I haven't changed to any type of hydraulic cam since the early 80's....somewhat explaining my lack of knowledge in this area (I've always gone to flat solid tappets). My Gen VI 502 has the factory cam that I am changing, but when I was setting the preload on the valves/rockers/lifters, I noticed that only 6 of the 16 lifters have any "bleed" in them. The other 10 are as stiff as solids. Is this normal? The last time I set hydraulic preload, I remember them all allowing some plunger "give".

TIA,

Mike

What cam are you changing too?

Lee

A Lunati hydraulic roller (50249). I should have gone solid as these lifters are making me lose sleep :rolleyes:

Mike

Mike,

I assume you went with the Lunati replacement lifters or similiart. Unless I am mistake, anything much over the factory lobe lift does not leave much safety margin. Did you look into this?

Originally posted by GRN69CHV:
Mike,

Unless I am mistake, anything much over the factory lobe lift does not leave much safety margin. In what area? The lift for the factory cam was around .514 or .520 gross from what I remember. Are you saying that the GM lifters will fail much above that? I do have a new set of Crane lifters which I may or may not use, depending on my ignorance on the original hydraulic lifter issue.

Personally, I think the biggest issue with Hyd Rollers in a rat is the fact that they are heavy (like baseball bats) and limit RPM capability. 6000 rpm will be pushing things.
Depends on your intended use for the engine I guess.
Ron

Mike,

Did you switch the rocker arm studs and rocker arms to adjustable ?

The factory rocker arms are non-adjustable and generally made to only work with the factory cams only.

Also, be careful with the base circle of the cam. Measure the the difference in the base circle. The factory lifters are made to work with the factory style cams that have a certain base circle. When the base circle on the cam gets smaller (greater lift cam) the lifter sits lower when on the base circle and could drop under the lifter retaining "dogbone".

Mike,

Don't bet on this, but I'm somewhat sure I read that the max lobe lift for factory roller lifters is between .32 - .33. Don't think it is so much an issue of the lifter coming out of the bore as it is that the lifter will drop down too far when on the base circle of the cam. The GenVI aftermarket lifters are real tall - actually much taller than the MarkIV retrofit rollers.

You may want to check on this.

Originally posted by Just_Another_Mike:
Anyone?[/b]

Originally posted by mc71454:
[QB Did you switch the rocker arm studs and rocker arms to adjustable ?

The factory rocker arms are non-adjustable and generally made to only work with the factory cams only.[/QB]Say What????

Yup

ARP sells a rocker arm stud kit that is 3/8 on the head side and 7/16 on the rocker arm side. You then use either stamped rocker arms like the 7/16 long slot or use roller rockers.

They're Edelbrock heads, the same junk,I mean stuff, that everyone who can't afford Canfield or AFR's use. They already have ARP studs.

Oh, all it said in your post was that you were changing the cam in your Gen VI motor.

Pushrod length OK ?

On both my cars we ran a crower cam with 1.8 rockers with stock lifters for over 3 years and shift at 6300 RPM. The cam was 245/253 at .050 and .66x lift! We have well over 1000 qtr mile runs on the camaro and it runs 10.90's with this setup plus 3500 street miles.

Lee

Soooooooooooooooo.............are the plunger and seats on hydraulic lifters supposed to have play in them or not? Six of mine have 1/8 to 1/4 inch of travel and 10 do not. The brand new set does not have any play in them either.

I'm going with the new set, but I'll mail someone either 10 good ones and 6 bad ones or 6 good ones and 10 bad ones if they can elaborately answer the question. They're yours for FREE graemlins/waving.gif

I'm still not sure on your question but I know that all 16 of my Crane hyd. roller lifters have equal plunger "give", not what I would call play, so you can set the preload. None of them had "no" give. If they are pumped up some might feel stiffer but they should all blead down under pressure and feel the same. I hope I read your question right..

Lee,

So you are saying you run/have ran a 660 lift cam with stock 502 hydro rollers. Someone has a heck of a propaganda machine going then to sell new taller lifters. If the stockers work - great!

Mike, all of the lifters should have some play. It is possible that they are just gummed up a little and are not bleeding down. Unless these were extremely high mileage, you should be able to get the plunger to move.

It sounds like to me that not all the lifters are pumped up. New lifters will have play in the plungers until they have oil pressure. Be sure to prime the oil pump, then turn the engine a turn and continue to prime untill all the lifters/rockers are flowing oil. Is this a new motor? You may have to set them on the loose side and start you engine and let in run for a few seconds to get oil to all the lifters, then set the lash.

Lee

Originally posted by GRN69CHV:
Lee,

So you are saying you run/have ran a 660 lift cam with stock 502 hydro rollers. Someone has a heck of a propaganda machine going then to sell new taller lifters. If the stockers work - great!
... You are correct, we run the crower 0404LM which has these specs: 245/253 .648/.673 with the 1.8 rockers. In fact the stock springs have better spring rates then what was recomended! This is still in the camaro and runs real strong. I just changed the chevelles to a solid roller and upon inspection the valve trane looks brand new despite 3 years of torture!

Lee

Lee,

Thats great to hear..

Have you been using the retainer tray and dogbones with that cam?

http://www.boomspeed.com/mc71454/retainer.jpg

Originally posted by mc71454:
Lee,

Thats great to hear..

Have you been using the retainer tray and dogbones with that cam?

http://www.boomspeed.com/mc71454/retainer.jpg Yup! With the 1.8's I had to change the length of the pushrods to get the correct geometry but other than that I made no other changes.

Lee

Okay, thanks for the answers. Strangely, my absolute brand spanking new set of Crane lifters do not, I repeat *do not* have any plunger give in them whatsoever. In fact, if you stick a pushrod in them and push down with all your weight, they do not move at all........this was what was confusing me about my old one. BTW, if anyone wants a used (less than 3000 mile) set of GM hydraulic rollers, they can have 'em. I wasn't kidding graemlins/beers.gif

Mike

if no ones taken them yet i will, i can paypal you shipping $$ today

It sounds like you got solid roller lifters!

Lee

Originally posted by Just_Another_Mike:
Okay, thanks for the answers. Strangely, my absolute brand spanking new set of Crane lifters do not, I repeat *do not* have any plunger give in them whatsoever. In fact, if you stick a pushrod in them and push down with all your weight, they do not move at all........this was what was confusing me about my old one. BTW, if anyone wants a used (less than 3000 mile) set of GM hydraulic rollers, they can have 'em. I wasn't kidding graemlins/beers.gif

Mike =
Stick them in a vise with soft jaws & something in the plunger like a short bolt & gently tighten the vise a quarter turn or so at a time & see if they don't collapse. They may be full of oil. & if so will be very stiff.

Lee,

That is encouraging new regarding the factory rollers. Supposedly they are lighter than the aftermarket rollers and a heck of alot cheaper - like about 250.00/set with guide and retainers and compared to about 400 - 500 for retrofit, depending on which ones you buy. I kinda wonder if the cam issue is something particular to Crower that makes it work. Not knowing the particulars, they may be grinding the lift in without really affecting the base circle of the cam. Crane for instance, [at least from what I understand] requires the taller (heavier) lifters.

Well, the new lifters should not be solid rollers, but who knows? They are Crane 13532 hydraulic rollers according to the package and part number, they came from Summit(pretty reliable), and they were sealed. Mike(Wolfplace), tomorrow I morning I will do as you described. Bigblockelky.....send me an e-mail, it's in my profile, and we will work out the shipping.

Mike

There`s no way you can mix up hyd rollers vs solid rollers.
Pushrod length is the 1st clue, not even close to one another.
Take them to 0 lash then give them 1/4-1/2 turn and be done with it.