The Stovebolt Site Forums The Shop Area Engine Shop 235 camshaft gear

Going through my 235, replacing gasket and seals. Engine is a pretty fresh rebuild, .030 over, no ridge and plenty of hone marks. Water was left in it and it sat for a number of years. The camshaft has a fiber drive gear which looks fine but is now the time to replace with a metal one? Does someone make a metal one? what is everyone's experience with the fiber drive gear and this motor?

Moderate RPM, low (stock) valve spring pressure, frequent oil changes and it should hold up.
Change any of those and a metal pair is better.

Here is a link to a metal one. Cars came with the fiber gears and trucks came with the metal ones.

https://www.rockauto.com/en/moreinfo.php?pk=8304792&cc=1326091&jsn=438

If you have the engine torn down, it is easy to swap gears. You might mangle the old one getting it off with a gear puller. No problem if you do. If the gear breaks, you can finish the job carefully with a chisel. Just be careful not to hit the cam itself with the chisel.

The metal ones are a very tight press fit. There are different methods to install them. I use a propane torch to get the gear really hot (propane will not melt aluminum, so don't worry), use welding gloves to line it up, then pound it on to the cam with a large hammer and a piece of wood.

I have read about others heating the gear in the oven or on a gas barbecue grill. Some put the cam in the freezer to shrink it.

Be sure to have the cam thrust plate and spacer on the cam before you install the new gear. You'll have to remove the gear and start over if you don't. Don't ask me how I know this!

Matt

Good info/advice above.

Unless you are taking the engine apart, stay with the fiber cam gear.
It was used in cars because it is supposedly quieter.
All truck engines cam with the metal cam gear- it is supposedly longer lasting (stronger).

Don't try this with the cam in the engine, you will end up driving the cam out the back of the block and damaging the lifters while you are at it. Also, don't try and just press the gear on, heat to expand the gear, cold to reduce the cam diameter, then when the temps equalize, the gear has the proper " grip " on the camshaft. A press can open up the gear creating a loose fit.

Joe

Serial # of engine dictates a truck motor. It's not going to be a daily driver but I've also seen the fiber gears fall apart on other engines newer then this one. Thanks for the input, now I just need to decide which way to go

Getting the aluminum gear onto the cam without damaging its bore can be a challenge. I was unable to do it the first time. The second time I had to first freeze the camshaft and then get the oil bath really hot for the gear, then moved on to propane, as Matt stated above. But I have an aftermarket camshaft, so perhaps that was a contributing factor? I have read here of others having similar difficulties, though.

If any aluminum is skimmed off of the inside of the cam gear during installation, then you are doing it wrong and have damaged the gear. Just saying to be very careful, as it's a serious bummer to have to go out and buy yet another gear...as I had to do.