Thread: Roller rocker adjustment review:

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I'm not a newbie at lashing rockers, but I don't have a dial indicator any more, so I'm tossing this out for opinions. My Fast Burn 385 (similar to ZZ4) 350 Chevy has a LT4 'Hot Cam' with 1.6 roller rockers. These are the specs:

Lobe Separation (Deg) - 112
Duration at 050 inch Lift - 218 int./228 exh.
Valve Lift - 0.525/0.525

Your choice of procedures:

Option 1: At #1 TDC, adjust 8 rockers, at #6 TDC, adjust the rest (I know which ones)
Option 2: Set #1 at TDC, rotate the crank and set #8, etc., etc. (I have a timing tape know the firing order)

Isnt this a hydraulic cam? I set my "GM hot cam" just like any normal hydraulic
SBC. Mine also has the 1.6 roller GM rockers. I do the "Option 2" by rotating the
motor.

Originally Posted by robot

Isnt this a hydraulic cam? I set my "GM hot cam" just like any normal hydraulic
SBC. Mine also has the 1.6 roller GM rockers. I do the "Option 2" by rotating the
motor.

Yep, it's hydraulic. Option 2 is what I normally do. I don't think this cam is wild enough to have to put a dial indicator on every valve stem to make sure it is at TDC I did degree the cam, so I know it's installed straight up, and I have a timing tape on the harmonic balancer.

Thanks

Okay, I will ask the question, is it easier to remove the engine and place on the engine stand so that you can rotate it or do you guys have a ex-large Harbour Freight type of stand that you attach the car to to enable you to rotate the engine ? I have never done this sort of engine repair before so I will appreciate all help thanks.

It's not a new engine. I'm just going through a rocker adjustment because it sounds a bit louder than I would like, and I haven't done it for a while.

Taking the engine is out of the question. I would have to disassemble the entire front end, grill shell, radiator and a boatload of other parts.

As it is, because of the narrowed frame, low stance and other 'stuff' in the way, I had to remove the A/C compressor and bracket and the master cylinder just to get the valve covers off.

And no, I had no other place to put those accessories.

This project was a case of putting five pounds of 'stuff' in a four-pound bag.


Maybe this photo will answer your question.

EngineCompartment.JPG

No expert here but I guess your trying to find TDC to start your adjustment without a indicator I always used a piston stop in the spark plug hole, take off the flywheel cover get a flywheel rotating tool, rotate the engine clockwise to hit the stop, mark it on the balancer, rotate it counterclockwise til it stops mark it on the balancer and TDC is exactly half way between those marks. Then run your valve adjustment procedure as listed Maybe Jerry or Tech can tell us whats best. Best of luck Matt

I use a screwdriver down the spark plug hole.

You can feel exactly where TDC is.

Thanks for replying, but I'm not trying to find TDC. I used a piston stop several years ago, so I know exactly where TDC is and then I accurately set a timing tape to mark the entire circumference of the harmonic balancer. I mentioned two methods of setting the rockers. I'm just asking which one will work better with the cam specs I posted.

I can't see where the cam specs change the methodology for the mechanical adjustment.

Perhaps TECH can chime in...

Originally Posted by firebird77clone

I can't see where the cam specs change the methodology for the mechanical adjustment.

Perhaps TECH can chime in...

On certain aggressive cams, the adjustment procedure is different, and this procedure is used. It's foolproof, and best done with a dial indicator. I'm just trying to determine if this cam requires it, or if I can safely use one of the methods I mentioned in my first post.

Intake Valve Adjustment: ENGINE OFF!
with #1 cylinder Intake Valve at full valve lift .... Adjust #6 Intake Valve
with #8 cylinder Intake Valve at full valve lift .... Adjust #5 Intake Valve
with #4 cylinder Intake Valve at full valve lift .... Adjust #7 Intake Valve
with #3 cylinder Intake Valve at full valve lift .... Adjust #2 Intake Valve
with #6 cylinder Intake Valve at full valve lift .... Adjust #1 Intake Valve
with #5 cylinder Intake Valve at full valve lift .... Adjust #8 Intake Valve
with #7 cylinder Intake Valve at full valve lift .... Adjust #4 Intake Valve
with #2 cylinder Intake Valve at full valve lift .... Adjust #3 Intake Valve

Exhaust Valve Adjustment: ENGINE OFF!

with #1 cylinder Exhaust Valve at full valve lift .... Adjust #6 Exhaust Valve
with #8 cylinder Exhaust Valve at full valve lift .... Adjust #5 Exhaust Valve
with #4 cylinder Exhaust Valve at full valve lift .... Adjust #7 Exhaust Valve
with #3 cylinder Exhaust Valve at full valve lift .... Adjust #2 Exhaust Valve
with #6 cylinder Exhaust Valve at full valve lift .... Adjust #1 Exhaust Valve
with #5 cylinder Exhaust Valve at full valve lift .... Adjust #8 Exhaust Valve
with #7 cylinder Exhaust Valve at full valve lift .... Adjust #4 Exhaust Valve
with #2 cylinder Exhaust Valve at full valve lift .... Adjust #3 Exhaust Valve

I am not as accurate.....I use:
Intake Closes...adjust Exhaust
Exhaust Opens.....adjust Intake

Whiplash....good question. It is a situation of relative movement.....you can hold the engine still and rotate the car if you like.

Heck, thanks Robot, I thought my weird sense of humour had been missed. Sorry to you Jack, I'm not able to help with an answer.
I will go and rotate something now.

Originally Posted by Whiplash23T

Heck, thanks Robot, I thought my weird sense of humour had been missed. Sorry to you Jack, I'm not able to help with an answer.
I will go and rotate something now.

Sorry Mark. I was temporarily on another planet.

Originally Posted by DennyW

With those cam specs--- Intake opens, intakes closes, (compression stroke) turn crank from 12 to approximately 3, adjust. Puts you on the base circle of the lobe for sure. Continue on to next.

Denny, when I do that for #1 cylinder, my timing tape says TDC, which means that my method #2 above works just fine for this cam.
Thanks for the confirmation.