Valve train question

[jakewalter]

Greetings from Northern Michigan,

I am in the process of building a stroker for a 2002 TJ.

I need to check the pushrod length.

The engine is still on the stand.

Do I need to prime the lifters to get the proper pre-load?

Thanks so much,

Jake

[Russ Pottenger]

Two separate issues to cover.

For the purposes of measuring pushrod length the lifter can be dropped in the lifter bore dry.
With the lifter resting on the heel of the camshaft adjust your pushrod tool to zero lash. Now order your pushrods that are approximately .020 to .070 longer than the pushrod tool.

Now when you're getting ready to install the lifters go ahead and drop them in some oil and let them sit overnight. Do not pump them up.

Coat the cam lobes with a Molly paste, and on the bottom of the lifters.

Unless you're using a specified engine break in oil, make sure you add a ZDDP oil additive to your favorite brand of petroleum oil and you should be good to go

[jakewalter]

Hey thanks Russ,
The thing that was confusing to me was that head would have to be removed and reinstalled to lube the cam with installation lube.
Jake

[jakewalter]

I placed a straight edge across the valve tips and found a significant difference in the length of the valve tips so I took the head back to the machine shop to have them adjusted. Than I checked the pushrods I came up with a difference .005. The length of the pushrods are between 9.5 and 9.55.
If I’m correct using a pushrod that is 9.6 should give me the correct preload.
Would that be correct?
Thanks so much,

[Russ Pottenger]

Perfect.
Good that you took it back and had them fix it.

Any reputable automotive machine should know when they're rebuilding a cylinder head or doing a valve job on a head that has a non-adjustable valvetrain, setting valve stem tip heights are critical

[jakewalter]

I ordered some Manley pushrods from Russ Pottenger at Bishop-Buehl Racing Engines (Thanks Russ) so I hope that issue is solved however when I went to put on the oil pump I noticed that the piston skirts are going past the end of the cylinders.
Is this normal?
I’m using a Scat 4.2 crank with custom 4.0 rods and Keith Black pistons.
I'm not sure how to attach pictures.