As I understand it the main problem with running unleaded in engine designed for leaded is valve seat recession. If an engine has been run on leaded for all its life, converting to unleaded initially you won't see a problem until 6-12 months down the track(depending on use) when the embedded lead in the metals is eventually cleaned away. Recession then only occuring in engines with soft valve and seat materials. The US has been running dato's on unleaded for years, here in OZ the only L engine that may have a problem with unleaded is the early L16 that used softer valve seats. The other area of concern has to do with valve material. Since lead acts as a lubricant it reduces friction and therefore heat. Exhaust valves can then get too hot running unleaded creating a number of problems such as burnt valves that dont seat, valve/seat pitting or become preignition points. As long as the octane of the unleaded is adequet I don't see a problem with using it is a datto. Keep an eye on valve lash setting for indication of wear just to be safe. Optimax raises another issue to do with the amount of aromatic compounds used in it as a replacemnt for lead to increase the octane level. There can be problems with rubber seals/hose in the fuel system being eaten away over time, and synthetic rubber is then called for. Optimax does have limited lubrication abilities but nowhere near enough for soft valve/seat engines. Even LRP is not as good as leaded for lubrication and cooling. I personnaly wouldn't use unleaded without a working catalytic converter either. Just this week I saw on the news where BP somewhere is OZ released a low sulfur content Diesel fuel that did just that, eat the rubber seals. seeya, Craig. Richard Webb wrote: > > What do you have to do to run optimax? I run Leaded at the moment. Do they > have a lead supplement? or can you just swap straight over to optimax! > Thaught it would be a good idea now petrol is down in the 80's = ) > > rich > > ----- Original Message ----- > From: "Michael Foreshew" <[EMAIL PROTECTED]> > To: <[EMAIL PROTECTED]> > Sent: Friday, January 05, 2001 9:55 AM > Subject: Re: LRP > > > Ken, > > > > Had a similar story with my rally car. It is an L18 and has not been > modified other than carbs (SU's), extractors and elec. dizzy. I found mine > would run really crap until I revved the rings off it and then would be OK. > > > > I have been running Optimax for the 4-5 months and the thing is so much > happier. Idles better and non pinging, hesitation, whatever. Part throttle > response is good. The only problem was I had to replace fuel filter (twice) > as the Optimax has a cleaning agent which removed all the crap from the fuel > lines and tank. > > > > --- "Ken Abraham" <[EMAIL PROTECTED]> > > > wrote: > > > > > > > > > > > ><DIV><FONT size=2>List Members,</FONT></DIV> > > ><DIV><FONT size=2>I have discovered the reason for my rough running > > >L20.</FONT></DIV> > > ><DIV><FONT size=2>Lead Replacement Petrol.</FONT></DIV> > > ><DIV><FONT size=2>On part throttle openings when the vacuum advance is > working > > >it runs poorly, but when you WOT it the vacuum advance ceases > to advance > > >and the engine 'comes alive'.</FONT></DIV> > > ><DIV><FONT size=2>Strangely, it doesn't 'ping' it just > misfires.</FONT></DIV> > > ><DIV><FONT size=2>Modified engines should probably not drink LRP > even for > > >commuting.</FONT></DIV> > > ><DIV><FONT size=2>What are your experiences?</FONT></DIV> > > ><DIV><FONT size=2>Regards,</FONT></DIV> > > ><DIV><FONT size=2>Nick</FONT></DIV> > > ><DIV><FONT size=2> </FONT></DIV> > > > > > > > _____________________________________________________________ > > Get Your free Ozdat Email Account > > ---> http://www.ozdat.com > > > > > --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.ozdat.com/ozdatonline/index.htm http://www.ozdat.com/ozdatonline/listindex.html http://www.mail-archive.com/[email protected]/ ---------------------------------------------------------------------
