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| Joined: | 05-01-2005 |
| Location: | Minneapolis, Minnesota USA |
| Posts: | 575 |
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Tim,
How about specs for the N/A Esprit 2.2? My 107 cam specs differ from the 107 specs you listed, and I think they may be an earlier version.
While it's possible they could be regrinds, my first set came from DBE and were non-touched-up, 'pull-outs'. I later shattered one of those cams when I lost a timing belt. One call to JAE and they found a replacement on the shelf with exactly the same specs.
Judson,
The Esprit S2.2 used two 107 cams while the S3 used a 104 on the intake and a 107 on the exhaust. The cam data I quoted above is right out of the Lotus manuals.
50° BBDC Exhaust Opens
22° ATDC Exhaust Closes
22° BTDC Intake Opens
50° ABDC Intake Closes
252° Duration, 44° Overlap, 0.378" Lift
What timing data do you have for the 107 cam? In the book, "The Third Generation Lotus...", the author quotes the Turbo cam as being 265° Duration, 55° Overlap, 105 MOP and 0.380" lift (57.5, 27.5, 27.5 57.5). However, I've never seen a reference to such a cam in a Lotus manual. The only thing I can think of is that the original Turbo Esprit was introduced in the UK and Europe a few years before it came to the US in 1983. For '83, the car was substantially re-engineered and the engine used two 107 cams for all markets. What were the pre-83 Turbo cams?... I don't know. But if the timing was substantially different than quoted above for the 107, then it was a different cam entirely. The 107 didn't evolve... it was what it is.
Lotus quotes cam duration as seat to seat. I've never seen that written anywhere, but I've played Lotus for a long time and that's the way I've always found their cams to be.
Later, Tim Engel