Rocker arm issues

[Medic]

Looking for some advice/help- I have a 1968 Charger with a Blue Print engines 440 (493) crate engine. The only problem I've had with the motor is the rocker arms. They are Comp Cams 1.5 ratio rollers. Twice the adjusting screws have snapped off. and now I had one lose the lock nut, creating the situation you see pictured. So far, no engine damage, but I don't want to push my luck. Has anybody else had this type of failure? Any recommendations on another brand? It's a restomod, show car, and driver. Never raced, well not officially, and seldom driven hard. Any

input would be appreciated!

 

[69L48Z27]

The one that backed would probably because it wasn’t tight.
Do you have a picture of what ‘snapped off’ looks like?
Also, what’s the lifter type - solid or hydraulic? If hydraulic, how far past zero are you lashing them?

 

[Medic]

The one that backed would probably because it wasn’t tight.
Do you have a picture of what ‘snapped off’ looks like?
Also, what’s the lifter type - solid or hydraulic? If hydraulic, how far past zero are you lashing them?

The first time I had a problem, the adjustment bolts snapped off flush with the rocker arm. I found them both with the lock nuts still on them. I had not touched them until I heard a "tick" and pulled a valve cover to investigate. This time the lock nut backed off, allowing the bolt to back off until the push rod jumped out. It's a hydraulic lifter Comp Cams set up. The lash was set to 1 turn past zero lash I believe. The engine has about 4000 fairly easy miles on it.

 

[Medic]

The first time I had a problem, the adjustment bolts snapped off flush with the rocker arm. I found them both with the lock nuts still on them. I had not touched them until I heard a "tick" and pulled a valve cover to investigate. This time the lock nut backed off, allowing the bolt to back off until the push rod jumped out. It's a hydraulic lifter Comp Cams set up. The lash was set to 1 turn past zero lash I believe. The engine has about 4000 fairly easy miles on it.

 

[33 IMP]

When i broke off an adjuster from the bottom of my crane rockers, it was because of too-short pushrods. There was too much adjuster below the rocker body. .100 longer pushrods solved the problem (along with regrinding the billet roller that was damaged, two new roller lifters, and of course, two new adjusters.)

Edit: just now saw your pics. Never heard of adjusters that broke off the TOP of rocker arms! Hitting the bottom of cast valve covers? The only guess ive got.

 

[Medic]

When i broke off an adjuster from the bottom of my crane rockers, it was because of too-short pushrods. There was too much adjuster below the rocker body. .100 longer pushrods solved the problem (along with regrinding the billet roller that was damaged, two new roller lifters, and of course, two new adjusters.)

Edit: just now saw your pics. Never heard of adjusters that broke off the TOP of rocker arms! Hitting the bottom of cast valve covers? The only guess ive got.

Mine are breaking above the rocker, so not sure if it is the same issue. Thanks for the suggestion.

 

[451Mopar]

I have heard of that problem with the off-brand rocker arms where the bolts were hardened wrong making them brittle.
It was suggested to anneal them (heat to a controlled temperature, and slowely cooled, to remove internal stresses.
I would just replace them all with new adjusters and nuts. Should be able to get them from Comp Cams if that is where the rockers came from.
Not sure how much adjusters would be from Smith Brothers or Manton, but the quality is likely better than Comp Cams.

 

[Medic]

I have heard of that problem with the off-brand rocker arms where the bolts were hardened wrong making them brittle.
It was suggested to anneal them (heat to a controlled temperature, and slowely cooled, to remove internal stresses.
I would just replace them all with new adjusters and nuts. Should be able to get them from Comp Cams if that is where the rockers came from.
Not sure how much adjusters would be from Smith Brothers or Manton, but the quality is likely better than Comp Cams.

This sounds like it could be my problem. In one of the first pics, where the nut is gone but the adjuster bolt remained in the arm, I put a hex wrench in it to loosen it and it snapped off with very little force. I was very surprised it snapped so easy, with just one hand. Thanks for the help.

 

[tonysrt]

When the crate Hemi engines came out back in 2000 we had the same problem with the adjusters breaking off and I believe they were made by comp.. Do not know if yours are that old but it was 1 of the many problems we had with those motors when Cummings was putting them together.

 

[440Coronet500]

Replace all those adjusters, something is wrong with either the material or heat treat. 440'

 

[1 Wild R/T]

Agreed.. New adjusters... Smith Bros, Manton or RAS (Now RAU)... Contact info for all three attached..

Smith Bros. Pushrods

2895 SW 13th St.

Redmond, OR 97756

1-800-367-1533

Fax 541-389-8840




Manton Pushrods
601 Crane St., Bldg C
Lake Elsinore, CA 92530



Direct: 951-245-6565
Toll Free: 1-877-626-8667
Fax: 951-245-6563

Email: [email protected]



CONTACT Rocker Arms Unlimited



16575 Clear Creek Rd. Redding, CA. 96001
Tel: 530-242-1316 ~ Fax: 530-242-1332 ~ Email: [email protected]

 

[RemCharger]

I agree with all the above and will add; they were over torqued.

 

[moparedtn]

If I've learned one thing hanging out here on FBBO all these years, it's not to use anything
from Comp.
My own experience with them was similar, I might add.

 

[1 Wild R/T]

If I've learned one thing hanging out here on FBBO all these years, it's not to use anything
from Comp.
My own experience with them was similar, I might add.

They use to have really good stuff... In the last fifteen or twenty years not so much...

 

[moparedtn]

They use to have really good stuff... In the last fifteen or twenty years not so much...

Exactly so, sahib!

 

[dvw]

I used a similar appearing rocker arm 10 years ago. Same issue, kept snapping the top of the adjusters off. We even machined the top where the nut tighten against the rocker. The theory was the adjuster wasnt square to the rockers lock nut surface. They still broke. New adjusters solved the issue. I'd contact Comp.
Doug

 

[PRHeads]

This isn’t what you’re asking about, but I’ll throw in my .02 about it anyway.

The adjuster in the pic looks to be adjusted totally wrong.

These rockers do not use the “number of threads showing below the rocker” as the determining factor for proper positioning of the adjuster.

There is a section of threads that are missing on the adjuster that line up with an oil feed hole in the body.
The correct positioning of the adjuster screw is...... screw it up into the body as far as it will go, then back it out one turn. That is the correct position.
You can go up or down one full turn from there, but further in is better than further out.

 

[PRHeads]

This is a Comp big block rocker with the adjuster set to the correct “one turn from seated” position:



If you look at where the OP’s adjusters are breaking, it’s where it’s broached for the hex key.
If the adjuster were properly positioned in the body, that area of the adjuster would be above where the stress is being placed.

Buy new adjusters, and the correct length pushrods so the adjusters can be positioned correctly in the body, and the problem should go away.

 

[PRHeads]

I’m curious....... is this a trick of the light....... or is there like a copper colored washer there?

 

[LemonWedge]

Dwayne (PRHeads) is correct here. The design of the stud you’re using leaves very little tru adjustability. The drilled oil galley in the adjuster stud compromises it’s strength. If you’re too far out, that drilled galley gets up to the point where you’re now putting torque with the nut on the portion of the stud that is drilled..... SNAP!
I had this exact same issue with some ProComp knockoffs of this design years ago. I called procomp and surprisingly they were Super. They readily admitted that they had some stud issues, and explained the scenario I describe above. They sent me a complete new set, different design with no oil passage in the stud. They’re not needed, the oil galley is redundant. There should also be a hole in the body that sprays oil on the pushrod / stud joint. The bottom of the pushrod is doused in oil returning from the head. Ran mine with the non-oiling studs for years after that. No issues.