Glowing down pipe.

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Mally T

Mally T

Member
Posts
46
Location
North Wales
Coming home from Scotland in our D1 300tdi on Sunday and after travaling 300 miles we
stopped at one of the services on the M6 for fuel and my partner just happened to see a
red glow under the disco.
Thinking the worst i opened the bonet quick to see the downpipe glowing red just under the
manifold, never seen it before on a long journey, we were doing between 60 + 70 all the
way home.
I was just wondering if any one else had noticed the same thing?
Happy new year to every one.
Mal
 
Not on a Land Rover, but when I was driving a D8K on heavy clay one winter I used to enjoy watching the turbo glow as it got darker.

I wouldn't worry about it too much, but if it does concern you then perhaps you could fit an exhaust gas temperature gauge to see how hot it's getting?

I take it she's had a tweak on the pump and boost?
 
As above - if it's standard, then I'd be concerned... If modified then how ? I'd also recommend an EGT gauge - and possibly, if it is modified, as a matter of urgency... 60-70 isn't that fast - shouldn't need that much power....

I drive a D1 300Tdi auto with FWIC, and tuned to 145HP - highest EGT temps I allow are 600C - which will probably be dull red at the manifold... last time I looked my downpipe isn't discoloured as I'd expect if it had been red hot...
 
Mally T said:
Coming home from Scotland in our D1 300tdi on Sunday and after travaling 300 miles we
stopped at one of the services on the M6 for fuel and my partner just happened to see a
red glow under the disco.
Thinking the worst i opened the bonet quick to see the downpipe glowing red just under the
manifold, never seen it before on a long journey, we were doing between 60 + 70 all the
way home.
I was just wondering if any one else had noticed the same thing?
Happy new year to every one.
Mal
Click to expand...
The pipe could have an excessive internal carbon build up layer from lots of short runs. A long sustained higher speed type run would heat up the pipe and the carbon layer burning out could produce the red glow. As previously said the temp at which the pipe will be red heat is around 900deg F (460degC), it is not uncommon for your egt to reach above that. The fact the pipe remained glowing would indicate that some type of insulation effect was in play.
 
Thanks for the input gentlemen, yes the previous owner fitted a boost pin to the pump
and put a straight through exhaust and blanked off the EGR.
Not sure how good the boost pin is, i think it makes the engine smoke on acceleration
and the extra power isn't that noticeable in my opinion.
Many thanks.
 
Might be worth checking the injection pump timing as well, only need to remove the little round plate on the front of the timing housing to get to the timing pin holes.
Im thinking if the downpipe is glowing the turbo must literally be cooking!
The problem with the boost pin is you get loads of excess fuel with very little boost hence the smoke.
 
Mmm, yeah, boost pins :oops:

Guys who tend to fit them and rave about how amazing they are either got paid to, had a **** poor tune on it to start with or were seen a few months later buying new engines where theirs had self destructed from the over enthusiastic tuning of an engine whose design dates back 50 years.
 
sierrafery said:
That's why i'm insisting on the necessity of an EGT gauge :rolleyes:
Click to expand...
I have read a hundred or more threads on fitting EGT set ups, I considered it but time & money have never gone hand in hand when I wanted to so not yet got round to it, maybe if I can spare some change when I do the head gasket?

But on a heavily tweeked engine it's a must!
 
Gazbo has it right, a glowing down-pipe classically means the catalytic converter is blocked (it's just before the join to the centre silencer, on the downpipe), very little else it can be. Steel glows a very dull red around 500c, takes on the orange hue nearer a thousand. For a functioning exhaust to reach these temperatures that far down the system you'd have holes in the pistons and a melted head face long before the glow.

If the cat on your down-pipe hasn't outlasted the flex joint, that's a sure sign of fairly poor emissions as well

I'd say bung a hole through the existing blocked cat (reduces any minimal risk of fire or damage to 0), find out if there is an underlying issue and then sort it - and top it off with a nice new downpipe after.

Or just chop it out / delete it as many do and live with the stink and enraged cyclists :rolleyes:
 
Red down pipe, is too much fuel at injection, which hasn’t finished burning when exhaust valve opens, the heat will distort turbo ( if it hasn’t already ) and will need replacing
 
Goc3k said:
....a glowing down-pipe classically means the catalytic converter is blocked....
Click to expand...
this thread is about a 300tdi so which cataliytic converter? ... although on those fitted with a catalyst if it's clogged nothing will evervglow too much cos there will be no power and eventually the engine will stall under load.... as said high EGT is the result of overfuelling under load
 
Edit: ah, scrap all that. Totally skimmed the part where we were informed it had a straight through (woops!)

Is it a recent purchase / problem? excess unburnt fuel can also be traced back to boring service problems such as a balding intercooler, poor valve seating / clearances, over retarded injection timing, poor injector spray pattern / limited boost getting to the inlet manifold, etc.
 
Last edited:
Yes, it's a recent purchase, excess unburnt fuel is what I think it might be (boost pin).
The engine is supposed to be reconditioned, I think not, she does run ok but smokes on
acceleration.
If it happens again I will take a picture and post it.
 
I'd check to see if the max fuel screw still has its security collar as well, as usually a boost pin alone wont cause much noticeable extra smoke in the daylight from the drivers seat with usual / steady driving, especially worth checking if it really smokes when you pull away a bit hasty. Might be a cheap softy ebay pin that has started to bind as well potentially, easy to check at least.
 
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