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RE: Running hot under load during hot (90F degrees+) days

To: "Bill Zenkus" <mgb_zenkus@yahoo.com>, <mgb-v8@autox.team.net>
Subject: RE: Running hot under load during hot (90F degrees+) days
From: "Jim Stuart" <jimbb88@comcast.net>
Date: Mon, 17 Jul 2006 22:44:00 -0400
In-reply-to: <20060717174041.80754.qmail@web82509.mail.mud.yahoo.com>
Reply-to: "Jim Stuart" <jimbb88@comcast.net>
Sender: owner-mgb-v8@autox.team.net
I drove a 1977B V8 for several years and this is what I found:

LE spoiler was very effective at speed in keeping the water cool, but it
needed a bit of aluminum wrapped around the radiator extending to the
spoiler to be sure that cool air went through, and not around the radiator.

the car ran cooler with a 180' thermostat than with a 160'.

cut your coolant mix to 15-25% antifreeze. Water is a better coolant.


You don't say what headers you are using, but if they are block huggers, you
need to consider opening up the inner fenders to allow the hot air an exit
from under the hood. The under hood area in an MGB is pressurized by air
entering from under the body, having no way to escape. Front spoilers help
to reduce the air pressure, but do not eliminate it. The faster you go, the
higher the pressure and the more heat.

I am not sure what you are telling us about your engine size, but if it is
much larger than 215 CI, the V8 spec radiator is inadequate. It was barely
enough in England where 80' is a heat wave.

You should get a measure of your oil temperature. If your oil is 230' at
speed, it is raising your water temps as well, and you may need to add an
oil cooler. My multimeter has a temp probe that is good to 480', and the
meter was a $25.00 Harbor freight special. You could check through the
dipstick opening after a run, without having to plumb a gauge.


Jim Stuart

Reply to <jimbb88@comcast.net>


-----Original Message-----
From: owner-mgb-v8@autox.team.net [mailto:owner-mgb-v8@autox.team.net]On
Behalf Of Bill Zenkus
Sent: Monday, July 17, 2006 1:41 PM
To: mgb-v8@autox.team.net
Subject: Running hot under load during hot (90F degrees+) days


Need some help from the list.

I finally got to use my car on a hot day (yesterday in Connecticut) 95+
sunny degrees.

Engine temp was very good at idle no load, but it would get hot (220F -
230F) even on a highway drive at 65 - 75 MPH.
As soon as I stop and let the car idle for 8 to 10 minutes, it would "cool"
back down to 180F - 190F. Runs great on cooler (75F or less) days.

I am running the OEM V8 radiator with a 50/50 mix of water to antifreeze. I
have one large electric fan (puller) with a full shroud directly between the
radiator and the engine. 160 degree thermostat. The fan cycles as it should
at idle to maintain temp and is running constantly when the engine is "HOT".

At this point I am thinking it may be due to lack of air flow at speed due
to the bottom third or so of the radiator being "blocked" by the rubber
bumper and solid air dam mounted below it. At idle the fan can pull
sufficent air through but at speed, the air dam is creating a negative
pressure just in front of the lower portion of the radiator thus reducing
flow just when the load and requirement has increased.

I plan to fabricate a duct from the air dam to this area of the radiator,
but at this point I would sure appreciate some advice from all the experts
on this list. I wish to use the "B" as my daily driver but need to solve
this first.

Bill Zenkus
74 MGB, 64 Stroked Olds 4.3 l
 Email: mgb_zenkus@yahoo.com

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