[cold coffee]

Hi, this is my thread from 2 years ago:

http://forums.maxperformanceinc.com/...d.php?t=803702

I'm just now putting the engine together, and as it's my first I'm a bit confused about these two things. I've read lots of threads here and watched lots of you tube videos and I think I almost have it.

https://www.youtube.com/watch?v=76wbtu9l09A

Measuring pushrod length the way this guy does, I come up with 9.1857". This is with the non adjustable rocker snug and the plunger on the lifter all the way up.
Pattern on the valve tip is dead center.

I have these lifters: https://www.summitracing.com/parts/rhl-9518l/overview/
I'm not sure what I should add for preload.

This says the plungers should be down between1/16 and 1/8th from the top.
http://www.rhoadslifters.com/Pages/Installation.html

So do I take that pushrod length and add an extra 1/16 to 1/8 to it?
Very new to this, please be gentle.

Edit forgot engine specs.
455
6x heads w/ new springs and valves
crower 60919 cam

[Formulas]

You got 7/16 fine thread studs ? Which are 20 threads per inch if you go 1 full turn of preload you in effect have used a 20th of an inch so divide a inch x 20 in decimal that's preload distance
.050

[cold coffee]

Originally Posted by Formulas

You got 7/16 fine thread studs ? Which are 20 threads per inch if you go 1 full turn of preload you in effect have used a 20th of an inch so divide a inch x 20 in decimal that's preload distance
.050

they are whatever stock is.

[steve25]

First some question need to be asked here.

Have the heads been milled and or the block?



Has a valve job been done to the heads?

Milling the heads or the deck of the block will make for the need of longer then the stock 9.130" push Rods as will applying a valve job to the head since that sinks the valves deeper.

Stock Pontiac rocker studs are 5/16" fine thread on the top and the rocker ball is non adjustable.

You have two problems here , 1 the factory non adjustable valve train and 2 the fact that the .470" lift of that Cam stands a good chance of snapping off that small stock 5/16" rocker stud top section due to the added leverage of that .470" lift!

Ask me how I know this!!

The start of the fix for both is to install 7/16" top and bottom size studs with a set of the needed size poly locks for adjustability.

[gtofreek]

Actually, stock studs are 3/8" on top and that equates to .042" movement for 1 turn. Like Steve said, best to get rid of the bottle neck studs and get straight 7/16" studs.

[tc]

Originally Posted by cold coffee

So do I take that pushrod length and add an extra 1/16 to 1/8 to it?

Yes you do add to the pushrod length. You probably are not going to order custom made pushrods, so you will purchase whatever length increments they offer, .050 or .100 length differences. Go with a shorter length if your dimension falls between two offered lengths. I would only add 1/16.

What did you use for a lifter when checking the pushrod length? Are you sure the lifter plunger did not move down? Is the checking lifter plunger height the same as the lifters you will use in the running engine?

[Schurkey]

Originally Posted by Formulas

You got 7/16 fine thread studs ? Which are 20 threads per inch if you go 1 full turn of preload you in effect have used a 20th of an inch so divide a inch x 20 in decimal that's preload distance
.050

Not exactly. Moving the adjuster nut .050 moves the lifter plunger more than that because of rocker ratio.

Originally Posted by steve25

Milling the heads or the deck of the block will make for the need of longer then the stock 9.130" push Rods as will applying a valve job to the head since that sinks the valves deeper.

Milling the block deck or the head deck may require SHORTER pushrods, depending on the amount of travel in the lifter plunger, and the amount of material removed.

Sinking the valves may require SHORTER pushrods. In the old days, the amount of material taken from the valve face (and seat) was compensated for by shaving material off the valve tip. I don't suppose folks do that any more, in part because the valve tip hardening layer may not be thick enough.

[steve25]

Sorry, I always make that mistake , and I know better!

I need to review my post before posting!

[glhs#116]

Originally Posted by Schurkey

Sinking the valves may require SHORTER pushrods. In the old days, the amount of material taken from the valve face (and seat) was compensated for by shaving material off the valve tip. I don't suppose folks do that any more, in part because the valve tip hardening layer may not be thick enough.

I'm pretty sure all of that was done because of the crimp lock factory nuts that had a fixed height. Anyone doing anything these days will first put on the thicker studs and polly locks. I bet this is the real reason you don't see such things being done now.

Sam

[HWYSTR455]

Use this method:

https://www.youtube.com/watch?v=o5is9BsH5OU

No need to take any lifter plunger movement into account.

This method determines the correct valvetrain geometry, and you calculate using half the lobe lift of the cam and rockers that are installed.

Screw that valve tip marking method, which usually has you changing the pushrods after a few 1000 miles.

.

[beertracker]

take a look here; https://www.lunatipower.com/how-to-v...train-geometry