I just installed a new XE 224/230 cam in my 95 Z. I am using stock lifters with about 5,000 miles on them out of a crate motor. The springs are 612's from CMS and were installed previous to the cam install. I also put in a hydra-rev kit too. For initial start-up, I set all of the valves at about 1/4 turn past zero. After running the car for about 50 miles, I lashed them with the engine hot and running. Every lifter adjusted fine - you know, back them off till they click, tighten up until quiet andthen 1/8 turn. Well, on the #2 cylinder exhaust valve, I backed it off a slight bit and it clicked. Then I went to tighten it up and it stopped clicking , but it wouldn't go any further than that without making the engine stumble and miss a bit. It was like there was a very very small amount of preload available. I backed it off quite a bit the second time, and it was really loud! Then I raced the engine up to about 2500 to get the oil pressure up and see if it would pump up. When I went back to adjust it, it went the same as the first attempt. Is this lifter collapsed or what?

 

Probably, you don't set hydraulic lifters with the engine running.

Hydraulic lifters need a pre-load to prevent damage to the seat. Without
any load, the lifter will pump up putting strain on the snap ring which may
cause it to fail.

If you suspect damage, pull them out and inspect them all throughly.

 

I don't really have anything more to say than Zero already said but i just had to comment on his quote "Welcome to the Internet where everyone's a mechanic & has a 10 second car." That just made me laugh out loud and drop my cigarette in my lap!!


Oh....one more thing. Lots of people have adjusted their hydraulic lifters with the motor running...including myself. That's why they sell "rocker clips" to keep the oil splash down. Check out Shoebox's site here http://shbox.com/1/4th_gen_tech1.html

 

Thanks RealZ, I hope you didn't burn anything important.

I was taught to use a feeler when setting up the motors in the shop. It would
be interesting to know what other tuners use the 'engine running method' for
hydraulics.

Here are some quotes from Crane's tech page. I have yet to see a hydraulic
cam setup with the motor running. I guess everyone has their method.

What is Hydraulic Lifter Preload?
Mechanical cam designs require a running clearance or valve lash; hydraulic lifters are just the opposite. When the rocker arm assembly is properly torqued down into position, the pushrod must take up all the clearance and descend into the hydraulic lifter, causing the pushrod seat to move down by .020” to .060”. The distance that the pushrod seat moves down away from the retaining lock is the “Lifter Preload”. The hydraulic mechanism requires this precise amount of “preload” for it to do its job properly.

Measure the distance between the two scribe marks, it represents the amount of lifter preload. If the lines are .020” to .060” apart you have proper lifter preload. If the lines are the same or less than .020” apart you have no or insufficient preload. If the lines are further apart than 060” you have excessive lifter preload.

What happens if the amount of Hydraulic Lifter Preload is wrong?
If clearance exists between the pushrod and the seat in the hydraulic lifter, after the rocker arm assembly has been torqued down, you will have no lifter preload. In this case the valve train will be noisy when the engine is running. All of the hydraulic force produced by the lifter will be exerted against the lifter’s retaining lock, and this could cause the lock to fail.

 

I have never set the lash with the motor running. It makes no sense to me.

Rich

 

I never set them with the engine running either until this time. We better call Combination Motor Sports and tell them because the running method was the "only" way they recommended to get the lash right. I figured they would know what was going on. Maybe I was talking to a new guy.

 

I set them on a running motor all the time. Back off till they click, toghten until it just stops and then turn them another 1/2 turn down from there. It's effectively doing the exact same thing as measuring the preload, but you can't screw it up (unless you are hard of hearing). It's how I tell/show people who are inexperienced to do it themselves the first time. It's auditory confirmation of where the zero lash point is. It's very EASY to screw up finding the zero lash point by measuring on a fresh set of lifters that haven't pumped up with oil yet, or set a few valves that aren't actually on the heel of the cam, etc.

To the question... some lifters are "tight". Might take them 30 seconds or more to bleed down as you tigthen down the adjustment nut beyond zero lash. Half a turn beyond zero lash could take what feels like forever to bleed down when you're standing there listening to it run on only 7 cylinders but you have to have just a little patience. If it takes longer than that the lifter is probably toast. Most will bleed down from 1/2 a turn in only a few seconds of running.