Ok, I think have an idea why my car won't run right.

[Mart]

I tried to drive my roadster today with my rebuilt engine, and guess what? Yes, I came home on the end of a rope.

Earlier investigations revealed this problem.

http://www.fordbarn.com/forum/showthread.php?t=136196

Anyway, what I didn't mention at the time is that the main bush on the distributor was damaged. I thought at the time it was just lack of lube, due to having to run at a fast idle straight away.

I built up a new distributor, and fitted that.

I just removed it and the bush is damaged like the first one.

I took a distributor body, bolted it on and tried to insert a shaft through the body into the end of the cam.

It won't go in! I can see why. The slot on the end of the cam is not machined at the correct offset!

I am really annoyed about this. If you knew what that cam cost me, you wouldn't believe it.

So, here is the question. Is this a common problem? Is there a bunch of bad cam blanks out there?

I believe this cam is ground on a new blank.

I won't say the name of the cam grinder until they have had a chance to make good.

But here's the thing - if the grinder sends me a new cam at their expense. (I think that may be unlikely with me not being on the doorstep) , if they did, I would need a new set of lifters as these are now no longer new as they have been run on this cam, and I now have two damaged crab distributors.

But the big thing is I will have to pull the motor and tear it down to fit the new cam.

If I go the other route, and make it work (more like I am used to) I could modify the tangs on the distributor shaft to match the offset. Problem then is that distributor would only be able to be used on this car. I couldn't carry a spare or swap parts from car to car like I do now.

Boy am I annoyed about this.

Mart.

[BUBBAS IGNITION]

Mart ,

Would love to see a couple pictures etc...
I get a crab every now and then with a eat up bushing and also get one from time to time that has been put in at the wrong offset etc.......

Send me your cores and i will fix ya up a couple good ones ....

[Russ Gaylord Fontana]

Mart, my heart goes out to you!!! Mike

[alan]

post a few pictures--cam offset slot, end of dizzy showing offset tang would help us to figure out what went wrong and to offer some help

[Ross F-1]

If it's a billet cam, I'm sure you could weld up the slot and re-machine it in the correct place. Still a buttload of work, but no lifter issues. Is the slot too far from center or too close? How far off is it?

[Bruce in southern OH]

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Bad deal, hope it works out on parts replacement, disassemble and time to re-install is problem, not close enough to come over and help!!!!

[alchemy]

There's a thread on the HAMB somewhere discussing issues with some recent cams from a long-time manufacturer with a name that rhymes with Risky. Is that who made your cam?

http://www.jalopyjournal.com/forum/s...cams&showall=1

[flatjack9]

With such little time on your engine, I would have no problem reusing those lifters on the new cam. Good luck and I hope they stand behind their cam.

[scooder]

Sorry to hear you'm having issues with the cam Mart, hopefully the cam company should monkey up for your agro (there a fairly big company, I'm sure they wouldn't want the bad press) I'm with Flatjack, the lifters should be fine with such little time on them. I'd still give 'um a good Look over when there tugged out to be sure, no odd looking patern on the base and they "rock" on a straight edge. Should be good to go. But I think the cam company should sort you out new lifters with the new cam, it is after all the "proper way to fit a new cam" I also think they should sort you a rebuilt dizzy. And get a new quality control dude.
Fingers crossed you get it sorted quickly.
Martin.

[Mart]

As I like to make stuff work I decided to see what it would take to modify the drive tangs of a distributor to work with the cam as it is.

I held the camera at the back of the rad and got a shot of the end of the cam. The distributor body is just an old core unit, not one that I had been trying to run with.



Even looking at the pic it is hard to see that there is an offset at all on the slot. You can just make out that there is slightly more of the countersink on one side.

Here is a shot of a stock unmodified but used shaft. The offset is clearly visible, and the tangs are more or less parallel both sides.



I started filing as carefully as I could, and I was surprised that after only a short while I had taken enough off for it to slot into place.


I then realised I had taken more off one side than the other. I studied what would be going on when It was being driven and realised I could use the angled filing to my advantage, but this one was filed the wrong way.

I took a second shaft (actually the one out of the first failed dizzy) and redid the filing job, this time intentionally favouring one side. I then rebuilt up another distributor and put all the best parts in it.



If you envisage the cam driving the shaft, in this view it is turning clockwise. the left side (in the pic) will be driven on the filed back side of the tang. The right side will be driven by the untouched upper side of the right hand tang.

That's my theory anyway. If I had filed it parallel, it would have only been driven on one side. The other side wouldn't have been touching.

The upshot is, though, that the angled filing throws the timing off. Luckily I invested in a pukka timing jig and reset the points and the static timing.



Here you can see that to get the timing heads up with the reduced tang width I had to rotate the points plate quite a bit from central.

Anyway, it fired up ok and I did manage to take it for a run around the block and arrived back safe and sound.

Not a great way of fixing it, but it does work and for now at least, I can manage this work-around.

Mart.

[Ross F-1]

Sure beats the alternative! What's the word from the cam mfr?

[Mart]

They're not in until Monday, I havn't written to them yet.

Mart.

[Mart]

I measured an Isky cam I recently removed and an older stock cam and as far as I can measure, the offset is .030". Measuring from the side of the slot to od of the flange gives a measurement .060" bigger than the same measurement on the other side. This means the centre of the slot is .030 offset from the centre of the cam. When viewed end on the offset is much more clearly visible than in the pic above. I can't measure the one with the problem as it is still in the engine.

Can anyone confirm this? Is it written down somewhere?

I have written to the cam grinder, I am awaiting their reply.

Mart.

[BillM]

This was posted by Bruce Lancaster:

The Ford of Canada 1946 shop manual contains a lot of wartime info as well as current, and they give full dimensions for fabricating a short-cam to long-cam adaptor because the Canadian military in WWII had both pre and post 1942 equipment in service.
Drive tab dimensions given: .177-.178 thick, length .21
Slot dimension: .187-.188 thick, .210-.215 deep



Offset in the Canadian drawing is expressed as .031-.032 difference between centerline of slot and centerline of the overall piece.

[Mart]

Thanks BillM, that could be useful.

Mart.

[scooder]

Mart, I got one of those adaptors pictured above. Brand new old stock never been on a man's back. Old as in military stock. So should be spot bolok, you're welcome to borry it to use as a go nogo type thing. Might help pinpoint the out of kilter situation you have yourself.
Just shout and I'll stick in the post.
Martin.

[Bruce Lancaster]

Somebody forward that pic to Risky Cams!

[alchemy]

How about you build one of those extension buttons with an (almost) straight tang on one side and the offset (like it's supposed to be) groove in the other. Then build a spacer the same thickness for your distributor, kinda like the ones guys use to adapt a two-holer to a three-holer front cover.

This way you can use a good, non-modified distributor.

[Bruce Lancaster]

That's an excellent idea there...I don't like reliability related parts becoming non-interchangeable!

[Mart]

Originally Posted by alchemy

How about you build one of those extension buttons with an (almost) straight tang on one side and the offset (like it's supposed to be) groove in the other. Then build a spacer the same thickness for your distributor, kinda like the ones guys use to adapt a two-holer to a three-holer front cover.

This way you can use a good, non-modified distributor.

Originally Posted by Bruce Lancaster

That's an excellent idea there...I don't like reliability related parts becoming non-interchangeable!

Yeah, I know - I did think of that as soon as I saw it.

Hmmmmmmm.

Thanks for the deep thoughts guys.

Mart.