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Lead additive

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jaybird

jaybird

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My son (the new Midget owner) wanted me to ask if he needed to use a lead additive with the unleaded gas. I suppose he didn't trust my answer.
/ubbthreads/images/graemlins/jester.gif
 
There are some A-series pundits in the U.K. who say there are benefits to using lead substitute even when you do have hardened valve seats. In the U.S., the acquaintances I have swear by Red-Line additive over all the others.
 
Jaybird

I run a race Sprite and a road Sprite and have even had problems with the hardened valve seats in the racer until I started using a product called Tetraboost. I don't know if it is available in the USA , in the UK we get it mail order from Tetraboost, it contains Tetra Ethyl Lead, the real thing and since I started using it valve and guide wear have reduced dramatically. One warning, it is evil stuff, take care when handling it! Good luck.
 
Pardon my ignorance, but how does adding lead help if you already have hardened valves? I could see how it might help with detonation, but wouldn't higher octane fuel have the same effect? The only reason I don't use it is that having a later Midget it clearly says "unleaded fuel only" on the filler and gas gauge. Granted, that's because of the catalyst which is no longer present, but how would adding lead help?
-Dave
 
Tetra Ethyl lead is a better lubricant for valve seats and guides that any of the substitutes. With lead sustitute and hardened seats I thought I was safe, the seats were OK but the guides wore at an alarming rate.Since going back to leaded fuel the wear has been minimal. This is on race engines with Cooper S spec bronze guides. Aero engines still use leaded fuel, got to be a good reason for that. I would imagine that you may have legal reasons for the "unleaded fuel only" stickers. If no cat then leaded is ok.
 
The benefit of lead (even with the hardened seats) is apparently from increased lubricity and agents that prevent material transfer. Again, this is hearsay from me, not first-hand experience. As mentioned by Hoppy, there are legal issues with using TEL in a road-going car in the U.S., whether it has a cat or not.

BTW Hoppy, I flipped and flopped about the bronze vs. cast iron guides. The Cooper-S guides in my old AEG163 head were bronze but most people I talked to said I would be equally happy with the cast iron guides. In the end I bought a big-valve 12G940 head for my engine and it came with new cast iron guides. I'm not racing so I can't comment on that aspect but the cast iron guides do appear very suitable for a street engine.
 
Back to the original question about "lead additives"...

I don't think you can easily buy such a product in the US, but there are plenty of "lead subsitutes".
These substitutes are pretty expensive relative to their effect.
A $5.00 (USD) container of lead subsitute typically only raises RON octane about 0.1 in 10 gallons and does not seem to have any guarantee of increased valve life.
And honestly, for street cars, I don't think unleaded fuel is such a bad thing (and a good thing in terms of lead fouling on plugs).
For racing, I'm running 100 octane (RON) *unleaded* Sunoco with no problems (10.3 compression ratio and 30 degrees of spark advance).
 
I too race sprites and I don't use bronze guides(too much wear) Unleaded fuels work great. I do put a bit of marvel mystery oil in the fuel to lubricate the floats and jets in the carbs. Seems the new fuels are designed with fuel injection in mind and are bit dry for the carbs(sticky floats) I have run sprites on the steets with unleaded stuff...no problems..go figure
 
HI Aerog, there is a product called "Real Lead" sold here in the Golden state which circumvents the rules by stating "For Off Road Use Only"--Yeah sure---Keoke /ubbthreads/images/graemlins/laugh.gif
 
He does not need a lead additive. Any car sold in the US since 1971 had to be able to run on unleaded. After 1974, they had to run on unleaded only. I am not sure if MG's came with hardened valves that early, but I would think so.

Mike
 
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