[madtexan]

I am trying to find out why my engine misses and sputters up through the carb after only changing my rocker studs from OEM bottleneck to 7/16 adjustables w polylocks. I have located TDC and adjusted the valves 4 times now. Started at Zero Lash + 1/2 turn and gradually adjusted back to Zero Lash - 1/4 turn tweaking it 1/4 turn with each adjustment but still misses and dies when put into drive.

My question about the heads is do they have any rocker stud holes that poke through to the intake chambers that I need to seal? I pulled the number 3 cylinder intake stud and it appeared to be sealed. Rather than removing every one, I thought I'd ask here.

The compression of the cylinders all peaked in the 160-170 range. Some of the cylinders seemed to be more jerky on the compression measurements than others but the peaks were all close. I just bought a leakdown tester today so that's my next step. I also replaces all ignition parts like plugs, wires, cap, rotor.

[PunchT37]

You don`t have to use any sealer on the studs.
I don`t understand your adjustment comments.
Was the engine running fine before? What rockers are you running? Stock?
You might want to check for binding at the poly lock area or the rocker hitting the stud at the bottom, meaning you would need a long slot rocker.

[Pontiac signman]

No to sealer...............

Sounds like the rockers are out of adj......no question

Unless you've done this before, ask for some help. I'd start all over with the rockers all loose (obv. not running)....do a search on adj. rockers for the best way for you (probaby 4 turns at crank)

In my mind.....you've over adj the rockers and it won't run.

Remember ZERO LASH is SUCH a slight drag on the pushrod and it can be hard feeling that happen w/o over adj. with a hyd. lifter (assumed).

Good luck

[madtexan]

The engine was running much better than it is now. The exhaust smelled really bad and I think it was dumping unburnt fuel out of the exhaust. IT didn't run quite as strong as I think it should but at least it ran before.

I have stock rocker arms.
How would I check for this binding at the polylock?
How could I tell if the rocker is hitting the stud and would it do this at idle?

This is a higher lift cam than stock.
Part # - Advertised Dur - Dur @ .050 - Lift w 1.5 Rocker Arms - Lift w 1.65 Rocker Arms - Lobe Separation Angle - Intake Centerline
H.O. HC-01A - 276/288 - 222/232 - .465/.492 - .512/.542 - 114 - 109

I'm also running Rhodes anit-pump up lifters if that makes any difference.

I had another thread in the 69 Tech area about changing the cam in the car and it evolved into replacing the studs and locks and then fizzled out.

http://forums.maxperformanceinc.com/...d.php?t=613707

I sure do appreciate your help.

Mike

Originally Posted by PunchT37

You don`t have to use any sealer on the studs.
I don`t understand your adjustment comments.
Was the engine running fine before? What rockers are you running? Stock?
You might want to check for binding at the poly lock area or the rocker hitting the stud at the bottom, meaning you would need a long slot rocker.

[madtexan]

I backed the rockers out to what I thought was Zero Lash - 1/4 turn and when I ran it the rockers were very noisy. At Zero Lash adjustment I could hear the Rhodes lifters ticking. Anything tighter than that and the ticking went away. I considered zero lash to where the rocker arm had no verticle play. At this setting the rocker still had plenty of side to side play though.

Originally Posted by Pontiac signman

No to sealer...............

Sounds like the rockers are out of adj......no question

Unless you've done this before, ask for some help. I'd start all over with the rockers all loose (obv. not running)....do a search on adj. rockers for the best way for you (probaby 4 turns at crank)

In my mind.....you've over adj the rockers and it won't run.

Remember ZERO LASH is SUCH a slight drag on the pushrod and it can be hard feeling that happen w/o over adj. with a hyd. lifter (assumed).

Good luck

[OINK 1]

If you have STOCK non-adjustable lifters, when you took off the rockers the lifters sucked in additional oil and now they are pumped up all the way. This makes the valves stay slightly off the seats, causing the EXACT problem you're talking about. You may call if you
like and I'll give you detailed procedure to fix the problem. Basically what you have to do is
get the oil out of the lifters and them reset the valve lash. Then, if they are stock lifters, NEVER adjust them again , for the life of the motor !!

Call !!, I'ts Saturday, i'll be home all day !
1-303-776-0877
Pontiac Gregg

[PunchT37]

Originally Posted by madtexan

I have stock rocker arms.
How would I check for this binding at the polylock?
How could I tell if the rocker is hitting the stud and would it do this at idle?

You`ll have to do a visual on the poly binding. On the slot problem, you`ll have to remove the rocker and have a look see at the stud facing the valve to see if there is any gouging or line like color change where the slot of the rocker would sit when adjusted.
Also, adjust the rockers to 1/2 turn on the BASE circle of the cam.

[PLAY400]

I have done Rhoads lifts adjustments several times. This method works best for me.

1. Pull all the plugs so I can turn the motor over easy.
2. Back off all the valves as far as I can with the polylocks.
3. Let the set-up rest for awhile so all the lifters will come up all the way. I have found that Rhoads collapse quite rapidly when sitting under valve spring tension.
4. Then I find TDC and follow either, Hand's, Dude's or Classic Pontiac's valve sequence adjustment procedure. About a 1,000,000 different write ups on this.
5. To find zero lash I keep lifting the push rod up and down, NO ROTATING, while turning the polylock assembly down by finger. Once all slop is gone I figure I hit zero lash. If you rotate the pushrod you can bottom out the lifter per Rhoads' instructions.
6. Using a ratchet I set my Rhoads lifters 3/4s turn down to insure I have the 1/8 clearance. Most people go 1/2 turn. Then I lock it down with a wrench and allen key.

Should work for you.

[lust4speed]

Which Rhoads lifters? The original or V-Max? The V-Max require from .010" to .030" of lash adjusted somewhat the same as solid lifters - the adjustment lash is from the collasped lifter plunger bottoming out (no oil). The original are set like stock lifters and are preloaded from the fully extended plunger.

If you have stock rocker arms with the pivot ball, you don't have to worry about any interference with the polylock.

[madtexan]

Well I'm not sure exactly which Rhodes lifters they were but I installed them about 15 yrs ago and have driven the car maybe 1000 - 2000 miles since then.

I have decided to remove the Rhodes lifters because some of them stay pumped up and some are springy after the engine not running for a week. Even if that is OK, it makes it really hard to adjust properly. Ken Crocie of HO Performance who I bought the cam from said they wouldn't have recommended Rhodes with an HC-01 cam. No need to use them since it isn't that radical of a profile anyway so out they go. I've tried to adjust these 4 or 5 times so removing the intake and adjusting the lifters for zero lash and having the lifters visually exposed while I do it will help in assuring i'm not getting them too tight.

I am using the stock rockers with the stock pivot ball.

Thanks guys!

[mels80ga]

If the car ran fine before and all you changed were the rocker studs, thats where I would look. Maybe the stock rockers are binding on the larger studs. With the lash backed off there should be no missing, usually it will idle smoother with some valvetrain noise. An inexpensive way to check would be to put your old studs back in and see if your problem goes away. If it does, you may need to upgrade your rockers.