Bill -
A series of ideas that may help, in random order, some of them gleaned
from my experience with my similarly equipped '77.
Idea 1: Get a better heat shield. A cookie sheet is okay, but you're
going to need to do better with that CatCon under there. I'm running a
heat shield made of 1/8" aluminum plate with strips of header wrap
riveted to it. I can send you drawings if you like.
Idea 2: Check your fuel/air mixture. If you're running even a little
rich, the CatCon will make a lot more heat.
Idea 3: Rig a second heat shield over the CatCon.
Idea 4: The 1500 hurts for airflow anyway, with that big honkin' bumper
diverting most of the airflow. I added a "chin scoop" under the bumper
to direct air into the two slots under the bumper.
Idea 5: If you do get the header, have it coated inside and out, but
skip the header tape. It doesn't retain heat evenly, leading to stress
cracks in the header after about 5 years (ask me how I know). Actually
just going to a header will help immensely. You wouldn't believe how
much heat the CatCon makes...
Idea 6: Insulate the fuel lines in the engine compartment. Delivering
cooler fuel to the float bowls helps a lot. This was step 1 on my
Midget.
Idea 7: Polish the carbs. This isn't just a vanity thing, it helps the
carbs reflect heat away.
> Now that it is getting warmer out I seem to have the following problem
> with my MG. When the tempeture is in the low 80's the car will run
> rough, stumble on acceleration after I have sat at a light for about 1
> minute or more. I have the same problem if I turn the car off and
> then restart it in the next 5-10 minutes. The problem goes away once
> I start to drive at speed for about 30 to 60 seconds. I figure the
> problem is excess heat under the bonnet.
>
> The car is a 77 Midget with twin SU's. There is a heat shield between
> the SU's and the catalytic converter. There are no plastic spacers
> between the carbs and the intake manifold; there is not enough room
> to add a spacer. The heat shield is a little bit bigger than the
> area of the 2 carbs and was made from one of my wife's finest cookie
> sheets.
>
> First I think the problem is the carbs are getting to hot. Does
> anyone disagree?
>
> The most obvious solution is to replace the exhaust manifold and
> catalytic converter with a header. It would make sense to have the
> header coated by the likes of "jet-coat". Then a layer of header tape
> on top that should help even more. Has anyone done this and did it
> lower the under bonnet temps very much? Were your feet any cooler?
> Does the coating help keep the out of the engine compartment? Anyone
> have any other ideas?
>
> --
> Later,
> Bill "feet of fire" Gilroy mailto:w.gilroy@verizon.net
>
> 77 Midget
> 01 Irish Terrier
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