what rod length for 4.8 crank + ls2
12-01-2007, 06:50 PM
#3
On The Tree
Join Date: Jan 2007
Location: IL
Posts: 152
Likes: 0
Received 0 Likes
on
0 Posts
Deck Height Are The Same
But The Crankshaft Is Only 3.28 Inch Stroke
Where As A Ls2 Has A 3.62 Stroke
THE STOCK 4.8 ROD IS 6.400
6.0 = 3.625 STROKE 6.125 ROD AND 4.00 BORE
5.3 = 3.625 STROKE 6.125 ROD AND 3.77 BORE
4.8 = 3.28 STROKE 6.400 ROD AND 3.77 BORE
But The Crankshaft Is Only 3.28 Inch Stroke
Where As A Ls2 Has A 3.62 Stroke
THE STOCK 4.8 ROD IS 6.400
6.0 = 3.625 STROKE 6.125 ROD AND 4.00 BORE
5.3 = 3.625 STROKE 6.125 ROD AND 3.77 BORE
4.8 = 3.28 STROKE 6.400 ROD AND 3.77 BORE
12-01-2007, 08:33 PM
#4
Off the top of my head I think it is 6.300. You can use the deck height formula to figure it out, but I don't know if it's going to be exact. If you told me what pistons you were going to be using I could figure it out for you as I need the compression height. Right now I'm just assuming you're using one for a 4 inch stroke. It's still going to be a little rough.
stroke / 2 + rod length + compression height - deck height = amount piston is in or out of the hole.
You want rod length so that changes the equation to:
rod length = deck height - compression height - one half of stroke.
x = 9.24 (variable that makes this semi innacurate) - 1.125 - 3.270 / 2
x = I get a 6.480 rod, but.... You could deck the block to use a 6.300 rod.
You'd also have to take the decked block into account when figuring out the compression ratio also. What do you have planned with this setup?
Here's some additional reading:
https://ls1tech.com/forums/showthrea...ght=rod+length
https://ls1tech.com/forums/showthrea...t=6.0+long+rod
https://ls1tech.com/forums/showthrea...ght=rod+length
stroke / 2 + rod length + compression height - deck height = amount piston is in or out of the hole.
You want rod length so that changes the equation to:
rod length = deck height - compression height - one half of stroke.
x = 9.24 (variable that makes this semi innacurate) - 1.125 - 3.270 / 2
x = I get a 6.480 rod, but.... You could deck the block to use a 6.300 rod.
You'd also have to take the decked block into account when figuring out the compression ratio also. What do you have planned with this setup?
Here's some additional reading:
https://ls1tech.com/forums/showthrea...ght=rod+length
https://ls1tech.com/forums/showthrea...t=6.0+long+rod
https://ls1tech.com/forums/showthrea...ght=rod+length
