Matts94Z28

iTrader: (6)

Im in the process of doing a rebuild and have decided to run nitrous within the next couple of months. I plan on going with something like a 150 at first but will definatly move up to a 200 in the near future. My main concern right now is deciding on ring gap.

My new set up will consist of LW Eagle I-beams, SRP LW forged 11:1 flat top pistons with -5cc reliefs, and a turned stock crank. The whole assy. has been balanced.

The first thing i noticed was that JE calls for less ring gap on the top ring and more on the bottom. I always thought it was the other way around. The rings are .005 over sized so i have plenty of room to play with. Has anyone here ran the same combo? If so what ring gap did you go with? Im probably going to call JE here in a few but i figured i would get some input here first.

Thanks in advance!

1997bird

iTrader: (2)

Here is another thread on the second ring end gap. https://ls1tech.com/forums/advanced-engineering-tech/760040-second-ring-end-gap.html I would follow JE's instructions on the end gaps. You might want to leave the end gaps a little tight, b/c once the motor is fired up the end gap will increase several thousands with the heat from the combustion.

ZONES89RS

iTrader: (25)

Honestly it is best to go with what they would recommend. I am just wondering, is it a stock rebuild? If not then why use a stock crank? The stocker is only good for 50 FWHP on the safe side. If you are making 400-500 before dope you are really pushing it. If it is a stock build you will be fine. I ran a 200 hit on a 305 in a third gen a long time ago, worked for a year till the fuel pump went south.

1997bird

iTrader: (2)

Actually the stock crankshaft is stronger than most people give them credit for. They will handle 550-600 flywheel HP without problem's, it is usually the rods that create all of the problem's. If his block is still a 2 bolt, then he needs to at the very least run a main girdle to keep from killing his thrust bearing & crank.

Matts94Z28

iTrader: (6)

I have a 4-bolt block. No this isn't a stock rebuild as you can see by my sig and my description of parts. Everything in my sig will be going back on the car, the only new parts are the rods and pistons along with longtubes. The rods are the lightweight cast version from eagle and the pistons are Forged SRP flat tops good for 11:1 compression.

Now don't get me wrong im not going to be hitting the car with a 200 all day long. It will be more than likley a 125-150 shot but i want room to hit it with a 200 if i need to. The stock crank will be more than enough for that. By the time i get some awsome heads on the car i will probably hit it with a 150 and leave it at that.

JE said to run a .24 on the top and bottom ring so thats what i will be doing.

396D1SS

iTrader: (21)

I ran 624rwhp on the stock crank before. When I stroked it I took it out and it looks awesome. Just sold it to a buddy a few days ago...


let it eat

Like another person said....Rod failure usually comes first.

the stock crank is stronger then alot of people think

skinnies

iTrader: (33)

The stock crank is a lot stronger than most believe. I've put around 850 crank HP to a stock one and it held up, and LOTS of nitrous at the 750 crank HP range.

ZONES89RS

iTrader: (25)

Well, yea they will handle it, but for jow long, i just say that a STOCKER will go 500 for a long time without problems what so ever. So yea, i didnt mean the crap out at 501HP. Sorry for the confusion and as for 850 on a stocker.....i refuse to believe it would live verry long at all.

GMRACER13

iTrader: (1)

I think you mean .024". A gap of .24" would be almost a quater of an inch! at any rate my 396 is gapped .032" top ring and .036" bottom ring. For what it's worth you really won't lose much horsepower with a bigger gap (maybe 2-3 H.P.) but the extra insurance is worth it to me. I have been running this engine for close to 10,000 miles as my daily driver with no smoking or oil consumption problems.

I would follow the instructions that came with the rings. If I remember corectly I think they give two different specs for the gap depending on the amount of nitrous you'll be using (something like up to 250 shot gap .0xx", over 250 shot gap .0yy"). I would use the specs for a nitrous shot bigger than what you plan to spray. That way you have "room to grow" if you decide you want to spray more down the road as well as added insurance.

When you run a tighter gap you run the risk of the ends of the rings touching as they expand from the extra heat generated while on the nitrous. If the ends touch then the ring has no room left to expand and can break ring lands or push the crown of the piston up. Also, I would run a larger gap on the bottom ring than the top ring. If combustion gasses do get past the top ring due to the increased cylinder pressure while on the spray you want them to make it past the second ring too. Again, just a little insurance.

I'm no master engine builder just giving my opinion based on my experience.