3000S: use of unleaded

[zo-fo]

I'm going to Le Mans and this year would like to go in the TVR. I've always used leaded petrol (never LRP) which has been readily available where I live. I don't want to get the car converted to unleaded until I'm forced to, but does anyone have any experience of running an unconverted Essex engine on unleaded? I don't know if this makes a difference but when I bought the car in 1981 I was told that it had been built at the factory with "big valves."

Zo-fo

[nwarner]

I run both my 3000S and my Scimitar on unleaded and have done since they stopped selling Leaded petrol near me and covered many 1000's of miles. I have had to retard the ignition timing a bit to stop it pinking on normal unleaded but when I used Super unleaded I didn't get any pinking problems. I know of other Scimitar owners who have done 30,000 miles on unleaded with no valve seat recession.

You won't cause any problems just going to Le Mans & back as the Lead memory on the valves will protect them in any case and if your still worried you can always take a Lead Replacement additive with you and then carry on using Leaded when you return.

I wouldn't worry about it, just go and enjoy yourself.

Nige

[Terminator]

zo-fo said:

does anyone have any experience of running an unconverted Essex engine on unleaded?

Running on unleaded makes little or no difference until you've done about 40000 miles and have run the car consistantly over 3000rpm. I've seen valves from an unconverted Essex engine run on unleaded and there was some slight regression but nothing to cause alarm.

I'd not worry about it but put in super unleaded on the continent (98RON) plus some lead-replacement additive if you're still concerned.

[zo-fo]

Thanks for prompt replies. Any recommendations from anyone on best additive?

[Terminator]

Whatever you can find, but Millers VSP-Plus and Valvemaster have got good reviews.

[nwarner]

Valvemaster is probably the easiest to get as you can get it from Halfords.

[adrian@]

This is not as simply as it seems .....2 things can happen, 1 the engine will start to pink (because the octane is lower), as Nigels say's retard the timing to suit 2 the valve seats will ruin in a very short time..... but with these point taken into account. The amount of lead required to protect the valve seats is very low and the amount in leaded petrol was almost 3 times more than required for that protection ...The halides and oxides that protect the seats do not disappear as soon as they are introduced and this is why people are advised that they should use one tank of leaded to 3 of unleaded (good advice if you can get real leaded) BUT, maybe the seats are, after say 30-50 thousand plus miles hard enough for you to use unleaded with impunity, hence this is why both Colin and Nigel say they carry on regardless, I too believe that this can be done with cars that a person has this full and informed knowledge/history of the car in question (you seem to have this) but for the forum archive's, the point must be made that using unleaded without the additive should be a considered decision by the owner, given that a engine that was in with me recently where the previous owner had decoked and replaced ONE valve ONLY, he then informed the new owner that he had been running on unleaded for years who then had that valve burn out and damage the engine due to the assumption that it had been "running on unleaded before" this was due to the fact that one valve did not have the protection of the 'age hardened' old valves and seats.
Adrian



>> Edited by adrian@ on Thursday 27th January 22:15

[stigproducts]

If you fancy a tank of leaded from time to time then here is the link to find a local garage.

www.leadedpetrol.co.uk/list.htm

[zo-fo]

The car's done 80,000 miles, all on leaded, so I'll wait until the salt on the road's gone, run it locally on higher octane unleaded with additive and see how I get on. I'll try to remember to post up progress.

Thanks everyone.