EFI Distributor gear swap question

[hauland]

I have a 351W distributor but need to swap out the steel gear on it for a cast gear due to my 94 351W having a flat tappet cam and requiring a cast gear.

I bought a MSD gear from Summit, but the msd gear has a very short "shoulder" about a 1/4 inch and the gear on the distributor has a tall "shoulder" (about an inch)

Similar "tall shouldered gear" ebaymotors.com item 170268633883

here is the msd gear from summit
http://store.summitracing.com/partdetail.asp?part=MSD-85852&autoview=sku

So if I put on the msd gear there will be a gap between the top of the gear tube (shoulder) to the Thrust collar(?).

Is this gap ok??

Can I reused the old roll pin hole??

Thanks, P.J.

 

[bronko69er]

Im not sure how much thrust is generated by that particular gear cut, so I'd be concerned that the roll pin couldn't handle the extra load. If it were me and wanted a quick fix, Id' cut off a piece of the sholder of the old gear and press it on the shaft as a spacer to take up the gap. Just a thought.

 

[dieselracer]

The gear presses on so that the teeth are on the top. There should be no gap. There is a step on the distributor shaft, when putting the new gear on you just press it slowly until it stops. You can try to line up the original hole, but usually you will have to re-drill the roll pin hole. The new gear only has a hole in one side for this purpose, so you can make a new clean perfectly straight hole.

 

[bronko69er]

The gear presses on so that the teeth are on the top. There should be no gap. There is a step on the distributor shaft, when putting the new gear on you just press it slowly until it stops. You can try to line up the original hole, but usually you will have to re-drill the roll pin hole. The new gear only has a hole in one side for this purpose, so you can make a new clean perfectly straight hole.

I think we are understanding his problem differently...
What I get from it is that in order to line up the roll pin hole on the new gear, he cant press it all the way to the shoulder.

 

[Recko555]

When doing my 5.0 conversion on my bronco, I had to put a cast gear on my distributor. I bought it from Ford. I followed the instructions to a tee and it has been working perfect. From what I remember, the directions said it wouldn't line up with the old hole.
I pressed it on to the desired measurement and then drilled a new hole for the gear and inserted roll pin.

 

[needabronco]

An even easier route would be to go down to autozone pick up a reman. efi dizzy with the cast gear already on it. Should run right at $100, you get the right gear and a rebuilt dizzy to boot (mine also had a new tfi module on it)

 

[hauland]

Thanks for the replies. If the dizzy shaft has a shoulder machined into it then it would seem that extra part or shoulder on the gear wont matter. Just press on the new gear to the point it connects with the machined shoulder in the shaft.

But I wonder if this dizzy doesnt have that and that is why the gear has the extra length of the "shoulder". I guess I wont know untill I get out there and press off the old gear.

The directions for the new gear say that you will probably have to drill a hole. Based on your comments it makes sense now. There is little chance that while pressing it on you will get the old hole to line up.

I may try calling either summit, msd or the dizzy manufacturer to see if they can provide any advice. Maybe I just need to get a different gear.