glowing pipes 3.9 V8

[PSI250]

Recently put a fresh 3.9 in my 86 rangie.
Ever since it has been putting out a heap more heat from then enginebay then the old motor did and even to the point were free revving around 1500-2500 i can get the exhaust pipes to start to glow.

Driving the car on the road even just putting around on a 15deg night i can feel alot of extra heat comming out of the engine bay and if i give it a little squirt (nothing over 3800rpm according to the log) i can get the pipes to glow.

After a 30-45min sedate drive the chassis rail near the exhaust downpipes are too hot to touch, and the steering shaft has a lot of heat in it. when you pop the bonnet you can feel the excess heat, way more then before.
Ends of the spark plug leads are also starting to discolour from getting hot.

I've pulled the plugs out and they look really good and this is backed up by checking the mixtures

its running an aftermarker ECU and I've got a wideband o2 gauge on it and the mixtures seem pretty much spot on.
Timing is on around 8deg BTDC
and coolant temp sits on about a 1/4 on the gauge (which is about 80deg)

engine has done about 250-300k since rebuild.

I would have thought timing or fuel would make the pipes glow, but these seem to check out ok?

rebuilt motor running hot as its still tight? would have thought it would have free'd up a bit by now?

just wondering if theres something i've missed?

[101RRS]

Glowing exhaust normally points to a lean mixture - what is the colour of the plugs - do they show anything.

The engine maybe running hot as a result but with a good cooling system the heat in the engine may be being dealt with - glowing pipes reflects high combustion temps - often caused by a lean mixture or sometimes poor timing.

Garry

[justinc]

Check the timing is actually advancing when revving. Disconnect the vac advance and check that the timing advances at least 10 or 15 degrees above 2500rpm. Or take the dist cap off and see if the rotor button moves against the advance weights and springs back again.

If the timing is not advancing sufficiently, the still burning fuel charge will be heating the exhaust manifolds( and valves:o) excessively.

Leanness can also cause this, so even though you say that the mix seeems right when driving, these engines are pretty dirty and need more fuel to run at their best. Trying to run them at modern car engine emissions levels with stock injection and ignition systems will kill them off...at least yours is adjustable?

Tight engines DO work harder, but getting the manifolds to glow is(Apart from a good caning on a Dyno) a sign of incomplete combustion caused by timing or fuelling IMHO .

JC

[harry]

what exhaust pipes do you have? extractors?
what engine did you replace?
if the water and oil temps are normal then i would consider the heat to be normal.
if you upgraded to a bigger engine then it would be normal to assume greater heat output due to bigger engine does more work.
or else it may be running leaner than you think.
if you have done 300km since installation you can safely assume it's run in and can run safely to max rpm.
another thing to ask is has the exhaust got a blockage, kinked pipe or something?

[Rangier Rover]

If timing is ok sounds like its running lean.Does it knock when laboured(Lean detonation) A small air leak causeng a thermal? I thought the O2 should pick it up:confused:. With EGTs that hot be carfull you don't drop a valve or burn/break a piston.
Tony

[Lucus]

We ahd exactly the same problem when installing the Wold ECU on Jezzaol's 4.6 coil pack conversion.. The problem in the end turnd out to be massivly retarded timing as the trigger wheel was installed 1 hole out. This ment 8deg BTDC(indicated on the ecu) was closer to 22deg ATDC. How are you verfing Acutal ignition timing versus what the ecu is telling you?

What ecu are you using? does it have an ignition offset adjustment?

[PSI250]

exhaust is a 2.5" from the downpipes back with a straight through muffler, stock exhaust manifolds and downpipes.

Engine doesn;t knock/ping actually drives pretty well. i'm not pushing it hard though due to this getting hot.
Haven't got them glowing cherry red but if i get into it a little bit it starts to glow in the thinner down pipes. exhaust manifold doesn;t glow.

AFRs are mostly around 14.8-15:1 and swing into the 13s under acc.

Inspected the plugs and they seem really good.

will have a play around with timing/ dizzy a bit more today and see how i go.

thanks for the help/suggestions, will keep you updated.

[PSI250]

What ecu are you using? does it have an ignition offset adjustment?

megasquirt fuel only ECU. timing is taken care of via std disco dizzy and coil

[Lucus]

What sort of injector firing sequecing are you using?

Does the mega squirt have not ignition control at all?

[mcrover]

Is the Cam standard or custom high lift/long duration.

With a lot of overlapp you can get glowing pipes.

If those levels are acurate then they are good so it's not lean and if it's not pinging then then timing sounds ok.

As JC said, tight engines normally get a bit warm while running in.

[PSI250]

What sort of injector firing sequecing are you using?

Does the mega squirt have not ignition control at all?

alternating injection, Left and right bank.
My version of megasquirt is just purely a fuel only ecu no ign control.


Is the Cam standard or custom high lift/long duration.

With a lot of overlapp you can get glowing pipes.

If those levels are acurate then they are good so it's not lean and if it's not pinging then then timing sounds ok.

As JC said, tight engines normally get a bit warm while running in.

std 3.9 in good nick.

i can understand tight engines getting hot, but the thing is my coolant temps are no higher then 80deg, its only the exhaust getting hot. PLus its done about 300km, i would have though this would have been sufficiant run-in?

Checked the timing, dead on 8deg BTDC, mechanical advance is working fine, vac isn;t working at all, can just suck through the hose with no effect.
Wouldn;t have thought this would effect the heat issue though as cruising and even at idle it can start to get quite hot.

My next angle is to advance it till i get it to ping, then back it off a bit and see if that changes the temps.

if that doesn;t fix it then i don't know, do i start thinking internal issues? :confused:

[Lucus]

Definatly no air leaks in the exhaust system?

[PSI250]

Definatly no air leaks in the exhaust system?

not that i can see,
the narrowband is in 1 bank where the only joins before it are head>manifold and manifold>downpipes and they all are sealed pretty well.

wideband it just after a flange after the 2 pipes from each bank meet, and also looks to be sealed quite well. Have done the rags blocking the exhaust trick and cant hear any leaks.

Both sensors correspond with what the other is showing too.

[PSI250]

Ok had a bit of a play,
advanced the timing to 12deg. noticed bit of a drop in temps with my el cheapo laser thermometer, took it for a drive, had to retune it a little as it was now a little lean. No pinging heard.
Bumped it up again and now its on around 16deg BTDC. drove it and no signs of pinging heard. Will have to wait till tonight for my 'glow test'.
Also should i keep advancing it? i'm on 16deg atm which i though is fairly well advanced! i guess if it will take more give it to it?

Thermometer now shows roughly 200deg at each port on the exhaust manifold and around 235 at the collector on the exhaust manifold. This is at idle after a 30 min drive.
ambient temp 24deg.

on a side note, grand final day in Vic is an awesome time for tunning test runs on the road, next to no traffic!!

Will see how i go tonight.

[harry]

not a bad time in qld either, she is watching the footy too, and i am able to do whatever, can't mow as it is too loud
and back to the tuning,
checking the glow in the dark is probably more of a scare than you need, it probably always glowed in the dark.

[mcrover]

Ok had a bit of a play,
advanced the timing to 12deg. noticed bit of a drop in temps with my el cheapo laser thermometer, took it for a drive, had to retune it a little as it was now a little lean. No pinging heard.
Bumped it up again and now its on around 16deg BTDC. drove it and no signs of pinging heard. Will have to wait till tonight for my 'glow test'.
Also should i keep advancing it? i'm on 16deg atm which i though is fairly well advanced! i guess if it will take more give it to it?

Thermometer now shows roughly 200deg at each port on the exhaust manifold and around 235 at the collector on the exhaust manifold. This is at idle after a 30 min drive.
ambient temp 24deg.

on a side note, grand final day in Vic is an awesome time for tunning test runs on the road, next to no traffic!!

Will see how i go tonight.


Ummmmmm, I may be wrong as Im not all that much of a petrol head, Im more comfy with Diesels but if your running 16 deg advance then it should really be pinging........are your timing marks correct?

Even if it is 5 deg out this may be the cause of your problem.

If you havnt already done it I would pull the plug on No.1 and check the timing mark is spot on or pop the rocker cover off the bank on No.1's side and get the rockers rocking on 1 and then check the mark would be even better.

Ive seen it on more than 1 occasion when a harmonic balancer is changed that the timing marks are out, I cant explain why but Ive seen it on a couple of 4clys in Datto's, at least 1 holden 6 and and a couple of 308's but Im not sure about Rovers, the only ones Ive played with have all been fine.

If the mixture is leaning out as you advance it then your obviously getting more burn in the combustion chamber rather than in the exaust ports/manifold so your getting closer to where you want to be.

I'd keep advancing it until it started pinging and then back it off and see where you are, it may give you a clue as to whats going on.

[PSI250]

Ummmmmm, I may be wrong as Im not all that much of a petrol head, Im more comfy with Diesels but if your running 16 deg advance then it should really be pinging........are your timing marks correct?

Even if it is 5 deg out this may be the cause of your problem.

If you havnt already done it I would pull the plug on No.1 and check the timing mark is spot on or pop the rocker cover off the bank on No.1's side and get the rockers rocking on 1 and then check the mark would be even better.

Ive seen it on more than 1 occasion when a harmonic balancer is changed that the timing marks are out, I cant explain why but Ive seen it on a couple of 4clys in Datto's, at least 1 holden 6 and and a couple of 308's but Im not sure about Rovers, the only ones Ive played with have all been fine.

If the mixture is leaning out as you advance it then your obviously getting more burn in the combustion chamber rather than in the exaust ports/manifold so your getting closer to where you want to be.

I'd keep advancing it until it started pinging and then back it off and see where you are, it may give you a clue as to whats going on.

yeah i thought 16deg advance would be close to pinging but cant hear any signs even when loaded up in 5th gear. has anyone else had to advance this far?

did the screwdriver trick and got it to TDC and the marks seem to correspond fairly well, so wouldn;t have thought the harmonic balancer could have slipped.


i'll see how i go tonight. will see how it goes as is then maybe advance it till it pings so then i know where i stand in that area.

[PSI250]

took it for a run last night, no pinging or glowing on 16deg advance. Still can feel a fair bit of heat throwing out but no glowing even when giving it a bit of a hard time, so starting to look better.

Will replace the vacuum advance unit this week and then advance it some more and take it out and see how it goes.
i shouldn;t be able to get too much more advance out of it before it pings, but we'll see.

thanks to everyone who replied in this thread. i'll keep you updated on how it goes.

Cheers,
Cal.

[mike 90 RR]

Ok had a bit of a play,

Bumped it up again and now its on around 16deg BTDC.


.

I think that you are running at 16 degrees.... because you don't have the vac advance operating .... You are advancing to compensate for no vac advance

When you install a new vacuum advance unit ... you will find that you will have to go back to the original settings
I am unsure of your 3.9 motor ... but my "factory setup" for 3.9 EFI is 3 degrees ...so check what degrees you are suppose to set for

[mcrover]

I think that you are running at 16 degrees.... because you don't have the vac advance operating .... You are advancing to compensate for no vac advance

When you install a new vacumm advace unit ... you will find thatyou will have to go back to the original settings
I am unsure of your 3.9 motor ... but my "factory setup" for 3.9 EFI is 3 degrees ...so check what degrees you are suppose to set for

Yes actually thats spot on, static timing on max advance would be around 30deg so your about mid way there.

It would have been hugely retarded under load and close to spot on at Idle/coast.

[Tank]

Just wondering if you have anything, like, Spotties, High Mount Winch or anything else blocking air-flow into engine bay, if so, may be the cause, Regards Frank.

[rovercare]

Just wondering if you have anything, like, Spotties, High Mount Winch or anything else blocking air-flow into engine bay, if so, may be the cause, Regards Frank.

Of glowing pipes?:confused: that heat is coming from inside the motor

To rich/incorrect advance

[Tank]

Of glowing pipes?:confused: that heat is coming from inside the motor

To rich/incorrect advance
ALL of the heat comes from the motor, where else could it come from!
The engine and radiator are cooled by air passing over them, if you block the air the engine interior and exterior will get hotter than if there was free and ample airflow, DOH! Thats why cars have them big holes at the front, Regards Frank.

[mike 90 RR]

Hi Tank
I think that the radiator is keeping the block cool enough .... but the flame of the burn is way too hot .... The radiator can control this extra heat but it does not cool the exhaust manifold ... so therefore the manifold cannot cope with the extra heat

You know about the bit on ... "IF you run it too lean you will burn a hole in the top of the piston" .... That is the risk of what is going on here

Mike

[PhilipA]

I don't think that anyone has yet suggested that your centrifugal advance may be frozen.
The fact you advanced to 16 degrees and it runs cooler suggests it is a retard issue.
Grab the rotor and see if it moves freely by something AFAIR about 3-4 MM. and then springs back.
Regards Philip A

[PSI250]

I don't think that anyone has yet suggested that your centrifugal advance may be frozen.
The fact you advanced to 16 degrees and it runs cooler suggests it is a retard issue.
Grab the rotor and see if it moves freely by something AFAIR about 3-4 MM. and then springs back.
Regards Philip A

just checked that then when putting the reco'd vac advance unit on (highly recommend performance ignitions in nunawading!), definately moves freely by roughly 4-5mm and springs back nicely.

Took it for a drive, still on 15-16deg BTDC and everything seems to be ok, can't get it to ping even if i try which is a good sign, mixtures seem spot on and pipes don't glow so i'm happy to leave it as is for now and just drive it and see how i go.

Thanks to everyone who replied.

cheers,
Cal.

[rovercare]

ALL of the heat comes from the motor, where else could it come from!
The engine and radiator are cooled by air passing over them, if you block the air the engine interior and exterior will get hotter than if there was free and ample airflow, DOH! Thats why cars have them big holes at the front, Regards Frank.

Yep, my bad wording, but anyhow, bad cooling wont be the reason behind glowing pipes

[rovercare]

just checked that then when putting the reco'd vac advance unit on (highly recommend performance ignitions in nunawading!), definately moves freely by roughly 4-5mm and springs back nicely.

Took it for a drive, still on 15-16deg BTDC and everything seems to be ok, can't get it to ping even if i try which is a good sign, mixtures seem spot on and pipes don't glow so i'm happy to leave it as is for now and just drive it and see how i go.

Thanks to everyone who replied.

cheers,
Cal.

Are you controlling timing with your MS? sorry I can;t remember:angel:

If not, just advance it till it pings then retard it a little, if it struggles to crank once this is done, you'll need to retard it till its fine as its still to far advanced

Vacuum advance merely improves economy and rich running, it wont heat your headers like that

Have you checked your mechanical advance is working right?? simply disconnect the vac line and rev it with a timing light, you should see ROUGHLY 30-35 degrees @3-3500rpms, then do as mentioned at the start:D

[PSI250]

Are you controlling timing with your MS? sorry I can;t remember:angel:

If not, just advance it till it pings then retard it a little, if it struggles to crank once this is done, you'll need to retard it till its fine as its still to far advanced

Vacuum advance merely improves economy and rich running, it wont heat your headers like that

Have you checked your mechanical advance is working right?? simply disconnect the vac line and rev it with a timing light, you should see ROUGHLY 30-35 degrees @3-3500rpms, then do as mentioned at the start:D

nah MS is only controlling fuel at this stage, will go spark control one day.

seemed to be advancing up around that mark with the vac line off so seems all good there.

doesn't ping, starts fine, coolant temp is fine and drives well so i'm happy with it as it stands, will clock up some more k's and see how i go. might advance it till it pings sometime just so i have a referance point of how far i can go.

[Tank]

Yep, my bad wording, but anyhow, bad cooling wont be the reason behind glowing pipes
Have to disagree, the only time I ever had Glowing exhaust manifolds, was when driving in Bulldust between Julia Ck. and Hughenden in my ZB Fairlane back in the 70's, was cruising at 60mph+ when noticed floor was getting hot and could smell melting tar. Pulled over and lifted bonnet and both exhaust manifolds and exhaust pipes were glowing almost white hot, the insect screen I had stretched across the entire grill was blocked solid with grass seeds and bulldust.
Water temp. was only just a tad above normal and ignition timing was spot on, shook out the screen, reinstalled and drove hard for another hour, noticed heat again and tar smell, lifted bonnet pipes a glowing again.
Had to stop every hour and clean screen till I reached the bitumen road.
So my glowing pipes were not from ignition timing or problems but from restricted air around engine, radiator was getting enough air to survive, Regards Frank.

[mcrover]

Have to disagree, the only time I ever had Glowing exhaust manifolds, was when driving in Bulldust between Julia Ck. and Hughenden in my ZB Fairlane back in the 70's, was cruising at 60mph+ when noticed floor was getting hot and could smell melting tar. Pulled over and lifted bonnet and both exhaust manifolds and exhaust pipes were glowing almost white hot, the insect screen I had stretched across the entire grill was blocked solid with grass seeds and bulldust.
Water temp. was only just a tad above normal and ignition timing was spot on, shook out the screen, reinstalled and drove hard for another hour, noticed heat again and tar smell, lifted bonnet pipes a glowing again.
Had to stop every hour and clean screen till I reached the bitumen road.
So my glowing pipes were not from ignition timing or problems but from restricted air around engine, radiator was getting enough air to survive, Regards Frank.


So did you think to maybe clean out the air cleaner of the bull dust so it wasnt running so rich, I think you would have found that this may have helped your situation.

The old ford V8's (a mate had a 351 windsor in a XYGT replica in prestine condition) had a habbit of doing this when running excessively rich or excessively lean.

A above said GT did a run up though the outback somewhere (I cant remember) when the same happened to him but he was following other cars on one of the charity bashes.

He's a fitter and turner and pretty cluey when it comes to this stuff and when he pulled the cleaner it was chockers with red dust.

They made a make shift snorkle out of poly fittings and pipe and fitted a cyclone type precleaner and all was well after that.

[Tank]

So did you think to maybe clean out the air cleaner of the bull dust so it wasnt running so rich, I think you would have found that this may have helped your situation.

The old ford V8's (a mate had a 351 windsor in a XYGT replica in prestine condition) had a habbit of doing this when running excessively rich or excessively lean.

A above said GT did a run up though the outback somewhere (I cant remember) when the same happened to him but he was following other cars on one of the charity bashes.

He's a fitter and turner and pretty cluey when it comes to this stuff and when he pulled the cleaner it was chockers with red dust.

They made a make shift snorkle out of poly fittings and pipe and fitted a cyclone type precleaner and all was well after that.
That was my first thought when I pulled up and seen the pipes glowing, filter was OK, no crap at all in it, the chockers insect screen was acting like a pre-cleaner, letting enough air through to breathe and cool the radiator, but that's all, within 45 minutes of cleaning the insect screen floor and firewall temps would rise and the smell of melting underbody tar paint would start to smoulder, stop, shake out the screen and away, no problems for about 40/60 mins. Bulldust was like a wave in front of the wheels, as noted by watching cars going other way. Pipes stopped glowing once on the Bitumen, Regards Frank.

[rovercare]

Have to disagree, the only time I ever had Glowing exhaust manifolds, was when driving in Bulldust between Julia Ck. and Hughenden in my ZB Fairlane back in the 70's, was cruising at 60mph+ when noticed floor was getting hot and could smell melting tar. Pulled over and lifted bonnet and both exhaust manifolds and exhaust pipes were glowing almost white hot, the insect screen I had stretched across the entire grill was blocked solid with grass seeds and bulldust.
Water temp. was only just a tad above normal and ignition timing was spot on, shook out the screen, reinstalled and drove hard for another hour, noticed heat again and tar smell, lifted bonnet pipes a glowing again.
Had to stop every hour and clean screen till I reached the bitumen road.
So my glowing pipes were not from ignition timing or problems but from restricted air around engine, radiator was getting enough air to survive, Regards Frank.

Well, I can;t argue with that:D

I've never had it happen to me, a radiator blockage NOT causing the motor to overheat the water but cause it to run with glowing headers

Not that it could of been the lack of air in the engine bay, caused by all the air being sucked in and nothing entering from the front, causing it to run excessively rish or anything:angel:

[rovercare]

The old ford V8's (a mate had a 351 windsor in a XYGT replica in prestine condition) had a habbit of doing this when running excessively rich or excessively lean.

.

Pretty crappy replica of an XY GT, having a Windsor in it, when it should of been a cleveland:p:D

[mcrover]

Pretty crappy replica of an XY GT, having a Windsor in it, when it should of been a cleveland:p:D

yeah it was originally a fairlane or fair monet or something like that and was the original drive train just all GT get up on the body.

Went pretty well though until he stacked it :(

[Tank]

Well, I can;t argue with that:D

I've never had it happen to me, a radiator blockage NOT causing the motor to overheat the water but cause it to run with glowing headers

Not that it could of been the lack of air in the engine bay, caused by all the air being sucked in and nothing entering from the front, causing it to run excessively rish or anything:angel:
Radiator was not blocked and water temp rose about 25% above normal, which was dead centre, the insect screen was attached to the outside of the grill, so there was an air gap before the radiator. I believe the "wave of Bulldust" was stopping air going under the front of the car along with the insect causing the glowing pipes, Regards Frank.

[MoodyBlue]

You can also wrap the extractors with fibreglass heat wrap. It tames the under bonnet heat. Assumin g of course you've checked all the other factors. I used the wrap on my 85 with perfect results in lowering the cabin floor temp.

Cheers
Jeff

[PSI250]

You can also wrap the extractors with fibreglass heat wrap. It tames the under bonnet heat. Assumin g of course you've checked all the other factors. I used the wrap on my 85 with perfect results in lowering the cabin floor temp.

Cheers
Jeff

yeah this is also something i'm planning on doing if the heat gets too much. seems to be not as bad as it used to be lately so we'll see what happens.