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 Posted: 09-13-2017 12:27 am
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Esprit2

 

Joined: 05-01-2005
Location: Minneapolis, Minnesota USA
Posts: 282
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tonyhawker wrote:
Offhand, are the valves specific to only the 907 engine and made of unobtanium or are there more generic replacements available?  I have the machine tools to modify and regrind valves if necessary.Tony,
The valves Lotus sold were expensive. They were very good valves, but expensive.

All the 9XX intake valves were all the same, until you get to the 910 in the 1995-96 Esprit S4s and the then-new Zeus head. Those intakes were 1 mm larger diameter.

All the exhaust valves had the same head diameter, but the turbo 910 valves had sodium filled stems that were larger in diameter and required larger ID guides... and the larger guides required larger bores in the head. Not that you want any of that for your J-H 907, but when you're searching around, you'll know what you're looking at.

Most Lotus specialists also sell aftermarket valves that are more affordable, and the J-H specialists probably do as well. I know Garry Kemp at Kemp Performance Engines has aftermarket valves available. That's pretty common.

Regards,
Tim Engel