Push Rod Length

**meathammer** · 03-21-2011, 05:48 PM

Hey guys i am having a problem with breaking valve springs i have the v2 cam and some head work done, with comp cam dule valve springs and they broke on me with in 500 miles on them. I measered the 0 lifter preload which was 7.275, and i am running the stock size 7.400 i was wondering if i should go down to a smaller size like 7.375 what do you all think?

**Speed_kills_WS6** · 03-21-2011, 06:15 PM

Have you measured pushrod length after installing the cam and heads? Not sure where you're getting this lifter preload number, but it doesn't sound right. What are the specs of the cam and what is the lift the springs are rated for?

**meathammer** · 03-21-2011, 07:23 PM

232/234 .595 .598

and the valve springs are rated for .650, so that is why i think i need smaller push rods?

**mark21742** · 03-22-2011, 06:19 AM

If your using stock lifters I'd go with a 7.300 pushrod

**meathammer** · 03-22-2011, 10:01 AM

I just replaced the lifters with ls6 ones will running a smaller push rod cost any power loss ?

**redbird555** · 03-22-2011, 10:44 AM

Let me ask a question. How did you get the 7.275 measurement at 0 preload? The v2 has a smaller base circle IIRC which would normally mean you would need longer pushrods than stock so thats why I'm asking. Did you use an adjustable pr and go to 0 lash then take the measurement? If not you'll want to repeat that step in order to get a good measurement. If the 7.275 measurement is right then simply add .075 which is the recommended preload for stock lifters and you get 7.35 which would work great. Now you say you just got new ls6 lifters, if you bought them new recently they are more than likely ls7 lifters seeing as they replaced the ls1/6 part numbers in 06. This sometimes matters because the cup height is different in ls1 lifters than the ls7 but it shouldnt be any substantial difference here. If your current pr's are way too long then they could cause coil bind which in theory could be breaking the springs if too short they could be slapping the rockers and causing other issues.

**meathammer** · 03-24-2011, 09:54 AM

I used the adjustable push rod to get the zero lash, i ended up getting 7.325 push rod, i had a few people help me figuring out what size i needed to get so i hope it all works out now. thanks for the help!