What size connecting rods do I need!
What size connecting rods do I need! Hey guys, just picked up some new Diamond pistons yesterday. They are -8.6cc dished with a 3.905" bore, 3.622" stroke. Now it says they are for a 6.125" rod. If I get a 6.125" rod with a .927" pin, will that combo work with my stock crank on my stock cube motor? I understand that the stock rod length is about 6.100". Obviously I'm looking to lower compression and I don't know if the slightly taller rods will raise that at all. Or could 6.100" rods still be used with these pistons? The most important thing obviously is that everything fits together. So to recap:
-Stock crank
-Stock bore/stroke except for a small amount of machining for a rebuild
--8.6cc dished 3.905" bore, 3.622" stroke pistons
-6.125" .927" pin connecting rods
-Stock crank
-Stock bore/stroke except for a small amount of machining for a rebuild
--8.6cc dished 3.905" bore, 3.622" stroke pistons
-6.125" .927" pin connecting rods
Rod length is determined by the stroke of the crankshaft, compression height "Distance of the center of the wrist pin to top of the piston" see attached picture, and the deck heigth.
If the piston is designed for a 6.125 rod then that is what you will need to use. A shorter rod will lower the piston in the hole and a longer rod will raise it.
Here's another pic that may help ya.....
Hope this helps,
-Dave
If the piston is designed for a 6.125 rod then that is what you will need to use. A shorter rod will lower the piston in the hole and a longer rod will raise it.
Here's another pic that may help ya.....
Hope this helps,
-Dave
Last edited by dacajun; Sep 15, 2010 at 04:14 PM.
Here's an exact thread that covers what you are asking about:
https://ls1tech.com/forums/generatio...n-effects.html
https://ls1tech.com/forums/generatio...n-effects.html
Thanks guys! That thread was a good read. Guess I'll just go ahead with the 6.125"s. Just wanted to make sure everything listed will work with the stock crank and cubes. I just hope that the mild rise in the rod length over stock doesn't raise my compression much if any. Would sort of defeat the purpose of getting the dished pistons.
