Board logo

Exhausts
brynhamlet - 9/4/06 at 08:19 AM

To help the uninitiated.
I've had my engine running (Ford Kent with twin dellortos) and when held at about 3000rpm (no tacho so guessing) the exhaust by the head quickly starts glowing red. The engine is not running too hot as the electric fan doesn't kick in if I only do it for a few minutes.
Is this normal?

rusty nuts - 9/4/06 at 08:26 AM

Could be ignition timing or incorrect mixture. You should see some of the F1 exhausts, almost white hot

owelly - 9/4/06 at 07:22 PM

I agree with Corroded Scrotum, the timing will be out.

flak monkey - 9/4/06 at 09:20 PM

As has been mentioned your ignition timing may be out slightly....

Exhausts get bloody hot by the head. I've said it before, take the car for a hard run, lift the bonnet when you get back and you will be able to see the exhaust glowing, especially if its dark.

You dont tend to see it on production cars, but its more noticeable on a seven with a thin tubular exhaust.

If you are doing this test stationary theres no airflow over the exhaust to help cool it either, so it will get even hotter.

trogdor - 9/4/06 at 09:28 PM

yep exhausts right by the head will glow orange, even if the car is only idling. I was puzzled once in the dark as too what was glowing in my engine bay, l did not realise how hot the exhaust would get!

brynhamlet - 10/4/06 at 12:35 PM

Thanks for the help.
As I didn't set up the engine I wasn't what to look for, although I suspected the timing. I'll just have to buy a timing light now and check it against what the engine manual says.

02GF74 - 10/4/06 at 12:46 PM

quote:
Originally posted by trogdor
yep exhausts right by the head will glow orange, even if the car is only idling.


when idling?!?!?!?

mine is about 250 C at idle.

tubular manifold will run hotter than product cast iron ones simply becasue there is more mass in he cast iron one and I'm think I'm right in saying cast iron is a better conductor of heat ... or is it the other way round

derf - 10/4/06 at 10:22 PM

I dont think that cast iron is a better conductor, I think its a better insulator, and holds the heat deep in the bowels of the manifold, I think that because of the thickness of the cast manifolds the whole thing wont heat up unless you really get on it. I have seen the cast iron head of a stock exaust on a rotary glow after hard driving.

NS Dev - 11/4/06 at 07:26 AM

If a tubular exhaust glows at tickover the timing is retarded.

If it glows at 3000 revs the timing is almost certainly retarded as well.

It will definitely glow but only under load and when making a reasonably percentage of the engine's power output. My 16v XE glowed for the first 6 inches of the primary pipes when held at 6500rpm for 1.5 minutes at full load, making 200 odd hp, to put things in perspective, and that was with 1.5mm thick tubes.