Distributor gear size?

[RenegadePete379]

Re: Distributor gear size?

but if its a tighter fit up top wouldnt the .491 gear have play when installed on the .427 part of the shaft unless the inside part of the gear is tapered some way?

 

[sytyguy]

Re: Distributor gear size?

Cool, thanks for all the info guys. Now I don't have to drive out 4 roll pins when I get home.

 

[RenegadePete379]

Re: Distributor gear size?

well i couldnt resist i just drove out the pin on my distributor and the measurement on it on the top portion is .427 so whats the deal now with what composite gear to use on the stock distributor?

its .491 on the bottom of the gear where it goes to the oil pump and .427 on the top so what is the options for composite.

 

[Quickstop [UK]]

Re: Distributor gear size?

I just looked thru my collection of stock distributors and found this extremely interesting.The shaft dia. of the dis. is .427 however the gear is both .427 on top(at the gear),but .491 at the oil pump shaft.When I got my composite gear I got a .491 and it fit perfectly.I checked 4 different dis.that I know came stock and they were all the same.Hope this clears up this question.

What brand did you get for the .491? The OP says his didn't work.. I believe you, I just want to understand why his didn't work!

This is anecdotal, but I ran into this with big blocks in a boat a few years ago. I changed a flat-tappet MK IV engine to a MK VI with a roller cam, and knew I had to change the distributor gear. I ordered a distributor gear from Mercury Marine, but the hole was too small.

I feel the smaller size dist shaft is used with hardened gears used with roller cams. This way the hard and 'soft' gears can't be inadvertently interchanged. The 4.3 received fuel injection, ECM-controlled distributor, and roller cam in 1987. Makes sense that the distributors we find are small diameter.

The lower diameter remains the same for the oil pump drive, as that dimension never changed during the life of the SBC.

DaveP

Sorry if I am misunderstanding but if ours is the smaller shaft, that means it's harder gears so how come our gears are getting eaten?

well i couldnt resist i just drove out the pin on my distributor and the measurement on it on the top portion is .427 so whats the deal now with what composite gear to use on the stock distributor?

its .491 on the bottom of the gear where it goes to the oil pump and .427 on the top so what is the options for composite.

Seems like you need to get lucky with the dist gear, get a new dist that fits the composite or get a cheap bronze dist gear.

 

[JSM]

Re: Distributor gear size?

well i couldnt resist i just drove out the pin on my distributor and the measurement on it on the top portion is .427 so whats the deal now with what composite gear to use on the stock distributor?

its .491 on the bottom of the gear where it goes to the oil pump and .427 on the top so what is the options for composite.

I guess my response earlier didn't clue in on the fact I knew this would be discovered.

Not to say aftermarket or replacement shafts were different.

Something I noticed yesterday, you can buy stainless tubing with a .500 OD and .430 ID, could be an easy spacer for someone if they had to.

 

[RenegadePete379]

Re: Distributor gear size?

hows the chromoly type drive gear in comparison to the composite or bronze unit will it work with the material that the comp 422 cam is made out of?

 

[bezerk]

Re: Distributor gear size?

I guess my response earlier didn't clue in on the fact I knew this would be discovered.

Not to say aftermarket or replacement shafts were different.

Something I noticed yesterday, you can buy stainless tubing with a .500 OD and .430 ID, could be an easy spacer for someone if they had to.

i just ordered 3 gears 1 for mark and 2 for me, i offered to make those spacers for mark, but if you can get your hands on that stainless steal? would you be kind enough to sent me some? ofcourse i pay you big time.

Thanks

 

[JSM]

Re: Distributor gear size?

www.speedymetals.com is where I was looking. I haven't ordered any yet, if I was to make one for myself I have solid stainless I would just machine up but that would only be good for 1 time, not a production run of them.

 

[RenegadePete379]

Re: Distributor gear size?

just boughtthis baby comes with a chromoly gear is why i asked plus you can beat the price for what your getting.

http://cgi.ebay.com/ebaymotors/CHEV...156759QQ_trksidZp5197Q2em7QQitemZ330401705003

 

[RenegadePete379]

Re: Distributor gear size?

is chromoly material any good for these dist gears to be made out of?

 

[SYCLONE#1531]

Re: Distributor gear size?

I purchased this same distributor from them. Worked great and dropped in with no issues!!!

 

[TYRODD]

Re: Distributor gear size?

How does that Dizzy compare to the MSD? Other than the attractive price tag?

 

[Quickstop [UK]]

Re: Distributor gear size?

I purchased this same distributor from them. Worked great and dropped in with no issues!!!

When did you get it?

Has the distributor been out? If the metal is TOO hard then presumably it's eating your cam teeth....

This is an incredible issue after 20 years - every day is a school day!

 

[RenegadePete379]

Re: Distributor gear size?

well thats what i was asking is CHRMOLY har then composite?

 

[Syclone#2960]

Re: Distributor gear size?

The part number I used on my stock distributor is Crower 76002 brass .427".

 

[dead2me]

Re: Distributor gear size?

Other than some of the later model items such as our trucks, as a general rule, All chevy distributors, SBC, BBC, whether HEI or otherwise, if they are original, i.e. from Chevrolet, came with your car, etc.. have a .491 shaft..

Aftermarket distributors, i.e. Mallory, MSD, Accel, have a .500 shaft...