We had a demo at a "Nifty Fifties" meeting from Shell Oil Co (They brought
lots of photos of long term tests) and it seems that their gas (in Canada,
anyway) has Potassium as a spark enhancer which acts like Tetraethyl Lead in
that it seems to prevent many of the problerms with valve seats, etc.
associated with unleaded gas. I've used it over long periods with no
problems. Of course you WON'T notice any problems with unleaded for quite a
while anyway, but when you do its too late! Check with your Shell
supplier...
norm from Calgary
----------
=>|From: tigers-owner
=>|To: 'Tiger List'
=>|Subject: RE: Re[2]: "K" vs "HP"
=>|Date: Friday, May 31, 1996 6:30PM
=>|
=>|
=>|
=>| I don't think that pinging is the major issue with lead free gas.
The
=>|newer methods
=>|that are used to raise octane still produce ping resistance (octane
rating).
=>|What is missing from
=>|the new fuels is the lubrication/heat properties that lead provided on
the
=>|valve
=>|seat areas. In an
=>|engine that is constantly run hard disassembly will show that the valve
seats
=>|have become
=>|recessed into the head; literalily pounded back. Engines with inserted
and
=>|hardened valve seats
=>|do not suffer from this but the earlier iron heads had no inserts, the
seats
=>|were machined from the
=>|head material and therefore unable to withstand the unlubricated
conditions
=>|present under heavy
=>|load for extended periods of time.
=>|
=>|Aftermarket heads and head rebuilds now include hardened inserts which
are
=>|simply installed in
=>|place after spot milling a recessed area to press fit them into.
=>|
=>|Jim
=>|
=>|
=>|
=>|----------
=>|From: INTERNET:LeBrun@hii.hitachi.com
=>|Sent: Friday, May 31, 1996 11:07 AM
=>|To: INTERNET:GARY_WINBLAD@CA.CREDENCE.COM; Roland Dudley
=>|Cc: 102430,3640; INTERNET:TIGERS@AUTOX.TEAM.NET
=>|Subject: Re[2]: "K" vs "HP"
=>|
=>|
=>| Roland;
=>|
=>| -Right after purchasing our TIGER, I went by my "local" 76
=>| station & there were some, older faded bottles labeled
=>| "lead substitute". Reading the fine print, they contained
=>| MEL, so obviously pre-dated the phase out in CA. The bottles
=>| were so faded, they'd been on the "rack" outside for quite
=>| some time. The newer stuff of course, has dropped the MEL
=>| from the ingredients list.
=>|
=>| -I put in a bottle every 2-3 tanks of gas & I use 87 Octane
=>| with no pinging. Even without the additive, I have no
=>| pre-detonation on the 87. Since my engine is slightly
=>| "pumped", I thought this would be a problem, (nothing a
=>| 2-3 degree retard in timing won't cure) but it hasn't been.
=>|
=>| -I haven't experienced any "gumming" either and our car may
=>| not get driven every week. I sprayed a couple cans of B-12
=>| through & over my carb(also good for cleaning c. chambers of
=>| all your carbon buildup) after getting the car home 6 months
=>| ago. I haven't had any deposit problems since then either.
=>|
=>|
=>| Phil
=>|
=>|
=>|______________________________ Reply Separator
=>|_________________________________
=>|Subject: Re: "K" vs "HP"
=>|Author: Roland Dudley <cobra@cdc.hp.com> at ~INTERNET
=>|Date: 5/31/96 10:33 AM
=>|
=>|
=>|>
=>|> >I have a 2V 289 in my snake at the moment (CR=9.3:1 + 31 years of
=>|> >carbon build-up) and it runs just fine on el cheapo 87 octane.
=>|>
=>|>
=>|> And that is the engine your Tiger has (only if its a Mark II, all
others
=>|> are 260 engines).
=>|>
=>|> Octane enhancer is not required but is lead substitute??
=>|>
=>|> Gary
=>|
=>|And another question: do any of the lead substitutes really work?
=>|I've head that none of them do anything except gum things up.
=>|Note I said substitutes. Adding MEL doesn't count, since it's not
=>|available for street use here in CA.
=>|
=>|Roland
=>|
=>|
=>|
=>|
|