Distributor gear dilema
 

Ok, here we go. Before I ordered my Summit HEI distributor (SUM-850021) I chatted with Comp about the gear and was told the iron gear was compatible. Now that I know more about my engine (was dropped in my lap by the guy owing me $20k that builds engines & this was trade for some of it) I know that my Comp roller cam is aust ductile iron and that iron gear is NOT compatible. It is long past time to return the distributor and it would be much cheaper to fix this than to order another distributor. Easy enough fix....just order the right gear. Wrong. This wasn't there when I ordered the distributor, but is now part of the description on Summit's site: There is no gear available for this distributor, to use with a factory Ford steel hydraulic roller camshaft. After looking at a ton of gears, they are correct. So here is what I planned to do. Stock gear ID is .491" and I can't find a melonized or composite gear that is .491". I have a buddy that works at a machine shop and he can mill the shaft to match the gear to the Comp .467" gear. Here is my main question since I have very little experience with distributors. Does the gear have to be the same length?? The stock gear (on this distributor) is 1.753" and it appears the Comp gear and others I can find are much shorter. Does it really matter how long it is? It has a stop above the gear with a roll pin, so the shaft can't move up or down. The gear has a roll pin, so it can't move up or down. Is the length of the gear that important as long as the roll pin is in the same place and the gear meshes correctly with the cam? Any thoughts would be greatly appreciated. What a mess....

Honestly at under $150 new I'd just buy the distributor with the right gear and sell the one you have online for $100. If the gear has an issue it does not just throw your ignition off but also takes out your oil pump. No oil pump = very dead engine. More power to you if you want to get creative but I'd play it safe in this one area.

Good luck with whatever direction you choose to take,
-Jason

Thanks for the input! Forgot to add....the cheapest HEI distributor with the right gear is much more than $150. If I can fix it and it's ok to do so, I'd rather do that. :)

I was also going to say to just get another one. How much is one with the proper gear that you'd need?

More than double that. If I have to get a new one, I will, but why not use the other if I can. Hence the post. :)

I have replaced many "correct" distributor gears on aftermarket distributors in small block Fords. Most of them after all of the teeth from them were in the oil pan. Put a factory EEC-IV distributor in it and be done with it. If you need more spark, add an MSD box to it.

I am carbureted so I don't need EEC. I'm sure glad I double checked and didn't throw this thing in there and mess everything up! I'm going to post a pic in a few to illustrate what I'm talking about.

Here's what I'm talking about. On the left is the iron gear off the Summit distributor. On the right is an old stock distributor. See the gap between the gear and the stop (for lack of a better word) above it? If I used a shorter gear (that I CAN find) it would look exactly like this. There is no gap on the Summit because the extra metal above the gear fills it in. My question is...is it really needed? The stock one doesn't. I hope the pic shows up...

that upper part in my opinion would only maybe strengthen the dist shaft from a bending condition which it should not be subjectted to. if there is enough meat there on the dist shaft to machine down then that should work. The key dimension is the distance from the bottom of the gear to the bottom of the dist housing that seats on the engine block. A little up/down clearance is needed when the dist is installed to ensure it is free and not trying to shove the dist shaft up throough the housing when it is clamped down.

Like someone said above... dist gear problems can create oiling problems which can create engine problems...

Considering that the melonized steel is much harder than the iron gear, I wouldn't think it would need the extra strength. (Edited: You said the shaft...not the gear. Gotcha!) Below the gear, the shaft that meets the oil pump is smaller than what the final turned size would be. The bottom is .450" and the rest is .488" or so. I looks like the gear i would use would have an ID of .467", so I would think that would work.