V<VV> Milled head tech tip (per CORSA Tech Guide)

[Dale Dewald]

At 12:28 PM 8/30/06 -0400, Mark wrote:
>This spring I finished installing a freshly rebuilt 110 manual trans
>engine in one of my cars. The engine was expertly rebuilt by master
>mechanic Mike McKeel, using heads and pistons that were modified by
>Warren LeVeque. The mods were limited to milling the gasket "step" out
>of the heads (while Mike deflashed them), and octane cutting the pistons
>opposite the open area to compensate for the milled heads. Otherwise, it
>was a stock rebuild (including stock bore.) Part of the purpose of this
>was to see if a 110 could be run on regular, as indicated in the CORSA
>Tech Guide.

<<snip>> (comments on dieselling)

>While it's still too early to tell if the head mods will improve
>effeciency (and gas milage), I'd have to say that the Tech Guide needs
>to be amended so as to discount the switch to regular gas. Maybe it
>worked before, but not now.

A point of reference; the Tech Guide article "Running on Regular" was 
written by Bob Helt in either 1980 or 1981.  If you remember those days, 
leaded gasoline was still commonly available as 89 PON and was referred to 
as "regular gas."  "Unleaded gas" was available as it still is today at 87 
PON and most places had "premium unleaded" at 91-92 PON.

I believe that the basic science of the article is sound, it is just that 
technology and terminology has changed in the past 25 years.  Based on my 
experience, I think that the modifications are good for about 2-4 points of 
octane tolerance depending on the engine--140's seem to respond better than 
110's. In most cases it is about enough to use mid-grade unleaded 89 PON 
instead of 92 PON premium in a 140, and permit a 110 to operate on any 
91-92 PON fuel instead of only the best quality 93 PON stuff.

>BTW, the first tankfulls seemed to only get around 22 mpg, but the last
>one got 24.3 mpg. So maybe after a few thousand more miles, I should see
>even better milage. For sake of comparison, I have been able to pull
>26.5 mpg out of my 110 automatic convertable while running the a/c and
>cruising at 70mph. I'll have to see what this 110 manual gets up to.

Excuse me, but was that 26.5 mpg an average of 5 or more tank fulls doing a 
long, cross country round-trip; and have you made an odometer correction?

Dale Dewald
Hancock, MI


-- 
Internal Virus Database is out-of-date.
Checked by AVG Anti-Virus.
Version: 7.1.375 / Virus Database: 268.8.3/362 - Release Date: 6/12/06