Stumpy Mallory

[bcatcmc]

Is there anyone out there can tell me why a purpose manufactured Mallory 3 bolt Breakerless distributor that basiclly fits no other engine needs a separate cam button ( spacer ) .400” long between the camshaft and the distributor drive dog. As far as I am aware all timing case covers are one thickness and camshaft lengths are constant with cam direct drive mounted distributor.

I was not aware of the shortcoming when I installed it, lining up the shaft with the cam slot ( gee, that went on easy. ) wondering why no spark, finally spotted no rotor going round and round.

My one and only post to the H.A.M.B. last year and I was put straight.

Even Vern Tardels excellent book neglects to mention this spacer when describing the distributor.

Attached photos shows machined spacer required and longer cap screw.

 

[Mart]

I imagine it's made to fit both short and long cams. Bolts right up to a long cam, needs a button for a short cam.

 

[Tim Ayers]

I imagine it's made to fit both short and long cams. Bolts right up to a long cam, needs a button for a short cam.

I would agree. Three bolt distributors used the long snout cam. Two bolt did not. I guess they were making it so it can be used on both types.

 

[Bored&Stroked]

As both these guys noted, there were TWO types of distributors and associated cam snouts. In your case, you have the flat-faced cam (no little .400 snout) - so the adapter is needed. If Mallory made it WITH the longer drive, then there would be no easy way to use it on the other style of cam (without adding a .400 spacer between the distributor and timing cover).

 

[petehoovie]

Is there anyone out there can tell me why a purpose manufactured Mallory 3 bolt Breakerless distributor that basiclly fits no other engine needs a separate cam button ( spacer ) .400” long between the camshaft and the distributor drive dog. As far as I am aware all timing case covers are one thickness and camshaft lengths are constant with cam direct drive mounted distributor.

I was not aware of the shortcoming when I installed it, lining up the shaft with the cam slot ( gee, that went on easy. ) wondering why no spark, finally spotted no rotor going round and round.

My one and only post to the H.A.M.B. last year and I was put straight.

Even Vern Tardels excellent book neglects to mention this spacer when describing the distributor.

Attached photos shows machined spacer required and longer cap screw.

 

[bcatcmc]

Thanks guys, As i stated in my post I didn`t know of different length cams ,now I do.

 

[Mart]

Hi bcat. When Ford needed to cut down the overall length of the motors, they introduced the crab type distributor. This is a very clever design, and has a very short overall length. One of the things they did to achieve this is to extend the bearing bushing out of the back of the distributor. To accommodate this rearward extension the cam was shortened.
Just thought you might like to know the reason for the two lengths.
That's my take on it anyhow.
Mart.

 

[Bored&Stroked]

My guess is that it was about parts count, cost, maintenance, etc..

They went from a distributor with 4 caps and a pain to setup/install, to a distributor with 1 cap and easily plugged in wires. The crab was easy to install and service as a result - and cheaper to build.

Ole' Henry was a master at shaving costs and making improvements - I'll bet this was a bit of both.

There is my totally unresearched take on it! LOL

 

[bcatcmc]

Fortunately I had a 2 bolt distributor on hand to lift some dimensions for machining the spacer. I was considering refurbishing the unit but as the repair manual devotes 10 pages to that task and includes a service kit that would do a RR Merlin proud. I put it in the too hard basket and looking at the photos I think the kindest thing I could do is bury it in the back garden.

 

[petehoovie]

Fortunately I had a 2 bolt distributor on hand to lift some dimensions for machining the spacer. I was considering refurbishing the unit but as the repair manual devotes 10 pages to that task and includes a service kit that would do a RR Merlin proud. I put it in the too hard basket and looking at the photos I think the kindest thing I could do is bury it in the back garden.