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Re: TECHNICAL RESPONSES #2

To: MR JOHN H TWIST <VRHS43A@prodigy.com>
Subject: Re: TECHNICAL RESPONSES #2
From: "John M. Trindle" <jtrindle@tsquare.com>
Date: Sun, 6 Oct 1996 07:08:18 -0400 (EDT)
On Sat, 5 Oct 1996, MR JOHN H TWIST wrote:

> WEBER or DUAL SU's:  If you MUST replace your Stromberg, the Weber is an
> often suggested replacement.  Properly fitted the MG will perform very
> nicely.  But remember, if God had wanted Italian parts on MGs, then He
> would have made Kimber work a deal with Mussolini.  Besides, most Webers
> stall on heavy acceleration from idle.

The downdraft and the sidedraft Webers have different characteristics,
don't they?  My understanding is that a downdraft Weber conversion can be
made to be a compatible replacement for the Stromberg, with no negative.
The choice between downdraft Weber and SU isn't quite as clear.

Sidedraft Webers are for wierdos like me who idle at 1100 and spend more
time above 4K than most.
 
> RUBBER TO CHROME CONVERSION: Why?  If you want a chrome bumpered MGB, buy a
> chrome bumpered MGB.  If you want to lower your rubber bumpered MGB, then
> purchase the shorter front springs and de-cambered(?) leaf springs.  We
> converted a rubber bumper to chrome bumper years ago, under strict
> instructions from our customer.   It was hideously expensive, and for what?

Bravo!  I'm not an originality freak by any means, but the car should
resemble what it started as... There are plenty of rusty chrome bumper
cars that need only a >little< more TLC than they're worth.  You end up
with a proper VIN number to model match at the end.

Lowering the car is one thing, but making believe it is a different car is
something else.
 
> 1977 MGB ELECTRICS:  Several peculiar problems are common with the 1977
> MGB. First, the electric cooling fans were wired to the BROWN circuit.
> This allowed the fans to run for up to 20 minutes AFTER the car was shut
> off!  The wiring was changed in 1978 to the WHITE/BROWN circuit, allowing
> them to run only when the key was ON.  Second, the ignition WAS wired
> through the ignition relay.  This was changed in 1978 but the relay
> continued to be called the ignition relay.  In the 1977's, it is possible,
> if the anti run-on system is NOT working, to have the engine continue to
> run for up to a minute, ignition switch turned OFF and key in your palm.
> Also, in the 1977 -> 1980 models, a failure of the brake warning light
> diode can allow the engine to start when the handbrake is pulled UP!

You frighten me with this... that's why I stay out of the 75-80 cars and
all the Naderisms/emissions on mine have stayed disabled (were removed by
Previous Previous Owner).  However, the fan issue: 

On aftermarket fans, anyway, you can add an ADJUSTABLE fan thermostat to
the system for < $50.  Adjust this so the fan does not keep running for 20
minutes under your prevailing weather conditions.  Mine runs for about 3
minutes in the hottest conditions, cutting off after < 1 minute in regular
70-80 degree ambient and normal driving conditions). 

I would not run the electric fan to switched power with this setup, as
running after the switch is off prevents heat soak.  The coolant still
moves a little bit as long as the thermostat is open.  You want the fan to
cut off about the same time the engine thermostat is not allowing any
significant flow.  This adjustment point will turn the fan on immediately
when the engine thermostat re-opens.  Adjustment procedure is documented
from the fan thermostat manufacturer. 

John M. Trindle | jtrindle@tsquare.com | Tidewater Sports Car Club
'73 MGB DSP     | '69 Spitfire E Stock | '88 RX-7 C Stock
"Budget: A method for going broke methodically."


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