The Stovebolt Site Forums The Shop Area Engine Shop 250 woes

I'm running a early 70's 250 in my '63 c-20, with 5.13 rearend. Its been running just fine even pulling about 7500 pounds. I recently started pulling a larger gooseneck trailer which I estimate to be about 10,000 to 11,000 pounds fully loaded. This weekend I was cruising down the highway (bare truck, no trailer) and the camshaft timing gear decided to have tooth failure. The only gear I could get locally to replace it was the stock fiber gear. Am I expecting too much of my little 250? Was the cam gear failure a result of my excessive towing? or was it just time for it go? I hate to think of trying to put a small block in it. I'd probably have to fabricate motor mounts, get a bigger radiator, etc..... Any comments or suggestions would be appreciated.

There is no correlation between cam gear failure and engine load. Fiber gears fail.

You can get a replacement aluminum gear from cloyes. Part # 8-1016

Go to page 11 of there catalog.

Instead of going to a V-8, why not scavenge up a 292 somewhere? It will work better pulling heavy loads than the small block V-8, because the low-end torque is better. With the exception of a little motor mount tinkering, it will be an almost drop-in fit. Get a bigger radiator to handle the extra heat load, though!
Jerry

A little update. I had to pull the cam to change the gear. Spent a good amount of time flushing shredded gear fiber out of the block. i adjusted the valves but had a couple that never sounded quite right. Fortunately a friend of a friend had given me an old 250. I took that head to the machine shop and had hardened valve seats and new guides put in. I spent today swapping out the heads. From the looks the valves in the old head, I was due for a valve job. Runs pretty decent now but it has a little bit of "singing" or whining noise from the front end. I assume that is just the new camshaft gear running against the old crank gear. Anyone else had experience with this kinda noise?

Didn't you replace both gears? You should have; it's important! The whining noise is present anytime you use steel gears. At least that has been my experience.
Boo

If you replaced the cam gear with fiber, what you are hearing now will probably go away once the fiber gear gets enough wear to break in. I don't see a need to replace the steel crank gear unless it had some burrs on it. The fiber gears aren't as noisy as aluminum, but the don't last near as long either.

You are putting a big load on the 250, but with 5.13 gears you should be okay as long as you don't try to run too fast. I would keep the rpm under 3,000 on the highway, don't know what that figures to without knowing the tire diameter. A 292 would be nice if you can find one. They're not an easy score around here, the farmers use them for running irrigation pumps.

The fiber gear is all I could get without having to special order it. I'm looking for a 292, but they are kinda hard to find. I found one in a salvage here, but he wants $350, condition unknown. I'm running 265/75/16s on the rear. Hopefully I can get another year or two out of the 250 and in the mean time I will keep looking for a 292 to build.