<VV> 140 hp Engines - Powerglide vs 4 speed
Bill Hubbell
whubbell at cox.net
Fri Nov 18 11:00:28 EST 2005
The difference between the 140-MT and the 140-PG is not just in the cam but
also in the crankshaft timing gear, which is retarded 4 degrees on all but
the very early 1965 140-PG engines.
Of course, there are other (external) changes as well, such as distributor
timing, carburetion, etc.
My whole point here was to impress upon all of you that GM obviously spent a
lot of time researching the best combination of adjustments in timing, gear
ratios, etc. to get the most out of the 140 when it was mated to a
Powerglide, but after 40 years of tinkering, many of these engines have been
mated and tuned to less than optimal conditions. I'm not saying that GM had
the only "best possible" configuration, but rather that we need to be more
precise in our discussions when comparing different powertrain
configurations to make any sense out of the results.
Bill Hubbell
----- Original Message -----
From: "Norman C. Witte" <ncwitte at wittelaw.com>
To: "'Bill Hubbell'" <whubbell at umich.edu>; <virtualvairs at corvair.org>
Sent: Friday, November 18, 2005 10:05 AM
Subject: RE: <VV> 140 hp Engines - Powerglide vs 4 speed
> So, assuming that you could put any 140 with any diff and any trans, that
> would give 320 possible combinations! Still, the gist of the discussion
> from what I gathered was that if you want to convert a 140 MT car to a PG,
> you really need to rebuild the motor or get a motor with the PG cam as
> well.
> Since the original post was seeking advice regarding the feasibility of a
> conversion of a 140 Corsa to PG, the upshot to me seemed to be that you'd
> be
> farther ahead to get a 140 PG Monza and "Corsafy" it.
>
> Norm
>
>> -----Original Message-----
>> From: virtualvairs-bounces at corvair.org
>> [mailto:virtualvairs-bounces at corvair.org]On Behalf Of Bill Hubbell
>> Sent: Friday, November 18, 2005 9:41 AM
>> To: virtualvairs at corvair.org
>> Subject: <VV> 140 hp Engines - Powerglide vs 4 speed
>>
>>
>> Just catching up on a number of old VV posts, and I must admit even a
>> veteran Corvair person like myself found this thread
>> confusing, because you
>> guys were not all talking about the same setups. Just to
>> clear the air for
>> all involved, and especially those new to the hobby, I would like to
>> introduce the following information.
>>
>> DISCLAIMER: The following information is not all-inclusive -
>> some exceptions
>> are known to exist.
>>
>> There are eleven different engine suffix codes for the 140hp
>> engines, and
>> this breaks down into roughly 8 different engine types:
>>
>> (MT=Manual Transmission, PG=Automatic Transmission, CAC=Car Air
>> Conditioning, AIR=Air Injection Reactor)
>>
>> Type # Engine Code(s) Application
>> 1 RM, RB MT (RB has thermister for CORSA)
>> 2 RN PG
>> 3 RZ, RR MT with CAC (RR has thermister)
>> 4 RY PG with CAC
>> 5 RQ, RT MT with AIR (RT has thermister)
>> 6 RX PG with AIR
>> 7 QQ MT with CAC and AIR
>> 8 QR PG with CAC and AIR
>>
>> Now to add to the confusion, there are 6 different possible
>> Transmissions
>> that were made from 1965-69, but if you count the ones from
>> previous years,
>> there are a total of 11, of which 10 have uniquely different drive
>> characteristics
>>
>> Type# Application
>> 1 1st version 3-speed (1960 - aluminum case)
>> 2 2nd version 3-speed (1961-3)
>> 3 3rd version 3-speed (1964-5)
>> 4 4th version 3-speed (1966-9)
>> 5 Early FC 4-speed (1961-3)
>> 6 1st version car 4-speed (1961-3 and 1964-5 FC)
>> 7 2nd version car 4-speed (1964-5)
>> 8 3rd version car 4-speed (1966-9)
>> 9 Powerglide (60-3 and 64-9 64-9
>> designed for 164cu
>> engines)
>> 10 140-Powerglide (65-9)
>>
>> Finally, there is the Differential to consider - seven
>> versions (4 for MT, 3
>> for PG), representing four different ratios:
>>
>> Ratio: Applications
>> 3:08:1 Special Application - 1963 only (4-speed MT)
>> 3.27:1 Standard Ratio for all MT cars and low HP PG
>> 3:55:1 Standard ratio for higher HP PG cars,
>> 64-5 FCs, Turbos,
>> and cars with CAC and/or AIR
>> 3:89:1 Standard ratio for FCs 60-63
>>
>> Note that the 140-PG engine was meant to be mated to the
>> 140-PG transmission
>> and a 3:55-Powerglide rear axle to give optimum performance.
>> Also, if the
>> car was equipped with either AIR or CAC the engines were
>> modified to have
>> lower compression ratios, and this also affected performance.
>>
>> Finally, and this should be obvious, the 140 was never
>> offered for early
>> Corvairs (1960-4).
>>
>> So please, if you are going to have a discussion of the
>> differences between
>> 140-MT and 140-PG be sure to state which 140 engine you are
>> using along with
>> which transmission and which differential. You certainly
>> cannot expect that
>> a 140-PG CAC engine installed onto a 1964-5 four speed with a 3:89
>> differential to perform as well as a 140-MT engine mated to
>> its proper 3rd
>> version 4-speed MT and 3.27 differential!
>>
>> Bill Hubbell
>>
>>
>>
>>
>>
>>
>>
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