Lotus Elan

plus 2 S on dellortos

PostPost by: nitch » Sun Jul 02, 2006 9:09 am

I'll be using this trade on the way...
I'm currently rebuilding the engine on my +2 130s. The engine is not the original that came with the car, and has been replaced about 10 years ago. How can I tell if this is a big valve engine?
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PostPost by: rgh0 » Sun Jul 02, 2006 11:36 am


You can tell what the head was orginally from the letter stamped on the boss at the front of the well next to spark plug 1.

What valves it has now you will not know until you pull it apart and check the seat and valve head diameter as many standard heads have had big valves installed over their life. You can measure the cam lift which is the real difference between the heads using vernier calipers buy pulling the cam cover.

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PostPost by: Madbury » Fri Jul 07, 2006 8:41 am

alaric wrote:Hi.

I bought "How to build and power tune Weber and Dellorto DCOE, DCO/SP & DHLA carburettors" from ebay. Author is Des Hammill. Published by Veloce. ISBN 1-903706-75-0.

I have the third edition. I've found the book to be very informative, and the tune up procedure worked a treat with my own Dellorto carbs.


Ah thanks Sean,

I'll be sure to keep a look out for a copy :)
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PostPost by: trw99 » Fri Jul 07, 2006 1:13 pm

In the Lotus supplement by Autosport of October 1971, there is a discussion about the fitment of Dellortos to the Europa and of course Dellortos were fitted to the Europa twincam from late 1971. Therefore Dellorto was a supplier to the factory by then. An Elan service bulletin was issued on 9 June 1972 detailing the specification of Dellorto carbs. So Dellortos must have been fitted to Elans in the factory in May 1972, or earlier. I assume the factory used up what Webers they had before fitting Dellorto as standard to Sprints and Plus 2?s.

Apparently Dellorto had been quicker and more willing than Weber to change their designs to comply to new European regulations. They may also have been cheaper than Webers too. Or Lotus may have fallen behind in their payments to Weber, who refused to make any further supplies!

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