Lotus Elan

Jackshafts

PostPost by: ardee_selby » Fri Sep 30, 2011 4:51 pm

Elsewhere Mr. GrUmPyBoDgEr has written: <snip> I...removed the cam lobes & shortened twincam jackshafts <snip>

In addition, Club Lotus (July '79) said:
Jackshaft.jpg and

Is the CL advice 100% accurate? Has anyone ever followed it?
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PostPost by: types26/36 » Fri Sep 30, 2011 5:13 pm

I doubt the Cortina camshaft is worth much these days but that aside the Cortina/Escort/Anglia camshaft is not exactly the same as the Lotus Jackshaft, both will drive the petrol pump and the distributor/oil pump with no problem.
The difference comes in that the Lotus Jackshaft has extra slots cut into the front bearing face to supply more oil to the head, you can mill the extra slots into it if desired.
Its also a common mod to shorten the shaft and only run it in the two front bearings but then you would need an electric fuel pump.The third bearing is then fitted to blank off the oil supply to that bearing.
Brian
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PostPost by: garyeanderson » Fri Sep 30, 2011 5:50 pm

Some other jackshaft info that may be of interest.

elan-f15/jack-shaft-adaptor-t21051.html
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PostPost by: GrUmPyBoDgEr » Fri Sep 30, 2011 9:04 pm

ardee_selby wrote:Elsewhere Mr. GrUmPyBoDgEr has written: <snip> I...removed the cam lobes & shortened twincam jackshafts <snip>

In addition, Club Lotus (July '79) said:
Jackshaft.jpg

Is the CL advice 100% accurate? Has anyone ever followed it?


I presume that they meant that the pre-crossflow GT Cortina camshaft was a "tuned" component & a bit hotter than the standard Cortina camshaft.
If that was the case, they were saying that the twincam jackshaft could be sold for the princely sum of 25 GBP to someone hoping to get a bit more performance from his/her standard Cortina.

I doubt that there would have been many takers; back then there were so many companies offering re-profiles on an exchange basis that anyone paying so much (25 GBP) for what was basically a "cooking camshaft" would have had to have been slightly nuts!

I thought that the Weber downdraught progressive register carb' was what made the GT Cortina that bit better. Can't remember but maybe it also had a fabricated exhaust manifold as well?

John
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Editor: On Sunday morning, February 8th 2015, Derek "John" Pelly AKA GrumpyBodger passed away genuinely peacefully at Weston Hospicecare, Weston Super Mare. He will be missed.
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