My machinist claims that part of the problem we have with cam/distributor gears is sloppy clearances for the oil pump shaft. I have some connections that can get custom bronze inserts put into the timing cover. Does this sound like a good idea?
Another potential for improvement is the gear pocket. Alot of covers get worn there, increasing the clearance around the gears. If you could machine the pocket, install some sort of bushing or sleeve, and set (machine) the gear-to-pocket clearance to a tight number.....
I had that done My machinist put a bushing in my cover.He showed me the slop back and forth in the dist gear.This slop will lead to wear on the bottom of either the gear or the flat surface if alluminum.He matched up the shaft and bought a bushing the length that was needed for the cover.Machined it to fit the cover and that was it. I had never read anywhere someone doing this in the Buick community but I could see no reason not to.I must add I have the distributor oiler in my cover.This should lube the bushing also.
I've wondered FOR YEARS why I've never heard of this being done before, or at least tried.o No: How hard could it be really? Anything would be better than a steel gear running inside an aluminum housing! I've felt for years that this was a source of oil pressure loss when hot. Steel gears inside a bronze bushing would run cooler with much less expansion (and loss of pressure) than the alum.:Smarty:
Jeff, I think he is talking about the clearance where the oil pump drive gear shaft goes through the cover. That you can put a bushing in. It probably wears in part due to misalignment of the shaft and distributor in the cover. Or the shaft isn't straight and it wobbles. Once the pocket itself is worn, the timing cover is junk. I often wondered why it wasn't cast out of iron, that would make the expansion differences smaller, and give less of a pressure drop off when hot. It would be heavier, but what are we talking about 5 or 10 lbs?
Yes Larry, I understood that part. But we were also talking about where the gears ride, not just the shaft. If not bronze inserts there, then why not the cast iron?? Since the gears are not supposed to actually touch, why can't there be a bushing machined to press into that cavity??
I guess that part would get the most heat. Not sure you could fit a bushing considering the dissimilar metals and expansion rates. Wouldn't the bushing get loose as the aluminum expanded around it?
I assumed that since aluminum head use bronze guides, o No: I'm sure that inserts would have to have an interference fit, be pressed into the cover, and then machined to final dimension. I don't think would be an issue with it getting loose. Just think of all the covers that could be saved. :eek2:
Thanks for all of the opinions and thoughts. I have an extra cover so I think I will have the bushing put in for the shaft. Will let everyone know how it works out and post pics.
I built a bushing into a front cover about 10 years ago for a worn shaft hole in the housing. This needs to be done correctly or the oil pump will not function, the shaft bore must be aligned with the pump. The oil pump area was not that bad and it saved a cover. A bronze insert in the pump housing would not be cost effective if it was possible. There are ways to repair worn oil pump housings if a new one is not in your budget. Contact Earick racing engines if you want a front cover restored in the oil pump housing.
My bronze distributor gear wore out in about 6000 miles. I'd keep an eye on any bronze parts you install, it's pretty soft. I know we're talking about a bushing, but still... John
