Richard,
The first fact of Tiger life is
1. The cooling system is marginal. Especially a stock one.
Two things make it marginal.
1. Radiator size. If you compare a tiger core to any other car that uses a
Small Block Ford you will see that they are all 20 to 50 percent larger.
2. Lousy air flow patterns through the radiator and engine compartment.
I have a fiberglass LAT hood on my Tiger. At 70 mph the corners of the hood
are flexed up almost an inch from the air pressure under the hood. Just
reving the engine at a light will make the corners flex. That air pressure
buildup restricts the amount of air the can flow through the radiator.
No lets discuss your temp readings. I will assume that your system is
working and calibrated. Others have told you why that assumption may not be
valid, so check it out.
Since you are not complaining about boiling over just inquiring about temp
reading differences , I think my assumption is valid.
What temp rating is your thermostat? It most likely a 180 (what I use) or
160.
If it is either of these a temp reading around 200 means that the thermostat
is wide open. Once the stat is wide open the water temp will vary quickly
with any change in airflow or hp output.
My car does pretty much what yours does. It sits at 195 in town or on the
road at 55-60.
The faster I go, the hotter it runs. At 80 it runs about 220. I know my
gage is accurate, I have compared it to a thermocouple mounted in the
radiator tank and an Infrared thermometer. They all agreed within 3 degrees
or so.
Erich
----- Original Message -----
From: "Richard" <rcsphx@qwest.net>
To: "Tiger List" <tigers@autox.team.net>
Sent: Sunday, May 08, 2005 9:58 PM
Subject: heat at speed
> Ok guys ....here's another engine temp question.
>
> I have 67 MKII....all stock. If you are driving in town in stop and go
> traffic and the temp gauge stays at around 200. Why when driven on the
open
> road at 65 mph and 3000 rpm does the temp rise to over 212? Then when
back in
> slower in town driving with the engine at around 2000 rpm the temp starts
to
> drop back to around 200.
>
> I have always assumed that faster is better for cooling. Why wouldn't
the
> increase in air flow thru the radiator at the higher speed compensate for
the
> increase in engine temp and keep the temp at around 200. Would this
indicate
> that the water pump is not pushing enough water thru the system to cool
the
> engine?
>
> Thanks
> Richard
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