Discussion
After nearly burning my hand on the bonnet stay the other day, it got me thinking how hot it was under there(and this is winter time) as reports suggest that some conponents don't last long due to the heat under the bonnent ( starter motors, master cylinders etc). Would it be a good idea to bind the huge exhaust pipes from the manifold to under the engine with heat proof tape. This would surely reduce temp slightly and help performance as the plenum casing would be cooler.
Just interested what everyones views are on this, results/costs?
Thanks!!
happy new year to all
Just interested what everyones views are on this, results/costs?
Thanks!!
happy new year to all
loads of threads on this...
all air flow thru engine bay is heated.
by radiator minimum. then by cat manifold. then by engine.
some cars have been vented (bonnets)
some exhausts wrapped.
but most not. they seem to manage!
it depends on personal feeling. i don't like it that hot for the reasons you gave.
i have...
put s/steel heat sheilds on manifolds.
modified air filter guard.
added extra foil protection to inner wings.
added water wetter and samco hoses.
am about to fit splitter and additional ducting.
MAY wrap cat manifold.
negs for wrapping are...
can hold moisture, rusting manifold
increases internal temperature as is not allowed to air cool. (the point of the exercise)
moves heat further down the exhaust, possibly causing other probs (or just going out the pipes - opinions vary)
take your pick!
>> Edited by Guillotine on Saturday 4th January 14:50
all air flow thru engine bay is heated.
by radiator minimum. then by cat manifold. then by engine.
some cars have been vented (bonnets)
some exhausts wrapped.
but most not. they seem to manage!
it depends on personal feeling. i don't like it that hot for the reasons you gave.
i have...
put s/steel heat sheilds on manifolds.
modified air filter guard.
added extra foil protection to inner wings.
added water wetter and samco hoses.
am about to fit splitter and additional ducting.
MAY wrap cat manifold.
negs for wrapping are...
can hold moisture, rusting manifold
increases internal temperature as is not allowed to air cool. (the point of the exercise)
moves heat further down the exhaust, possibly causing other probs (or just going out the pipes - opinions vary)
take your pick!
>> Edited by Guillotine on Saturday 4th January 14:50
Not necessarily.... Too many cars are modded and end up running too cool. The car needs to reach 90 while stationary for the ECU to adapt. Many also run below 70 on a cruise and the ECU still enriches the fuelling so there is a sweet spot to maintain.
Big big section on the pros and cons in the Bible 2.
If the car does not overheat and runs fine then don't touch it.
If it overheats it has a problem.
The only bit of heat protection that I would say do is the starter motor. Everything else has pros and cons (mostly cons) that I would leave it as is.
Steve
www.tvrbooks.co.uk
Big big section on the pros and cons in the Bible 2.
If the car does not overheat and runs fine then don't touch it.
If it overheats it has a problem.
The only bit of heat protection that I would say do is the starter motor. Everything else has pros and cons (mostly cons) that I would leave it as is.
Steve
www.tvrbooks.co.uk
shpub said:
If the car does not overheat and runs fine then don't touch it.
If it overheats it has a problem.
The only bit of heat protection that I would say do is the starter motor. Everything else has pros and cons (mostly cons) that I would leave it as is.
Steve
www.tvrbooks.co.uk
I agree.
Peter Humphries (and a green V8S with lagged starter motor, alternator, chassis rails, fuel rail, manifolds, catalyst etc
)ahhh yes...
so cracking insulation, failing coils, failing starter motors, failing alternators, failing dissy amps etc. etc. are not problems caused by excessive heat in the engine bay?
I'd disagree. IMHO.
there is plenty of evidence of these on older cars, the majority now, and they are all caused by or aggrovated by HEAT! PARTICULARLY ELECTRICS!
not a problem on range rovers, where the parts work fine (ish)
AIRFLOW GOOD...EXCESSIVE HEAT BAD!
IMHO
>> Edited by Guillotine on Sunday 5th January 12:05
so cracking insulation, failing coils, failing starter motors, failing alternators, failing dissy amps etc. etc. are not problems caused by excessive heat in the engine bay?
I'd disagree. IMHO.
there is plenty of evidence of these on older cars, the majority now, and they are all caused by or aggrovated by HEAT! PARTICULARLY ELECTRICS!
not a problem on range rovers, where the parts work fine (ish)
AIRFLOW GOOD...EXCESSIVE HEAT BAD!
IMHO
>> Edited by Guillotine on Sunday 5th January 12:05
Don't confuse the fact that old cars do not go on for ever and their parts will die. Yes they may be under a bit more stress but the main failure mechnaism with coils and dizzy amps is the electrical stress and resulting internal heating. Increased far more on a TVR because of the high revs.
The problem is that while you can do things to dramatically reduce the engine temp all that happens is that the engine wear increases and the ECU doesn't do as good a job as it should. Most owners don't notice this until they need an engine rebuild or they find that their fuel bills are higher. At this time the costs are many times higher than that of a coil or a dizzy amp.
I did say there were a lots of pros and cons.
The problem is that while you can do things to dramatically reduce the engine temp all that happens is that the engine wear increases and the ECU doesn't do as good a job as it should. Most owners don't notice this until they need an engine rebuild or they find that their fuel bills are higher. At this time the costs are many times higher than that of a coil or a dizzy amp.
I did say there were a lots of pros and cons.
Peter Humphries (and a green V8S with lagged starter motor, alternator, chassis rails, fuel rail, manifolds, catalyst etc
)But with an engine that puts out about 50% more power/heat that the original...
Steve
520 with custom ally radiator, wrapped exhaust manifolds, cerbera spec fans, 1 meter air outlet vent a la Elise in the custom bonnet.
steve, i think we're at cross purposes here.
I'm talking ( and the original question was )about premature component failure due to excessive engine bay temp, NOT reduced engine running temp - tho i feel running 115 degrees in traffic with fans permanently on, is NOT favourable!
excessive (normal) BAY temps in griffs WILL play a major part in the failure of engine components...FACT!
I'm certain that on your monster, you've gone to great lenghts increasing the cooling as you've increased BHP / BRAKING / ETC. Well i'm not so confident that TVR did the same as they increased the 4.0 upwards.
YES double fans revised grill, but neither improved cool airflow to the engine. ie radiator hot air only...very hot air only.
FOR EXAMPLE, the inner wing seams are so close to the exhaust manifolds, they're actually cooking! giving an acrid smell in the cabin airflow (via the inner wing) as they do so. hence the modified later car seams...and my heat shields. I'm about to improve airflow in this area again as i believe its preferable to modifying the bonnet, or constant headaches when roof is up.
alot of poeple seem to REVERE TVR and the cars (its a given that the griff is the most beautiful car ever created) and feel that they have to "live" with its problems. I don't.
TVRs have evolved over the years and almost car by car off the line, this is needed as the development costs were next to zero (in automotive terms), so much can be learned from other marques, race teams (inc tuscans)
and after market co.s like ACT, V8 developments, Leven and your mates at TOWER VIEW. All with ideas that were incorporated (read nicked)by later TVR'S - alledgedly
ALL IMHO ofcourse
PS i don't think you'll find many Porkers falling to bits at 10 years and 40,000 miles was that a TVR marketing strategy that you uncovered whilst researching "BIBLE 2"
>> Edited by Guillotine on Sunday 5th January 14:16
>> Edited by Guillotine on Sunday 5th January 14:18
I'm talking ( and the original question was )about premature component failure due to excessive engine bay temp, NOT reduced engine running temp - tho i feel running 115 degrees in traffic with fans permanently on, is NOT favourable!
excessive (normal) BAY temps in griffs WILL play a major part in the failure of engine components...FACT!
I'm certain that on your monster, you've gone to great lenghts increasing the cooling as you've increased BHP / BRAKING / ETC. Well i'm not so confident that TVR did the same as they increased the 4.0 upwards.
YES double fans revised grill, but neither improved cool airflow to the engine. ie radiator hot air only...very hot air only.
FOR EXAMPLE, the inner wing seams are so close to the exhaust manifolds, they're actually cooking! giving an acrid smell in the cabin airflow (via the inner wing) as they do so. hence the modified later car seams...and my heat shields. I'm about to improve airflow in this area again as i believe its preferable to modifying the bonnet, or constant headaches when roof is up.
alot of poeple seem to REVERE TVR and the cars (its a given that the griff is the most beautiful car ever created) and feel that they have to "live" with its problems. I don't.
TVRs have evolved over the years and almost car by car off the line, this is needed as the development costs were next to zero (in automotive terms), so much can be learned from other marques, race teams (inc tuscans)
and after market co.s like ACT, V8 developments, Leven and your mates at TOWER VIEW. All with ideas that were incorporated (read nicked)by later TVR'S - alledgedly
ALL IMHO ofcourse
PS i don't think you'll find many Porkers falling to bits at 10 years and 40,000 miles
was that a TVR marketing strategy that you uncovered whilst researching "BIBLE 2" >> Edited by Guillotine on Sunday 5th January 14:16
>> Edited by Guillotine on Sunday 5th January 14:18
So if i bind the starter motor to give it some protection and leave it at that.
I've only driven the car in cold weather at the moment and it seems to run about 80-90 when driving around and stopping in towns. I have seen it reach 95 when still for afew minutes. Is this ok? as surely it will run hotter in the summer or do you run wetter water just for the summertime?
I've only driven the car in cold weather at the moment and it seems to run about 80-90 when driving around and stopping in towns. I have seen it reach 95 when still for afew minutes. Is this ok? as surely it will run hotter in the summer or do you run wetter water just for the summertime?
With the early 4 litre cars there is/was an issue with the heat shielding but it certainly isn't the case with the later cars. Most of the 4.x cars that were affected were modded. Sounds as if yours wan't and escaped the net. The cure was to cut away the wing and recess it back so that there is a bigger gap. The later cars like all the 500s have this and this is the way to address the problem instead of trying to reduce the engine bay temp by increasing the air flow. The problem is caused by localised heating (as is the starter motor issue where a shield is great).
If you want to do something about it with the air flow, this needs to be vented from the rad out of the engine bay. The problem with that is that the cat if fitted gets extremely hot and there is even less air flow now from the rad so that and the engine will heat up the engine bay quite nicely. To compensate, a more efficient rad is needed to allow the rad to take more of the work to cool the engine. The engine air flow cooling effect is taken by the radiator.
The issue of reducing engine bay temperatures and the affect on component reliability is true but what about vibration and other effects due to the rougher ride? Mechanical and thermal shock have a bigger effect on early failures than anything else. Shouldn't you be softening the ride and not accelerating and braking as fast? The worst thing is when the hot components get showed with water from a puddle/flood or even a too adventurous jet wash!
Heat accelerates the chemical failures that cause the end of life failure mechanism but components for automotive are designed to cope with high ambient temperatures such as -40 to +150 ish or higher.
As a result, running lower engine bay temps may extend life but it is not magical and does not remove the failures that are experienced because of other failure modes. The main failure mechanism with the coil is internal localised heating (heat is a by product of the coils operation) causing the internal insulation to break down. The newer design Bosch coils are better at preventing that which is why Rover switched to them when the same problem appeared on the Range Rover etc. The dizzy amp fails because of electrical stresses caused by having to cope with a V8 rather than a 4 cylinder device. On early cars this unit is on the coil at the front of the car. On later ones it was moved onto the plenum which would act as a big heat sink.
The point to consider is that most of the techniques described like increased air flow through the front of the car, water wetter etc etc all have an effect on the car's running temperature and this means that it is easy to go from one set of problems to another.
>> Edited by shpub on Sunday 5th January 17:09
If you want to do something about it with the air flow, this needs to be vented from the rad out of the engine bay. The problem with that is that the cat if fitted gets extremely hot and there is even less air flow now from the rad so that and the engine will heat up the engine bay quite nicely. To compensate, a more efficient rad is needed to allow the rad to take more of the work to cool the engine. The engine air flow cooling effect is taken by the radiator.
The issue of reducing engine bay temperatures and the affect on component reliability is true but what about vibration and other effects due to the rougher ride? Mechanical and thermal shock have a bigger effect on early failures than anything else. Shouldn't you be softening the ride and not accelerating and braking as fast? The worst thing is when the hot components get showed with water from a puddle/flood or even a too adventurous jet wash!
Heat accelerates the chemical failures that cause the end of life failure mechanism but components for automotive are designed to cope with high ambient temperatures such as -40 to +150 ish or higher.
As a result, running lower engine bay temps may extend life but it is not magical and does not remove the failures that are experienced because of other failure modes. The main failure mechanism with the coil is internal localised heating (heat is a by product of the coils operation) causing the internal insulation to break down. The newer design Bosch coils are better at preventing that which is why Rover switched to them when the same problem appeared on the Range Rover etc. The dizzy amp fails because of electrical stresses caused by having to cope with a V8 rather than a 4 cylinder device. On early cars this unit is on the coil at the front of the car. On later ones it was moved onto the plenum which would act as a big heat sink.
The point to consider is that most of the techniques described like increased air flow through the front of the car, water wetter etc etc all have an effect on the car's running temperature and this means that it is easy to go from one set of problems to another.
>> Edited by shpub on Sunday 5th January 17:09
Aland said: So if i bind the starter motor to give it some protection and leave it at that.
I've only driven the car in cold weather at the moment and it seems to run about 80-90 when driving around and stopping in towns. I have seen it reach 95 when still for afew minutes. Is this ok? as surely it will run hotter in the summer or do you run wetter water just for the summertime?
First thing is to check that the temp guage is accurate. Then chcek that the fans all switch on, cooling levels are correct and so on. All detailed in the bible.
PS use the aluminised shielding not exhaust wrap on the starter.
mines a 94 500
runs beautifully
Goes like stink (404 cam)
75 - 85 degrees running temp
is tracked regularly
DOESN'T have scalloped inner wings
only current airflow mod is cut down No plate
PS does have air con, reducing airflow further
as steve says...use proper heat sheild, purpose built item isn't expensive from your independant specialist.
as i said...it's all opinions!
runs beautifully
Goes like stink (404 cam)
75 - 85 degrees running temp
is tracked regularly
DOESN'T have scalloped inner wings
only current airflow mod is cut down No plate
PS does have air con, reducing airflow further
as steve says...use proper heat sheild, purpose built item isn't expensive from your independant specialist.
as i said...it's all opinions!
For my Griff, a standard water thermostat and half speed fans when the radiator reaches 70 degrees, followed by full speeds if required works just fine. Much like the Range Rover that has a fan all the time, winter or summer, keeping the air moving out of the bonnet area. I have a spoiler ramming air into the mouth and still mine gets to reach the water stat temp, even today at minus 2 this morning. Ok it took ten minutes to get there but it did. My Rangie gets up there a bit quicker, but then again its a little heavier and has to work a little harder.
shpub said: Just another thought....
Are the manifolds starting to glow? This would cause a lot of excessive heat and the problems you are talking about. Caused by cam shaft/valve timing problems.
I have seen some cars where they have got cherry red.
Don't manifolds on pretty much all cars get cherry red at motorway speeds (saw a TV prog on this once)
Certainly noticed this on various cars of mine after a good thrash at night - if you stop with the engine running & pop the bonnet, the manifolds will be glowing nicely to themselves (only noticable at night, really)
I've seen them glow cherry red at idle!
Can't help thinking that Guillotine's car has some problems here if the inner wing is melting because to be honest that is not normal. The 500 had a slightly wider body/bay internally and don't suffer in the same way that the 4.x cars so the wing problem must be caused by something else. It is not scalloped because it doesn't need to be. The running temps are fine so again localised heating or a GRP/heat prevention failure must be happening. If the heat barrier is gone/failed then that will cause the heating.
I have heard of GRP melting problem on one 4.x car before but never on a 500 so my conclusion is that there is something different with your car that is causing it.
Might be worth having a good prod with an IR thermometer see what is happening and what temps the manifolds are reaching. If they are getting that hot then wrapping them may be a solution or alternatively there is a problem with the cam/ignition timing. I have seen the cherry red problem on my car before I got the cam and the ignition timing sorted out. The car was still pulling 280 bhp though so the problems may not be that apparent.
If the wing melting only occurs at standstill, the Mod wise two speed fan kit might also help but to be honest the type of localised heating that is needed to decompose GRP is pretty high and it is not clear how effective it would be.
Can't help thinking that Guillotine's car has some problems here if the inner wing is melting because to be honest that is not normal. The 500 had a slightly wider body/bay internally and don't suffer in the same way that the 4.x cars so the wing problem must be caused by something else. It is not scalloped because it doesn't need to be. The running temps are fine so again localised heating or a GRP/heat prevention failure must be happening. If the heat barrier is gone/failed then that will cause the heating.
I have heard of GRP melting problem on one 4.x car before but never on a 500 so my conclusion is that there is something different with your car that is causing it.
Might be worth having a good prod with an IR thermometer see what is happening and what temps the manifolds are reaching. If they are getting that hot then wrapping them may be a solution or alternatively there is a problem with the cam/ignition timing. I have seen the cherry red problem on my car before I got the cam and the ignition timing sorted out. The car was still pulling 280 bhp though so the problems may not be that apparent.
If the wing melting only occurs at standstill, the Mod wise two speed fan kit might also help but to be honest the type of localised heating that is needed to decompose GRP is pretty high and it is not clear how effective it would be.
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