Hi Mike
This sounds like a fuel vaporisation problem, I have had the same thing on a
Dolomite where the fuel pipes went around the back of the engine, move them
to the front and the problem is solved. I think your fuel line is already to
the front of the engine so that won't help much. A temporary solution is to
do what a lot of the owners of modified Dolomite Sprints seem to do which is
pop the bonnet (hood) whilst in traffic to let the heat out, when you start
moving again just reach out lift and drop the bonnet so that it catches. The
problem they have is that the air in hole is larger than the air out holes,
so popping the bonnet allows more air flow. Another trick is the use of an
electrical fuel pump as this removes the pump from the hot spot on the
block. Also if it were possible to create a flow and return system for the
fuel so that the fuel didn't travel slow enough to take the heat of the air.
Graham.
Ps I have seen a Pepsi can used to great advantage to lift the bonnet that
little bit higher!
----- Original Message -----
From: Mike HIMELFARB <mhimelfarb@ShoppersDrugMart.CA>
To: Triumphs <triumphs@autox.team.net>
Sent: Thursday, May 11, 2000 4:05 PM
Subject: TR6 Heat Problem
>
> I'm looking for some advice re a heat problem which affects idle and
> acceleration in my 76 TR6. Here's the scenario:
>
> 1) Cold start and normal highway driving are fine. Normal running is
> fine under most conditions.
> 2) When I'm stuck in traffic and hot air builds up under the hood I
> start to get uneven idle and, when I try to accelerate from a stop, the
> car jackrabbits and the engine behaves like it's starving for fuel.
> 3) This behavior appears once the temp gauge creeps over the 1/4 mark
> while idling. If I'm running on a very hot day and the temp creeps up
> while air is flowing no problems appear, thus my conjecture about hot
> air buildup under the hood.
> 4) When I turn off the engine when hot it is very difficult to start
> again, until it cools down below the 1/4 mark on the gauge.
> 5) Carbs are balanced and mixture is correct and set when warm. The
> carbs were cleaned and checked out a year ago so should be ok.
> Diaphragms are intact.
>
> I checked vtr.org and found an article related to calibrating the
> temperature compensators on the carbs which described most of my
> symptoms. I followed the instructions and calibrated both of them to
> start opening at 115F and fully open at 140F but no change in operation
> occurred.
>
> Obviously, because the tuning is done with the hood open the air temp
> never approaches stop and go conditions so I can't replicate the problem
> standing in the driveway.
>
> Here's what I'm considering:
>
> 1) Blame it on the temp compensators again but validate by loosening
> the adjusting nuts so they operate at a much lower temp. This way I
> should be able to replicate the problem standing in the driveway. If
> this works then I'll tighten them down so that I don't approach their
> opening temp until way beyond the 115F current setting.
> 2) I'd like to think an electric fan would help but I don't think the
> engine operating temp is excessive as it never goes beyond the 1/2
> mark. If I did use one I'd have to trigger it at a low enough temp so
> that it ran at the 1/4 mark.
> 3) Plug the passage being metered by the TC's to eliminate them from
> the equation and start troubleshooting elsewhere.
>
> Any advice would be appreciated as I don't want to waste anymore time
> than necessary on this. Can't drive the lbc to work right now because
> of this problem which is becoming frustrating with the beautiful weather
> we're getting in Toronto...
>
> --
> Mike Himelfarb
> Manager, Office Network Services
> Shoppers Drug Mart
> (416) 490-2754
>
>
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