Date:         Thu, 13 Mar 1997 16:41:12 -0500
Sender:       Vanagon Mailing List <vanagon@vanagon.com>
From:         Leavitt <mleavitt@tiac.net>
Subject:      Re: Gasoline Grade?

SyncroHead@aol.com wrote:
[snip]
> midgrade(R+M/2=89).  Listen closely for pinging under hard accelleration,
> like up a hill.  If you hear any, go back to premium.  If not, thry the
> regular(R+M/2=87) grade and listen for pinging again.  If you hear any, go
> back to the midgrade.  If not, continue using the regular and continue to
> monitor for pinging.
[snip]

I find that's it's difficult to drive up steep grades with my head under
the rear mattress! Any suggestions?

 Seriously, that description of octane was right on the mark, bravo! I
might add though, that for those not familiar with the actual sound that
pinging makes, for instance people who drive *newer* vanagons and EVs
(nya!), I would have to describe the actual noise to be more like a
strange tinny rattle that you aren't even sure that you heard.
Especially in a Westy where the motor can be buried under quilts and
sleeping bags and dirty laundry...etc. I'd say that if you even suspect
that you have pre-ignition use a higher octane. 
 Lately I have been using 87 in my '81 Westy (budget cutbacks!), but the
engine was freshly rebuilt. If and engine is older and has a lot of
carbon or fuel additive deposits inside the combustion chambers (most
well used engines) then knocking can be more prevalent. The deposits can
continue to burn like glowing charcoal embers and in conjunction with
the high compression can pre-ignite the mixture long before the spark
plugs have a chance to. ...and voila, pretty soon you've got a big hole
in yer' piston! OUCH! 

 A temporary solution might be this spray that my cousin swears by, it's
called 'GM top end cleaner'. It works the same way as the old method of
people dropping a glass of water down their intake manifold while
revving the engine (the ol' steam clean). Well, I don't know if that
ever worked, but this stuff is based on more scientific princible...at
least I hope, it might just be a can of kerosene! Anyhow, you spray it
into the intake manifold while it's hot and rev the engine. It usually
stalls out the engine, but that's okay because your supposed to let it
simmer for a bit (maybe add some carrots ;) and then restart the engine
and *in theory* it's supposed to blow out excess carbon deposits and
other crapola. You can find this miracle spray at any GM dealer. [No, I
am not selling the stuff, I don't even really like GM products!] 
 The way I figure it, it can't really hurt in an old dirty engine, but
please don't hold me liable. After all, dry revving any VW engine can be
a very percarious undertaking. That's why I always keep spares ones
handy! ;) I myself have tried it, but the engines really weren't running
badly to begin with so there wasn't any remarkable improvement that I
could notice. 

Noel

                                VOLKSWAGEN
                                          
                                _--````--_
                              / _--````--_ \
                            / /  \ \  / /  \ \
        '81 Vanagon Westy  | | \  \ \/ /  / | | '68 Sunbug Autostick
                           | |\ \  )--(  / /| |                  
              (named Vana) | | \ \/ /\ \/ / | | (named Rachel)
                            \ \_\  /  \  /_/ /
                              \ _``----``_ /
                                 ``----`` 
                                          
                                1937--1997


      ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
                 "Sealed with a curse as sharp as a knife. 
               Doomed is your soul and damned is your life!"
                 -Doctor Emilio Lizardo/Lord John Whorfin
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