
 
I've worked with a few types but don't think I've used a one-piece oil ring.

The kind I was recently supplied (Grants?) had a middle piece painted (in different colors) on the ends so it was obvious when they were mounted correctly (one did not want the ends to overlap and the absence of two colors would indicate a problem).

What brand of rings are you using?
 
I have seen all sorts of different designs on oil rings, there does not seem to be one or two standards, as long as it fits OK I would not worry about it.
 
hmmm.... good question. i have no idea what brand was on the pistons (the multi-piece oil ring) when I took them off (probably 60 years old) nor do I know what brand are the ones I just put on (they were given to me in a bag. brand new, but not original packaging). They fit into the grooves perfectly... i just figured they were "new-age) rings versus the originals. I'm not worried about them at all... i was just wondering if anyone else came across them. Quite honestly, there were so many pieces to the multi-piece ring that I don't even know if I would have been able to put them back on correctly. lol
 
I've seen the one-piece oil rings as well, many years ago. Just different manufacturers, IMO.
 
The new pistons I just installed have 4 rings. Two on top are compression, followed by a modern 3-piece oil ring. The 4th ring, below the pin, is a one piece. I figured it was designed to add oil to the cylinder, while the top ring was designed to remove it. Of course that's all conjecture on my part...



 
2billydavies said:
hi everyone, me again!
question for you: recently took out the pistons in my 58' tr3a. putting a new set in with everything. I was wondering about the oil rings on all 4 pistons.
The pistons I took out all have multiple-piece oil rings. first layer was some sort of thin metal ring that went underneath a 3-piece ring. When I took them off, all three pieces to the rings came apart and then I took out the small thin metal piece. The oil ring was 4 pieces total for each piston.

The new rings i put in were a one-piece oil ring. ever see this before? this is my first tear down i've done down to the pistons, so i've never seen this type before. are these multiple-piece oil rings just old, from back in the day and the newer ones are all one piece?

I'm just wondering... thought it was odd, but i'm guessing maybe just newer technology, or whatever. Thanks to anyone who can answer this... for my own personal knowledge!
I can post a pic or two if need if my description doesn't do it...

thanks!
Billy
Click to expand...
Just a thought for when you install your pistons and rings.I got burnt once with repros,not triumph, were the rings gaps and land clearances where fine but motor was way tight.After taking apart I noticed the rings would not compress to close the gap with my fingers when on the pistons.Turned out grooves were slightly shallow,so now I always also check for that.
I like cast iron one piece rings because they are simple to install and tend to wear more than the cylinder,but I am building old motorcycle motors.

Have fun
Tom
 
When I restored my 1958 TR3A from 1987 to 1990, I found broken rings in my engine with 80.300 miles from new. It was losing lots of oil. So I put in new pistons, rings and liners from Peter Hepworth in Yorkshire England. Like John above, these Hepolite pistons had 4 grooves. I had to add a quart of 20w50 Castrol oil every 600 miles. (I can only assume that the cylinder bores had not been honed so the rings never bedded in).

In 2007, I took it apart and put in new Hastings rings which I ordered directly from Hastings in Michigan (they arrived in 3 days) and I've driven another 21,300 miles since then using Castrol 10W30. Only once, have I had to top up the oil level since 2007.
 
Don, you's looks just like what I got from Moss. Same solid bottom oil ring and large oil passages under the top oil ring. I looked all over on the box for a manufacturer, but there was none. I think you may have educated me on Moss' source!
 
John - The pistons etc. I installed in 1990 from Hepworth are 1991 cc (the original 2 liter ones). Peter told me those were the last ones he had in stock at that time in 1990. Maybe you have larger capacity ones - such as found in TR4s.
 
This discussion came up in our club related to three engines that were rebuilt. Two burned a lot of oil and the third did not. The one that did not burn oil had a one piece oil ring. The others had the 3 piece. All three came from MOSS. We replace the 3 piece with a one piece from hastings and oil use dropped to normal.
It appeared the 3 piece have two tabs which touch each other and the tabs broke off.

Jerry
 
I just reringed a Tr4A motor with 87mm pistons. The new rings from hastings via moss had a two piece oil ring, there was an inner spring ring and solid outer ring. I only have 100 miles on them but I don't notice much different over the three piece oil ring I removed.
 
CJD said:
The new pistons I just installed have 4 rings. Two on top are compression, followed by a modern 3-piece oil ring. The 4th ring, below the pin, is a one piece. I figured it was designed to add oil to the cylinder, while the top ring was designed to remove it. Of course that's all conjecture on my part...



Click to expand...
Those look like Vanguard sedan pistons with the extra oil ring below the gudgeon pin. TR ones only have 3 rings. The theory is that under hard use which a TR will get more of than a sedan, the lower ring reduces the oil available to the gudgeon and causes seizures. As a poverty stricken student, I put (cheaper) 4 ring Vanguard pistons in my first rebuild of the TR3A in 1968, giving 2088cc. When I started work the following year I rebuilt it again with TR4 3 ring pistons giving 2138cc. Never had a problem despite frequent cruising at an indicated 90-100mph over the next 30,000 miles. Guess it depends on how hard you are going to drive.
 
Foura said:
Those look like Vanguard sedan pistons with the extra oil ring below the gudgeon pin. TR ones only have 3 rings. The theory is that under hard use which a TR will get more of than a sedan, the lower ring reduces the oil available to the gudgeon and causes seizures. As a poverty stricken student, I put (cheaper) 4 ring Vanguard pistons in my first rebuild of the TR3A in 1968, giving 2088cc. When I started work the following year I rebuilt it again with TR4 3 ring pistons giving 2138cc. Never had a problem despite frequent cruising at an indicated 90-100mph over the next 30,000 miles. Guess it depends on how hard you are going to drive.
Click to expand...

That's an interesting observation!
Even though the piston has a very long skirt I have never seen any with a fourth ring.
 
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