In the process of reconditioning my distributor. I noticed that there are shims available to take up some play between the lower gear and the cast housing. Wondering how much clearance I should have here. .015 more or less? Thanks.

You didn't mention a year, but according to the 1969 Chassis Service Manual the end play on a V-8 distributor should be .002"-.007".

Tom

one of the dist. rebuilders that had a link to this site talked about .020 on the ones he rebuilds.

For alum housing dist I always set shaft end play at .015-.025. You can go tighter but that's pushing it IMO the aluminum expands when hot. Typically from the factory end play is around .080-.090 (real loose). There should be no shaft side play. If there is the bushings must be replaced.

This is a cast iron distributor, for a 66 BBC, and original distributor. I looked in the service manual, guess I had better look again.

Found it in the 66 service manual, .002-.007. Its at .035 right now, so I guess I had better put a shim in. I am going to go with .014 or so, half way between the rebuilders recommendation and the book. Thanks.

In the event new bushings are needed, who carries them. I know the corvette venders do; but is there a difference between the bushings of the tack drive distributors and the regular chevy distributors?

Von - would an aluminum intake factor much into the clearances?

Von - would an aluminum intake factor much into the clearances?
I don't know. Maybe a thou or two but that's just a guess. I once ran an alum dist with .010 end play and an alum intake with no problem but after hearing some other opinions I think that's pushing it too close. Better to be safe than sorry on this. A GM blueprint of an alum dist in Chevy By The Numbers specifies .025 to .096. So with that much tolerance it's not super critical. But the more end play the greater chance for a slight timing variation.

Von - would an aluminum intake factor much into the clearances?

The intake makes no difference at all. All it could do is move the distributor up and down, cannot affect the length of it.

Found it in the 66 service manual, .002-.007. Its at .035 right now, so I guess I had better put a shim in. I am going to go with .014 or so, half way between the rebuilders recommendation and the book.

If the service manual calls out .002"-.007", why would you set it to .014"? I'm pretty sure GM had good reason to spec their distributor the way they did.

Tom

i set mine around .012 never had a problem MSD set their Pro-Billet distributors around .010.

Mine is at .012 and no probs.

I'm getting ready to send my 5M6 dated cast iron distributor to Jerry MacNeish at Camaro Hi-Performance http://www.z28camaro.com/ check out the restoration services link for distributors.

He states they are set to .020 or less, and are tested to 8000 rpm and come back with a spec certificate after testing. I would say thats good enough for me.


Rocky

The logic here is if it has a bunch, I think .060" to .100" is common for factory crude assembly line stuff as the cam drives the distributer and distributer drives the oil pump the load of the oil pum causes drag and the distributer shaft will try to lag behind. The screw effect thru the bevel gears causes the shaft to raise up against the thurst washer and thats OK?? Well good enough for production stuff but as the shaft moves up the spark retards. WHen you are whatching the timing light and see timing fluctuating this one of the major sorces, another being the cam may work forward & back. THus if it has little end play the timing when the engine has no load on it will be more consistant. Under .010" for a cast iron dist makes good sence and a bit more for aluminum definatly to accomodate growth as Von recomended. Having raced an aluminum block push rod engine and seen valve adjustment move .015" as the engine warms up I can confirm the growth of aluminum parts can be huge