Re: compression & optimax

[Wayne]

Craig,     Thanks for the reply. I don't drive the old girl much, so I will give it a go.The head should be pretty good as it is a yella terror that I got a local head wiz to work his magic on. But it still has steel valves.Might pay to be safe and have hardened seats & bigger stainless valves put in. It's due for a dizzy regraph and dynotune, so i'll get that done with a tank of optimax.   Regarding dizzy's, the dizzy in it (COMMODORE HEI ELECTRONIC) retards when you first open the throttle, then advances as your revs rise. As it is a worked atmo holden 6, shouldn't it advance only?               -Wayne     > What fuel are you currently running it on? If its Leaded(Super) then > Optimax is supposedly higher octane than Leaded so it should have no > problem. Try a small tankful out. > I've read that lead actually stays in your engine up to a year in normal > driving after you stop using it. After that time that your valve seats > get eaten away. You are supposed to be able to get a lubrication > additive from Shell so that you can run your leaded engine on Optimax. > Try that if you don't trust running without leaded fuel for the valves. > Also remember, it is not just compression that determines whether an > engine experiences knock. Swirl/Tumble in the cylinder created by the > port(s)/valve(s), as well as squish/quench area turbulence and fuel > atomization, greatly improve air/fuel mixing reducing lean pockets and > increasing knock resistance. > Your exhaust valve will probably run hotter with unleaded so a > harder/higher temperature resistant material valve may also be needed, > ask the experts. > > Craig. > --membersozdat------------------------------------------------------- OZDAT Mailing List Please Note:- Send (un)subscribe requests to [EMAIL PROTECTED] Send submissions to [EMAIL PROTECTED] No unauthorised redistribution of this email http://www.datascribe.com.au/ozdatonline/index.htm http://www.datascribe.com.au/ozdatonline/listindex.html http://www.mail-archive.com/membersozdat@datascribe.com.au/ ---------------------------------------------------------------------