JimMueller

iTrader: (9)

I bought a used stock displacement LS1 block a few years ago which has a stock crank, Eagle rods and Wiseco pistons.

The pistons were basically flat except for valve reliefs, so I assume they are the model K398A07 -2.2cc piston based upon Wiseco's site. Is that a safe assumption?

How do I know which length Eagle rods are installed and how do I find my piston deck height (preferably without disassembly)? The comp. height on the piston is listed as 1.3045, if that matters.

Thanks

cablebandit

iTrader: (37)

pistons should tell you which rods it needs. Eagle has 6.125 marked on the side of mine that you can see from the bottom

JimMueller

iTrader: (9)

Edit: The Wiseco piston says it can accept a 6.098 or a 6.125 rod on page 13.

http://www.wiseco.com/PDFs/Catalogs/AB05_chevy.pdf

Is the deck height info on that page useful in calculating my deck height?

briannutter

Our catalog has it. W/ a 6.125 rod, it will be zero deck at 9.240...the stock deck height for an ls1/2/6/7 ... If the block has been milled before and you're worried about running over .005" above deck, you can run a extra thick head gasket or go down to the 6.100 rod (and deck again to your needed spec). Just make sure you end up w/ at least .036" piston to head clearance net. Have fun with it! -Brian Nutter-Wiseco Piston

JimMueller

iTrader: (9)

With it being a used block, I don't know if it's been milled. I did blow a head gasket early last year on the same block but they didn't need to cleanup the deck. I guess what it boils down to is I won't be able to determine by true deck height nor how much my piston is in/out of the hole without disassembly, eh?

Whistler

iTrader: (46)

Your pistons had valve reliefs and a small dome, if you recall.

JimMueller

iTrader: (9)

I remember the reliefs, but I don't recall the dome being that much. The only Wiseco pistons for a 3.9x bore are either a volume of -2.2 or -25cc. I find it hard to believe I have anything but the -2.2cc. Maybe the small dome was to offset part of the volume lost due to the valve reliefs. Do you happen to recall which length rods I had?

And since you are here, are you comfortable using cometics and head studs, and getting it to seal correctly?

Whistler

iTrader: (46)

Your pistons were definately domed. It's been a long time, but I remember us estimating your compression at close to 12:1. We never took the reciprocating assembly out of the block, so I can only guess that rods to be 6.125, as that's the most common.

Cometics are fine, you could use the GM MLS with the same result for less money though.

JimMueller

iTrader: (9)

I remember you saying they were ~11.25:1. I can't find a .04x stock bore gasket for a decent quench, though.

briannutter

Sorry, the only domes Wiseco does are as customs...which could be built to any compression height. Our -2.2cc flat top is within the valve pockets.

If you want to see if you have "too little" piston to head clearance, you can get a bore scope in through one of the spark plug holes. If the piston IS hitting the head, you'll see the outer ring land area on the major and minor thrust being a bit shiny. If you don't see a carbon track between the chamber and the outer perimeter of the piston, you could have gone a little tighter, but it would be tricky to know exactly how much without bridge indicators etc. to get the measurement.

Good luck! -Brian Nutter

JimMueller

iTrader: (9)

Brian - since you're here, can you tell me what the ring land depth is as well as the piston outside diameter? I found the number for the original owner, so hopefully he'll shed some light on the parts tomorrow.

briannutter

Wiseco's are usually run .004" smaller than the bore. That's most easily measured at the bottom of the skirt. Because of expansion, the top land of the piston is about .054" smaller than the bore for most of our pistons, but that is often tweaked as well depending on application.

Groove depth on a typical 1/16 ring is .1865 deep on the top and .189" on the 2nd groove.