Hi guys, I recently converted a gen I 327 to retrofit Comp Pro Magnum roller rockers and Comp 276 roller cam. These roller lifters specify something like 0.004-0.006" preload (plus or minus a few thou, I forget the exact figs). I usually set preload w/ the engine off by carefully finding each base circle and then adjusting preload accordingly for each rocker, one at a time. When you are setting 20 thou preload on a regular non anti pump lifter, if you are off a few thou either way it does not matter. But with these new lifters, plus or minus a few thou can mean you end up with lash and a rocker is noisy. I adjusted them cold, carefully, and ended up with one or two slightly noisy rockers. So I decided to adjust w/ the engine hot and running to be more accurate. I have poly locks which makes adjusting w/ the engine running very difficult. W/ oil restrictors I am still oiling down the headers and making a toxic fumey mess.

Has anyone with these exact roller lifters adjusted them w/ the engine running? With old school flat tappet cams and regular stock jam nuts, it was very clear when you backed off until a rocker was noisy, and then found zero lash when it just got quiet. With the pro magnums, and the roller tip rockers, it is very difficult to tell when the rocker has quieted.

Any tips or tricks? I'm thinking I'm going to have to get a long extension w/ the 5/8 socket on it and put my ear up to the handle, so I can really hear what is going on, as I adjust

 

All rockers adjust the same. How much they're adjusted depends on if you use a hydraulic or solid camshaft. They're all adjusted when the lifter is on the base circle.

Hydraulic lifters need .030" preload from zero lash. .030" is roughly 1/2 turn.

Solid lifters need valve lash. Your cam card will have that spec however you can reduce the valve lash up to .006 if using aluminum heads.

 

I already know how to lash/set preload. And you are incorrect in that, not all hyd lifters are made equal. An anti pump hyd gets almost zero preload because it is valved differently. Here is what comp says regarding the difference between conventional and the pro magnums:

How do I adjust my hydraulic lifters (non-adjustable valvetrain)?

A. When installing a hydraulic camshaft or lifters, or new rocker arms, it is necessary to establish the correct lifter preload in order to ensure great performance and long engine life. Insufficient preload will cause excessive valve train noise and wear. Excessive preload will cause rough idling and low manifold vacuum, and can even lead to severe engine damage. With a non-adjustable valvetrain, proceed as follows:

COMP Cams® offers several series of hydraulic lifters which require different amounts of preload. High-Energy™ lifters will require .030” to .050” preload. The more competition-oriented hydraulics lifters, such as the Pro Magnum™ series will require only .002-.004” preload, which will typically require a dial indicator to set correctly.



So my point is, setting 0.002 -0.004 running, is difficult because there is very little room for error when you find "zero" lash and then preload. 1/8 turn is about 0.005" preload, which is what I am shooting for just because it's easier to measure. It would be easy to measure lifter plunger preload with a dial indicator if I had the intake off, but I don't


I guess I will warm the engine up and set preload with the engine off again, but hot this time to take tolerances into account. Anyone else?

 

Your first post and title asked about adjusting Pro Magnum rockers

What are you installing these on that has a non adjustable valve train? SBC engines are not non adjustable. I know on Mark V BBC with a non adjustable valve train, you just torque down the rocker bolt to the torque spec. There is no measurement.

 

Yeah you're right about the title, but the body text of my post asks about how to hear zero lash w/ the pro magnum lifters. I'll correct the title. I hate adjusting these friekin things. 2 thousandths preload on a hyd lifter? There is more error induced in finding zero lash than that spinning a pushrod by hand, because what each person considers "slight" drag will be different. When I set "slight" drag plus 1/8 turn on the base circle w/ the engine cold, I obviously ended up with at least a couple lifters that are running with a tiny bit of lash. I'm going to cut my spare POS chrome valve cover tops off so I can run the engine without the oil restrictors and see if that helps me not oil down the headers. What a cloud I made last night.....

 

You can save yourself some time by not finding each base circle. That cam is far from big enough not to use the factory method, as are 99% of the cams out there. If you're using a dial indicator, shouldnt be a problem getting the lash dead on. I'd be more suspicious of the lifters, people have had problems with those refusing to collapse and hanging valves open. Hope you did not soak them in oil as apparently thats an issue. I have no idea why it would be... but thats what I heard.

 

I soaked the needle end w/ t/he rollers in a cup of oil but I did not fill or pump up the plungers. With any lifter there is a chance of crashing the valve train if you pump them up first. I have no idea why people still do that.....

The engine runs excellent. I can get everything to quiet down if I sneak up a little at a time on the adjusters, but "quiet" doesn't tell me where my preload is. Using a dial on the rocker end is going to have more than a tolerable amount of error when shooting for such a small amount of preload. If I had the intake off I'd really want to check plunger travel but I really don't want to have to pull the intake. I will chuck a dial indicator up on the rocker tip over the pushrod cup later tonight, and see if the amount of wiggle allowed by the guide plates really throws the readings off too much to be useful or not.

Yeah I agree on being able to set the valves rotating the engine only once but I was just trying to be extra precise because I haven't used lifters w/ this small of a required preload before.

 

That's what I would consider a case of "measure with micrometer, mark with chalk, cut with dynamite".

The parts themselves move more than .002" just during warm-up. In fact, if you had aluminum heads, they would move at least 3 times that much.

Consequently, it is not sustainable in the real world.

Solid cams have around .020" of lash, at the rocker tip (almost always .012" - .030", typically somewhere in the .018" - .024" range); that translates to about .014" at the lifter. And even THAT is temperature sensitive.

The best way I know to be CERTAIN of being on the cam base circle, is to use the "180°" method; i.e., adjust each valve when the same one ont he cyl 4 cyls away in the firing order is at peak lift. I.e., adjust #1 intake when #6 intake is at peak lift. The "EOIC" method is usually good enough for practically ANY cam that you could possibly run on the street.

The "Chilton's" (adjust half, turn the crank one turn, adjust the other half) DOES NOT work on almost any performance cam; and even on a stock-ish cam, is only good enough if you're using LOTS of preload, so that the preload swamps the errors. I don't ever bother with that, even on a factory motor, because it's so inferior.

I think you're probably making too much out of it.

Copied straight from Comp's installation instruction pages:

Pro Magnum™ Hydraulic Lifters

Applicable Part #s:
858-12, 858-16, 862-12, 862-16, 863-16, 865-12, 865-16, 867-12, 867-16, 875-12, 875-16, 885-12,
885-16, 887-16, 8920-16, 8921-16, 8931-16, 8934-16, 8953-16, 8954-16
Thank you for choosing COMP Cams® products; we are proud to be your manufacturer of choice.
Please read this instruction sheet carefully before beginning installation, and also take a moment to review the included limited warranty information.
The following instructions cover the correct guidelines for installing COMP Cams® Pro Magnum™ Hydraulic Lifters. All Pro Magnum Lifters™ require an adjustable valve train for proper operation. Through various testing we have discovered that lifter preload should be set between zero and 1/8 of a
turn for optimal performance. Although the method for setting preload on a hydraulic flat tappet and hydraulic roller lifter are the same, the break-in procedure for each lifter is not. Please review this break-in procedure for flat tappet camshafts.

http://www.compcams.com/Technical/In.../COMP4-115.pdf

I think if you do it by the engine-running method, and set them to 1/8 turn, they should be fine.

I have no trouble whatsoever hearing "zero lash" with those rockers.



These in the pic are the 1100 series ("Hi-Tech"), but they work about the same. I have 1300 series ("Pro Magnum") in other motors, and they aren't any different, really. With your cut-out VC you shouldn't have any trouble at all.

 

The so-called 'Chiltons' method is fine. Dont forget that even a cam with "360 degrees" of duration (advertised or total, doesnt matter to me) has 180 degrees of its lobe on the base circle. I can hit that with a stick of dynamite on more than 2 valves at a time with no issue.

I think though that sofa is onto something with the cold/hot thing. You said originally you adjusted them with a cold engine. Thats not likely going to work, and would explain the noise.

 

how else are you to set up the valve train if the lifters are not somewhat pumped up already? if they have no oil in them, they are collasped down and will throw your pushrod measurement off. If you adjust the motor cold with un-pumped lifters, wouldnt that be a bad thing for your pushrods and valves when the lifter finally pumps up and raises the pushrod? That just doesnt seem right to me?

 

Not really. With the valve spring pressure and the preset pre-load, the oil
pressure is not enough to pump up the seat.

The lifter should only pump-up when there is slack in the assembly, or under
float situations. It will bleed down eventually (seconds, milliseconds) and
take up all the lash to the previous amount.

The hydraulics are very forgiving and act like a shock absorber in a sense.

 

LOL, no. There is a spring in the lifter body that is very stiff. As long as you are not trying to hold a valve open w/ the plunger spring, it will stay popped all the way up, with no oil in the lifter. The lifter only bleeds down if you have a load (from the valve spring as the cam lobe is ramping up off the base circle) against the plunger. You set zero lash using such a light touch as you come up on it, that you don't compress the plunger against the spring.

Sofakingdom, thanks. Yes I used 1/8 turn on 3/8" studs w/ the engine cold, and that was pretty close but ended up w/ a few being misadjusted, probably due to variances in where I "felt" zero lash was occurring when I set the motor up. That's why I want to set the 1/8 turn in running. It just made such an ungodly mess last night that I gave up. I'll try again tonight w/ my cutaway cover and see what happens.

 

hmm, my one lifter i have now had no oil in it, and the pushrod cup fell down a good ways into the lifter body. its such a big difference that you'd expect to have to run a longer pushrod. When its filled with oil, the cup is at the top, and it clearly looks like you will not need a longer pushrod. Maybe i have a bad lifter? the other ones are all full of oil at the moment, as they were LS7 takeouts



Here is a little lifter preload article using a dial indicator
http://www.hardcorels1.com/vbulletin...read.php?t=622

 

When the engine is stationary, several valves will always want to open because those lobes will be off the base circle. Is your collapsed lifter under tension from a lobe wanting to open against a valve spring? If not, your lifter is toast. A lifter with no load will expand itself pretty quickly (30 secs-a minute). That is not right. It sounds like you have a collapsed lifter.

 

they are not in the car.. I just picked them up. One wasnt full of oil and teh cup was down. when we put more oil in it seemed to stiffen up/pump up. I'll have to check them thoroughly again.

 

I would not even chance running that, it would go in the trash. It sounds like it is sticking.

 

Solve all your problems. Go to solid rollers.

 

dont mean to hijack but i checked my lifters and 2 of them (i believe the ones we took apart, inspected and filled with oil to try and pump them up) have a little bit of play at the plunger, the rest are fine and dont compress when i push down. I think the other 2 just need to pump up with oil. Its not completely collapsed, the ls1 guys tell me they just are bleed out alittle. you can push down the top maybe 1/8 inch before it stops. i think it needs pumped up.

 

No thanks on solid valve train. I have been told that the knock sensor picks up the valve train clatter and will pull timing. I am very much interested in keeping the knock sensor active so that is not an option. Plus then you still have to lash, so that doesn't really change anything, just the spec you are shooting for changes.

 

you can always tell the ECM to pull only a degree of timing out when it hears knock. There are tables for that. That way the false knock isnt pulling out much timing...but then if you get real knocks you'll be alittle screwed if it needs to pull alot of timing and cant since the ecm tables are telling it to pull only 1 degree

 

I burn my own chips and am not interested in effectively rendering the knock sensor useless. Having a knock sensor is a beautiful thing. I would just run a carb if I didn't want the computer control to remain effective. Been there, done that, got bored. I don't want to go backwards and end up with a setup that can't compensate for real world conditions and is only tuned for WOT at 70 deg F. The payoff in driveability is worth it when the ECU is happy.