We all know there's nothing better than first hand experience. I am looking to see if people can post up what ring gaps you all are running on stock pistons using only gas (no e85/alky), what boost/psi levels, and if you have had success or any failures.

Most manufacturer calulations (~.006" x bore size) say ~.022-.024 for a stock 5.3l engine that's turbo charged. However, most advice guys are giving on the forum and articles usually mention around .025-.030.

 

Mine's still in project form and hasn't been run yet. But, I gapped them on the safe end of the spectrum, 0.030", (+/- 0.001) to remove any mental emotional stress about them butting.

A couple relevant things to consider for my application, which is a boat, to account for, or at least acknowledge;

1) Engine temps will likely be very close to 100ºF, which adds to the rings ability to transfer thermal energy to the cylinder walls.

2) Boat's are always under load, like constantly driving up hill towing a trailer, which creates more average cylinder pressure and temperature over time... generally increasing the need for additional gap.

The two unique conditions kind of offset each other. However, I couldn't say how much one way or the other. So, I just went right to the "safe" gap for any situation. Who knows what's actually "needed", without breaking a few pistons? Not what I'm about for this build.

 

4.005 bore turbo motor, I set mine at .028 and .032

 

How many PSIs are you running? Any excessive oil burning or blow by that you've experienced so far? Interestingly enough, I have also seen some manufacturers recommend smaller gaps on the second ring versus larger as well.

 

.017 top .02 bottom

1157 whp ls3, e85, twin turbo.

Factory bearing clearances too.

 

Only hit 15psi so far, still working out the kinks. Plan is to go much higher just haven't gotten there yet.

No oil control issues, car runs great.

 

.026-.028 on stock flat top LS3 pistons. Im in the very early stages of driving/tuning and have only been to just under 7 lbs. Plan on stopping at 12 psi. 93 pump only

 

.028/.028 SBE 5.3. No issues.

 

Mahle 3.905 forged pistons with total seal rings. .021 top ring .023 bottom ring. Only making 8#'s of boost so far.

 

6.0

28
25

 

6.0
28
30
Which is what the 250k mile rings had on all cyls lol didnt have to file any. Just started it yesterday however

 

Simple...follow instructions for your specific ring set in use and the application.

But even simpler...never too tight. You'll never do any harm by making them a little bigger and any talk of blowby is just bullshit, unless you were to make them ******* massive.
ie you attacked them with a 40grit flap wheel in an angle grinder or something.

Whether the gap is bigger top/bottom, again depends on specific rings in use. Follow instructions.

Some of mine are around 40thou after getting carried away with a new powerfile, almost zero oil usage and no blowby issues.

A 5...10, even 15 thou difference in terms of percentage of overall ring seal available is still negligible, and that's just one ring, nevermind the combination of seals they all form which is require for milliseconds at a time.

 

.028 , .032 on my 6.0 running 20psi right now on C14 and going up to about 25 eventually. No meth. Has a little blow by but really not bad at all.

 

Any blowby will largely be bore finish or ring sealing relating to that, not the gap.

 

Yea it was visable until it seated. Now you cant see anything.