Pre-war timing question

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Tony Fearn
Posts: 1743
Joined: Thu Feb 09, 2006 5:33 pm
Your interest in the forum: Early pre-wars. Owner of 1933 'Flying Fox' 'Sarah Jane, and 1934 Short saloon 'Mary Ellen'.
Given Name: Anthony
Location: Clayton le Moors, Lancashire, the Premier County in the British Isles!!

Re: Pre-war timing question

Post by Tony Fearn »

I photographed four of the crankshaft keys which are all different in a small way.
IMG_0133.JPG
IMG_0129.JPG
Tony.
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k. rogers
Posts: 480
Joined: Thu Feb 23, 2006 9:43 pm
Your interest in the forum: 1933 7hp Kingfisher
1935 7hp Weasel
1928 7hp Sports replica
1952 Bradford special
Given Name: Ken
Location: Cornwall

Re: Pre-war timing question

Post by k. rogers »

Wow, I had no idea there would be so many minute variants, each one giving just a slight difference on the timing. Makes you realise how precise they were when setting up these engines in the factory! Also, how important it is to get things spot on when reassembling a rebuilt engine to get best performance.
Bruce, obviously the measurements in the chart apply to a cam in perfect condition. I would guess than any wear on the lobes would happen at the same rate on each side unless someone has had the opposite experience, but I've never tested that.
7hp Weasel & Kingfisher
Tony Fearn
Posts: 1743
Joined: Thu Feb 09, 2006 5:33 pm
Your interest in the forum: Early pre-wars. Owner of 1933 'Flying Fox' 'Sarah Jane, and 1934 Short saloon 'Mary Ellen'.
Given Name: Anthony
Location: Clayton le Moors, Lancashire, the Premier County in the British Isles!!

Re: Pre-war timing question

Post by Tony Fearn »

Ken wrote: Sat Apr 09, 2022 8:25 amObviously the measurements in the chart apply to a cam in perfect condition.
I remember that Roy Braddock had some patterns for various pre-war camshafts, so that if needed, the lobes could be 'stellite' welded, re-ground to original spec and case hardened again.
If the wear on the lobes was minimal, he suggested that they could be re-ground, but was wary of the depth of the case-hardening.
I've a feeling that someone might have these patterns if JCS don't have them in their possession.
Tony.
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