IML: Lead Additive

["Geoff Fors" <wb6nvh@xxxxxxxx>]

About eight months after lead was removed from fuel in California, in the
late 1980's, I lost all compression on three of eight cylinders in my '67.
I did have about 160,000 miles on it at the time, and had been using the
"additive" Union 76 was selling at the time, which was just something like
Marvel's Mystery Oil rather than a lead substitute. The combustion chambers
were pretty full of carbon and crud.

Anyway, I had four pac-man looking cracked and burned exhaust valves,
although the seats were OK.  Since it was apart, I rebuilt the heads with
hardened seats and stainless (I think) valves.  As you may know, the 440
heads in this era do not have valve seats, so you have to have the heads cut
for them and the seats inserted.  By doing this the heads are then unleaded
capable.

I suspect that if you have a clean engine (inside the combustion chambers)
and don't overload it, you can get by without leaded fuel and probably
without the additive.  I have seen quite a few original Imperials in the
'66-68 vintage around here still running fine without having been converted
to unleaded.  There are some additives which actually contain tetraethyl
lead, however they were/are expensive and primarily raise octane rather than
protect exhaust valves and seats.

Geoff
Monterey CA


-----------------  http://www.imperialclub.com  -----------------
This message was sent to you by the Imperial Mailing List. Please 
reply to mailing-list@xxxxxxxxxxxxxxxx and your response will be 
shared with everyone. Private messages (and attachments) for the
Administrators should be sent to iml.webmonster@xxxxxxxxx
To UN-SUBSCRIBE, go to http://imperialclub.com/unsubscribe.htm