Javelin / Jupiter Timing Case Cover

[Nick Webster]

I had always assumed that the different part numbers for the timing case cover was to do with the change in camshaft thrust arrangements, but this may have masked an additional alteration which is the distributor mounting. On some covers there is a two bolt flange going fore - aft while on others it is only a single bolt flange pointing across the engine. Does anyone know when and why there was a change and is there any important significance to it?

Nick

[johnairey]

Nick,
It was for different distributors the early DYK had two mounting bolts the later DM2 just one.

[David Morris]

Hi Nick,

I have a couple of thoughts? I think the earlier front timing cover had just the one stud and was fitted with the DKY distributor, which had an external vacuum advance. I am fairly sure the later ones had the two mounting studs and, as John mentions, suited the DM2 distributor, which has an integral vacuum advance unit and micro-adjuster.

I have seen some front timing covers which incorporated a spring operated 'slipper', presumably to reduce timing chain chatter. But these may have been fitted as an after-market modification.

The change to the cover to fit the adjustable camshaft peg was introduced as an engineering modification and presumably could be retro-fitted to the earlier cover, should the later camshaft be fitted? This might have happened to an earlier engine, ( which might have had the earlier front cover ) possibly where the owner was changing from hydraulic tappets to conventional tappets and would have hence needed the later camshaft?

All the best,

David

[Keith Clements]

I met the London Jowett agent mechanic who said he put his idea for the adjuster in the JCL suggestion box and was thrilled when he received recognition when it was adopted.