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lead additive

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lead additive
  This topic is about my 1950 Morris Minor
The Putz Avatar
The Putz Jim Dickey
Oro-Medonte, ON, Canada   CAN
1950 Morris Minor "Miss Daisy"
1974 Volkswagen Beetle "Elsie"
1974 Volkswagen Beetle "Rosie"
Hi folks. I have a 918 side valve and was wondering if I should be using a lead additive in my gasoline. I have read different opinions on the internet and thought I should ask the experts on minors.

thanks Jim

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emjay Jim English
Marietta, PA, USA   USA
It's been about thirty years since leaded petrol was readily available. Forums have been fairly popular for the last ten years or so. There have been a lot of talk about lead, but next to nil about first hand accounts of destroyed valves/seats. Even in the beginning the general consensus was under average/typical driving styles one should not encounter a problem. In other words if you are not racing or pulling a heavy trailer the engine should be fine. Some people install hardened valve seats and others say they are not needed. Even the choices of lead substitutes additives have dwindled on the store shelves. If you choose to use an additive, don't bother with the ones that are meant to boost octane.

66jalopy Avatar
66jalopy Silver Member Phillip Jolliffe
Lake City, FL, USA   USA
I had a valve job done on my head 4 years ago and about 2 years ago had to pull the head again, the valve seats were heavily pitted. I had another head that I had hardened seats installed in and so far so good. My understanding is that it takes a long time to wear the effects of using leads gas so it wasn't a big issue with light duty use. I would probably use the substitute to be on the safe side... I think I still have 2 or 3 bottles of the stuff, I bought it at a going out of business sale for $0.75 a bottle.

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shoebone Stuart F
tempe, AZ, USA   USA
Differing opinions on this subject, I have never used an additive and never had a problem, I could be considered an enthusiastic driver at times, and I probably average 7K miles annually. Pretty sure I will of 'saved' enough money to cover the cost of a replacement head as and when. Ah, l just saw you have a sidevalve .... personally, I still would not bother with an additive, keep an eye on valve gaps, if they start to close up its time to get the head off for a look.

Edited 1 time(s). Last edit at 2017-05-25 06:15 PM by shoebone.

emjay Jim English
Marietta, PA, USA   USA
Phillip, that's interesting. Your valve job obviously removed any residue lead deposits, leaving you with no protection. That would indicate with fresh steel, the lack of lead may be an issue.

0123 Mike D
Biddulph, Staffs, UK   GBR
How well do your valves seal Jim?

Lead additives are a lot of fiddling about.
Pointless if you need a valve job.

Some lead additives work thumbs up
Some don't thumbs down


52MMaurice Avatar
52MMaurice Marc Darisse
Salem, Massachusetts, The Witch City, USA   USA
1952 Morris Minor "52MMaurice"
I rebuilt the sidevalve engine in my '52 MM six years ago. I have never used an additive, engine runs great.

Caveat: My engine is fitted with a Alta OHV cylinderhead with hardened seats and bronze (Saab 900) valve guides.


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Roger46 Roger Webb
East Grinstead, West sussex, UK   GBR
Remember that the seats in a side valve engine are in the block not in the head. So work involved in fitting hardened seats is much greater, but then if you wreck the seats the result is much more serious too.

usmh3 Avatar
usmh3 Rob Thomas
Cardiff, Wales, UK   GBR
Marc. Are you sure they are Saab 900? The Saab site suggests they are 12mm OD whereas the hole in the Alta head is 12.7mm. I had awful trouble finding a suitable substitute guide and ended up making brand new ones from scratch.

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