VCCA Home Forums GENERAL DISCUSSION New User Forum Cam shaft bearings on Stovebolt 194 cu in

I have a 31 Chevy in mostly excellent condition that has been in my family since brand new. It has a serious engine knock caused by play in the rear crankshaft journal and bearing. There are no bearings other than the machined bore. The difference in the cam journal and bearing bore is .005". The cam gear is chewed up and made of a plastic type material. The crank, rod journals and babbett bearings are in excellent condition. Interestingly, the main bearings are split-half bearings. The crank gear is steel. My question is, what have others done to remedy this issue? I'm taking the block and cam to a machine shop to see about getting it bored and a sleeve bearing inserted. Is this my my best option? Any suggestions are appreciated!

The Filling Station has the fiber timing gear. RW-593

The Cam shaft on the early Chevy engines ran directly in the cast iron block. If the rest of the engine is in good shape I would recommend just having the camshaft spray welded up and ground down to fit your block. Or you could ask around if anyone has a camshaft that might be closer to your block diameter. Generally it might not be a good idea to take an engine that most modern shops have no idea how to work on to a modern machine shop. They of course will tell you otherwise. Like Bare Feet told you those bakelite/frenolic gears are available. Expensive but available. If you find a camshaft with a good gear on it do not take it off. Many times the gear will be destroyed by taking it off. The cam shop I go to here in Vancouver can do all of those repairs and regrind the lobes and followers with the gear on it. Art

Flamespray Northwest (of Seattle WA) can build up a journal. You might have to ask if running on cast iron is OK. It probably is. The result is pretty tough. IIRC the only thing they told me I couldn't do was run needle or roller bearings directly on it.

We found that and they're proud of it! Either way, the cam gear is nuked! Thanks

Thanks for your help. Apparently running the cam journals right on the cast iron block was a common thing. I have it in a machine shop now and will talk to the machinist to find out what he thinks is the best course of action. I'll post it. Thanks

I'm afraid we're too late on the cam gear. It was pretty well chewed up already so I had to take it off. They are available for about $150 for the fiber gear. It's entirely possible that in my tunnel vision the cam is not the issue. The machinist I took it was skeptical that a cam could cause that kind of knock. I'm going home to use a dial bore gauge on the #5 cylinder (and all the others for that matter). There may simply be a piston slapping the cylinder walls. We got the car running on Christmas day after it had sat for about 14 years. It ran rough and after pulling the valve cover off to check the valve lash I found the #5 valve lash backed way off. The valves had been disabled from opening and closing. When I adjusted it to specs it caused the knock. I suspected rod bearings and when it wasn't the rod bearings it was suggested to check the cam play. It seems a bit excessive but still may not be the complete problem. I never checked for cylinder out-of-round, but will now. i can't help but think it's something simple and obvious. Thanks for your help - I'll post what I find.

I am curious as to what Flamespray might want to build up a journal? I had my 29 camshaft reground to add .060 lift. I think it should breath a lot better. Art

I don't know, it just occurred to me that it was probably something that they could do. The most recent thing I had done was the front bushing area on the internal driveshaft in my torque tube, about 2 years ago. They sprayed it and machined it for a perfect fit to my new bushing. It was very nice looking work.

It is hard to imagine if a journal on the end of the cam would be in the same neighborhood or not. Spray welding is never cheap, but it wasnt THAT bad. If it would help I could dig for the invoice. I asked them about all sorts of things they might be able to fix, I probably even asked about camshaft journals, as I have a car that might need that someday soon. IIRC the stuff is really tough, and the only limitation I recall is that you cant run bearings directly on it, like needles or rollers. It was a couple of years ago so I am a little foggy on that.

If there was a problem with a lobe (you mentioned extra lift), that is another matter. I have used Delta Cams (Tacoma WA) many times. They can fix just about any cam, not matter how bad it is. Custom grinds too if you want. Prices are reasonable.