There is one other consideration -- what are the ingredients in the
additive? I used a lead substittute briefy in the 80s, but the witch's brew
of known-toxic and evil-smelling ingredients convinced me to take my chances
without it.
--
Max Heim
'66 MGB GHN3L76149
If you're near Mountain View, CA,
it's the primer red one with chrome wires
on 2/23/09 12:57 AM, Paul Hunt at paul.hunt1@blueyonder.co.uk wrote:
> This is it. Research claimed to be from BMW some years ago stated that if an
> engine had done at least 40k on leaded and hadn't had the valves replaced or
> the seats recut then there would be enough lead leached into the surfaces to
> protect them for the rest of their service life (whatever that is). Tests in
> the UK have shown that it is only when the engine is run at full throttle or
> very nearly so for long periods do you get any recession anyway. I choose to
> use an additive and haven't had to open up the clearances since the UK lost
> leaded 10 years ago. I don't do a huge number of miles each year but what I
> do are done 'enthusiastically'. It is totally uneconomic to have a head
> converted purely to avoid buying an additive, an MGOC study in 2002 reckoned
> 70,000 miles if you did the work yourself, double that if you paid someone
> else. That was at UK prices, from what I have seen of the costs of parts and
> labour in America it would probably be much more. Of course, if the head
> needs replacing anyway due to cracking or warping and you are buying from a
> reputable source it makes sense to fit one that has been converted, unless you
> choose to buy an unknown quantity from a scrapyard or somesuch. Even then the
> MGOC study said that hardened seats and valves offer no more protection
> against recession than the best additive, it just saves you buying and adding
> it.
>
> PaulH.
> ----- Original Message -----
>
>
> My '67 MGB has 330K miles on it and I've never made any modifications to
> the
> head for unleaded fuel. I bought the car in '79 with 100K miles on it and
> have rebuilt 3 engines for it, the first when I first got the car. No
> removed
> head has had excessive valve seat wear and I don't use any additives.
_______________________________________________
Support Team.Net http://www.team.net/donate.html
Mgs@autox.team.net
http://autox.team.net/mailman/listinfo/mgs
http://www.team.net/archive
|