Engine heat evacuation syste

[Joe Schiavone]

Additional actions. I noticed after reading more posts that by raising.the hood slightly with modification to the hood strikers you will constantly release trapped heat in the compartment
That is sealed in with weatherstrip unlike most cars also if you make a slight air scoop under the front balance and flow cooler air in front of the center cross member. This will direct the engine air upward verses rearward toward the firewall. Just a thought. I have already extended the hood strikers. Right now I am making devices to raise all hoses so as not to lie on hot metal and have a chance to rub a hole in the hoses as one did exactly that releasing no freeze. Had to fix that unexpectly. Should be back on the road next week.

[AH1951]

Joe,
You are doing all these things, with admirable skill, but have you got the air-conditioning working yet?
Driving the car with the bonnet raised even only an inch or so at the trailing edge is going to spoil its appearance completely.
People will be constantly drawing your attention to it being open.
And won't it move around and vibrate with the motion of the car, imposing extra loads on the front hinges?
It's an unsightly solution and I'm not convinced there really is a problem.
Your car is a convertible.
If you drive with the hood/fabric top down, are you really going to have a problem of heat build-up in the cabin?
When did you last drive this car?
I wouldn't worry too much about the heat in the engine bay.
It's a big lump of an engine, so of course, it's going to be hot in there.

[garyc]

Hello Joe

Very interesting subject this I’ve been looking at this problem for a while now as well

I think your idea of releasing the trapped heat out of the engine bay is the way to approach the problem rather than trying to cool down the hot air after its been created

I also think the louvres were an attempt by design to let the hot air come out of the engine bay and im sure they work to some extent but not enough.

The existing double fans work but they can only do so much as the air gradually gets hotter and hotter.
I know they also displace some of the existing hot air but the best way would be to remove all or most of the trapped hot air and then replace it with new fresh air from the fans.

Your additional fans and ducting look like they would do this Joe so will be interested to see if it works in practise.

I have been designing a catch that would in effect keep the bonnet locked in position but it would still be open but only by about ¾ “ to an 1” gap so it wouldn’t look really out of place or too obvious when driving the car.

The part can be slipped over the existing bonnet latch and would require no tools to install you would just push it in position on both latches and then shut the bonnet,
The bonnet could still be opened and closed as usual.

I wanted something to be able to use if I was going out on a really hot day/ a long drive or maybe somewhere where I could get stuck in traffic.
My cars do not have an overheating problem as such but I think by removing the trapped heat out of the engine bay this can only be a good thing the heat can and does destroy components in the engine bay wiring, leads etc.

I was at a regional meeting the other night and I mentioned the idea of the extenders and it has in fact been done before by a few other people and from what was saod it seemed to have worked.

Sounds like you have already done this now Joe so would be interested to see what yours look like

Good luck with your project and I look forward to seeing an update when you have it up and running
GaryC

[Steve Payne]

How about just using fans with a huge CFM for the radiator, you wont overcool the engine as the thermostat will cut in and it will be a lot less complcated. It will also give you plenty of spare capacity if your engine gets hot.

Steve

[AH1951]

Hello Joe
My cars do not have an overheating problem as such but I think by removing the trapped heat out of the engine bay this can only be a good thing the heat can and does destroy components in the engine bay wiring, leads etc.
GaryC

Guys,
This is like Global Warming, or Climate Change, in that you are going to a lot of trouble to tackle an imaginary problem.
Was this a problem with the cars during their first few years of operation?
If not, why do you see it as a problem now?
Yes, certain components will need to be replaced after years of operation.
Especially on a 50-year-old car. And part of the reason will be heat degradation. So what?
My guess is that the heat doesn't really build up until the car is hot-soaking after shutdown, with fans off and large hot masses of metal such as the engine and exhaust manifolds radiating heat.
What are you going to do about that?

[Grant]

How about just using fans with a huge CFM for the radiator, you wont overcool the engine as the thermostat will cut in and it will be a lot less complcated. It will also give you plenty of spare capacity if your engine gets hot.

Steve

And where would the heat go though Steve? or are you also meaning to use the bonnet openers like Gary and Joe are suggesting ?

[Grant]

Guys,
This is like Global Warming, or Climate Change, in that you are going to a lot of trouble to tackle an imaginary problem.
Was this a problem with the cars during their first few years of operation?
If not, why do you see it as a problem now?
Yes, certain components will need to be replaced after years of operation.
Especially on a 50-year-old car. And part of the reason will be heat degradation. So what?
My guess is that the heat doesn't really build up until the car is hot-soaking after shutdown, with fans off and large hot masses of metal such as the engine and exhaust manifolds radiating heat.
What are you going to do about that?

But the cabins do get bloody hot even in a 383ci on a hot day Adrian as I am sure you must remember for your Jensen?

[garyc]

Hello Steve
Yes that’s another way that could work…would have to be powerful fans though as you said
I was just thinking the extenders could be a simple way to do this without going to the expense of fitting new fans and would be easy to take on or off if and when you needed them or thought you may need them.


Hello Adrian
I’m an engineer and I always find a little something to modify on most things I buy as the saying goes if you not got a problem then you make one so you can solve it ……….but seriously I know the cars are 50 years old and components will wear but things wear quicker in a hot environment that’s a fact… the Engine Oil, HT Leads, the wiring looms, plastic components etc all will have their life shortened drastically due to being in a high temperature environment.

The other thing that has changed is the amount of traffic on the roads how many times do you get stuck in traffic now compared to 50 years ago or even 30 years ago.
Im stuck in traffic every day for at least 10mins
I even see modern cars overheating in traffic jams I would feel more comfortable sitting there in my Jensen with my bonnet raised than not, after all if your cars getting too hot you either drive faster to get more airflow (not an option when you stuck on m25 bumper to bumper) or pull over and open your bonnet.

The engines would have run cooler when new I agree, the radiators would have been clean as would all the pathways through the block etc……but most people’s cars are not like new now and a lot of people don’t want to go to the expense of making them like new again.

For me the engine and gearbox are positioned too far back in the engine bay also proportion wise the engine bay is too small and does not allow for airflow around them I know at design stage this may have been done for a number of reasons one probably to allow for better weight distribution etc. but you wouldn’t design it like that now.

Am I going to start rebuilding the engine bay and gearbox tunnel to allow for more airflow of course not but the car would certainly run cooler if the engine bay was larger and the gearbox wasn’t so far back in the tunnel.

Also when driving the car you can feel the heat building up from inside the car especially without the air con on.
You can only insulate the bulkhead so much so perhaps something as simple as lifting the bonnet would make the heat transfer less due to the air now having an escape route.

The engines were not designed for Jensen’s as I’m sure you already know
If you checked the temperatures of these engines running in other cars or trucks you would I’m certain see that they would not be running as hot as they do in a Jensen

I agree that heat build-up will continue after the car is stopped but most Jensen’s have the fans running on a circuit with a thermal cut-out so the fans keep running after the car has stopped until the desired temperature is achieved then they cut out so that problem has already been addressed

As I mentioned earlier it’s in continual slow moving traffic or traffic jams when the cars get hotter when driving at say 50-70mph I think the air probably does get expelled or cooled down.

When I get some made ill update you….Joe seems further ahead with this so he may update sooner

Finally all these posts are about maybe making your car run better and offering possible alternative solutions or suggestions they are not saying you have to do this or that and the bonnet extenders seem to have been looked at before so not a new idea.

We all have our cars and do things to them that perhaps other people don’t think are necessary but surely that’s all part of the fun.
If I wanted a car I didn’t have to mess around with I would have got an Audi S5 or something but I like tinkering and so do a lot of people on the forum and most do a much better job on improving their cars than I do.

Whatever way I look at it I still think if we can reduce the build-up of hot air in the engine bay this can only be a good thing whether everyone agrees and thinks this needs to be done or not is another question

Gary C

[AH1951]

Hello Gary,
My first brand-new car was a 6.6 litre Pontiac Trans-Am bought in 1979.
Like the Interceptor, it has a big V8 engine positioned way back against the bulkhead.
On long trips, after, say, two hours, the carpet over the transmission tunnel became too hot to touch!
So I stopped touching it. But it didn't keep getting hotter & hotter, then bursting into flames, it just got to its equilibrium point.
So the Interceptor isn't unique in this behaviour.
The A/C worked well, so cabin comfort was never a problem.
I think it was the hot gearbox and heat from the exhaust mufflers, especially from those catalytic converters, that was responsible.
And it wasn't only the Trans-Am that got Hot-Tunnellitis. My Mercury Grand Marquis was exactly the same, and that had lots of space under the bonnet.
You say there isn't a lot of space under the bonnet of the Interceptor, but look at modern cars with big engines - the engine compartment seems jam-packed.
I wouldn't like to work on this Mercedes.
Maybe fitting a thermostat with a lower opening temperature would help?
I'll be very interested to hear how you think the mods are working.
But how do you measure such a thing?
Yes, I know that doing these mods can be a lot of fun. I did it myself a long time ago.
But I feel you are fighting something that is just a characteristic of the car: "They all do that, sir". And it's very difficult to make any significant improvement.

autowp.ru_mercedes-benz_s230_3.jpg (237.84 KiB) Viewed 3995 times

[garyc]

Hello Adrian

By coincidence I was in a Pontiac the other day with a LS1 engine conversion and noticed how hot the tunnel was so as you say I didn’t touch it again

The comparison between the Jensen and new cars is not really a like for like now is it as you well know the modern cars have far more efficient cooling in place and that is a major part of the design criteria from the start.

I agree in modern cars the newer engines are crammed in the engine bay but even on the picture you posted you can see the large plastic air scoop ducts that run the air back into the centre of the engine bay and I’m sure there are others not as visible as well, the porting in modern engine blocks is a massive improvement to the old 440 s and other engines of that time, then add in additional oil coolers, water coolers, more efficient radiators plus high cfm ECU variable temperature control fan systems and the Jensen seems like Fred Flintstones car in comparison.

After driving my Jensen and then getting back in my day to day car an old V6 4motion Golf I always think how much cars have improved in 40-50 years on pretty much every aspect….but still love driving my Jensen.

We could put pros and cons for both our points and go on back and forth for ever but I still think if you can remove any of the trapped heat from the engine bay it can only be a good thing

I will get back to you with my findings but the test will not be of a calibrated sort it will literally be if I feel cooler in the car when driving and if when I open the bonnet I get engulfed in a wave of hot air as I do now.

I have other projects on the go and this was just an idea that I felt would be easy to implement although its taking me ages to get round to getting it machined as its not top of my long list of things to do.

I found these pictures last night while looking for something else ......John Donegan`s fantastic looking SP check the bonnet extenders out above his head in first pic and in one of the others
The ones I am doing will not be anywhere near as long as that but looks like they work as he drove around Europe with them on.
https://www.joc.org.uk/forum/viewtopic. ... sp#p129369" onclick="window.open(this.href);return false;

GaryC

[AH1951]

That SP is beautiful, with the bonnet shut, but I wonder if the hot air expelled from that gap at the bonnet's trailing edge gets drawn into the cabin air intake?
Driving around like that is only advertising to the world that the car has a problem.
Would fitting a lower-opening temp thermostat have helped?
Would the car have overheated without doing that fix?
But if your cabin heat is coming from the gearbox & exhaust, the bonnet mod is unlikely to change that situation, is it?

[kenny38]

I have been following this subject and would think my post last year about the Phycologist visiting me and his theory that most contributors including myself have a form of Aspergers Syndrome is astoundingly appopriate. For God's sake, Joe give4 up on your quest especially about raising the trailing edge of the hood. This whole discussion is now bogged down. You have a bloody great lump of very hot metal not many inches away from you. It's a converted truck engine that was meant to be used in a larger bay. Suffer a little discomfort and think of the starving millions as you drive.Kenny38

[AH1951]

Suffer a little discomfort and think of the starving millions as you drive.Kenny38

OR, you could always just get the A/C working again, Joe.

[AH1951]

TOP TIP
In order to prevent being cooked in the cockpit by cabin heat, remove the thermostat completely and wire your radiator's fans to be permanently on in order to ensure that the engine never warms up in the first place.

And if that doesn't work, then you'll know it was heat from the exhausts and gearbox that has been the culprit all along.

Brilliant, or what?

[Joe Schiavone]

I may have posted this befor I have a friend with a Series III with the A/C pumping out 45 degree cold air and the heat soak overcomes the very efficient A/C and he thus is a victim of heat soak. What do you do now? With this as fact do you shoot for 35 degree A/C which I do not know how to do or do you search for a possible solution. I may fail but failure is not part of my mindset. If you look at a post from SP Tim about a project I took and finally completed. The outcome was the normal I'n most of my restoration history of well over 40 years. When I love a challenge I Jump In. Yes I may Fail but I am not addressing the project with failure as an alternative. Hopefully I will be driving in total comfort verses heat soak. RacerJoe