CHADsterss

Question: Since I'm using the Morel "street" link-bar lifters how much preload do those have? I did a search and came up with 0.050 in an aluminum block with aluminum heads and 0.030 - 0.034 in a iron block with aluminum heads (which I have a LQ4 block with 317s). Do I subtract the preload of the lifters from over all length of the pushrods after I check the preload using the EO/IC method??

badazz81z28

iTrader: (6)

The best advice I can give you.

1. Call the manufacutre and ask what they reccomdned for their lifters.
2. Get the Comp Cam measuring tool (ETEC) and measure per instructions.

-Joseph-

iTrader: (12)

Those specs you found are what you set the preload to, its not a built-in value. Preload is the measurement the pushrod pushes the lifter plunger down when the lifter is on the base circle of the camshaft and the intake or exhaust valve closed. I find it best to use a dial indicator along with an adjustable pushrod when you are dealing with such stringent specifications (like your .030-.034" range)

Scenario: Let's say when you measure pushrod length with a length checker... that the closest value (with no preload) is 7.350". Well with a non-adjustable valvetrain you then take that value and add your desired lifter preload to it: 7.350" + .030" = 7.380" ideal pushrod length. Now depending on how close your 7.350" measurement was, you have a few choices... you could either run a 7.375" (for .025" preload) or bump up to the 7.400" (for .050" preload). Finally you can always get custom pushrods in your exact length but you'll pay $$$.

One other heads-up: Check an intake and exhaust valve on each engine bank for pushrod length, often they can vary a few thousandths. Last one I checked with low-lash lifters had a variance of .010" bank to bank. Just makes it all the more complicated. Sometimes you will have 2 different pushrod lengths due to intake/exhaust variances from valve tip height or camshaft lobe design, but then if you have a bank to bank discrepancy you can need 4 different lengths!

CHADsterss

Thank you!!! This was exactly the answer I was looking for. This preload stuff is kinda confusing as I am new to it but that really explained it well.

therabidweasel

iTrader: (5)

I checked every valve on every cylinder several times and ordered 4 different lengths to cover the 25 thou of total variation across the motor. My lifters are short travel as well. Custom prods are not expensive, look at manton's site. Like $12ea.

My cam is 227r with 617 lift, so pretty fast ramps and my valvetrain is much quieter than stock thus far.