All Pontiac WS6

iTrader: (9)

Hello All,
How much can you mill a set of 799 heads before you have to change push rod length?

Thanks, David

G Atsma

Actually, you should check pushrod length any time milling is done. Even .01 (ten thousandths) is enough to need new pushrods, if the lifters are to do a proper job.

poltergeist 02

iTrader: (65)

8.Lug

With stock lifters you'd probably run your valves into the pistons before you ran out of preload.

slogo

I always enjoy learning new stuff, would you please explain this theory.

G Atsma

Yes; this should be enlightening...

All Pontiac WS6

iTrader: (9)

Please do......

00pooterSS

iTrader: (40)

It would be ideal to shorten the push rods by the amount that you shaved the heads. Picture the rocker arm on a stock deck head, now take .030 off the head, the rocker is now .030 closer to the lifter, so you just took .030 out of that distance.

However, lifters have a pre load range, and you can be in about a .100 range and be pre loaded just fine, so if you take the head .010 to .030 down or so, you should still be in that general range and be fine.

I was gonna google and try to find out what the factory pre load is and before I got to it I came across this article, this article is a good read for you guys interested in pre load etc.

I know the basics of pre load and that there's a range, range is different with different lifters, but I'm not sure what the factory pre load is, anyone know off the top of their head? Be good to have that info in here.

https://www.lsxmag.com/tech-stories/...oad-ls-engine/

8.Lug

MuhThugga

You think someone is going to knock .125" off the deck?

G Atsma

Consider the source....

KCS

iTrader: (20)

Crysis

So when is the ideal time to change push rod length after new cam???

MuhThugga

When your measurement concludes that your current set of pushrods won't work.

00pooterSS

iTrader: (40)

During the cam swap