Bronze distributor shaft gear wear
I have a Comp billet solid roller cam in my 340 with approx 50 miles on it, don't have the cam ID but it's definitely a billet cam. The engine was completely rebuilt by an experienced Mopar builder for another mopar guy, I bought it from him with only run time on the break in stand. All is well and I'm overall happy with it.
But, it ran great to start with then has gotten a little rough, thinking it was either timing or carb I started checking and discovered a worn bronze drive gear. I've learned through reading in this site that bronze gear wear is expected, but not this fast. It was really difficult to get the gear and shaft out- I had to use an old distributor shaft and wrench to turn it but finally came out. The pics show the wear on the gear teeth and also some wear on the seating surface that runs on the bushing in the block. I measured and compared to a new gear this old one is a little over .010" shorter and is missing the beveled edge of the new gear. I have to guess that the worn gear was simply riding too low on the cam gear and that's what caused the quick wear. But that's a LOT of wear for the little time on the engine. I note the shaft also shows scars where it was riding in the bushing, either from particles going through the bushing or it's an old shaft. I didn't assemble the engine so I don't know if that is an old shaft or if the wear happened in this new motor.
I've read here that the bronze gear can wear against the bronze bushing and some folks have used thin stainless shim washers between them. I've also tried to find/buy a melonized gear but I guess Crane Cams is no longer in business and everywhere I've checked has nothing in stock. Hughes shows it in their online site but when I called they said they didn't have any and no idea of when they might have more.
My choices are: put in a new shaft with new bronze gear and hope for the best, or try the Melling IS72 manganese phosphate gear and hope for the best. I'm not real happy with bronze particles in my engine but would be even less happy with iron particles. I really don't want to replace the cam if I can help it- all inside the engine is new including the cam.
If anyone can share any thoughts to help me out, I'd really appreciate it.
Thanks,
Ken
I have a Comp billet solid roller cam in my 340 with approx 50 miles on it, don't have the cam ID but it's definitely a billet cam. The engine was completely rebuilt by an experienced Mopar builder for another mopar guy, I bought it from him with only run time on the break in stand. All is well and I'm overall happy with it.
But, it ran great to start with then has gotten a little rough, thinking it was either timing or carb I started checking and discovered a worn bronze drive gear. I've learned through reading in this site that bronze gear wear is expected, but not this fast. It was really difficult to get the gear and shaft out- I had to use an old distributor shaft and wrench to turn it but finally came out. The pics show the wear on the gear teeth and also some wear on the seating surface that runs on the bushing in the block. I measured and compared to a new gear this old one is a little over .010" shorter and is missing the beveled edge of the new gear. I have to guess that the worn gear was simply riding too low on the cam gear and that's what caused the quick wear. But that's a LOT of wear for the little time on the engine. I note the shaft also shows scars where it was riding in the bushing, either from particles going through the bushing or it's an old shaft. I didn't assemble the engine so I don't know if that is an old shaft or if the wear happened in this new motor.
I've read here that the bronze gear can wear against the bronze bushing and some folks have used thin stainless shim washers between them. I've also tried to find/buy a melonized gear but I guess Crane Cams is no longer in business and everywhere I've checked has nothing in stock. Hughes shows it in their online site but when I called they said they didn't have any and no idea of when they might have more.
My choices are: put in a new shaft with new bronze gear and hope for the best, or try the Melling IS72 manganese phosphate gear and hope for the best. I'm not real happy with bronze particles in my engine but would be even less happy with iron particles. I really don't want to replace the cam if I can help it- all inside the engine is new including the cam.
If anyone can share any thoughts to help me out, I'd really appreciate it.
Thanks,
Ken
