syncmaster710n14

Hi guys, just want your thoughts on this,

I have milled the heads on my LQ4 by 0.040''. Standard LS pushrods are 7.400'' so you would think i need 7.360'' pushrods to compensate, but I have just checked with a pushrod length checker and I am only getting to 7.225 with no lash. So even with a preload of 0.050'' that is only 7.275 which seems to short?

Anyone have any ideas how this works?

Thanks

Sam

Che70velle

iTrader: (6)

Are you mocking it up with head gasket in place?

syncmaster710n14

Heads are on with gaskets and torqued up ready to go.

Che70velle

iTrader: (6)

What headgasket did you use? Was block decked?

syncmaster710n14

Standard Block and gaskets (AC Delco I think)

1FastBrick

iTrader: (16)

I just had a set of heads milled .025 . I installed them with OEM GM gaskets and with some 7.350 pushrods I already have, I have too much preload.

FWIW the OEM pushrods are not 7.400 they are actually in the 7.38 range.

syncmaster710n14

That's interesting, I have been looking through the forums and some people are running preload at over 0.100''! Thinking I might go for 7.300'' pushrods that should give me 0.075'' preload.
Thanks for your response
Sam

syncmaster710n14

The head gaskets I got are ACDelco 12610046 6.0/6.2

syncmaster710n14

What length pushrods do you think you are going to need?

1FastBrick

iTrader: (16)

I suspect 7.325 to achieve proper pre load. I already had 2 spare sets of pushrods from other projects laying around.

With 7.375 I achieved 1 3/4 full turns past 0 preload Torqued to 22 FT LBS
With 7.350 I achieved 1 1/2 full turns past 0 preload Torqued to 22 FT LBS

I did not have my adjustable pushrod length checker with me. I need to pick it up and Verify

1 Full turn is .079 Pre load.

So 1 1/2 full turn Should be roughly .0118 Pre load.

I dont want to post a non sponser site since they sell parts But I found a really good tech article on lifter preload
Here is the video they made showing actual lifter preload as you turn the factory bolt 1 full revolution.

syncmaster710n14

Thanks bud, that video explained it really well, I'll let you know how I get on.
Thanks again.
Sam