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rootsman's picture
Joined: 03/16/2008
Posts: 4

Hi Guys,
I'm overhauling a camshaft assembly (1928 R42) that had been quite abused in the past. I've got the correct timing sprocket for it, but there is no keyway on the camshaft that would locate the sprocket. From what I can remember, the sprocket timing marks should be at a 90 degree angle to TDC of one of the cam lobes (?). Can anyone verify and clarify this? Is the cam-nose keyway slot inline with TDC of a cam lobe? If so which one?
ALSO, I was looking through the DEC.2007 thread of this subject (without timing marks) and noticed the photos of Darryl's R62 engine.
In one of the photos of his upper crankcase, you can see a hole and plug about an inch in front of the exhaust cam-follower on the RIGHT side of the case. What is this hole for? This R42 case has a hole there too, but very mangled and I was hoping to permanently seal it. I don't know what that hole is for (possibly cam timing?).
Steven Seftel

Darryl.Richman's picture
VBMWMO #6285
Surf City, USA (Santa Cruz, CA)
Joined: 10/27/2006
Posts: 2185
R42 Cam sprocket position; Crankcase hole

I'm afraid I don't have a good answer for your timing problem, but I can tell you about the hole on the right side of the case upper half.

That is a threaded hole, and there's pointed screw that goes in there. The point mates to the front camshaft bearing carrier, and locks it into place.

You'll notice there there's a "pinch" of metal directly in front of where the hole is on the case half. This pinch is drilled, and the head of the screw is drilled, so they can be safety wired together. This is necessary because if you crank down on the screw, you'll either strip the case hole or put an unwanted radial load on the camshaft bearing. The screw should just be snugged down and then wired.


VBMWMO Webmaster,--Darryl Richman

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