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| Joined: | 03-14-2005 |
| Location: | Atlanta, Georgia USA |
| Posts: | 406 |
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One school of thought is to send your head to a Lotus expert like West Coast Racing Cylinder Heads and let Richard work some magic...like a $1,500.00 porting job...if you've got the budget!
Alternatively, if you know how to talk to your local machinist, you can have good results for less money. Start by assembling parts: You'll need a new set of valve guides and valves which will cost you ~$250.00.
If you want to spend another $100.00 on competition valve springs from Delta, feel free. Personally, I've yet to have any of my machinists come back to me and say that any of my springs needed to be replaced due to sag.
The next trick is to find a machinist. I usually walk in w/ the head and parts and ask the guy behind the counter if he can do a valve job on it. Do NOT go walking up and say 'you guys ever see a Lotus'. If they ask, I usually tell them it's a GM Quad4 head, then after I've broken the ice, I fess-up about it being a Lotus.
All you are basically needing is a standard valve job. With the proliferation of Import Drag and such, 16-valve heads aren't so exotic anymore. My current machinist is a younger guy who came from Toyota, he does great work (when I can get him!).
I usually request my machinist to remove ~0.010" from each Intake valve stem and 0.020" from each exhaust stem. This is usually enough to account for removing the cardboard gasket and to account for the seat recess).
You can casually mention that the shimming process is a PITA and it would be nice if each valve had a similar height off the deck. The exact height is hard to report because I've noticed that heads and cam towers have differing flange thicknesses throughout the years.
It's really not that hard of a procedure, finding someone who will listen to you is usually the hardest part.
Best of Luck,
Judson