Air flow through engine bay.

[TR5convalescent]

Afternoon wise ones. Finally got the Stag back from Enginuity after an instance of brain fade, inadvertent reverse selection and picking bits of the garage out of the driver's side (don't ask!). Enginuity did a brilliant job of the repairs and addressed a few other issues at very reasonable cost, too.

I didn't ask them to do any mechanical work and took the Stag out for an Italian tune up earlier in the week. I am running a Mark 1 with a Mark2 rad, no viscous Dan, but a BMW fan in front of the rad and a variable stat filled with Evans Waterless.

Although ambient temp was about 22c the gauge did rise to about 4/5ths with the fan going full belt. Curiously, switching the heater on didn't make that much difference. Spanking her at 70 plus (3500RPM) did not help either. Only dropping back to 40 -50mph (2000-2500 RPM) reduced the temp to just above the mid point (which is where it's always been). I have never taken the car out for a sustained 2 hour blast before.

I suspect that this is the problem of air not getting to the bottom of the radiator and have ordered an LD secret spoiler as it's a cheap fix. But as a Mark 1, there's a lot of space at the top of the rad and I was wondering about sealing this with hardboard sheeting and possibly going round the rad and trying to force all the air through the rad. Is this a bad idea? Has anyone else done similar things?

[TR5convalescent]

For Dan read fan! iPads!

[V Mad]

If the fan is going full pelt, but the temp is still too high, then something is wrong. Maybe the fan is for some unknown reason not effective, or could the radiator be partially blocked? Since waterless coolant has a lower specific heat, could that be causing it to run hotter, and since it will not boil, does that even matter?

Most people have the gaps around the rad, and that has no ill effect, so why should it be a cause on your car?

(Oh dear, I seem to have answered your two questions with three questions..lol!)

[Staggard]

I use wide rubber strip riveted to the edge of the rad opening so that it seals against the outside of the rad. I had a LD secret spoiler found it made no difference so I gave it away. when the car was re sprayed I fitted a TR spoiler, that did make a difference. Graham

[badhuis]

Most people have the gaps around the rad, and that has no ill effect, so why should it be a cause on your car?

I have some temp trouble with the TR4 in hot weather / city driving. Responses from the TR forum suggested that to close off the gaps around the radiator should make a big difference.
I have heard the same about Jensen Interceptors so am inclined to think that it WILL make a difference. Just have not had the time to experiment on the TR4.

[V Mad]

I have some temp trouble with the TR4 in hot weather / city driving. Responses from the TR forum suggested that to close off the gaps around the radiator should make a big difference.
I have heard the same about Jensen Interceptors so am inclined to think that it WILL make a difference. Just have not had the time to experiment on the TR4.

I didnt say it wouldnt make a difference, just that maybe there is a fault that is causing the temp to read too high.

[Jeff]

Just driven 10 miles after 4 years of no movement (apart from regular engine warm ups), standard rad, VC (with Kenlowe backup), temp sat perfectly in the middle, no other mods apart from shhhhhhhh HT.

If the engine is good, then something is wrong if the coolant gets too hot.

As said so many times on this forum, cooling mods only mask a problem.

[Richard G]

OMG as they say, I have just bought a secret spoiler.................

I use wide rubber strip riveted to the edge of the rad opening so that it seals against the outside of the rad. I had a LD secret spoiler found it made no difference so I gave it away. when the car was re sprayed I fitted a TR spoiler, that did make a difference. Graham

[Staggard]

Just driven 10 miles after 4 years of no movement (apart from regular engine warm ups), standard rad, VC (with Kenlowe backup), temp sat perfectly in the middle, no other mods apart from shhhhhhhh HT.

If the engine is good, then something is wrong if the coolant gets too hot.

As said so many times on this forum, cooling mods only mask a problem.

Oh no you didn't go and buy one of those Jeff did you.

[Jeff]

Had one for the past 15 years Graham.

[Staggard]

Had one for the past 15 years Graham.

I am surprised that one went straight over your head Jeff with all the S'es and the H'es I thought you had missed out the I'es and the T'eee. I am truly wasted not in the Vodka sense

[Jeff]

Sorry Graham it did, even though I looked twice.

[Pete]

Any extra air that you force into the engine bay has to escape somehow. I've just spoken to a friend who races Midgets. His A series engine produces more BHP than a Stag. Now I don't know about he relative efficiencies of the two engines, but he, like with modern engines, has his enclosed. The only air going in is forced throught the radiator and then out of the engine bay via bonnet louvres and ducts vented through the back of the car, the engine itself is only cooled by the cooling system and not by air flow. Until the ducts were vented through the rear, he was racing an air dam.

[Staggard]

Any extra air that you force into the engine bay has to escape somehow. I've just spoken to a friend who races Midgets. His A series engine produces more BHP than a Stag. Now I don't know about he relative efficiencies of the two engines, but he, like with modern engines, has his enclosed. The only air going in is forced throught the radiator and then out of the engine bay via bonnet louvres and ducts vented through the back of the car, the engine itself is only cooled by the cooling system and not by air flow. Until the ducts were vented through the rear, he was racing an air dam.

The only thing is when you look under a Midget's bonnet there is a fair bit of space around the engine. I think we have to remember in the Stags case they stuck two engines in a space that was designed originally for one.

[TR5convalescent]

Badhuis- my experience with the TR5 was of higher temperatures as soon as leaded file became unavailable. Careful ducting round the radiator did help, but what really made the difference was having the exhaust manifold zircotecced. That put the temperature reading right back in the middle again.

But taking the manifolds off the V8 looks like a complete PITA fraught with risk to other things.

Chris, I hear what you say but the system was only recently flushed through and all hoses renewed and a new rad, Satgweber header tank and huge BMW fan fitted. I can always get the temp back within acceptable limits by pootling at 45MPH. I have also coincidentally noticed ( and just remembered) two things which might be relevant.

Firstly the fuel gauge is occasionally erratic. Is the temp gauge also connected to the famously variable voltage stabiliser? If so that might explain the high readings.

Secondly, at high speed the tachometer bounces a bit around 3500 to 4500 RPM. If it's electronic that would point to an ignition caused misfire at steady speed. Also, she does misfire at full chat on kick down leading me to suspect that the leads (7mm) and perhaps the coil are not man enough for the job. Fitting a Flamethrower coil, big leads and opening out the plugs to 35 thou transformed my TR5 into a road rocket that went like a scalded cat and returned 27mpg. At present I strongly suspect that the Stag is not burning all the fuel -just like the TR!