stang90gt50

iTrader: (6)

I have all the parts to put together a little different shortblock and I think I like the idea of putting the longest rod I can in the motor without going to far...


I have a stock 3.622" crank, standard 6.0L block, 6.300" Eagle H-beam Rods, Mahle 4.00" (402" stroker shelf pistons) forged pistons...

This would be a standard 6.0" but have a longer rod and would probably work better for the high rpm boost motor project...


Any impressions of the long rod setup?

69firebird

iTrader: (14)

wouldnt it move the wrist pin farther up into the rings making things weaker?

and will the stroker pistons work without the stroker crank?
I know regularpistons wont work with crank, wonder if you can do the other

stang90gt50

iTrader: (6)

No it uses a standard 402" ls1 piston...no one has a problem with strength on their 402/408 motors, this uses the same piston just a longer rod with the stock crank...

96 Comp T/A

iTrader: (8)

You may be in for a problem with an iron block. Wiseco lists the deck heigth of the iron blocks .020 lower than standard LS1' blocks. That will put you .010 out of the hole to start with, before any clean up or deck truing. As stated previously it works out great on a virgin LS2 block though. I don't have an iron block to measure against but I don't think that they would have just made it up either.

stang90gt50

iTrader: (6)

Well a GM MLS 6.0L Gasket is quite thick @ .060 so that alone should give plenty of piston/head clearance. (from my calculations, correct me if im wrong)

96 Comp T/A

iTrader: (8)

Be careful with running the ring package farther up the bore in a forced induction application. Excessive heat will kill the rings, especially in the iron block where the heat transfer coefficient is lower than the aluminum. Coatings will help, as well as proper ring material selection.

Demon SS

iTrader: (3)

pistons are designed to be at a certain deck height based on a number of factors, one of those factors is rod length.
if you use a piston setup for 6.125" rods on a 6.300" rod you are going to have many issues, main one is being way out of the hole at TDC

Sledgehammer

Umm...Only way that would happen is if he was using pistons for a stock stroke...

Since he is using a "stroker" piston, the pin height is going to be further up the piston...

As long as his extra length on the rod is matched with the pin height being higher on the piston...There is no way he is going to have the piston way out of the hole...

Demon SS

iTrader: (3)

your above statements would be true IF he is using a custom piston, he states he is usings a "shelf piston" , no one to my knowledge makes a shelf piston for a 6.3" rod,
so IF you use a piston for a 6.125" rod on a 6.300" rod it would be way out of the hole.

actually his stated combo is way mismatched; 3.622 crank, 6.300" rods AND 4.00" 402 stroker shelf pistons(402 stroker shelf pistons are setup typically for a 4" stroke and a 6.098 or 6.125 rod), these parts as stated will not work together.

69firebird

iTrader: (14)

thats what I was trying to say from the get go

if the pistons are for a 4.00 stroke, it isnt going to work very well on a stock stroke.

96 Comp T/A

iTrader: (8)

I would have expected more from a vendor If you would have taken the time to run the numbers instead of just running off at the cakehole you will find the combination is 100% possible. If it's not then someone ought to let the shortblock in my garage know.
For all the math illiterates out there:
The formula for finding deck heigth is (stroke/2) + rod length + compression distance = 0 deck height. So let's plug in our numbers (3.622/2) + 6.300 + 1.125 = 9.236 inches. Nominal standard is deck is 9.240. On an uncut LS2 block mine was .008 in the hole before pistons were coated and the deck trued. Totally acceptable. Nominal deck heigth of an LS1 is 9.240
If anyone wants to know the part # for the piston it's a standard Diamond part # 11520. With the 15 cc dish , and 72 cc heads I can get anywhere from an 8.4 to to 8.75 compression ratio by very mildy adjusting deck heigth, gasket thickness or even chamber size.

Demon SS

iTrader: (3)

your right I did not run the numbers and failed to consider the shorter stroke coupled with the longer rods. open mouth insert foot. I offer my apology for the mis-information.

moregrip

iTrader: (8)

I like this idea alot and have considered it myself, good luck and keep us posted please

chuntington101

i think its a great ideas!

you have to love V8s that can rev, and with FI it should be a real scream!

what sort of goals are you looking for? will you be running turbos?

thanks Chris.

427 LS1

iTrader: (10)

I have built these before and it works great, keeps the piston from coming out of the bottom of the bore for better piston stabillity and gives a better ring seal, just be sure to use a hellfire or a stainless top ring.

stang90gt50

iTrader: (6)

Whew! I was getting worried there with a few of the random ideas going around..


Ok so it would totally work? I think im going to put this together with the long 6.300" rod, it should make a killer rpm turbo motor....

I'll remember that on the hellfire/stainless top ring...

Bo Duke01

the gasket with .06 clearance isnt going to be enough if you need .01 of clearance because you have to have .06 of clearance to spare

stang90gt50

iTrader: (6)

Im not sure what you mean, but I ran the #'s and this setup is going to work with no problems. The .060 MLS gasket gives me more than enough piston to head clearance and also the quench wont be bad either.

SLED28

iTrader: (7)

Well your adding alot of weight over a normal 6.125 rod.....It will work though. Why are you looking at this type of combonation? Save from buying custom pistons?

stang90gt50

iTrader: (6)

The pistons are lighter and the rods are slightly heavier, not really any significant gain in weight as far as I can tell....


Improving rod ratio, less side load, etc, all good benefits to running the longest rod within reason you can. I see no reason not to build a motor with a 6.300" rod when they cost the same as 6.125" rods...