351 Cleveland, breaks distributor gear!

Cat 351 · #1 (**permalink**) 09-08-2003, 09:47 AM

Help,

I have 1 70 351 C, 4 bolt main, 4V,
Competition Cam 280 duration, 530 lift.
Runs fine for a few months, then breaks the pin off the distributor gear.
Am running an aftermarket High Volume oil pump.
Any Ideas?

Help !

Thanks
Jon

Mike Braddock · #2 (**permalink**) 09-08-2003, 10:48 AM

You can install two shear pins in the gear/shaft or run a regular oil pump. More importantly, you need to check that the gear is not bottoming out on the block or on the oil pump drive shaft.

Mike

Woodz428 · #3 (**permalink**) 09-08-2003, 11:20 AM

I have liked high volume pumps in my Fords for many years and have yet sheared a pin. I would look for some other problem, it may be the pump, but I've never had one in 30 years fail. Are the dist. bushings/bearings in good shape, the suggestion on gear bottoming would be a good check also.

DAVID GAGNARD · #4 (**permalink**) 09-08-2003, 11:22 AM

Jon;

You are not the first and probably will not be the last with this problem.... I have heard of a number of people with the same thing... All running high volume oil pumps and fairly heavy weight oil, and mostly happens in cold weather when the oil is thicker and harder for the pump to pump till it warms up and thins out....

Only suolution I know is to use a standard oil pump or lighter weight oil or both....

Going to extra pin or harder pin will put extra pressure on the cam and distibutor gears....

Sorry,this is no real help,but thought I'd let you know what I've seen and heard on other 351-C's,also seen the same thing on 460's....

David

Cat 351 · #5 (**permalink**) 09-08-2003, 11:35 AM

Its really weird.
I ran a stock distributor for several years after building this enging with NO problems for several months.
First time I noticed a problem, my tach was jumping up and down while running a constant speed. I pulled the distributor and found the teeth of the distributor gear as sharp as a razor blade ! I replaced the complete distributor with an Accel distributor, same problem, sharp teeth on gear after SHORT time.
Soooo, I went back to origional OEM distributor for a try. Ran great for a while then sheered the pin on the distributor gear. replaced pin, (checked out oil pump and removed pan to verify no "debri" floating around from pin/gear damage) . Installed new pin, OK for a couple months (2/3 short drives) and POW pin sheered again !

Whats the best way to check to see that the gear is properly alinged with the cam gear? Depth? etc.

Also, could this be a cam problem causing this? Its a competiton cam 280 duration 530 lift, not to radical but healthy.

Thanks guys!

Jon

trularin · #6 (**permalink**) 09-08-2003, 11:52 AM

I went with the suggestions of several people over the years on Cleveland motors and put a billet drive in and a steel pin through the gear.

I have never had a pin shear.

Time to check the oil, pump or drive. Fords twist up drives like a pretzel.

Just more ideas.

Tinker51 · #7 (**permalink**) 09-16-2003, 11:42 AM

A friend had the same problem on a very healthy 289 he had built. Found out the gear was too tall. We machined it (I forget how much we took off) and it has been fine ever since (over two years now). I have had more than one very knowledgable Ford engine builder tell me to let the oil get good and warm before you stand on it.

milner351 · #8 (**permalink**) 09-16-2003, 12:50 PM

a buddy just went through this nightmare in a mustang with a C.
A second custom ground roller cam later, he realized that you have to run the right distributor gear with a roller cam....

I drove tens of thousands of HARD miles on a C powered '70 mach1 with a trw hi volume pump and NEVER had any problems.

First do you have a roller cam which requires a bronze distributor gear? If that's not the case, if you have not already, put in the billet drive shaft, the stock hex shafts are just too fragile for a hi volume pump or a high performance engine.

Check the engagement, is there any end play between the dist and cam gears? Is the cam gear worn out / galled / damaged in someway?
Make sure you are not bottoming the dist gear in the block, shim if you need to, check the block bore face, and the dist gear carefully to see where it may be binding / heating up. Is the wear across the distributor gear teeth even or are they worn more at the top or bottom.... etc.
Good luck!