87caprice318

iTrader: (1)

Finally have my new engine back from the machine shop and its time to assemble but first I need to gap the rings for boost. According to the paperwork that came with the pistons, the gap should be .006 x bore (4.03) for the top ring and .0065 x bore 4.03.

top .024
bottom .026

would this be adequate for a s480 6 liter engine? I ask because I've been reading and seeing people go .028 and .030/.032. Which way would be the correct way. My machine guy said .028 for the top ring and leave the bottom ring alone....I just want to triple check.

ScottyBG

The engine building books would agree with the 0.026/0.028 for a mild build but more like the 0.28/0.30 for a more aggressive level like 12psi or more boost. The lower ring should always be gapped larger than the top ring so pressure doesn't build between the two rings and cause flutter. That's what the books say but I know people are having success outside of these recommendations, and exact ring alloy from manufacturer varies a little which is a factor.

87caprice318

iTrader: (1)

Thanks and that is whats getting me. I plan on pushing for 25psi max maybe and I just don't want to "under" gap my rings. Im sure someone has experience with these Wiseco GFX rings because the specs they want make me "think" they're not gapped enough.

squarles67

I went with .28 and .30 for my 6.0 S480 build, I figured a little extra insurance can only help.

If they're too loose only you'll know, if they're too tight everyone will know.....

roastin240

iTrader: (13)

I like this ha ha

stevieturbo

Exactly, you'll never hurt an engine from running the gaps a little bigger.

roastin240

iTrader: (13)

I accidentally opened 1 of my gaps up to 0.032 top and 0.038 on 2nd ring...I was shooting for 0.028 and 0.030 respectively. I decided to order a new top and new bottom ring for that cylinder just to be safe. Would you guys ran it and said F it?

stevieturbo

There isnt a chance you'd ever have noticed the slightest bit of difference if you had run it.

ScottyBG

You did the right thing getting the new rings though. I'm sure stevieturbo is right, but the problem is that if your the type of guy that's debating over 0.026/0.028 vs 0.028/0.030 it would give you fits forever knowing one cylinder was 0.032/0.038. You would wake in the night 6 months from now, cursing yourself for not doing it. I know I would, knowing it is less than perfect, I'd be forever second guessing my decision to run it. Every time I seen a little extra oil in the catch can, I'd be wondering "if I'd have gaped those rings right would I have this much?". Piece of mind is worth the price of the rings to me, and I'm betting you as well.

MY_2K_Z

iTrader: (1)

I did the same exact same thing. What I did was put the 2 that were gapped to large on cylinders 7/8 since those are the hottest and most problem prone cylinders.

stevieturbo

You'll never ever hurt an engine with ring gaps that are too large...and those are not too large.

In percentage terms as far as ring contact area goes it is almost negligible. I'll always leave my gaps a little larger that what some claim are "correct" even though there is no generic correct number.

87caprice318

iTrader: (1)

I ran into the same problem at the other guy on mistaking-ly gapping one cylinder too big by only a little bit BUT knowing the others were all correct I just ordered another pack of rings for that one cylinder. But here's the engine all together but still isn't tuned. going to get tuned Tuesday.

roastin240

iTrader: (13)

Thanks for the feedback. I think it would never have been noticeable like stevie said...but after all the time and money, for another $38 for 2 replacement rings and considering I am not in a rush to put it together, I figured why not.