Bristol Cars - Owners and Enthusiasts Forum  

Go Back   Bristol Cars - Owners and Enthusiasts Forum > Bristol Forums > 8 & 10 cyl Bristol cars

8 & 10 cyl Bristol cars Type 407 onwards - restoration, repair, maintenance etc

408: A lot of heat coming through the firewall.

Reply
 
Thread Tools Search this Thread Display Modes
  #1 (permalink)  
Old 01-05-22, 11:02 PM
Member
 
Join Date: Oct 2014
Location: Florida / Nova Scotia
Posts: 180
Default 408: A lot of heat coming through the firewall.

I get a lot of heat from the firewall. The last owner added insulation inside the car but I am wondering what else I might do to cool the engine compartment. The car left the factory with no valance under the front end as shown in the first photo.

A previous owner fitted a metal tray to mine to hide the visible suspension and smooth airflow, I suppose. Might it help cool the engine bay if I take it off?

Also, did the car leave the factory with a rubber seal along the rear edge of the bonnet opening? Mine has a nice new aftermarket seal fitted and I wondered about removing it to let air leak out from the engine compartment there?

Thanks for any thoughts.

David
Attached Images
File Type: jpg 19132177-45.jpg (133.0 KB, 27 views)
File Type: jpg 20220428_135655[1].jpg (61.8 KB, 42 views)
Reply With Quote
  #2 (permalink)  
Old 03-05-22, 02:49 AM
Member
 
Join Date: Mar 2020
Posts: 140
Default

I guess if it's not too difficult to remove the tray it's got to be worth a try..will have a look and see what I've got on rear edge of bonnet opening but the more you can do to let heat out the better. How bad is it? I had a '62 Thunderbird that had heat soak problems and it made life very uncomfortable in all but the coldest weather ...never really got a completely satisfactory solution..

Andrew
Reply With Quote
  #3 (permalink)  
Old 03-05-22, 10:10 AM
Member
 
Join Date: Oct 2014
Location: Florida / Nova Scotia
Posts: 180
Default

Quote:
Originally Posted by AndrewA View Post
I guess if it's not too difficult to remove the tray it's got to be worth a try..will have a look and see what I've got on rear edge of bonnet opening but the more you can do to let heat out the better. How bad is it? I had a '62 Thunderbird that had heat soak problems and it made life very uncomfortable in all but the coldest weather ...never really got a completely satisfactory solution..

Andrew
How bad? Well, I can live with it as I don't drive it in summers here in Florida (no AC installed) but it's very noticeably a source of heat in the cabin by your legs.

I wondered about maybe cutting some holes in the panels between the engine compartment and the wheel wells but I don't know enough about the aerodynamics of the car to be sure it wouldn't make things worse. Aston Martins of that vintage had louvred panels there.

David
Attached Images
File Type: jpg 5920sa16.jpg (174.1 KB, 5 views)
Reply With Quote
  #4 (permalink)  
Old 03-05-22, 12:05 PM
Member
 
Join Date: Mar 2020
Posts: 140
Default

Just a thought and not trying to send you off on a wild goose chase but I thought I had heat soak issues early on in my ownership of this car but sorting out which vents were open - and what heater controls were doing what has made the problem vanish - I didn't do the work myself but I can ask the fellow that did. The control knobs were swapped over and when it said everything was off - it wasn't!
I've still got a bit too much fresh air on drivers side - but I can live with that.


Quote:
Originally Posted by dwomby View Post
How bad? Well, I can live with it as I don't drive it in summers here in Florida (no AC installed) but it's very noticeably a source of heat in the cabin by your legs.

I wondered about maybe cutting some holes in the panels between the engine compartment and the wheel wells but I don't know enough about the aerodynamics of the car to be sure it wouldn't make things worse. Aston Martins of that vintage had louvred panels there.

David
Reply With Quote
  #5 (permalink)  
Old 03-05-22, 01:12 PM
Member
 
Join Date: Oct 2014
Location: Florida / Nova Scotia
Posts: 180
Talking

I will check the heater controls.

David
Reply With Quote
  #6 (permalink)  
Old 04-05-22, 02:52 PM
Member
 
Join Date: Nov 2011
Posts: 26
Default

Yes, to jump on a bandwagon - I had this too and the heater was constantly on. Drove from England to France in July and it was a bit of sauna.

If it's coming out from the heater, I'd check that the heater valve is working (not constantly on) and that the heater flaps are opening and closing.

You can also take the heater apart and check that the seals on it do close properly. If you are refurbishing it, the heater core is I think the same as one of the sprites.
Reply With Quote
  #7 (permalink)  
Old 04-05-22, 04:28 PM
Member
 
Join Date: Mar 2020
Posts: 140
Default

Yes - forgotten I'd done that as well - had little matrix in heater refurbished and getting the valve to work properly - and seal correctly took a bit of time.
Good luck - but I still can't see that removing your sump guard is going to do any harm.
Reply With Quote
  #8 (permalink)  
Old 04-05-22, 05:11 PM
Member
 
Join Date: Oct 2014
Location: Florida / Nova Scotia
Posts: 180
Default

Was just at the car (didn't check the heater controls yet) and noticed something glaring! It has a gorgeous, new aftermarket aluminium radiator and a big new single electric fan. However, I suspect the radiator is not as wide as the original because down one side there's a 1" gap and on the other side a 2.5-3" gap!!!!!

I don't think it will affect the under bonnet heat but I'll be blocking those off tomorrow!

David

Last edited by dwomby; 04-05-22 at 05:22 PM.
Reply With Quote
  #9 (permalink)  
Old 04-05-22, 06:03 PM
Member
 
Join Date: Mar 2020
Posts: 140
Default

Aren't gaps good?
Reply With Quote
  #10 (permalink)  
Old 04-05-22, 06:07 PM
Member
 
Join Date: Oct 2014
Location: Florida / Nova Scotia
Posts: 180
Default

Quote:
Originally Posted by AndrewA View Post
Aren't gaps good?
I think the idea is to get as much air as possible flowing through the radiator not around it. This is to benefit engine temperature, of course. As to what effect the gaps or lack of them has on engine COMPARTMENT temperature - I have no clue.

David
Reply With Quote
  #11 (permalink)  
Old 05-05-22, 09:45 AM
Member
 
Join Date: Jul 2008
Location: Bury St Edmunds, Suffolk, UK
Posts: 233
Default Hot Firewall and legs!

When I first bought my 407 the heat in the passenger footwell was horrendous, so much so my wife hated it! I then spent quite a bit on heatproofing the firewall and floor, it made a difference but not much. I flushed the radiator, a little more difference. Boiling in traffic was also a problem, the name kettle suited it well. I upped the % of antifreeze, this at least reduced the boiling but not the temperature . I read that the cabin cooing was only effective if the rear windows were open, that also helped. The fans were ok. I then, through another member, had the radiator exchanged for a rebuilt one which was thicker than mine by about 1/2 inch. Bingo, no more overheating, temperature remains 85 degrees whilst motor is running and I have just completed a 1,200 mile trip to Cornwall and 3 days tulip rally then back to Suffolk via Bristol staying in the Hotel Bristol! No problems at all, cruising on motorway at around 75mph at which the Bristol feels at home.
I have owned it for 23 years now and having fitted power steering a couple of years ago find it the the ideal car for a 78 year old one legged old git to be driving. Happy motoring!
Reply With Quote
  #12 (permalink)  
Old 05-05-22, 09:49 AM
Member
 
Join Date: Mar 2020
Posts: 140
Default

Brilliant!!
Reply With Quote
  #13 (permalink)  
Old 06-05-22, 11:12 AM
Member
 
Join Date: Oct 2014
Location: Florida / Nova Scotia
Posts: 180
Default

The 408 has a water valve to shut off the hot coolant going to the heater but, even though the valve is in the closed position, both the input and output hoses for the heater are the same temperature of approximately 140F after a run. Am I right in thinking that means the heater valve is not fully closing and letting hot coolant circulate through the heater?

David
--
Reply With Quote
  #14 (permalink)  
Old 06-05-22, 02:38 PM
Member
 
Join Date: Mar 2020
Posts: 140
Default

Yes...you could try just connecting the two together - bypassing the heater matrix and going for another drive....I checked with my fellow he felt the main problem with mine was cable related but I did put on a new valve as well. The old one was not great.
Reply With Quote
  #15 (permalink)  
Old 06-05-22, 02:48 PM
Member
 
Join Date: Oct 2010
Location: Vineyard Lodge Sydenham Hill
Posts: 56
Default

I had the same problem with a Jensen CV8 with a 6.3 engine. Apart from fitting heat insulators under the carpet I also had the exhaust wrapped in heatproof tape. (You can do the manifolds as well) This keeps down the air temperature in the engine bay.
Also I installed a Delta fan controller which prevents the engine from getting too hot in the first place. Auto Cooling Additionally it dealt with the occasional fuel vaporisation problem on really hot days and must help to provide desirable cooler air to the carb intake.
Try Summit for parts and advice https://www.summitracing.com/
Let us know how you get on.
Reply With Quote
  #16 (permalink)  
Old 06-05-22, 10:21 PM
Member
 
Join Date: Oct 2014
Location: Florida / Nova Scotia
Posts: 180
Default

Does anybody happen to know the internal diameter of the heater hose? I'd like to buy the fittings to bypass it temporarily before I drain the coolant and pull the hoses off the heater matrix.

Thanks

David
Reply With Quote
  #17 (permalink)  
Old 07-05-22, 06:11 AM
Member
 
Join Date: Mar 2020
Posts: 140
Default

On mine it's 13mm int diameter, 20mm external.
Reply With Quote
  #18 (permalink)  
Old 07-05-22, 09:05 AM
Member
 
Join Date: Oct 2014
Location: Florida / Nova Scotia
Posts: 180
Default

Quote:
Originally Posted by AndrewA View Post
On mine it's 13mm int diameter, 20mm external.
Thanks, Andrew. I thought it looked a skinny one!

Looking around the web, I think the heater valve is the same as the Jaguar MK2 C.16559. So that's what I ordered. Time will tell if I got it right.

David
Reply With Quote
  #19 (permalink)  
Old 07-05-22, 11:47 AM
Member
 
Join Date: Mar 2020
Posts: 140
Default

More money but probably worth getting a radiator guy to flush out/pressure test the little matrix as well - it wasn't much money in the scheme of things - about 70 from memory...or perhaps one thing at a time!
Reply With Quote
  #20 (permalink)  
Old 07-05-22, 06:04 PM
Member
 
Join Date: Apr 2021
Posts: 117
Default

I haven't tried it but ceramic coating the headers is supposed to help keep down under bonnet temperature. Anyone any experience of this?
Reply With Quote
Reply

Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is Off
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


All times are GMT. The time now is 11:22 AM.


This is the live site

Search Engine Friendly URLs by vBSEO 3.6.0 PL2