Camshaft

[allenj]

Did Model T camshafts ever had a keyway for woodruff key up front where the timer fastens? I have a Stipe 280 Cam that has nothing up there to secure the timer rotor etc - nothing at all. ?????

[TXGOAT2]

I believe that a small hole and a pin with a retainer is used to locate the timer rotor. A new stipe cam might lack the hole to permit the user to index the timer rotor relative to the camshaft to suit desired operating parameters.

[Scott_Conger]

Allen

are you saying that there is absolutely no hole drilled 1/2 way through the cam per this circled feature below?

timer pin hole on camshaft.png (286.47 KiB) Viewed 3308 times

[Mark Gregush]

I believe that a small hole and a pin with a retainer is used to locate the timer rotor. A new stipe cam might lack the hole to permit the user to index the timer rotor relative to the camshaft to suit desired operating parameters.

If the hole is missing, I would contact the supplier directly. I would be guessing; it would have been special order, as only a few would be setting up as suggested above, or it just got missed.

[greenacres36]

Case hardened in that area? I doubt it but that would be a little aggravating.

[Steve Hughes]

If I received a cam without the timer hole drilled, I would consider it defective and would be contacting the supplier for a replacement.

[Craig Leach]

Hi Allen,
The cam has no hole or does it have a keyway?

delco2.jpg (22.59 KiB) Viewed 3229 times

this distributor cam gear is broached for a key instead of a pin?
Craig.

[Mark Gregush]

The pin could have a thicker head to fit in the broached area. Bosch, for one, is like that. They did not use a key either. The clamping force of the nut was enough to hold the cam shaft gear in place, putting the pin back in the hole was a back-up. Some setups, the cam gear was screwed on using the existing thread on the shaft.

[Craig Leach]

as best as I can recall the cam was set up for a keyway also. Can't remember if it was straight or woodruff.
Craig.

[Dan McEachern]

Ford cams never had a keyway in them. The hole was in all factory cams to locate the timer brush. Atwater Kent Clip on distributor drive gears have no provision for a key or the pin and rely on the timer brush nut to prevent the gear from turning. One version of Atwater Kent front plate used the pin hole and pin to locate the drive gear while another version used nothing. The Bosch clip on distrubutor drive gears have a keyway that the pin fits in to locate the gear, but again, the timer brush nut provides enough load to keep the gear from spinning. You cam should at least have the hole.

[allenj]

Thanks guys for all of the information. It was really helpful. I am using a Bosch magneto set up introduced in 1914 that has a large gear that fits where the timer was, an idler gear, and the third gear drives the magneto which sits where a generator would be on later cars. The gear that fits on the camshaft is broached for a key. On further inspection, there is a pin in the camshaft, half-way in as you suggest, sheared off. The gear on the camshaft therefore has at present nothing to prevent it from rotating on the shaft which would of course affect the timing etc. I do not want to remove the camshaft to broach for a keyway. Can the camshaft front nut really be tightened enough to prevent the gear from slipping on the shaft? When I check it when the motor is cranked clockwise the gear seems to check securely on the camshaft, but will "spin" without engaging on the camshaft when turning the gear in the opposite direction via the mag gear/idler gear?!!?!?! What are your suggestions for securing the large gear to the camshaft? It does not have a lot of pressure/torque applied to it since it only has to run the idler gear and mag drive gear which offer little resistance, but the pin that presumably fits halfway through the camshaft appears to have protruded into the broached keyway on the driven gear and got sheared off. Any and all help/advice/suggestions will be gratefully and heartily appreciated.

Thanks and Happy Holidays. BTW, I'd like to get it back together to run on Christmas Day!!! But I do have patience.

Allen Johnson

[Norman Kling]

Every cam I have seen has the hole for the pin. I have a stipe cam in one of the cars and it has the hole. The other two have the cams which were in them when I bought the car or the engine in it, and other cars on which I have helped people work on have the hole. It could be that some cams have been drilled in a slightly different place and that is why the timers need to be set by finding the timing of the spark relative to the piston position. On most of the timers available now the gauge from the bolt to the timer tab is not exactly right. But anyway, I think you should return the cam. Any reputable supplier should give you a refund or exchange for a cam with the hole drilled.
Norm

[Craig Leach]

Hi Allen,
I think I understand your dilemma. You said you found the sheared off pin? Can you drill it out? When using a Model T Ranch distributor it is neccassary
to drill & tap the cam to secure the point cam with a set screw. By doing this you could make a screw with a square head that fits the keyway in the gear to drive it and srcure the gear with the nut. If the gear was driven by the pin before a screw should be much stronger. If you are worried about going back to a timer drill the hole all the way through and tap the other side for the Mag.
Craig.

[Scott_Conger]

I would either very carefully measure the dimension from the seating face for the roller/flapper, to the sheared off pin, or better yet contact STIPE and say "pretty please" and get the mfg value. Follow up with a precision sleeve with cross-hole for a drill guide and peck it out. You may not THINK there is much torque there with the gear, but I'm betting that's all that was indicating the gear in the first place and there is in fact a good deal of torque transmitted.

Better yet and if it was my car, I'd remove the cam and put in a proper woodruff seat after the pin was out, using the pin hole as my groove datum.

[Jerry VanOoteghem]

You may not THINK there is much torque there with the gear, but I'm betting that's all that was indicating the gear in the first place and there is in fact a good deal of torque transmitted.

Agreed. Think of the mag turning at speed, with the pulses in its rotation hammering away at the drive pin.

Better yet and if it was my car, I'd remove the cam and put in a proper woodruff seat after the pin was out, using the pin hole as my groove datum.

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