<VV> Re: Bad 110 piston > cruel captain

djtcz at comcast.net djtcz at comcast.net
Sun Nov 4 08:59:00 EST 2007


I suspect an insensitive (deaf) driver put significant miles towards the end on that engine.

Piston edge erosion and metal spray/transfer is classic detonation.
The fact it is concentrated near the spark plug and not in a remote region of the chamber is a little surprising.  

Was there a shop rag or mouse nest in that part of the head? or missing baffle?  Will the same distributor be used?  Just for curiosity, are all 6 plugs similar heat range? 

I might be putting timing tape on the damper to allow checking all 6 cylinders' dynamic ignition timings.

Spark plug reading for timing and mixture here.
http://www.strappe.com/plugs.html
timing note - http://www.strappe.com/plug_burned_16.gif
mixture note - http://www.strappe.com/plug_section_16.gif

Similar plug reading sentiments in Kevin Cameron's Sportbike book, which is biased at least partially toward air cooled 4 strokes. As a tuner Mr Cameron was building and tuning Kawasaki 2-smoke Triples that bested the factory bikes.  Long time tech contributor/editor for the late Cycle magazine, and now Cycle World.

--
Dan Timberlake

-------------- Original message -------------- 
Subject: <VV> Bad 110 piston
To: Virtual Vairs <virtualvairs at corvair.org>
Message-ID: <ED25D36E-EAB2-44E2-8F86-20BD74772D8D at skiblack.com>
Content-Type: text/plain; charset=US-ASCII; delsp=yes; format=flowed

Hi all,

So, last update on the '66 Corsa was I had put a "basement" 110 in it  
that was said to be a good runner when pulled.  On startup, it had  
enormous blowby out the vent tube, no apparent smoke out the  
tailpipe.  My thought and the concensus on VV was that most likely a  
broken ring.  Well, we were close, the #2 piston is eroded at the top  
of the cylinder all the way down to the top ring:

http://autoxer.skiblack.com/BlogPhotos/110piston01.jpg

The head looks ok, with just a little bit of aluminum sprayed into  
the combustion chamber:

http://autoxer.skiblack.com/BlogPhotos/110head01.jpg

I am replacing the cylinders and barrels, my concern is what caused  
this.  I'm using a different set of carbs but the head will go back  
on.  Anything else I should look at?  Thanks for any suggestions.
--
Bryan Blackwell bryan at skiblack.com
http://autoxer.skiblack.com/
   Corvairs: '61 Lakewood, '64 Greenbrier, '65 Corsa, '66 Corsa
   '69 Road Runner, '97 Ford F-150, '99 Neon R/T
"Why do something if you're not going to obsess about it?"


More information about the VirtualVairs mailing list