Engine Rebuild - How to set Lifter Preload

[jawort0]

I am rebuilding a 109 with a Comp Camps 206/206 Hydraulic Flat Tappet. I have a new set of Comp Cams lifters. Is there a procedure to set lifter preload on the Buick V6, or so I simply lube and install? If just lube and install, is there any other settings that need to be done on the overhead? This is my first 109 rebuild.

Thanks! Joe

 

[pacecarta]

when going with stock uncut heads , uncut block and stock height gaskets stock length rods installed with the shafts torqued to 24ft lbs is usually fine
but when is everything as it was from factory , little things add up
heads milled , block decked

so whenever redoing its always best to check first
with heads and headgaskets installed and torqued
install cam and timing set
install a lifter and set cam to base lobe ,
using an adjustable pushrod check tool screw it down so its a little shorter than the rods you think will fit
..drop it in and install and torque down the rocker assembly
adjust the tool to zero lash
then remove rockers and remove pushrod check tool and turn out an additional 3/4 turn for the preload (1 turn =.050" and your target is about .030") , compare the tool to the pushrods you have
you should also check at rear of that head and front and rear of the other head to ensure there arent any major differences---
if the tool and what pushrods you have are the same then use the rods you have
install them and bolt the shafts down to 24lb/ft
if they arent the same its time to order new pushrods, you can usually send the tool to the manufacturer and theyll build your pushrods to the same as the tool

 

[DaySleeper]

You need one of these to measure the preload of the lifter.

 

[machinegun]

follow the instructions from pacecarta and you should be good to go.

it takes time but once I installed I check the preload on all after installing

I am unsure however how a spark plug gap tool will help on hydraulic lifter preload?

Solid rollers would usually use an angled blade type gap tool not a wire one.

 

[pacecarta]

the spark plug feeler rod can be slid (hooked) under the lifter retainer along side the pushrod (intake off of course) and measure the distance between the lifter disc and the retainer , thats the preload
the adjustable test rod is the better method , though on stock stock parts with stock height gaskets stock pushrods and a std hydraulic cam even if the heads and deck have been cleanup milled the stock pushrods should be fine as even if the lifter preload gets near .100 it will still run just fine

 

[jawort0]

Pacecarta, thanks for the excellent write up. I have a stock block that is unmachined and stock heads that have been milled clean along with FelPro9441PT head gaskets, stock push rods and stock rockers with the Comp Cams 206 206 Hyd flat tappets with new Hyd flat tappets. Based on your input, sounds like I should be fine with the stock push rods. Do you agree?

Thanks, Joe

 

[gmmuscle]

I just went through this with my engine builder using the same flat tappet 206/206 comp cam, and comp lifters. No head milling on my stock heads and stock GM gaskets. When he did the preload check, I ended up not being able to use stock pushrods. Needed 3 different lengths. One of the cyl 5 needed 8.620, the rest needed either 8.640 or 8.650. Did not have new pushrods for engine breakin but the stock were close enough for that. Do not have engine back in car yet, but he says the proper pushrods will provide for quieter valvetrain and better WOT performance and operation.

Got pushrods from Smith Bros Pushrods in Oregon 541.389.8840. If I remember they were about $190. Great guys to work with and make sure to request them to etch length on each pushrod.

Good luck Carl