Broke timing chain



Well here it goes
I had to pull my 200 out and replace the rear seal after my fresh rebuild. I replaced the seal reinstalled the engine, fired it up, let it idle for about 5 mins., and then reved the engine a few times and then (pow) the engine shuts down.
I then turn my lights off and go back to the house to cry.
the next morining I pull the timing cover and find that the cam retainer (I think it is called that) the part that holds the cam inplace broke and went into the timing gear on the crank and broke the chain. Also broke some teeth off the crank gear.
The cam is all the way in the block so what could have caused this to happen?
Will my valves also have damnage?
AzCoupe had a similar failure some time ago. He figures the two cam retaining bolts came loose, jammed in the cam gear, and broke it apart.

The lift on the stock cam is not great and you shoud be ok with the valves, but check to make sure.
Oh yes, I know the feeling. About the same senerio, I had maybe twenty hours on my motor. Make sure to check the bottom end out very closely, I had a nick in one of the rod bearings so replaced them all just to be safe.


BTW If your looking for a dual roller chain, I sell them in my website.
Thanks for your help, my bolts were still tight. Where can I buy a new cam thrust washer. I had installed a new oil pressure gauge (the 1 with the tube for the oil to go thru) and it showed that I did not have any presure at idle and when I reved the engine it only went to 10psi
The engine has all new bearings and new oil pump, what could be the cause for this. Also after 2 trys my rear seal still leaks, looks to be fine on the engine stand, could the crank be causing the leak?
Low oil pressure and a new pump?

Faulty drive on the cam, obstructed pickup screen, poor pump clearances, foreign bodies in pump, blocked oil galleries - all are possible.

Best thing for the rear seal is to coat the running surfaces with assembly lube or oil, and hand turn the crank a few dozen times before startup, to spread the lube fully. A scratch on the running surface can be enough to chew out the seal. Polishing (whole circumference) with paraffin and wet/dry paper (800 through 2000) can smooth things out, but don't leave any residue!

For the retainer to break, it must have been pretty stressed prior. If the distributor or oil pump was stiff, the worm gear would push the cam to the front of the block.

Regards, Adam.
Another possiblity, if the cam bearings were nicked when installing the cam, it may not have been fully seated. Which would crack the retainer when tightning down the bolts.