Gipsy Cam

[byawor]

Attached drawing shows cam lobe and bearing. Am I wrong or will that lobe never pass through the bearing?
Bob

 

[Jasonb]

That is not a bearing, it is a spacer that fits between the loose cams and acts as the running surface for the cam bearings which are 0.5" bore, look at the assembled crank just above your snipped image and you can see several of them on the shaft. That is why those parts are case hardened steel and the bearing cages Ph bronze part 114/4

 

[byawor]

I guess the question wasnt clear. If the cam lobes are made to the dimensions shown will the cam pass through the 1/2" bore.

 

[bluejets]

I guess the question wasnt clear. If the cam lobes are made to the dimensions shown will the cam pass through the 1/2" bore.

I make it 0.4445" so why not..?

 

[byawor]

If there were no intermediate bearings it would clear easily. However there are three .5" bearings in the middle so you might wiggle the first couple of lobes in but it would get increasingly difficult to fit the rest. The major diameter of the cam as shown is .257x2=.514 so to my way of thing the bearings would have to be .515 at least. I am going to make the cam slightly smaller a bit less lift should not be the end of the world. Any real cams I have seen have journals slightly larger than the cam lobe its a tight fit but it works.
Bob

 

[bluejets]

The major diameter of the cam as shown is .257x2=.514

By my calculation the cam is half the base diameter of 0.375 ( 0.1875) plus the centre to cam lobe height of 0.257 so that is 0.4445" not 0.512.

 

[byawor]

I guess you don't understand the problem

 

[Charles Lamont]

Blujets, you seem to be forgetting that there will be cam lobes sticking out in eight different directions. I agree, you might wiggle it through, but it seems a bit risky, unless the bearing seats are narrower that the cam-to-collar distance.