SYRacing

iTrader: (2)

Setting pushrod lengths for my build in sig, machine shop didn't touch the deck, ls9 headgaskets, ls7 lifters. He removed an unknown amount of material from the heads to ensure they were flat. I'm guessing .005-.010 at the most.

Using a stock length LQ9 pushrod (7.350 end to end) I'm getting between 1.5/1.66 'turns'. Based on the document I found on tech this is acceptable. I have played with the length checker tool and set it to 7.375 and it did follow somewhat - 2.25ish turns which is too much.

Hardest part I'm finding is the zero lash. Requires a solid touch. A little bit here and there throws your measurements off considerably.

Since this is my first build do my measurements seem correct?

Should I just clean up my stock pushrods and run em' or is it worthwhile to get the fancy chromo hardened super zoot ones?

oakley6575

iTrader: (5)

If you have the length checker, then use it . What length gives you zero lash when torqued to 22 ftlbs?

SYRacing

iTrader: (2)

Haven't checked that, was using the bolt rotation method.

So your saying adjust tool length until zero lash is obtained @ full torque and then add desired lifter pre-load to the overall checker tool length?

oakley6575

iTrader: (5)

Yes exactly. It literally takes ten minutes to find the correct pr if you have the tool. I usually start 10 turns out. Then tighten the rocker to 22 ft lbs and check if you can wiggle the rocker or pushrod up or down. From there, either back the tool off a turn or add another turn and check again. Once you find the right length for 0 lash, add .75-.100" for preload.

6.800" + 10 turns x .050 = 7.300"
7.300" + .075" preload = 7.375" proper pushrod length

Hope this helps

SYRacing

iTrader: (2)

Alrighty I did some checking at lunch using the length checker -

9.5 turns, .05/turn + 6.8 = 7.275 + preload of .083 = 7.358

now for the next question - buy hardened 7.35s and lose approx .010 or go bigger 7.375 for around .100 preload.

lots of conflicting info

oakley6575

iTrader: (5)

I just built a little 4.8L with LS7 lifters and the triple 12 and went with .090"-.100" preload. I actually got the same measurement as you. 7.275" with the checker. I had a set of 7.375 comp rods around so I used them. Valvetrain is quiet and runs like a top. Either pushrod size will work though! A lot of guys run .075" of preload with good luck