RonSSNova

iTrader: (3)

Hey all,

I'm working on the L33 I got from LKQ. 136K miles, good compresion stated etc.

This is to be a turbo project, and thought I'd give the JY thing a try.

After reading about ring gaps, decided to do that, along with a good cleaning of the insides of the engine. Had a good layer of brown goo over everything.

Anyway, this is what all the pistons look like, (after cleaning) and wonder if those of you who have done the regap thing have seen the same? The scuffs aren't deep, I can barely feel them, but there just the same. FYI, I measured the top ring gap at .021".



I have not measured the pistons for size yet.

The rings were free, but a lot of crud behind them. Pin bores look great, as did the rod and main bearings, as well as the bushed end of the rods.

You guys really run them this way? And those of you who don't regap, well, you might have the same and not know it.

I am undecided on replacing with forged plus better rods. Although, the stock full float rods look quite nice.

Of course, if you buy pistons for the stock rods, they cost nearly $800. Or, you buy the $600 ones and buy rods to go with them because they have the smaller .927 pin. Reminds me of buying AN fittings.

Ron

a4ls2goat

That looks 100% normal

9sectruck

iTrader: (9)

If your going to keep boost under 15psi run them the way they sit any mor then that i would go 24-25thou to keep the piston happy

RonSSNova

iTrader: (3)

That was the plan. I'll keep cleaning! Slow work, but there is no rush.
Thanks

Ron

denmah

iTrader: (2)

im a stock piston and gap warrior and i still agree if you have them out and apart you could open them up to 24 at least and then turn it up to 25lbs

otherwise dont bother gapping em

RonSSNova

iTrader: (3)

Ok, will do.

So, do you all replace the rod bolts? Obviously you have to remove the caps to get the pistons out.

I understand they are NOT TTY, but that GM recommends replacement rather than re-use.

Thanks,

Ron

HRHohio

I reused my rod bolts on my 4.8 build in sig. Of course I haven't turned it over yet. Build in progress.

Ashton233

What is the purpose of gaping the rings? And when you say 24, is that .024? Trying to decide if I really should gap them or not. Seen people on both sides on this. Also how do you gap them? Thanks

stock48

iTrader: (17)

That's a little rougher than I like to see but should be ok. Thing was about to get metal transfer at one time. Savage with their foot burried pulling a trailer is what does that. .020~.022' gap is about right for a ~100K engine and will be ok on E85, long as tune is good. Where ppl get into trouble is on a low mile engine where you have .014~.015'' on pump gas. That is why a 150K mile engine on E85 might take 28 psi of boost no prob and a 20K engine on pump 91 might pop at 14.

Wicked69

I agree with this. I don't touch the ring gap. I don't touch the motor. If you I was going to forge the engine I wouldn't pay more than a $150 for one that was already blown. The point of paying more than that for one that runs is because you don't plan to do anything to the engine. Throw a turbo on it and go do some donuts.

RonSSNova

iTrader: (3)

Thanks Stock!

3, 5, and 7 looked like that. The rest fine. I'll touch em with 1500 grit.

Ashton. The rings grow with heat. If the end gap is too small, the ends butt together, have no place to go so the ring takes on an S shape and escapes the ring groove by busting the ring land.

You put the ring in the cylinder. Square it up with the piston (push the ring down about an ince with the piston top) and measure with feeler gauge. You enlarge the gap by carefully filing one end.

I see Scat makes a nice 4340 I beam rod for just a few hundred a set.

Ron

ajrothm

Ron, I'd just slap some cheap forged pistons in that thing while you have it down that far.. If you can find a cheap set that will work with the stock rods.. It will save you a ton of headaches for when the stock pistons lift ring lands.. Just a matter of time.. Especially knowing how you like your stuff to run.... (Hard)..

But I understand the budget thing for sure.

RonSSNova

iTrader: (3)

Weicso makes drop in pistons for the stock rods, but nearly $800. Or you buy thier cheaper pistons but have to also change rods due to the smaller pin. So you pay eiter way.

I haven't found any other shelf pistons available, and custom would get spendy.

Ron

stock48

iTrader: (17)

The stock piston is stronger than the rod. If changing pistons you might as well do rods. And if you do rods I would go with the H beams. The stock rod is pretty close to a aftermarket I beam imo. The rod bolts are tty and should be replaced when any kind of **** is given about the engine lol. If that block has the window style mains like my ls2, and L33 I wouldn't spend much $ on it.

silver_82

If you decide to put aftermarket pistons in there, send them bitches to me. I'd throw 25psi at them without blinking an eye.

Im being 100% serious too. Dibs

I reused stock rod bolts, bearings, rings, everything. Ive spun mine to 7200 lots of times, bounced the 7500 rev limiter once too when I blew the trans. The stock stuff will take a beating

silver_82

The rod bolts are TTA, as well as the mains. The head bolts are TTY though.

Windowed mains are perfectly acceptable, as they allow better crankcase breathing, the gen IV stuff is all like that.

RonSSNova

iTrader: (3)

I'll put it back together as is. At the very least it will all be clean.

BTW, this is an L33.

Ron

RonSSNova

iTrader: (3)

So I'm done with all the clean up. Also done waffling on forged parts. It will go back together as is.

I rechecked the top ring gaps and they were .019", so I opened them up to .023-.024". 2nd rings were .026-.027", so left them alone.

I know you guys yank em from the yard and run em, but this thing was pretty gunked up. Spotless now.

Would you all re-use the round wire pin circlips? I haven't hung the pistons on the rods yet.

The short is ready to reassemble, just need to find the TTA specs and procedure.

A few pics:

Parts is parts


Block be clean


Pinned the crank


this is with the ATI pinning tool that I used on my C5. This time, I aligned the pin with the key so the cam gear can go on w/o removing the pin. Much easier to do with the crank on the bench.....
Have a PB UD balancer and accessories for a C5 which I'll be using in the Nova.



Ron

Chevy406

iTrader: (12)

Looks like a great foundation for your Nova's turbo build Ron. I'll be keeping an eye on your progress. I finally got my new TH-400 sprag last night, so I should be back together for this weekend.

RonSSNova

iTrader: (3)

Good news! I hope this is the final fix for you. Sprag and drum?

My progress is going to go painfully slow I'm sure. But have been gathering some stuff.

I need help with turbo and cam suggestions.

Got a harness and PCM from a 99 6spd Firebird....