Transmission Heat Deflector and Seal Photo Needed

[BobHaskell]

FWIW ... OK... late to the party... and maybe nobody cares at this point.... but I'm kinda in Red57 camp regarding engine/transmission heat buildup.... at least that's how I read his comments. That was my concern ... and it is why I choose to allow the heat/air to continue to move out of the engine compartment and over the transmission. I used aluminum panels spaced 1/4" off the tunnel to direct air and isolated the transmission tunnel. I then added insulation on the outside of the tunnel (HushMat Ultra) to further isolate the heat from the interior. I did this on my last build and current build and have been satisfied with the results.

Of course, none of this meets originality issues if that's your goal.

But, as I said, I'm very happy with the results... tunnel stays cool and, seemingly, I don't add to the buildup of heat in the engine/transmission.

Cheers... Happy New Year!

I like it. Do you know if the aluminum panels would clear a factory center shift gearbox?

 

[HealeyPassion]

I like it. Do you know if the aluminum panels would clear a factory center shift gearbox?

Bob, well can't say for a fact... but I'm pretty sure they will. They don't really take up much space as they are only 1/4" off the tunnel.
Steve

 

[AUSMHLY]

Interesting that the early cars had the heat shield and it didn't seem to have any negative effect in the engine/transmission bay. Why wasn't it continued in the BJ7 BJ8?
Without the shield, I feel most of the heat coming from the two down pipes into to the drivers side of the bell housing (from the top bolt, red, to the bottom of that left side)

1. To address that I wrapped the top of the down pipes to the mufflers with DEI titanium rap. That made a significant reduction in heat and hot air.
2. I made a transmission heat deflector like the earlier Healey to address that entrance point.

As they say, it looks good on paper. I will drive with it installed and monitor if it makes an improvement or caused any heat issues in the engine bay.
With all my modifications, they are not permanent and reversible.

Maybe Bob Haskel will chime in, being he has installed a transmission heat deflector (similar to mine) in his BT7-tricarb.
I may have hear that with the tricarb cars, that deflector affects the carb near the firewall?
We'll see it the BJ8 duel carbs have issues or not.

What parts or performance does a hot engine bay effect. What should I look out for?

 

[BobHaskell]

Interesting that the early cars had the heat shield and it didn't seem to have any negative effect in the engine/transmission bay. Why wasn't it continued in the BJ7 BJ8?
Without the shield, I feel most of the heat coming from the two down pipes into to the drivers side of the bell housing.

1. To address that I wrapped the top of the down pipes to the mufflers with DEI titanium rap. That made a significant reduction in heat and hot air.
2. I made a transmission heat deflector like the earlier Healey to address that entrance point.

As they say, it looks good on paper. I will drive with it installed and monitor if it makes an improvement or caused any heat issues in the engine bay.
With all my modifications, they are not permanent and reversible.

The heat shield was dropped with the introduction of the center shift gearbox which took place during tri-carb production (BT7&BN7).

 

[AUSMHLY]

The heat shield was dropped with the introduction of the center shift gearbox which took place during tri-carb production (BT7&BN7).
WHY ?

Here are some poor photos of the heat shield fitted to our BT7-tricarb.
Bob did it make an improvement?
Did it affect the carb near the firewall?
Any negative effects with it added?

 

[BobHaskell]

The heat shield was dropped with the introduction of the center shift gearbox which took place during tri-carb production (BT7&BN7).
WHY ?

Here are some poor photos of the heat shield fitted to our BT7-tricarb.
Bob did it make an improvement?
Did it affect the carb near the firewall?
Any negative effects with it added?

Doubt that there's anyone around from the time that knows why. My collection of Austin/BMC service bulletins are currently buried.

One fellow that fitted one to his tri-carb had temperature issues. Haven't asked anyone else. I've had overheating issues, but don't know if I can tie it to the heat shield or not.

It does reduce the heat in the passenger compartment.

 

[AUSMHLY]

Sometimes both photos don't upload in my post #23. Let me try this way.

 

[Rob Glasgow]

Roger, did you apply the heat tape with the down pipes installed in the car? Or did you remove them first? Rob.
PS, still enjoying your Moto Lita steering wheel.

 

[HealeyPassion]

Since this discussion has kinda morphed from a simple heat deflector question to a cockpit heat discussion... I thought I'd offer more food for thought. As mentioned earlier, I'm of the opinion that you want to get heat out of the engine compartment, and keep the tunnel open for heat excavation. So I took a rather holistic approach to keep heat at bay, i.e. everything I could. I added aluminum panels over the original heat shields (which are now the replacement for the original asbestos), then the header/exhaust pipes were ceramic coated inside and out to reduce their temperature (the muffler is only ceramic coated on the outside). I already talked about the tunnel panels. The interior is Hushmat throughout with an extra layer of Extreme Plush on driver side and firewall. All in all, seems to make for a pleasant interior.

 

[Bob_Spidell]

Since engine overheating is attributed to lack of airflow through the engine compartment, maybe we should punch a bunch of holes in the scuttle to let all that hot air into the cockpit. I mean, we're halfway there already.

 

[AUSMHLY]

Another way to address heat

Roger, did you apply the heat tape with the down pipes installed in the car? Or did you remove them first? Rob.
PS, still enjoying your Moto Lita steering wheel.

Hey Rob, glad the Moto Lita is appreciated.
One can not wrap the pipe attached to the car as well as when removed. Sometime you just need to put in the extra effort.
I'll be posting the how to wrap (photos and video) install on Youtube soon.

 

[AUSMHLY]

Healey Passion, outstanding work!

I put a radiant-shield on the metal and placed the heat panels back on top.

Radiant Shield™ - Reinforced Foil Heat Shield

Reinforced, flexible foil and a high temperature adhesive backing combine for an easy to install car heat shield. Perfect for spot thermal protection.

www.secondskinaudio.com

 

[red57]

I took a similar but slightly different approach than HealeyPassion & AUSMHLY. The heat shields are not actually insulation but more 'deflectors' relying on 1/4" spacers to create a dead air space behind (especially the modern replacement non-asbestos versions) to insulate the cabin. Since the sheet metal will radiate any heat into the cockpit, I figured the best thing was to keep the sheet metal from ever getting warm (dead air space still means hot air against the metal).

I used a semi rigid foil backed fiberglass insulation typically used on industrial HVAC ducting - comes in 4x8 sheets but the thinnest I have found is 1" thick. The fiberglass is saturated with some kind of resin binder and it's really easy to 'shave' it down to 3/8-1/2" thick. I placed that directly on the metal and used aluminum foil tape to seal all edges and then placed the heat shields over it so I am not adding any to the overall thickness. I first did this on my 100-6 about 20 years ago and it worked very well so I have now got it on the BT7 I just finished. Upper interior of firewall is insulated with a foil backed 1/2 thick flexible felt insulation.

 

[HealeyPassion]

Since we have gone deep into the topic of isolating the driver/passenger compartment from heat, and Red57 added a pic of the inside of his firewall (all of which I agree with)... I'll add what I did to the firewall. First I filled unused holes (during manufacturing it seems obvious that when one hole no longer served its original purpose, they would put a rubber plug in and call it good... and as we know, rubber plugs harden and let hot engine compartment air through), then to reduce scuttle vibrations I put a heavier gauge metal backing, that is covered with HushMat foil backed insulation and finally that is covered with Second Skin Luxury Liner Pro (the same product that covers the driver's side of the car). Then, as needed, holes were added to firewall. FWIW .... or just overkill?

Steve

 

[AUSMHLY]

HP, is there such a thing as overkill in our Healeys? It's all for the good. I liked what you did and your attention to detail.

It is interesting how the topic of the Transmission Heat Deflector has morphed to other heat issues and how to address them.

Not to change my own topic, but I see you're using Second Skin Luxury Liner Pro (LLP). It's 1/8" Mass Loaded Vinyl (MLV) with 1/4" Closed Cell Foam (CCF) fused to the bottom.

LLP is a sound blocker and to some degree a thermal barrier. Under the LLP I've installed Constraint Layer Dampener (CLD).
I'm getting ready to start another post about why one would consider using these products in unison.

Here's a teaser of my LLP install.

 

[Editor_Reid]

It's going to be interesting when these cars are re-re-restored some decades from now. I can see the article in the club magazine starting out, "It's remarkable the number of variations and experiments the factory used in attempts to reduce heat and noise in the cockpit. There are virtually no two Healeys alike! And my great-grandfather knew Donald Healey, so everything I say is Gospel!"