Hemi Rocker adjustment

1969 426 Hemi. Have a Comp Cam Hydraulic Thumpr roller cam and lifters, using stock rockers, have 40lbs of oil pressure at idle.


Problem is I am getting some lifter tapping across engine. Talked to Comp Cams, need .020 to .040 preload. Turned engine to correct position to adjust each rocker, first they said go to zero lash and half turn.

That helped a bit but still have tapping, then they recommend adjustment zero lash and go one full turn, I tried that and still have some tapping, it was a small improvement.

Now they are saying with this particular cam and lifters I have go to zero lash and then go at least one and a quarter turn.

I'm getting a bit nervous going that much. I myself in the past with other motors (other then Hemi) never had to adjust preload on a hydraulic that far, usually half a turn max.

Are the factory adjusters on a Hemi a finer thread and require that much turning?

Thanks,
Wolf

What procedure are you using for setting the lash?

Exhaust start to open/ adjust intake.
Intake opens and starts to close/ adjust exhaust

Are the adjuster screws 3/8 fine thread? If so that would equate to .0416 per turn. So 1 1/4 turns come out to .0520 preload. They claim most lifters have up to .200 of adjustment for preload. If the Cam and lifter company is suggesting this I guess it is worth a try.

Thank You for that info. I will pop the covers off and find out what the adjuster thread is.
I noticed I didn't do the sequence correctly, I should be doing exhaust closes and intake starts to open on cyl 1 and then adjust both rockers on cyl 6, then do the same on 8 & adj 5, then 4 & adj 7 etc...etc.

I'm going to do this over again with the correct sequence and see what 1 1/4 gives me.

Thank You!

I would adjust them one cylinder at a time just like comp cam suggests. Mopar had a lash setting chart. I used to do it by the chart however they claim cam profiles have changed and you need to be sure you are setting the lash on the base circle of the cam. This should be your lifters and instructions.Adjustment

Ok, I will stay with the Comp instructions and do one cylinder at a time like I have been. Finding the thread pitch on the adjusters is first thing tomorrow.

Good stuff...thx!

Could be a bad lifter right out of the box.

I was just going to suggest that. He needs to re-lash all of them and run it. If it keeps making noise again re-lash and write down which ones changed. If this keeps happening on the same one or more there could be a cam and lifter failure.

Its crossed my mind. The motor was built and ran on a dyno, the shop says they didn't hear any lifter tapping. The motor then sat for a year in the shop, I turned it over by hand a couple of times a month.

I got to identify adjuster threads so I at least know how much preload is one turn. In the end if it takes me to 1 1/4 turn and I still have problems, I will go for a new set of lifters.

Thx..

You need to stay on the same cylinder and adjust the valves on that cylinder and move on to the next. Do not observe the valve closings/openings on one cylinder and adjust a different cylinder.

I had similar issues with mine , turned out four adjusters were tapping the baffles in my stock covers. Not sure what covers you have but if there stockers look for witness marks on the baffles.Good luck!

Loose baffles (broker spot welds) are another noise maker.

The method I was taught many years ago to has never failed me.

EO/IC rule (Exhaust Opening and Intake Closing). using a remote starter button/ switch to bump the motor around

Set the intake valve when the exhaust valve is beginning to open. This will put the intake lifter at the base circle which is where you want it to be.

Then set the exhaust valve when the intake valve is almost closed.

I have trouble remembering the above, so I wrote it on a piece of cardboard and prop it up for referencing as I adjust each valve

If adjusting hydraulics, loosen the adjuster until there is noticeable play between the rocker and pushrod / valve

While rolling the pushrod between two finger tips, begin slowly tightening the adjuster.

Just as you hit Zero lash you will feel a slight but distinct resistance. You can loosen a 1/4 turn or so and retighten to confirm several times until you get the "hang" of it.

The above resistance will be felt even with empty lifters. You will also note the " free play" is gone.

From that point, depending on adjusters threads per inch determines how far to tighten. Most are 3/8 x 24. So if one divides 1inch by 24 =.0416" per turn. All camshaft Manufacturers' I am aware of recommend. 0.020" to .040" preload.

With the above, I have always used 1/2 turn beyond zero lash.

I also agree with starting at the front of the motor, and do each valve working towards the back. Then repeat the process on the other side

Hemi covers don’t have baffles
I ran mine (440 & 383) at zero lash + 1/4 turn, no tap,

if this is a cam with fast ramps you are prob going to have some noise !

Uhhhh....yeah they do....

That little thing? I don’t even consider that a baffle

Nobody mentioned a sticking lifter. Sometimes they get a little buildup on the plunger causing them to get sticky. Use to put in a can of Rislone oil treatment to clean them up. 99% of the time the ticking went away.

and have re-tacked more than one spot weld on them.

Another thought couple of thoughts?
Are you sure it's a lifter tick and not an exhaust leak ? a small one can sometimes mimic lifter noise
I am not sure how pronounced the noise is but some hemis are known to make a bit more valvetrain noise
keep us posted

Its a roller, I was hoping it would be quiet.


Its a Comp Cam 24 600 11

Intake Valve Lift with Factory Rocker Arm Ratio:
0.536 in.
Advertised Intake Duration:
283

Pulled an adjuster this morning and they are 3/8 fine thread, they're in fact a 3/8 - 24 thread. I will go with a final 1 1/4 turn and see if it helps.
Thx

I use the Mopar chart.

That copy of the old GM chart is useless with todays cams
i use to set them at TDC on the firing stroke, that work well also

That's a bit too much preload IMO
BTW, There's an old saying about valves, It's better to hear them than to smell them

Never went 1 1/4 (or .052 preload) before on other cams, but its what Comp is recommending. I remember reading article some years ago on a build for a 440, they went to .065 before they found the right preload.


I made the adjustment to 1 1/4 and started the car, ran for about 10 seconds and then it just shut down, no spark, the Pertronix took a crap, how nice.., got a new one coming.

I'm having a similar problem with my 440 based 511. The engine builder speced a custom grind Comp cam. I had wanted hydraulic rollers due to less maintenance. Duration @ .050 Intake 243 Exhaust 251, 595 lift on 113 ICL using 1.6 Hughes roller tip rockers. When I started it up, it sounded like solids that were loose. I took the engine back out of the car and took it back to him. He pulled the heads and took them apart and checked everything. He has them adjusted 1-1/2 turns. Nothing wrong. I put the engine back in the car and it was just as noisy as before. I loaded the car onto my buddy's trailer and we drove the 120 miles to his shop. When I started it, he was surprised at how noisy it was. We decided to change to solid roller lifters, as he said that he was sure they would be quieter when properly adjusted. The car is at his place now, but he just had knee surgery. I don't know how long before the car will be ready.
I did find a tech sheet on Comp Cam's web site that stated that the hydraulic rollers tended to be noisy.

I don't know if your issue could be related or not. This came to mind when I read what you have going on.

Interesting, like to hear what fixes it.

I can tell some of the rockers are reasonably quiet, I can hear three or four on each side, some slight tap and some loud, changes with RPM. Comp Cams tells me the Thumpr roller cams in many cases may need a full turn or a little more to get them to mellow out. Of course you find this out after they sell it to ya. I'm close to trying new lifters.

I used one Hydraulic roller lifter cam kit from Comp years ago in a street hemi motor for a local customer, I could not make it quiet no matter what way i set the preload It sounded like a old 30-30 Duntov solid lifter cam that came in the early Corvette motors
The customer ended up saying don't worry about it after driving it.
I heard later that Comp Cams sent back 1500 sets of that brand hydraulic lifters for all motors, not just Mopar BB V8.
Evidently they bought a bunch of defective hydraulic roller lifters
OP, how old are yours?

Lifters were bought in March of 2018, they went in to motor November 2018 and ran on dyno early 2019 with no problems, now have the motor in car here in 2021 and here I am with problems.

Comp is not going to warranty at this stage, so if I have to change them I will have to buy a new set.

what did it sound like on the dyno ?

He said it sounded good, sent me the results and the motor is produced 499 HP on the Dyno. I doubt that would have happened with a set of bad lifters.

The motor was nicely stored and well covered in my shop for the next two years, primed it once a month and turned it by hand couple times a month. He does not see how that would cause a problem.

One thing I do notice is during the preload adjustments, I find that some lifters are feeling pretty solid by pushing on the push rod, they have very little give or none, and yet some surrender easily. I'm suspicious of those.

Is this normal to find after shut down? Should they all hold their pressure?

They should hold the oil (pressure) and if not I would say they are dirty or bad lifters due to excess clearances and are bleeding down. call Barton and buy a set from him
only other reason I could think of is excessive spring pressure
It seems as though Comp's once trusted quality has been slipping for quite a while IMO

Ok, I didn't think they should bleed down, thanks for confirming.

I will call and see what Barton has.
Thx!

I called Ray Barton, very nice man, his first bit of good information is to never go hydraulic with a Hemi, he's had nothing but major trouble and will never use them again, says the valve train is too heavy and it will lead to many problems, including bleed down when engine is shut down depending on the position of the lifters. He was not surprised I can't get them to stop rattling, and told to stop adjusting further, I'm just asking for big trouble. The hydraulic that came from the factory used special lifters that could handle the pressures but are no longer available. We discussed going to solid, I have to first contact Comp and see if the cam I have can switch to solid lifters, I will also have to change to a different length push rod.

Thank you TJP for telling me to contact him, it has likely saved me from a bigger problem!

Update: I called Comp and yes with this roller cam I can switch to solid lifters, what a relief! I am waiting for Ray Barton to call me back with a lifter and push rod solution.

glad to hear a [relatively] easy fix is available for you !
lately, it seems anything i have to fix stirs up huge complications.........

You're more than welcome and glad you made the call. I'm a 67 YO engineer that has been restoring and repairing customers classic cars for the last 25 or so years. I changed my first clutch in my brothers car (47 Ford closed driveline) at 13 years old in a gravel parking lot using a large piece of cardboard to lay on and have been at it ever since. So many times it appears the advice WE, (myself and other old farts) give falls on deaf ears.
Might also want to ask him for a cam recommendation
Good luck and keep up posted

In 1977 I was 17 and my first car was a GTX 440-6. Had only a pair of pliers and zero knowledge how to keep it running, but I got by somehow. I screwed up more then I fixed in those early days.

I am waiting to hear from the engine builder regarding me switching to a solid lift before I go do it. Comp Cams said yes the roller cam I have can be switched to solid lifters,... but its on me.

So like when I was 17 years old, here I am again at 62 trying not to screw it up more!

Pertronix I...?

I think its a I, same as this one.

https://www.ebay.com/itm/192937172529

Nice that they bail on the issue, As i mentioned earlier they used to be rock solid (no pun intended) but appear to have become quite lax on their QC over the last 5 or so years. With the new ownership I'm sure it'll improve though
Just wondering did they offer suggested lash settings ??

First guy was good. Second I called to discuss lifters on their page, he confirmed correct lifter, said it could be done with my Comp cam, but it’s on me.

I’m well aware.

I said I’m going to need different length push rods.

He agreed.....

end of call.

No hurry, I need more info anyway. Like who else can I buy from.

The early Pertronix I system have no safe guard to protect the HallCell from burning up if the ignition is in the run mode and the engine is not running, that's when they usually crap out, if you have to diagnose the engine for over 20-30 seconds without it running, but the key/ignition is in the run mode, disconnect the red Pertronix HallCell lead from the positive (+) side of the coil to prevent HallCell damage.... I assume your running the Pertronix I because you converted a Prestolite HEMI dual point?


MikeG

Yep, dual point Prestolite. I have heard about burning up if ignition left on and not running. Which I have tried to avoid.

To get above the min 8V minimum I convert the ballast resistor, dig out the resistor coil and solder jumper straight across, keeps the factory look, also easy to unplug cutting off voltage to coil when needed for ignition on troubleshooting. Looked at everything, not sure why it went bad, have 10.5v to module. Never had one go bad before and this one was early life.

I have a large stack of old Car Craft magazines from the mid 60's to the 70's. Browsing last night I happened to find an article from March of 1967 with Dick Landy explaining how he adjusts Hemi solid rockers, apparently he preferred a two step process.

I haven't adjusted rockers with the motor running in over 35 years. Granted I'm not Mr Landy but my cars have always performed well on the track and street. Wonder if a bit of that may have been a little BS to helps his competitors see his taillights ?

Talked to Ray Barton again this morning.

I am sending him a hydraulic lifter, one intake and exhaust pushrod for measurements and he will provide me with a solid lifter and pushrod parts solution. He also stated in this situation a valve lash between .006 and .010 is good, do it first cold and then do it again hot.

Were those his hot or cold settings?
If hot, I would add .002 - 3 when adjusting them cold using the EOIC method. Heat the motor up, do one side again using the EOIC. Reheat and do the other.

Been a while but yes I thought lash hot was different then cold. I asked if .006 to .010 is the correct lash, he replied yes for this situation. He said to set them cold, then go hot and set lash again. He didn't mention going more lash when hot or using EOIC method, but I imagine he presumed EOIC is how I plan to do it cold and hot.

I will be talking to him again when parts ready and will confirm his lash instructions.

Running parts up to UPS today.