Piston Ring Gap Position

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Picked up my replacement rings set and this pack has a small instruction note. What does this point mean:

MAKE SURE EACH RING GAP IS NOT POSITIONED IN LINE WITH PISTON PIN OR THRUST SIDE OF PISTON

My other set had no instructions, so I followed my Tom Monroe book on engine building. Here is how I positioned the gaps.

TOP RING = Gap positioned above piston pin hole
2ND RING = Gap positioned 180 degrees from top ring gap, above piston pin hole on opposite side
TOP OIL RAIL = Gap positioned 90 degrees from 2ND ring
BOTTOM OIL RAIL = Gap positioned 180 degrees from top oil rail
EXPANDER = Joint positioned identical to top ring (above piston pin hole)

A rebuilder told me the gaps for the oil ring are the most important and should be positioned apart. My concern is, i've now installed 1,2,4,5,6, and I don't really want to remove them AGAIN and risk damaging a ring or something - what do you guys think? Can I leave those as is? Do they move around anyways when the car is running.

Thanks.
 
While I can see one or the other (pin hole/thrust side) being something one could exclude, you can't exclude both and manage the required 180 out orientation. I guess if you were at 45° of the pinhole and the furthest you can be on the 'thrust side'.


..or am I missing something. Rings will/may walk ..and I'm surely no expert ..but just looking at the wording says "paradox" to me.
 
Your ring gap and oreintation is the most important. If you assemble them as stated above you will be fine.

I always lay them out according to the ring and soak them in oil. Install 1 set at a time and install the piston in the bore. After they are compressed there will be no issue of the rings moving in the groove. Install all 6 then torque the rods to spec
 
The way you did it is fine. As said above, the top 2 rings spin like crazy when an engine is running, so it really isn't super critical, but I like to align them as you did (no gaps on either thrust face). Oil expander is aligned with one of the top 2 ring grooves and the oil rails 120 degrees from the expander gap, but that is a personal thing.

As long as your oil ring pack is set up properly, it should be good to go.
 
Originally Posted By: berniedd
I've rebuilt my own engines in the past and, at the next teardown I noted the piston ring gaps are nowhere near where I put them years earlier.


Exactly. Because rings rotate.

Just stagger rings so the gaps aren't on top of each other.
 
This is what I used for my V8 engine.
Ringgaps.jpg
 
I saw rings that are a set of 2 on each groove and therefore gap-less. Is it just a gimmick or does it work well in certain application?
 
Originally Posted By: PandaBear
I saw rings that are a set of 2 on each groove and therefore gap-less. Is it just a gimmick or does it work well in certain application?


Total Seals are great. I've heard of problems in high rpm engines and even heavily boosted engines. Mine work great and have the lowest leakdown numbers by far of any engine I've ever built. My father's engine spins close to 9,000rpm and no flutter problems either.

The oil stays cleaner much, much longer. The usual vapor coming out of the breathers is non-existant. Even on the dyno there's little to nothing coming out of the breathers whereas before there was a ton of blowby coming out of the breathers with a fresh engine at 30psi boost. Oil temps even stay cooler with the lack of blowby.
 
Total Seal gapless piston rings would seem to make sense. Yet I do not know of any car manufacturers that have adopted the design. Anyone have experience with Total Seal rings?
 
The total seal top rings are very good, the second groove total seals are not so great. Anything that builds gas pressure below the top ring is generally a bad idea.

Total seal top with a napier second is hard to beat for oil control (as long as you pick a Napier that doesn't need heavy crancase vac). That being said, I have never found any HP differences with total seal rings, although it does make your leakdown numbers really pretty.
 
Quote:
Yet I do not know of any car manufacturers that have adopted the design.


My engine builder buddy uses them for his customer's engines. He says that you can use them on a street engine, but I think his idea of a street engine is one that you're never going to put 100k on.
 
It seems you aligned the ring gaps at the bore's pin position or 90 deg to it, from your description.

This is the only way NOT to do it.

But "above the piston pin hole" is very vague. All piston rings are above this hole, and this would be true of all 360 degrees.

I have no idea where your ring gaps are at.
 
Thanks everyone. I did it like Kestas diagram except for the oil rail gaps are 90 degree from the pin hole. Either way I just don't think this is really important considering 60RPM movement, how much they spin, there's no way they stay synchronized.

I asked another engine builder and he told me just don't stack the gaps on top of eachother, "the exact degrees are not that important because they move"
 
Originally Posted By: mechtech2
It seems you aligned the ring gaps at the bore's pin position or 90 deg to it, from your description.

This is the only way NOT to do it.

But "above the piston pin hole" is very vague. All piston rings are above this hole, and this would be true of all 360 degrees.

I have no idea where your ring gaps are at.


Not true
wink.gif


The 347 stroker kit for the Ford 302 has the oil ring through the pin bore on the longer-rod kits.
 
Originally Posted By: Gary Allan
Quote:
Yet I do not know of any car manufacturers that have adopted the design.


My engine builder buddy uses them for his customer's engines. He says that you can use them on a street engine, but I think his idea of a street engine is one that you're never going to put 100k on.


That's a big piece that I forgot to mention. Durability is supposedly the issue. I run a Total Seal top ring and their standard second ring. Right now I'm at 25,000 miles. When the heads came off, the hone marks were still there and leakdown tests haven't changed since it was first broken in. However, it's only 25,000 miles so I wouldn't expect any major wear even with a ring design that supposedly wears quicker.

I commuted with this engine 210 miles round trip a day. Gas mileage was better than stock ratings though there are way too many variables to blame it on the rings. The big thing is no vapor out of the breathers, practically no leakdown, and the oil stays cleaner much, much longer This car used to kill oil, it would be black in two days if run hard but it now stays somewhat golden through the entire (short) OCI.

With the benefits I've seen, there has to be a big reason why these things aren't OE on new cars.
 
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