Lead replacement additives - advice, please! (Essex V6)

I use an additive in my Spitfire 1500 - abou a fiver IIRC from Halfords.

For that sort of mileage, just use straight unleaded. Buy a pair of spare heads if you see any going cheap, but you'll probably never need them.

If only doing low mileage use Shell Optimax

Ken Parker ( snipped-for-privacy@verwood-dorset.fsnet.co.uk) gurgled happily, sounding much like they were saying :

And that'll prevent VSR how?

Lower combustion temps with standard tuning than using plain unleaded?

Same way it'll prevent damage from falling elephants. I've been using it for miles and not suffered from either. Seriously, I'm becoming convinced that VSR only occurs in extreme circumstances or in exceptionally prone engines (dunno if the Essex in question falls into the latter category).

By now the engine has probably built up a lead memory so the valves and seats should be pretty well protected for a long while yet. After all it's not as though you went howling up and down the motorways of the country in the thing.

If you do decide to add jollop to unleaded, the ones on the market are based on a variety of chemicals and it is not supposed to be a good idea to mix them, so find out what LRP uses and get something based on the same stuff. Quite honestly, though, I wouldn't bother. Just check the valve clearances occasionally - shouldn't be too difficult to get at ;-)

Ron Robinson

Jeremy realised it was Fri, 27 May 2005

11:55:26 +0100 and decided it was time to write:

I use unleaded and no additive in my Spitfire 1500. No valve seat recession at all over the last 20,000 miles. The big end bearings definitely need doing more often than the valve seats.

"Ed Hughes" realised it was Fri, 27 May 2005

11:46:59 +0100 and decided it was time to write:

It takes a l o n g time. If you only use the car for the occasional short trip, I wouldn't bother with additives. It's not worth the trouble and you'll be surprised how long it lasts. By the time you grow tired of adjusting the valves (the ones in my Spitfire hardly needed any adjusting over the last 20,000 miles of running on unleaded), you can always have hardened valve seats put in.

YMMV, of course. Literally.

You could do what I do, hit the closest airfeild and buy 5 gallons of

100LL, don't even dream about putting it in the Rover, put it in a 5 gallon gascan. When you go to fill up, put a gallon in the tank, then fill with whatever is cheapest.

SteveL

With this, it appears that you can 'roll your own'

Normal disclaimers. Roger

I have been using this in my PI, after looking into the possibility of doing an unleaded conversion and finding out that the fuel pump uses the lead in the petrol for lubrication, and for an unleaded conversion I had to replace the pump as well as modifying the head. It works very well, but it is not cheap (minimum quantity cost 110 quid, but for that you get a dozen bottles, each of which treats 110 litres of petrol at the concentration I use).

In my 2000, I have been using RedLine Lead Substitute, available from Delta Oils by mail order (01476 861195). I can't remember the exact price but it is around 13 quid for a bottle that will treat 100 gallons, and they do a discount on orders of 3 bottles or more. I started using it after risking unleaded alone and burning out a valve during a 100 mile trip down the M4 - so much for the acclaimed lead memory! In my opinion, this product works.

Others in the NG have used Castrol Valvemaster, and seemed happy with it. I have never tried it myself though.

Jim

"Sharrocks Thomas" wrote in my mailbox:

I set it statically - like the book says - at 10 deg BTDC and it runs perfectly. This is after a rebuild, in which the valve seats showed no discernable wear from at least 20,000 miles of running on unleaded. The rebuild involved new main bearings, new timing chain, a rebore, new pistons, new valve guides, camshaft regrind and new ignition from the coil onwards. No pinking after the rebuild. I used to set the ignition by ear, which always turned out between 8 and

10 deg BTDC, and I often had some slight pinking under load. That's on 98RON petrol.

K&N filters, extractor manifold and a freeflow exhaust. That's why I changed the damper springs and needles in the carbs, too, though I can't remember what's in there now. It's been ten years since I did all that.

You may get this effect if the carbs are running lean. They may well be with K&N filters.

With K&N filters, I'd consider stronger damper springs, richer needles or both. Check if the vacuum advance mechanism on the dizzy still works like it should.

Do you know if the engine's head has been shaved multiple times in the past? How old is the timing chain? What spark plugs are in there? How are the carbs? Any play in the throttle or mixture shafts?

I've replied to your e-mail in the newsgroup. I believe in keeping the discussion here, so others can chip in or learn.