Cam/oil pump helical gear combination

[gbritnell]

I started cutting my own helical gears for my small engines a number of years ago. 2 gears of the same diametral pitch and 45 degree helix angle produce 2 gears of the same outside diameter. I realized when making gears for my Ford 302 V8 engine that the cam gear and distributor gear are different diameters, like the model A engine that I'm working on,but rotate at the same speed, 1:1. This is accomplished by making the mating gears with different helix angles but the same tooth count. Cam 60 degrees, distributor 30 degrees. As long as the total angle is 90 degrees. I use a spread sheet provided by The Engineers Edge for my calculations. To get close to the required numbers for the model A I'm up to 14-16 Diametral Pitch which I'm guessing is much finer than what they probably are. Anyone have any numbers for the D.P. or helix angle?

 

[Jim/GA]

You need to look at the original Ford drawing for part A-6250. It should have those dimensions, as they would be required by the machinists originally to make them.

I have a low-res scan of the part and I cannot read that detail. You need a high res scan, which you can get from the Benson Ford Archives with an online form.

https://www.thehenryford.org/

Or, if you can find that drawing online on their website (which I cannot find right now) you can blow up the details in that center section of the drawing and read them or make a screenshot.

https://www.thehenryford.org/search?Tab=collections

I looked just now and their new Search function is horrible. I can't find anything like I used to be able to with the old system.
.

 

[gbritnell]

I went to the Benson archives site but it says they can only make low resolution scans

 

[jwmckenzie]

You have to order a High Resolution Drawing. Here is the last form I captured. Call the phone number and talk with them to verify that is the latest form.