697-04 inlet and exhaust valves

[RobinW]

Can anyone advise a source of inlet and exhaust valves for the bog standard 1470 697-04.  Is there and upgrade path for for any alternatives. I would like to keep the engine as standard as possible and avoid costly machining.

[MRN I J]

The Lotus 697 has 37.5mm inlet valves, 2.5mm bigger than the Renault 16 697 head, whilst both have 31mm exhaust valves AFAIR

[gideon]

Renault 16 Shop might be a good place to start. They carry some Lotus specific parts so it could be worth calling if you don't see what you need.

https://www.renault16shop.com/?Lng=en

Or there is this place in Germany

https://www.franzose.de/en/Renault/R16/Zylinderkopf/

Or, if you know what you want you might find it at Mecaparts

http://mecaparts.com/Moteurs/R18turbo.php?lang=0&col=R18&sortie=html#ok

You might find this thread interesting, for discussion of upgrades to the Renault wedge head

http://www.lotuseuropa.org/LotusForum/index.php?topic=1053.15

[jbcollier]

The key to working on any specialized engine is to find a really good machinist.  Most machine shops just do straight forward work such as seat and guide replacement on top of the usual machining.  Really good machinists are able to adapt other manufacturer's valves to suit, for example.  This type of work is expensive but you get exactly what you want/need.  Ask around.  The local high-performance European crowd will know where to go.

[MRN I J]

Luckily Oxfordshire, the neighbouring Warwickshire & West Midlands are full of superb engineers.
There are a couple of inlet & exhaust valves which will adapt easily, if you using K line bronze liners in the guides which you should be doing anyway