Glowing Exhaust Manifold - Cant Be Right !

[Kieran133 0]

Hello to all,

 

I have just completed a rebuild on a standard 205 1.6 gti engine - I have made no changes all standard parts have gone back in.

 

I started the car to run in the new (but standard) cam (I was told to run it in at about 3500 RPM for around 30mins).

 

After about 5mins I noticed that the exhaust downpipe was glowing a nice shade of red and after another 30 seconds the manifold was starting to glow. At this point I shut the engine off.

 

I should point out that this was running in the garage at around 4pm last night.

 

All of the engine settings, timing , mixture screw etc are all the same as they were on the engine when I took it apart - I dont think that anything should have been changed by the rebuild.

 

Is this normal?

 

Any advice or suggestions would be appreciated.

 

Ahh - one thing that has changed is that I have a cotton braided hose that I cant find a location for. It is not the vacuum advance for the dizzy or the vacuum hose for the brakes (but is the same size as this one).

 

I have located two push on hose fittings under the throttle position sensor which are unconnected - I also have one on the breather on top of the oil filler which has been blocked off since I bought the car - there must be another one some where - any suggestions?

[Faz85 0]

It sounds like the dizzy advance to me, as the charge is combusting on its way out of the chamber. I would check your ignition timing and ensure the vac advance is working correctly. If advancing the ignition doesnt work, It could also be due to mixture being over lean, due to an air intake leak somewhere.

 

Faz

Edited February 15, 2007 by Faz85

[Anthony 1,000]

Whenever I've seen this it's been due to excessively retarded ignition timing - advance the dizzy a fair whack and see if the problem remains (but listen for pinking under load and knock it back if needed until it stops)

[ALEX 98 1 Cars]

Stupid question, but have you put coolant in it?

Does your fan come on?

A lean mixture caused by advancing the timing can cause hot running temps.

If it idles OK then the hose you have spare is likley not required.

The only cotton bradded hose I know of is the Servo / Inlet manifold pipe.

There is a short length about 2" long which is used to tee in the pipe for the sunroof seal.

[Craigb 2]

When this happened on mine it was an air intake leak

[B1ack_Mi16 67]

Would say either the camtiming is out, or the ignition is too retarded.

[Kieran133 0]

Thanks for the responses - it seems we all agree its not right.

 

possible causes are dizzy timing - which I have tried changing, or an air leak.

 

This leads me to think that the hose I am missing could be critical - would it be possible for someone to tell and see what (if anything) is connected beneath the throttle position sensor, hose wise.

 

thanks

 

K

[pug_ham 242 3 Cars]

When I ran the cam in on my engine the downpipe was glowing so hot you could see the central split through it. That was only after 15 minutes though & with no cooling air flowing around it. I've seen cars on rolling roads with exhaust manifolds glowing due to the high under bonnet temps you get with no airflowaround the car from driving.

 

Wish I'd had a digital camera at that point, it would've been an ace shot.

 

3500rpm is bit high for bedding a cam in imo, max I was told to use on mine was 3k but 2.5k is enough.

 

Hoses to the throttle body underside should be two coolant hoses & the dizzy vacuum advance hose. There is one spare thats unused thats about the same size as the coolant ones. There should have a hose from the oil filler cap to the throttle body, its a small diameter hose & not the spare cotton one you have though.

 

Where does the cotton hose go if you follow its path?

 

Graham.

[brianthemagical 1]

whats the engine temp like (on the guage in the dash)? if you start the car again, check to see if there is any sution on the hose you have?

[chris1986 1]

mine did this when i first got it. it stopped doing it when i fitted new vac advance and adjusted the dizzy to suit. now everythings fine even after long motor way journey or track