hydraulic lifter valve adjustment

[dynoflo]

just had a old sting ray here for tune up. I drove it before tune up and it ran good for 300 hp. Pulled valve covers to adjust valves and they were all at least 2 turns tight. Got one side adjusted went to the other and decided to do it with motor running. Same thing 2 turns to clatter. I adjusted to 3/4 tight after 0 lash. Took it for ride and it ran about the same. I have noticed on dyno that hydraulic valve adjustment on race engines doesnt make much differance. I have done 1/4-1/2-3/4 makes no differance. 2 turns seemed excessive but it ran fine. This corvette never had the valves lashed since new. The guy bought it new in 1970. Any body noticed this before?

[BillK]

On most engines it really should not make any difference at all as long as the lifter "plunger" is somewhere in the middle of the travel. I think the only time it is real important is when you are revving the engine to higher rpms and there is a chance of valve float. That is when the lifter can hold the valve open and possibly hit a piston etc.

[Racer97]

A older racer told me to adjust my valves at 1\16 turn past zero lash. I did and it ran 11.90 113 et in a 3400 pound car 9to1 comp. Mild ported 041 heads 355 inch sbc with 355 rear gears 3000 stall .

[rebelrouser]

On a fresh engine before I prime them I adjust the valves, I want the lifter plunger preloaded .060 below the snap ring, on the base circle, which works out to about 1/2 turn. Then I prime the engine roll it over a couple times and make sure none are loose.

[Schurkey]

Lifters don't "pump up" and hold the valve open. The valves float due to inadequate valve springs, and the lifter does what it's designed to do--take up the clearance. If you've got trouble with "pump-up", you need different valve springs.

Some guys want the lifter plunger near the top of it's travel, so it can't "pump up" and hold the valve open.
Some guys want the lifter plunger near the bottom of it's travel, so the lifter can't "leak down" and cause loss-of-lift and loss-of-duration.

The engine will run fine with the plunger anywhere between the two extremes of it's plunger travel. Whether that gets you proper rocker-to-valve tip motion is dependent on pushrod length, given individually-adjustable "Chevy-style" rockers.

[ptuomov]

Lifters don't "pump up" and hold the valve open. The valves float due to inadequate valve springs, and the lifter does what it's designed to do--take up the clearance. If you've got trouble with "pump-up", you need different valve springs.

Some guys want the lifter plunger near the top of it's travel, so it can't "pump up" and hold the valve open.
Some guys want the lifter plunger near the bottom of it's travel, so the lifter can't "leak down" and cause loss-of-lift and loss-of-duration.

The engine will run fine with the plunger anywhere between the two extremes of it's plunger travel. Whether that gets you proper rocker-to-valve tip motion is dependent on pushrod length, given individually-adjustable "Chevy-style" rockers.

I like the hydraulic lifter bucket close to their maximum compression on the base circle because I believe that aerated/foamy/bubbly oil compressed and at high rpms a wet sump engine tends to have at least some air bubbles in it.

[BILL-C]

We have spent countless hours experimenting with hyd lifter adjustments on dyno and have noticed a few trends. If you have a good quality lifter and have proper lifter to bore clearance, and are not exceeding the rpm limit of the valvetrain package, then there is no significant change in performance with different preload. It's when you have a problem engine that you can benefit from different preload strategies. It all depends on what kind of a problem you are trying to bandaid. We have spent countless hours fighting with junk hydraulic lifters, given up on them and replace with another set , and suddenly all problems gone! Hydraulic rollers have been the worst by far.

[dfarr67]

Hydraulic rollers have been the worst by far.

Why? heavier..? Are SBC the worst for oem noisy roller lifters?

[hoodeng]

It's horses for courses,, there are a number of hydraulic lifter designs that will accept different adjustments.

In what i work on, one type of lifter can be bottomed out, then backed off half to one turn, which has given excellent dyno results and a quieter operation than the zero lash and down four turns method [depending on what TPI pushrods are used] which also applies to this same lifter.
On other brand lifters in the same application you can not do this as the internal supply to the lower chamber would be cut off, and severely limit oil supply to the top end.
The reason is different manufacturers place feed ports and supply bands in different locations in the lifter, one type that is used in this application does not even have a supply band machined into the lifter but relies on a metered bleed past the inner piston to supply the top end.

It's whatever the manufacturer recommends, unless you disassemble the lifter and actually measure it's physical limitations, even then you might not change the adjustment procedure unless it's proven to be of benefit.

Cheers.

[Hrdlx62]

On a fresh engine before I prime them I adjust the valves, I want the lifter plunger preloaded .060 below the snap ring, on the base circle, which works out to about 1/2 turn. Then I prime the engine roll it over a couple times and make sure none are loose.

Would'nt 1 turn put the plunger in aprox. .060? Am I doing the math wrong?

[dannobee]

As many of you know, Chevy had problems with valve stem seals causing smoking on startup for at least most of the 80's and 90's. At dealership level, the tool kit to fix included a manifold with 4 hoses to air up a bank of cylinders at one time and a steel plate that depressed all 8 valve springs at once, after removing the rockers and pushrods.

When reassembling and setting valve lash, the easy peasy quick way to set the valves was to measure the distance from the top edge of the rocker nut to the tip of the rocker stud. 0.190"-0.200" was what we used. It was so consistent at 0.190" on stock engines that we concluded that the factory adjusted them using some kind of go/no-go tool that indexed off of the top of the stud and the top of the rocker ball, resulting in the 0.190" measurement.

If someone was to make a tool, it would look like a 5/8" deep socket with a piece of bar stock inside the drive broach that would contact the top of the stud. As you tightened the rocker nut, the bar stock would either be recessed or protrude from the socket, which would contact the rocker ball. With the 0.190" measurement, it would sit flush with the socket. The socket would obviously need to be turned with a wrench or have some other way to turn it as the bar stock would protrude from the drive area.

[novadude]

As many of you know, Chevy had problems with valve stem seals causing smoking on startup for at least most of the 80's and 90's. At dealership level, the tool kit to fix included a manifold with 4 hoses to air up a bank of cylinders at one time and a steel plate that depressed all 8 valve springs at once, after removing the rockers and pushrods.

When reassembling and setting valve lash, the easy peasy quick way to set the valves was to measure the distance from the top edge of the rocker nut to the tip of the rocker stud. 0.190"-0.200" was what we used. It was so consistent at 0.190" on stock engines that we concluded that the factory adjusted them using some kind of go/no-go tool that indexed off of the top of the stud and the top of the rocker ball, resulting in the 0.190" measurement.

If someone was to make a tool, it would look like a 5/8" deep socket with a piece of bar stock inside the drive broach that would contact the top of the stud. As you tightened the rocker nut, the bar stock would either be recessed or protrude from the socket, which would contact the rocker ball. With the 0.190" measurement, it would sit flush with the socket. The socket would obviously need to be turned with a wrench or have some other way to turn it as the bar stock would protrude from the drive area.

That's really interesting that 0.190" worked every time. Of course, I guess you have a pretty broad range of acceptable plunger depth, so tolerance stack-ups on all the things that would affect plunger depth probably don't matter that much.

[BILL-C]

Hydraulic rollers have been the worst by far.

Why? heavier..? Are SBC the worst for oem noisy roller lifters?

Big block engines have been the worst. Almost certainly because of the weight and bigger springs.

[frnkeore]

When I was a kid, I exceeded the factory hyd lifter pre-load, a few times, mainly on my folks MEL engine. Thankfully the MEL has big valve stems and good valve relief pistons as, I only bent push rods. From that time on, I'm careful to set the collapsed lifter clearance on engines that I build.

I never liked the way that it was suggested to set Chevy's hyd lifters. It's messy and I always hated hearing the the engine miss as you cranked the rocker down but, I always did it that way, when I was a mechanic.

Ford does it a different way, their hyd valve adjustment is done at a collapsed lifter setting and I set the lifter at close to the max but, with all these different max settings, a setting of .150 will fall into the "desired" range, for all. .200 (300-6), .190 (SBF), .219 (360-390), .175 (429-460).

I've built mostly SBF's and so, for convenience, I use a piece of 3/16 CRS to set the lifters. My newest build will be a FE and I'll have to machine a gauge for it.

So, with that said, for the SBC, I would suggest that you try to get the max, collapsed lifter setting from GM or, at least the lifter manufacture and use that to set the clearance or pre-load. From there, you could just prime the system, put the valve covers on and not make a big mess adjusting the valves.

I know, some will say that the max setting will be to "soft" and loose lift so, to those, determine the pre-load you want but, it will make all the settings, exactly the same, if done this way.