Englishmaninwales Posted August 10, 2013 Share Posted August 10, 2013 Ok I've stepped back into history, moved away from Emeralds, 3D mapping, TBs, and fuel injection to a glorious sounding twincam in my Lotus Elan. BUT I need some help from the dark side from those of you with oily crossflows and prehaps even the odd twincam powered 7. Can I use standard unleaded? Do I need some additives? The engine was rebuilt less than 5k miles ago but in 1991. There is no way I can tell if the valve seats were changed (or indeed if they even needed to be changed for unleaded). I can check the static timing ( I forgotton about things like the timing light buried in my garage store!) - any idea what the static timing should be for unleaded? Should I use expensive Shell unleaded? Link to comment Share on other sites More sharing options...
Klunk Posted August 10, 2013 Share Posted August 10, 2013 Hi Malcolm , I would check the compression to try an figure out what compression ratio you have. My steel x/flow had a CR of ~11.5:1 and I was advised to run it on v-power plus and valve additive. Cheapest additive per tank fill up used to be a Castrol one here . They also do one with an octane booster in case you can't get v-power. Regards, Giles Edited by - Klunk on 10 Aug 2013 09:25:35 Link to comment Share on other sites More sharing options...
DJ. Posted August 10, 2013 Share Posted August 10, 2013 I rebuilt the engine for my Elan back in 96, QED told me the seats were fine, but I had tp fit bronze valve guides. The engine was designed to run on 5 star, so unless you want to retard the ignition a lot and lose power, I would suggest sticking to super unleaded, or even better one of the higher octane 98, or 99 if possible. The super unleaded will also have less ethanol which can cause problems in older cars as well. Duncan Link to comment Share on other sites More sharing options...
david nelson Posted August 11, 2013 Share Posted August 11, 2013 Malcolm Our highly tune Fiat 500 runs on unleaded and castrol addative. I did think about super unleaded but felt 22bhp and super might be OTT. I did go to race retro and there we quite a few addatives available. David Link to comment Share on other sites More sharing options...
pugwash Posted August 11, 2013 Share Posted August 11, 2013 My Elan twink was rebuilt to fast road spec (142) and I always run it on shell vpower. I also use the miller octane booster VSP. As said above, they were built for 5star. Regarding cost of fuel, I am not doing thousands so miles to the extra cost is negligible. Link to comment Share on other sites More sharing options...
Englishmaninwales Posted August 11, 2013 Author Share Posted August 11, 2013 Thanks for all the advice Malcolm Link to comment Share on other sites More sharing options...
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