Just curious how lazy I can be on small bore motors. I've run as tight as .021 on 26lbs (even accidently bumped 30ish lbs) with an IC and never butted a ring on the 3.78 bore stuff. Currently playing with a non intercooled setup. First motor is way down on power so I'm pulling it. I was overly cautious IMO with that motor and gapped it at .028. Really thinking I can get away with not gapping them at all... but curious what others have found. Basically just don't want to take the time/effort on a JY 5.3. I'v run a ton and never had an issue. I usually find them around .022ish or more on high mileage motors. So I just let it eat.

Aside form band wagon BS opinions with no experience... Has anyone actually butt a ring with a decent tune up on E85? Preferably non intercooled? I'm in a 2400lb race weight chassis with an 8.50 cage. It shouldn't take much to hit my cage cert. not interested in going faster. Twin 78/75 setup.

Please don't comment about pump gas or poor tune-up's. Or the fact that Holdner says I need to run .034 gap on a 4.8 to make it live. Not interested in those comments.

Thanks!

 

I set all my small bore motors at 0.025 top and 0.027 second ring. Lots of them all over 30psi and up to 46psi so far. No ring problems. All these are E85 only. 3.780 to 3.800.

 

You must be really bored, as you already answered your own question when you said "I've run a ton and never had an issue". Unless you start doing endurance road racing or towing, I can't imagine why that would change now. Even then, I think most people gap rings as an extra precaution that they will never know whether is actually needed.

 

The difference being that this is NON intercooled VS all my past setups that were intercooled. I yanked a piston out of curiosity today .024 is snug and .023 loose. Think I'm going to let it eat. It may bite me, but at least then I'll know. Shouldn't take more than 20lbs to hit cage cert anyway.

I'm seeing 230-240* IAT's at the 1/8th without an IC. VS 140-150ish IAT's with the intercooled stuff on similar boost. That is what had me concerned.

I also don't understand how GT55 clone guys are reporting such low IAT on big boost. (sub 160 at 30+lbs) Id think twin 78's would have less charge temp than a 107mm GT55 single. Maybe I'm wrong.

 

Played with any non-intercooled setups at that gap?

thanks!

 

When we gapped my LM7 rings a few were .019 but the rest were more than that.

 

https://ls1tech.com/forums/forced-in...l-i-think.html

Post #19

Kinda shocking, but there it is.

I'm not using an intercooler, either- I'll report back when it's tuned up and I have a few 100 miles on it.

 

It would be interesting to square up an old ring in the bore. Measure the gap.
Then heat the ring with a propane torch and see how much the gap closes up. Very crude test, but what the hell

 

I mean not necessarily though if you were able to determine how hot the rings gets under said conditions and loosely monitored the temp with a laser gun and got close right?
Would at least give you an idea, be a cool test too.

 

Whats shocking?

I wish I saw 160! But maybe I will now since I got bored and sold my holley stuff and setting it up as blow thru, not sure I even care to have an IAT sensor anymore

 

I can do that and report back- though I've always thought it was the bore itself that changed with heat and caused the ring ends to butt.

 

Everything is shocking when one is a LS newb like myself

But I was referring to one putting 30 psi to a bore with .021". I didn't doubt it; many things can be done with a good tune and fuel.

 

Putting 30+ to it isn't surprising to me. Would be if they ran no intercooler at that kinda boost w that gap though. Would have stopped me from being so paranoid anyway! I wimped out and gapped them at .028. I'm getting old and tired of pulling engines. Figure its one less thing to break. Rings were their usual nasty... took me about 40 mins per piston to clean them properly, get the carbon buildup out of the ringlands, gap, and reinstall. Could have gotten alot of other things done in 5 hours! But oh well.

On a side note does anyone smooth out the valve reliefs on the gen4 stuff? The edges seemed really sharp. I smoothed them out a bit.

Appreciate the input!

 

IMO this is cheap insurance (not full coverage however, lol) to keep the SBE stuff alive.

 

If going through that much trouble I'm slapping better rods and pistons in it! I like my SBE stuff quick and dirty!

 

I can def see the appeal. Honestly I'm rethinking the whole hot rod thing. I had the engine out in less than 2 hours. If it weren't for all the turbo junk I could have done it in an hour or less I'd bet. Even less with quick disconnect fuel lines and a carb. I'd bet a healthy cam and 200-250 shot of nitrous on a carb would get me to my cage cert. rough to lose all the cool turbo noises... but it'd be so so easy to work on and plumb. I'm sure I'd go through a motor or 2 before I had it dialed perfect. But its pretty tempting. Maybe fill and mill the heads to get base compression up to 12+.

 

I don't know about everybody else, but I was brought up on the idea that sharp edges=hot spots. I would round every sharp edge possible on just about anything.