94EvilZ28

wow...diggin up an old one...

quick question though...once the valve covers are off...it doesnt spew oil everywhere?

shoebox

It can (especially if you rev it).

JAKEJR

That .004" to .006" only applies for one particular type of Comp lifter, not all of them. It's their "R" type, IIRC.

.020"/.040" is their recommended range for their others. .030" is considered by Comp to be ideal.

GM, however, differs in their recommendation. In my 96 GM FSM the recommendation is one full turn (+/- 1/4 turn) which translates into quite a bit more than what Comp recommends, perhaps twice as much or more.

On this and other Forums this "preload" issue has been debated for many years. The recommended ranges in those posts cover the entire spectrum. All the way from one guy recommending "only one flat of the hex head on the poly-lock" all the way to Two Full Turns.

With the exceprtion of the "R" type lifters, my personal view is that the noisey valvetrain posts I regularly read are the direct result of too little preload.

Jake

brucer

op,i've done it that way for about 24 years

JAKEJR

It can also cause an oil fire too if oil leaks onto a hot exhaust manifold. One guy recently had it happen to him, but I can't recall if it was on this Forum or another one; (I visit so many I lose track).

Jake

ACE1252

Hehe, this is old. I did use this method and had no problems with the rocker adjustment...nailed it first time. Having the intake off to watch the lifters move helped tons. Just to add...I did torque the poly locks to 30 lb-ft.

JAKEJR

Younger guys need to learn, from the beginning, how to do this the right way.

Back in the day, when I use to build BB 1/4 mile engines for several teams, I would always try to attend the meets my engines were competing in. On several occasions I'd have four of my engines running at a particular meet at the same time. I'm talking trailered 8 second 1/4 mile cars, not streetable cars.

Since consistency in ET was paramount in the classes they ran in, I'd check and adjust valve lash on their engines between rounds. Running the valves became a real chore but it was necessary, in my way of thinking, to insure the cars remained competitive. I'm **** about a few things and correct valve lash is one of them.

The procedure for adjusting valve lash on solid roller cams, which all of them ran, is,with one exception, the same as adjusting a hydraulic cam. The exception is that with a SR cam lash (clearance) is set while with a HR preload is set.

Finding the base circle for each lifter was exactly the same on both types of cams and is the most critical part of the adjustment procedure. You watch the intake to set the exhaust and you then watch the exhaust to set the intake. Full race cars even have a bump starter button - most times mounted to the firewall - to facilitate that procedure.

I suggest attending a meet where the really fast cars are competing and spend some time in the pits, watching the engine mechanic work on the engine. Watch what he does when setting the valve lash. He'll be using the same IC/EO method; no dial indicators or intake removal or adjustments while engine is idling.

Whenever I read a post of someone using any of those procedures I just smile. Knowing they've never been in the heat of competition since there's no time for any of that goings-on when preparing for the next round.

Jake

JAKEJR

Here I am, many years ago, about to warm the engine before making another 8 second pass. Notice the concentration, that's what it takes.



Jake