What would cause the cam pin to break. I recently installed a new blower cam, Cloyes dual roller timing, and MSD Opti on my engine less than 200 miles ago. I had a header gasket blow out so at the same time I replaced the gasket and installed larger injectors. The car would not start after the injector swap so I double checked everything, and everything was good. So I decide to take the opti off to check and see if the rotor screws backed out and the cam shaft dowel pin was broken when I took the opti off. Has anybody else had this problem. Its a brand new compcams cam.

 

Were the cam bolts tight?

 

That would be my first question, also.

 

Yes. Brand New ARP Cam Bolts, Torqued to spec.

 

Where did the pin break? Did it break flush with cam gear? Flush with the cam? Different location? Does it look like it's sheared?

 

Looks to be flush with the cam. I have not had a chance to pull the cam out yet

 

never seen that happen before

 

This might be a dumb question but I'll ask it anyway...

Did the pin BREAK or is it just not there anymore (i.e., did it back out of the cam)?

 

Interesting - this guy has a Comp Cams cam that had the dowel pin break too:
https://www.camaroz28.com/forums/sho...d.php?t=677037

 

There is a difference, in the thread above, a machine shop broke it trying to remove it. The OP, in this thread, had it break in the engine.

 

What if the cam gear bolts were slightly too long and bottomed out inside the cam.
When tightened, they'd show the correct torque but wouldn't actually allow the back of the cam gear to fit flush with the cam.

So, if there was a small amount of gear to cam play, could that cause the pin to break?

Jake

West Point ROCKS!

 

Nope the cam bolt holes go all the way to the other side. It broke at the end of the cam face. I was able to remove the old pin by drilling it out. With the cam out i put the gear back on it with the bolts loose and there it can definitely move a little bit. I am checking into installing 2 pins in the cam and gear, leaving the second one flush with the surface of the cam gear. I see several company offer a dual pin service of upgrade.

 

I've never experienced it, but have read of the cam gear bolts loosening, even when Lock-Tite was used. I install the little device before starting the bolts (forgot what it's called) and bend it's tabs over the heads of the cam gear bolts. It's designed to help prevent the bolts from loosening.

Were the cam gear bolts still tight when you began to remove them from the cam gear?

If I come across a post from someone else who has experienced the same thing, I'll post the link here. I hope you do too, because I'll be swapping heads and cam on my son's 96LT1 Vette in a couple of weeks and am using a new CompCams camshaft too.

Thanks,

Jake

West Point ROCKS!

 

Cam bolts where tight, I also used lock-tite on them also. I have seen post on broken cam bolts but not on a chevy engine, It was a ford forum and it was a big-block ford runing 8k rpm.

 

Any other signs of contact? I recently read a post and looked at the photos posted along with it where the timing chain interfered with the water pump drive. I didn't make a note of the Forum it was on, but I'll try to find it and post a link when I do.

I also recall a member on the CF had Cloyes double roller interference problems with his LT1's timing chain cover. He and his Dad had to do a lot of grinding on the cover to get the clearance they needed.

So I'm wondering if the Cloyes T/C set could be contributing to the failure.

I'm just brain-storming this because there has to be a cause somewhere. It would be all too easy to attribute the failure to manufacturer's defect, but I'd first look at all the other possible causes before concluding that. Besides, putting everything back together without finding the cause of the failure may result in you being right back in the same situation.

We could run a survey to confirm, but I don't believe there are very many guys who have had to resort to double pins on their LTx engines to address a pin breaking problem. Wouldn't there be more posts about this pin breakage problem on this and other Forums if breakage was happening? My thinking is there has to be an under-lying cause for the pin to break.

Just my thoughts in trying to help.

Jake

West Point ROCKS!