[Guest]

Hi
I don't have much experience with Mopar engines so my questions might seem trivial.

Got a problem with my rockers last week. The adjusting nut broke off just at the point where the lock nut is on one rocker. Its a crane rocker (69-1.5 0.5 %) What can the reason be for this. What is the correct torque and gap clearance

The engine is a 340. I've been trying to identify the head to see if it a "correct" type the
Numbers I found were
1961
3 8 1 B,
AAWJ 360
Can I indetify the part with these?

[dave-r]

I will assume the rockers you are talking about are the gold roller tip rockers Crane sells that use a pushrod with a cup on the end?

Crane (and one or two others) had a problem a couple of years ago with their rocker adjusters where they would break like this. If there is no obvious reason for the breakage 'phone Crane and ask for replacements. They should send you some free of charge.

However I have also seen this on an engine where the pushrods were too long. If the pushrod is too long the adjuster does not come through the rocker enough and the cup end of the pushrod will contact the bottom of the rocker at full lift. For reasons I don't fully understand this breaks the top off the adjuster as you describe.

If the pushrods are the correct length you will have just one or two threads showing on the underside of the rocker. No threads showing and you could have problems such as you describe.

For correct adjustment and setting pre-load see;
http://www.cranecams.com/?show=techarti ... abe4c7e252

For a correct id on your block try this link;
http://www.yearone.com/updatedsinglepag ... einfo1.asp

Foe the heads take off a valve cover and look for a number cast on top of one port runner. Tell us that number and we can look it up.

[Guest]

Thanks for your answer

The numbers and letters on one headers runners are:
1961
3 8 1 B,
AAWJ 360

Ive got mechanical cams and actually I'm trying to get the correct values for the inlet and axaust valve settings but don't have them yet. Any Suggestions??

The pushrod seems to be correct length according to the picture you gave.

The Engine seems to be running quite well as I ran 14.08 s @ 102 mph with a reaction time of 1.25 and using General M+S tyres

[dave-r]

The numbers you have there look like the engine block numbers from the front of the block under the drivers side head to me? If they are it looks like a 360 engine.

I also do not know what you mean by a "headers runner"?

You need the seven digit number from the top of one intake port runner as in this (very poor) photograph.

[dave-r]

Oh and the Crane website will have the lash settings for your solid lifters.

[Guest]

Port Runner is what I meant

I didnt have the time now to look at the engine number but last year I checked it and remember it was a 340 made in 71. Ill have to check that again. Isn't the same casting used in 340 and 360 heads ?

[dave-r]

I didnt have the time now to look at the engine number but last year I checked it and remember it was a 340 made in 71. Ill have to check that again.

Look for a single seven digit number cast onto the runner.

Isn't the same casting used in 340 and 360 heads ?

Yes. They were the same from 72-78 and have 1.88-inch intake valves and 1.60 exhaust valves with bigger diameter exhaust port runners than earlier heads.

The 1968-71 340 only heads had a 2.02-inch intake valve.

[Follicly Challenged]

Incorrect pitch depth on the adjuster thread is the cause of this failure that was a common problem for awhile on the Crane gold rockers. The newer replacement adjusters actually thread in a little tighter.

What was happening, was you'll probably notice the old adjuster threads in somewhat "loose" in the rocker, when the nut was tightened, it was really only holding against the first 1-2 threads below the nut, (rest of threads too loose), leaving the rest of the adjuster and ball in the pushrod to act as a lever against the fulcrum(holding portion by the nut). Just add some run time for some work hardening and PRESTO the adjuster breaks off "at" or just below the nut.
Lotsa guys were scratch'in their melons about that one for awhile. Many thought their rockers were bang'in their valve covers, knock'in their nuts off.

If the threads are loose in the rockers, no choice but to start drill'in and coil'in. Not worth the effort, believe me, we used to weld the cranes up, redrill offset and heli-coil back in the late 70's so we could offset the pushrod, and bust out the port wall, putty up, when porting, to straighten the shot at the valve on iron heads, but now I'm rambl'in, forget it and get the new adjusters.

[dave-r]

Very interesting!!

Thanks.