Big Healey fender vents

[davidb]

I was just reading thru some of the recent posts, and I noticed some photos of Randy Forbes gorgeous burgundy Healey (nice house too, Randy), with the fender heat vents. I was considering these myself and was speaking with another Healey owner who has them but said he didn't really notice any appreciable difference in heat dissipation. Any views on this, before I go chopping up my fenders? Presumably insulating the floor/tranny tunnel is more effective for heat control, but the fender vents look so darn good, especially on the roadster models....

Cheers
Dave

 

[Randy Forbes]

Well, I don't have interior door panels on my car (working on that__Moss kit arrived last week, but the rear kick panels were not assembled correctly__<span style="text-decoration: underline">Moss</span> is working on that); anyway, without the door panels, the windlace doesn't seal tightly.

A few weeks ago, we attended a CarBQ (I took best of show over 4 Ferraris_see:https://www.rfdm.com/gallery/album198).

On the way home, through downtown Toledo, the heat pouring in through the leaking door seal was searing my leg! This was not at a standstill, but only when moving at 40 mph or so.

I have a data-logger that I use when I'm coating parts (cheaper than a strip-chart recorder) someday when I'm bored, maybe I'll rig the thermocouple up in the vent and see what comes out.

Thanks for the compliments on the house & car!

 

[RAC68]

Hi Dave,

Although I do like the look of fender vents and have considered them seriously, I have never gotten around to making that commitment. Of the friends that have installed the fender vents, all indicate reduction in engine and bay temperatures, however, all have installed coolant recovery systems, 6 blade fans and one had installed an extensive fan shroud for more efficient fan function.

An interesting additional effect was identified with the installation of the vents. It is not uncommon for a big Healey’s temperature to rise slowly when driving at highway speeds. This condition is the result of a high-pressure buildup within the engine compartment that impedes the free flow of air through the radiator. The introduction of fender vents and/or hood louvers allow this pressure to be released resulting in improved airflow.

Some simple, less dramatic, temperature-reducing resolutions, other than a radiator re-core or the installation of a 6-blade fan, which can be installed at little or no cost, are:
1. A coolant recovery system to maintain full-radiator coolant capacity (unpressurized systems similar to those used on modern cars are my preference).
2. Simple fan/radiator shroud, to improve fan efficiency consisting of 4”x Radiator-length vertical pieces of ridged material (I used aluminum from an old sign) with notches installed to fix on the radiator mounting bolts.
3. The installation of a set of engine compartment panels to eliminate the pressure build-up within the engine compartment. These panels consist of 1) A cover attached to the bottom of the frame covering the forward 1/3 of the engine compartment, 2) An additional panel extended forward from the compartment panel and rolled up to cover (but not contact) the lower 1/3 of the bottom radiator tank. Be sure to cut an opening in the forward panel for the radiator drain.

Although the above modifications will require some thought and work, they are easily reversed and do make a difference.

Let me know if you would like pics or additional information on any of these suggestions.

All the best,
Ray 64BJ8P1 (original owner)

 

[Randy Forbes]

Ray,

Wow, an original owner__very cool!

Do you have any pictures of the panels described above? I'm pretty sure I know what you mean, but not 100%, and there are likely others here that could use a little visual aid too.

Thanks!

Randy

 

[RAC68]

Hi Randy,

A while back I wrote an article for our club news letter “I always wanted a COOL car’ which described a number of things learned and did to improve engine cooling in my Healey. Click on the following for the pictures you have requested.

Pics "I always wanted a COOL Car"

All the best,

Ray 64BJ8P1

 

[Randy Forbes]

Thanks Ray, that's a gorgeous car!

I just took a quick glance (as we're checking out of a hotel at the moment) but you're description above did indeed match what I expected to see in the pictures.

Thanks for posting that link, and better still, for submitting that to your club's newsletter!

 

[Jerry]

No extra vents on my car but as Randy pointed out above, the door seals leak. The passenger side seals pretty good but the driver side has a vent of hot air that can get quite toasty. I keep putting my car up on the rack to see what can be pluged from below to stop this air, but I have not had success yet. I think what you need is something that pulls the air down, to exit below the car.
Jerry
BN4
BJ8

 

[JAV]

I was interested to note you are the original owner of a PHI BJ8 as I am, same color as well. And also looking at heat reduction. Small world.

 

[davidb]

Thanks to all who replied and in particular to Ray, for your extensive comments (and excellent photos)on cooling. Interesting comment on the under hood pressure buildup. Would never have thought of that. That would certainly affect airflow...I wonder how significant it is.

Cheers
Dave

 

[IanIrving]

I was talking to a BJ7 owner yesterday who has a novel way of increasing engine compartment cooling if he knows he's in for a hot drive. He has rigged two brackets on top of the radiator into which he fits two blocks of wood. They keep the hood open a couple of inches at the front, the hood held by the two side clips, and drags air in over the engine. He's used it for years, never had a problem with overheating, nor with the hood flying open. Must look weird though.
Ian

 

[RAC68]

Hi All,

Jay will probably remember when his Healey was new and he never gave much thought to over heating. We were young and we understood the tag Sports Car indicated you had to be a SPORT to own one. Heat discomfort and going back to pick up your exhaust after driving over railroad tracks were our Red Badges of Courage and we of the LBC community still like going to club meetings and contributing to discussions commonly emphasized by the phrase ”If you think that’s bad, let me tell you what happened to me”.

Over the years, there are many solutions I have come up with to make my Healey more enjoyable and safe but all are easily reversed and none have altered the original driving characteristics I first experienced. My Healey will never be my Acura and that is what I want. At 60mph or 70mph, my Healey needs focused driving and my concentration should never be diverted by anything like charging or heating problems.

The Healey was designed in the 50s and is filled with the thoughts and technology available at that time. Aerodynamic was more a tool for airplanes design and very infrequently used to discovering the presence of a high-pressure buildup in the engine compartment or driver’s foot-well. High-pressure build-up is the cause of our most frustrating issues as its presence in the engine compartment or foot-well will impede the free flow of cooling air.

With all that said, remember, we are Sports driving Sport’s Cars so don’t look to achieve the comforts of a Mercedes or the reliability of a Porsche. If that is your objective, you must go to the point of loosing your Healey and to those making that decision…all the best.

Sorry for the verbosity.

Ray 64BJ8P1 (original owner)

 

[Ed_K]

Heat buildup in the engine compartment is the last heat problem left I would like to solve on my car ( 65 BJ8 ).
Which of these two is the best at getting rid of the build up of heat in the engine compartment;
1. A louvered bonnet ? or
2. Installing the rally vents in the sides of the front wings ?

It would seem that the louvered bonnet would allow all the heat to escape out of the engine compartment, even when idling at a stop light. The rally vents would probably work well when underway but not allow heat to escape as well when at a stop light.

Ed

 

[Randy Forbes]

Have you ever driven a car with a louvred hood in the rain?

That makes a pretty strong argument in favor of the rally vents...

 

[Ed_K]

Hi Randy,

No, I have not. But now that you mention driving it in the rain, I have an image of dirty water mixed with a few drops of oil spraying up on the windshield.



Ed

 

[Randy Forbes]

Hi Randy,

No, I have not. But now that you mention driving it in the rain, I have an image of dirty water mixed with a few drops of oil spraying up on the windshield.



Ed

You got it!

Nasty mess, and your wiper blades are not likely to recover from it.

 

[Ed_K]

Hi Ray,

I read your article and it has some good information in it. I am especially interested in this air flow barrier that you installed under your car frame.

After messing around with heat problems in my Healey for the last three years, I have done some of the things you mentioned. I have also tried some things based on the advice from other members of this forum. I have determined by my observations that there is more than one " heat transfer " problem/symptom in our cars that needs to be addressed.
I have addressed the worst of these symptoms.
I added an unpressurized overflow tank along with the napa radiator cap so it would pull the coolant back in to the radiator after the car cools off while I was putting the car back together starting 5 years ago now. I had remembered it spitting out coolant back in the early 70s when my Dad let me drive it a few times so I didn't wait to see that happen again.

1.. The operating temp of the car was way over the rating of the thermostat. This was most noticeable on hot days 95 F and above. It would indicate 210 F or more after a spirited ride or cruising on the interstate. It would never loose any coolant so I was originally just trying to lower the summertime operating temperature. For this symptom, I tried the correct thermostat as you did, that helped a very little but not enough to matter. Next I tried a Norman Nock fan from BCS.
That seemed to help more than the correct thermostat but even combined with the correct thermostat did not " fix " this symptom. The problem was just slowed down a little. The last thing I did really fixed this one heat symptom. I went to a couple of local old radiator shops and asked what could be done to the radiator. Both shops took one look at the original Healey radiator and said " so they used a forklift/ industrial radiator core in these cars ? " The one shop said they had done many LBC radiator core conversions using my original upper and lower radiator tanks with a new modern high efficiency core as other forum members have said they did. I had this done and that absolutely fixed this symptom.
The car will always run a few degrees above the thermostat rating even on the hottest days of summer, no matter which thermostat I am using. But this was true ONLY when driving down the road.
2... When at a stoplight when the outside temps were above
90 F, the longer I sat at a stop light, the higher the engine temp would climb and at the same time, my car's idle would get lower and lower and eventually it would cut off. When I restarted it, it would run rough and backfire before moving. I figured that the heat was boiling the gas in the bowls of my carbs. Steve Byers said he once had the same symptom on his car and he fixed it by building a new heat shield for under the carbs so that is what I did and that completely solved the " rough idle on a hot day at a stop light " problem no matter how high the engine temp gets when at a stop light.
3... I wished I could get the cars operating temperature to stop climbing when at a stoplight on a hot summer day. For this symptom, I installed a 12 inch Hayden fan as a pusher. My logic was that this would keep the air flowing through the radiator and then push some out of the engine bay when the mechanical fan is running slow. This seems to have fixed most of this symptom. My car will only get to 185 F or so after a long stop light.
4... A side effect of installing a new heat shield under the carbs was that the fresh air vent's air seems to be heated so much that I need to close the vent. It doesn't matter how long I have been driving down the road and the engine temps have gone back down to a few degrees above the thermostat rating again, the air coming out of the vent is much hotter than before I fixed the heat shield under the carbs. Apparently the heat in the engine bay is being redirected and trapped in the wing where it is heating up the air in the vent pipe. If I can fix this last heat symptom, I think I'll have all the heat gremlins beat.
....
So now I am wondering how to get better air flow through the bonnet. I don't really need to get more air flow through the radiator so I don't know if Ray's under frame/ radiator barrier would help with moving air back out from under the bonnet... Unless I cut some reverse louvers in it so the air would push up into the engine bay ??
Or I could order one of those wrap around insulation products to insulate the whole air vent pipe ??
Or cut some holes in the wings to install the rally air vents ??

:hammer:

Ed

 

[RAC68]

Hi Ed,

Sorry for my slow response.

Wow, you did quite a bit. Although you have addressed and resolved your engine heat build-up problems with a number of good solutions, I am not so sure that your installation of an electric pusher fans will satisfy your objectives without unintended consequences. I also believe that (although I like the look of fender vents) you can achieve your objectives without cutting vent holes into your car.

First; the heat trapped in the wing comes from where? Your mechanical fan is less than efficient if you have not improved the fan’s original shroud. Using such fans, as the aggressive Texas Cooler, will have less than potential cooling results if something isn’t done to keep the activated air from rolling off the end of the blades. This condition would not only diminish the fan’s cooling effectiveness but would not power the air’s escape from the compartment.

I conjecture that your electric fan may not be giving you a full measure of anticipated benefit. Although effectively improving cooling when going slow or at rest, it may be contributing to reduced cooling, when off and at any speed, by blocking free airflow through the radiator. Further, when pushed air encounters your mechanical fan, it is redirected by the mechanical to the side and increases under hood pressure buildup. A non-aggressive mechanical fan will marginally diminish this airflow redirection and no mechanical fan would probably eliminate it.

Based upon my experiences, and assuming you have the forward radiator deflectors in place, I would suggest you think about a fan shroud around your mechanical unit and try one without the electrical pusher in place. You have a choice of a highly efficient fully encircling fan shroud, similar to that used by Steve Byers, or the relatively simple example presented in the document. I would start with the very simple and easily implemented unit, especially if an original compartment image is an interest.

Second; hot vent air is the result of the speed of the air moving through the tube, the temperature of the air entering the vent, and any additional heat absorption during passage. If you consider that the forward vent opening is behind the headlight and relatively close to the radiator, it is not hard to see that the Healey’s Cold Air ventilation has enough engineering problems to make us question whether its is a point of British sarcasm. Additionally, to add to this joke is the high pressure that builds in the foot well, during a top-down drive, which further thwarts vent-air from freely exiting into the cabin. It seems to me that slow airflow issues, slow moving high compartment pressure and heat pushed to the side by an ineffective fan, and High Ambient Temperatures may be all contributors to your heat discomfort,

One last point; in the article transmitted, I address the issue of engine compartment pressure build-up from air passing below and around the radiator and frame. The implementation of the panels mentioned would help deflect problem air streams from pressurizing the compartment and would also assist in air extraction.

So what am I saying? As you previously concluded, no one resolution will convert our Healeys into comfortably cool cars. I would suggest you look to implementing a fan shroud and eliminating your electric fan (I know it works). I would also suggest you implement the panels mentioned in the article to reduce the high-pressure buildup that diminishes engine compartment free airflow. As far as Cold Air vent improvement, I would suggest you review an article I will e-mail that addresses a way of supercharging ventilatating airflow.

I guess that’s about it.

All the best,

Ray 64BJ8P1

 

[Jim_Newman]

I've been following this thread with some interest. My BN7 has hood/bonnet and rally style fender vents and I have never noticed a problem in the rain (mind you I don't remember the last time I drove it in the rain). However, I just got caught in a driving rainstorm while out in my e-type coupe, which as you know has a bunch of hood/bonnet vents. No mess on the windshield with this car. (Though I am not pleased to have been caught in the unexpected rain in the first place).
Cheers

 

[RAC68]

Jim,

I have had the same experience with not having any negative hood louvers rainstorm problems with my TR7 and I do drive the car during rainstorms. However, I hesitate to relate my TR rainstorm/louver experiences to the Healey 6 as the TR, and some 100-4s, were delivered with hood louvers and I trust the manufacturer, prior to their product’s introduction, performed all necessary testing and design changes.

That being said, your actual positive hood louvers experiences on a Healey-6 are irrefutable and their location and specifications may be of interest to Ed.

All the best,

Ray (64BJ8P1) and modified and commonly used 1979 TR7 Roadster

 

[John Turney]

Actually, the early (100-6) rally cars had vents in hoods/bonnets. The area in front of the windshield is a high-pressure area and limited their effectiveness, so the Works went with the side vents that are now so popular.