[81Z-28]

i have a set of world product dart S/R heads on my 350,i had problems with the studs backing out,so i had them pinned
well now 100 miles later i snapped off one of the studs.
my question is: How important is drilling the pin in the center,because the stud that broke was drilled off center. Just wondering if that caused the failure

[geezer69]

screw in studs.sounds like your spring pressure is to high for them little press in studs.what rpm yopu runnin it to ?

[81Z-28]

Originally Posted by geezer69

screw in studs.sounds like your spring pressure is to high for them little press in studs.what rpm yopu runnin it to ?

I'm running a edelbrock RPM proformer cam an lifters como set,, and when it happened i was pulling up to a stop light. havent had it past 3000 rpm.. brand new rebuild just broke in the cam an probly have less than 200 miles on the motor

[geezer69]

wow, that shouldnt happen.fresh build,hummm. somethin aint matchin up. you need to check your parts.rods,springs,shims comes to mind.

[ap72]

Just swap to shoulderless screw ins. Its a relatively simple process. Its almost easier than pinning.

[327NUT]

A agree with AP on the screw in studs, much easier and MUCH better than pinning. I also agree with Geezer, something in the parts or geometry of all parts combined is mismatched. Better to have a pro look at it specially after the off center drilling.

[81Z-28]

Originally Posted by geezer69

wow, that shouldn't happen.fresh build,hummm. somethin aint matchin up. you need to check your parts.rods,springs,shims comes to mind.

yeah..all brand new everything from push rods to keepers, had the heads rebuilt,had a butt load of machine work done,not to mention a whole new top end.....just wondering if pinning the stud off center had anything to to with the failure. don't know what to do next...put on a set of aluminum heads an hope????coulda bought a crate motor for what i got into this pile lol

[BOBCRMAN@aol.com]

Off set pin will not cause failure. As a matter of fact. I always off set when I install them. LESS chance of failure.

You have a major geometry problem.. Have the setup checked for correct pushrod length, Coil bind/valve seal/retainer bottoming out. Rockers binding on stud etc.

[cobalt327]

Originally Posted by 81Z-28

i have a set of world product dart S/R heads on my 350,i had problems with the studs backing out,so i had them pinned
well now 100 miles later i snapped off one of the studs.
my question is: How important is drilling the pin in the center,because the stud that broke was drilled off center. Just wondering if that caused the failure

IIRC those heads all have screw in studs, right? If they ARE screw in studs, pinning them is not the way to fix things. Correct torque (maybe w/sealer or loctite, depending) is sufficient unless there are other problems as has been mentioned.

A Crankshaft Coalition wiki page that may have something of use to you is here.