SBC Distributor gear
 

Pulled my distributor yesterday and noticed that the gear is more worn than it should be. Not that many runs on the distributor or the cam which had lots of break-in lube on the gear.
What would cause that?

Re: SBC Distributor gear
 

Could be meshed too tight or loose, how much oil pressure do you have? the higher the pressure the more load on gear
Mike Taylor 3601

Re: SBC Distributor gear
 

std. oil pump. Oil pressure 60 lbs. cold. 30-35 lbs. hot.

Could it be because the block has been decked and the manifold has been cut to match the block? If so, would putting a couple extra distributor gaskets lift the distributor enough to take pressure off the gear?

I wonder if it hurt the cam gear any?

Re: SBC Distributor gear
 

First thing you should be using a Bronze/Brass dist gear this will allow wear but keep the distributor gear on the cam from experiencing excessive wear--Second yes it is probably wearing cuz you tightended it down too tight cuz of all the machining-Third not sure bout the cam gear but probably could be some wear--gaskets will work in a fix but see if you can find some metal shims and put them in til you achieve the correct fit. You dont have to torque that hold down to 100 pounds !!!! just tight enough to not allow it to turn. FED 387

Re: SBC Distributor gear
 

FED, I don't torque it to 100 lbs. but probably do tighten it more than I should. I always felt that the up & down free play in the dist. would cover that and I didn't want to take any chance that it might turn. I guess I overreacted on that and won't tighten it that much in the future. I see that the hold down clamp has some spring to it and I probably negated that.

The new dist. that I am going to use has a melonized gear. I don't know what that means, but assume that it's softer than a steel gear.

Re: SBC Distributor gear
 

Not trying to be a know it here but you can tighten dist clamp as tight as you want and it is'nt gonna be meshed in gear any tighter,well except if you mash gasket out from under it then it will sit the thickness of gasket deeper,only thing excessive tightening of clamp is gonna do is bend clamp.
If needs shimmmed can use extra gasket or 2,can buy shim kits Mr Gasket,Moroso, can also buy slip collar from MSD you remove collar from dist in lathe then replace with new slip collar,I usaully use the slip collars myself
Mike Taylor 3601

Re: SBC Distributor gear
 

most all late billet steel cams especially the roller cams are using the melonizing process on the distributor drive gears on camshafts--- it helps prevent wear on both gears---

Re: SBC Distributor gear
 

I use the Comp Cams composite gears now, on everything. They only wear if you have a problem, and if they do wear, they do no damage. Also, if you have a problem with an oil pump or drive, the gear will sacrifice itself, preventing damage to any other component.

For Stock and Super Stock engines, where there is almost always a fair amount of milling and decking, as well as various gasket thicknesses, I prefer an MSD distributor with an adjustable slip collar, so you can set the correct gear mesh.

Re: SBC Distributor gear
 

You can buy slip collar from MSD and convert any dist. to slip collar
Mike Taylor 3601

Re: SBC Distributor gear
 

Thanks guys,
I've been doing this stuff for 58 years, but being a hobbiest, I realize I'm still just an amateur drag racer.

Re: SBC Distributor gear
 

I was told years ago to take the pipe plugs out of the back of the block, at the cam oil galleries and " center" the distributor to the 2 cast collars on the bottom of the distributor. This will put the gear of the distributor in the middle of the camshaft gear ,so it is centered...Wife's tale or the truth?... Alan. ?

Re: SBC Distributor gear
 

Dang Bobby! You have five years on me. LOL

Re: SBC Distributor gear
 

Jeff,
That method could get in ballpark, but oil galleys,oil groove on dist. are'nt really located that close,to where I would use them that way.
Usaully I will place dist by checking the way the gears mesh together,I want them running where it meshes close to center on dist gear teeth and feel just a little bit of lash between gears.
You can check pattern on gears with grease or gear marking compound if need to
Mike Taylor 3601

Re: SBC Distributor gear
 

Make sure the bushings in the distributor aren't worn which will cause the shaft to wobble around and cause gear wear. We had the same problem with premature wear on the gear. In our case it was the gear itself..

Re: SBC Distributor gear
 

I may be misinformed, but I thought the bronze distributor gears were for roller cams only.

Re: SBC Distributor gear
 

Bronze must be used on billet geared roller cams,but can also be used on cast and ductile iron cores.
Can't use cast or steel gear(regular) on billet though,there are rollers that have gears on them that can have regular gear ran on them,those cams can be identified,if you look @ cam you will see where on rear bearing journal and gear are made separately and then installed on cam.
In the last few years they have came out with a few different gears materials,I have'nt tried any of them,I have just stuck with bronze,have good service with them so have'nt looked else where.
In case some don't know MSD maybe some others also have gears that are available oversizes,that will reduce backlash if needed.
Mike Taylor 3601

Re: SBC Distributor gear
 

the higher the pressure the more load on gearhttp://www.bettecets.com/4.jpg