Since you asked for comments, and I'm a bit underworked today...
1) Denise: I've heard that if you run your plain ol' leaded gas head
(without hardened valve seats) for a few thousand miles with leaded gas,
you've impregnated the seats with enough lubricant to last the rest of the
life of the head. Thus, your 200k '67 B motor probably has soft seats, and
will be fine for the rest of its life. If you could find an NOS head
without hardened seats, and put it directly into service on unleaded gas,
you might be able to find a problem.
2) Andrew: Did you include mention of the lead substitute and the PO's
pinging problem in your mail intentionally? That was the use of lead in the
old fuels - an anti-knock additive. Your lead substitute will be doing that
job now. If you go back to regular (a.k.a. low octane) fuel sans additive,
you may be able to recreate your PO's ping.
BTW, urban myth rebuttal: Higher octane fuel does not give an engine more
power. Octane is the ability of the fuel to resist pinging, or
'pre-detonation.' You can get more power from higher compression. However
this higher compression will increase the affinity for pinging. Thus, the
need for higher octane fuel in your big-hp motor.
Matt Kulka
Huntersville, NC
'74 B
-----Original Message-----
From: Proudfoot, Andrew [mailto:proudfa@NAVCANADA.CA]
I've put 200K miles on a '67 B using unleaded gas and haven't had any
problems with premature wear.
Denise Thorpe
Hi Denise & fellow listers;
Interesting to hear your high mileage with leaded fuel. I started using
a lead additive (STP) well it's a substitute actually. I find the 77 (74
engine) much happier with it. Also the PO thought there were some timing
problems with the engine ( pinging, low power etc. between 30 & 50 kph)
but I haven't noticed this...
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