Exhaust manifold temp

[iani]

Whilst trying to fit my new throttle linkage I had the car running at 1450 RPM, only for a couple of minutes and I observed that the exhaust manifold was obviously very hot but there seems a big difference across the pipes, does this look ok?

 

[ed_h]

I really don't think your manifold should be glowong red.  Check timing and/or mixture.

 

Ed

 

[peejay4A]

+1.  After a high speed run I wouldn't be too surprised but at <1500 RPM I would suspect way too lean a mixture or grossly retarded ignition.

[iani]

I think it is the timing, I removed the throttle linkage, fitted an overhead one and the car was idling too high. The butterflies appeared fully closed and the rods weren't activating the rods, I adjusted the timing to bring the RPM down, that worked but obviously it went too far off. Reset the timing to 11 degrees but idling way too high. I just don't seem to have any luck with this car, every job turns into a nightmare.

[peejay4A]

Never change timing to adjust idle speed. If you can’t get the idle down using the idle valve and the butterflies are close the you have an induction air leak. 

Edited September 22, 2018 by peejay4A

[iani]

32 minutes ago, peejay4A said:

Never change timing to adjust idle speed. If you can’t get the idle down using the idle valve and the butterflies are close the you have an induction air leak. 

Yes, I knew this really, I should have left the car alone today, I had my oldest dog PTS this morning and my head wasn't in the right place to do this work at all. In the end I have buggered one of the new Throttle rods too, it will prove to have been an expensive day.

Ian

[Mk2 Chopper]

Sorry to hear your news, the car can wait till you feel up to the challenge again.  

[Waldi]

Hi Ian,

sorry to hear about your dog.

When steel is heated, the color changes from black (or whatever color) to deep red to orange to yellow. It also matters if it is seen in daylight or in darkness. I once was inspecting a SS flue gas system at night, and through the narrow gaps between the external insulation, I could see the SS304H piping, wall thickness 32 mm, glow orange. Inside (normal operating) temperature: 750 degr.C.

At daylight it was just dark brown (typically for oxidized SS).

Yours may be a little colder, but not much.

Since your exhaust is cooled by convection and radiation, the metal temperature will be quitte a bit lower than the exhaust gas itself although not much, since this is a thin wall pipe. It is too hot anyway.

Waldi

Edited September 23, 2018 by Waldi

[iani]

Went back to the car this morning, all now running correctly, idling at 850 RPM and the exhaust isn't glowing anymore. Unfortunately I need to replace one of the new throttle rod ends as I foolishly levered against it and it broke, I have also bent the lever arm that it connects to, hopefully RTR will sell me spare parts.

Ian

[TriumphV8]

That is pretty normal for a race car with a cam beyond 320 degrees.

It simply releases the burning mixture very early when there is still energy to burn contained.

Nobody likes it but it is necessary to make place for a new cycle starting with inhaling new mixture

and that happens at very high rpm when time is short.

 

If we see that at a street engine we should first ask for the cam.

Next is ignition timing, it should fire the mixture that max pressure is reached about 10 degrees past TDC.

Next is mixture and filling of cylinders. Poor mixture and poor filling lets mixture burn slowly and if so

it will burn still in the exhaust.

 

I would check:

Is cam positioned around equal lift at TDC

Is timing mark at pulley correct and rubber holding the pulley properly

Is timing at 1500 rpm at 15 degrees

Check sync for the 6 inlets by flow measuring

Check exhaust gas with a wideband and set to 13.5-14

 

After that the trouble is gone unles you fitted a race cam

In that case please make a video when its on the track!

[Andy Moltu]

You often see it with tubular manifolds when breaking a cam in.

Otherwise how often do you do sustained revs over over 2000 rpm with the bonnet up? On a rolling road perhaps but otherwise we just don't see the plpes when really cooking.

[barkerwilliams]

I am in admiration that you are able even to attempt to adjust the linkages next to those pipes. My fingers have trouble with the heat even without an angry,  glowing exhaust, oh for a  single screw / locknut on each of the adjusters.

Alan

Edited September 24, 2018 by barkerwilliams

[iani]

1 hour ago, barkerwilliams said:

I am in admiration that you are able even to attempt to adjust the linkages next to those pipes. My fingers have trouble with the heat even without an angry,  glowing exhaust, oh for a  single screw / locknut on each of the adjusters.

Alan

What's needed is a fixed adjusting nut in the centre of the rods, John Mangoletsi does a great throttle conversion kit for E-types that uses this type of rod and it's far easier to adjust. https://www.sngbarratt.com/uk/#!/English/parts/8791d9e7-fc62-4945-935c-5faa7f3469d8

[TR NIALL]

19 hours ago, iani said:

What's needed is a fixed adjusting nut in the centre of the rods, John Mangoletsi does a great throttle conversion kit for E-types that uses this type of rod and it's far easier to adjust. https://www.sngbarratt.com/uk/#!/English/parts/8791d9e7-fc62-4945-935c-5faa7f3469d8

A small long nosed Vice Grips helps if you’ve the type without the Nut in the middle.

[TriumphV8]

20 hours ago, barkerwilliams said:

I am in admiration that you are able even to attempt to adjust the linkages next to those pipes. My fingers have trouble with the heat even without an angry,  glowing exhaust, oh for a  single screw / locknut on each of the adjusters.

Alan

Very easy If you know the tricks (for CP):

Remove air box and shorten the throttle wire and lock the air valve fully that you have 2000rpm.

Decide manifold 2 to be the master.

Compare 2 with 1 and stop the engine.

Now you have all the time to set the linkage for 1 in the required direction.

Push the pedal and let release quickly and start again.

Compare 2 with 3 and than 2 with 1 for a quick check.

Stop engine and if necessary give 1 a little correction.

Than set 3 in the required direction.

Again push pedal and start and check all 3 one last time.

 

A very easy way without burnt fingers!