Camshaft diamensins

[alexander]

Prior to getting the Javelin back home to check camshaft timing I sorted my spare camshaft out just in case it’s a worn camshaft and not timing. Does anyone have a drawing of camshaft diamensions please
Alexander

[David Morris]

Hi Alexander,

I have found at least four Jowett part numbers for Javelin camsfafts, 50662, 54151, J54538 and J54651. I believe the first number is for the hydraulic tappet engine, for which the camshaft was certainly different to the later camshafts. The later numbers might refer to vernier peg adjustment camshafts?

Looking back through the technical library, and using the search word 'camshafts', throws up around 80 entries. I see that Keith has included a table of measurements on 16 different camshafts, and they all have minor differences, so I am sure he can advise.

As JCS are having new camshafts manufactured, I am sure there must be a definitive drawing, so perhaps Paul Beaumont can help you?

All the best,

David

[Keith Clements]

The journal size and wear tolerance is in the Tech Notes but some oversize shafts have been made by Bill Lock to allow for wear in the block. The cam lobe size and shape will depend on the grind that has been performed. Some shafts have been reground and some have been metal sprayed or welded with stellite. There are also a number of other newly made shafts with different specs around used for racing and rallying.
If you are just checking shafts out then the main thing is to make sure the jounals are all the same size and fit your block. Also the lobes all give the same amount of lift. Philip Dingle has done extensive work on measuring the shafts so do a search.
Usually you can see a worn lobe and do not need to measure it to find out! The main cause of this is a non rotating cam follower so you can also tell by looking at them to see where the problem lies. Others will say it is the lack of zinc in the oil, poor running in or revving the engine on start up.
But it is worth checking the lift and the wear. The shaft also bends under load so setting up the tappets and the valve timing properly is important.

[alexander]

Thanks Both
Found the camshaft date in the tech note's
Alexander