Putting heating back into a car

[Jonny Hart]

If you don't have to go the traditional route, there's always electric heating if you want to keep your race headers.

Just a thought

Be careful.

I'm heavily involved in developing an electric heating system right now (I actually started looking at this in 2010). Our first protoype was 800W, used 60A and was next door to useless.

The absolute bare minimum requirement for heating a small cockpit like a 911 is 1600W but even that figure will struggle in single digit temperatures. Most heating systems in vehicles are at least 4000W. Divide by 12V and you will see that the minimum current required is in excess of 130A. This is part of the reason we are developing a new alternator.

The bottom line is you will be sorely disappointed at any aftermarket electric heating system currently available. Double the disappointment if you buy it from eBay!

[gturner008]

Covered I think in other threads. But I successfully wired in a hot air blower from a BMW convertible rear screen heater. Just plumbed it into the air vents to give a little bit of heat to the front screen. Did nothing to increase the cabin heat - but did demist and keep demisted the front screen. Did this to my old 67 912. Just a thought....

[scalino65]

What is wrong with your current heating arrangements?

Haha..never gets dull! You know, that was my favourite trip ever in a 911. Just perfect. What’s worrying there is (a) how young I look compared to know and (b) that it was end of may or early June...brrr..
Many thanks for all the replies chaps. The other option is a hot water bottle but you do get some strange looks when asking people for a refill.
MikeB c, I think we need to meet up to discuss..also I’d love to see your trans am, can I be Buford t justice?
Best
Will

[yoda]

Get the heating sorted Will and let’s go in the Spring.

[scalino65]

Sounds good to me!

[MikeyC]

MikeB c, I think we need to meet up to discuss..also I’d love to see your trans am, can I be Buford t justice?
Best
Will

No probs, Will, send me a PM and we can sort something out, and at the risk of going somewhat off-topic, teaser attached

[MikeyC]

So, because I can't bear the thought of Will having to spend another winter in a cold car, and because he clearly has a good appreciation of Burt Reynolds, 6.6L V8's and leaf springs, I thought I would document the process I've just been through to reinstate the heater circuits of my '68T, in support of this post. There are a few minor differences in a '67 installation, but you'll get the idea.

First job was to find a good pair of heat exchangers to replace the 'racy' manifolds that are on the car currently.

race manifolds on.jpg

Now I may be a bit odd, but I find the view above, the way the pipes exit the ports and collect to the rear as equal length 3 into 1's, absolutely gorgeous. But in the interests of winter warmth, however, they'll have to look gorgeous hanging on the wall. I've been collecting the right bits and pieces for this job for a while, and had a good set of SSI's around, plus a serviceable used set that with a bit of work would be just fine for my 'driver' car. I decided to keep the SSI's for another project, but as you can see the other set were not the prettiest pair:

exchangers and flappers pre strip.jpg

but after media blasting, cleaning and pressure testing to confirm there was no internal corrosion that could cause exhaust gases to enter the cabin air stream (very important this bit if you're thinking of fitting a second hand system of unknown history!), some repair welding around the outer skin, and 2 coats of a good spray-applied VHT paint, I was happy that they'd be just fine for the job.

exchanger post-paint.jpg

[MikeyC]

Turning attention to the flapper valves, the ones on the car were still there, but somewhat corroded, so removed, stripped and blasted them, then gave them 2 good spray-coats of a red-oxide paint plus a clear-coat over to give them a fresh, original look. Had a second set of these knocking around, so did them both at once:

flapper boxes before strip.jpg

flapper boxes stripped.jpg

flapper boxes painted.jpg

[MikeyC]

Whilst the flapper valves were off the car, it was a good opportunity to get to the area behind the valves and remove that cruddy old original underseal that I couldn't get to when I did the rest of the car, as the flapper valves were in the way at the time. With new underseal applied to the area, the rebuild could start:

flapper box area prepped.jpg

Here's all the parts that I needed to do the job, laid our before starting. (Don't ask me why I took a photo of 8 'thin-type' jubilee clamps, I only needed 6!).

parts laid out.jpg

First I installed the valves, because they looked nice and would give me a good early job satisfaction boost:

flapper box installed.jpg

[MikeyC]

Next job was to wire-up the control lever by the handbrake. The control lever is ahead of the h/brake on a '67 so you'll need the longer cable. For me, this was a fiddly job, which could have been made easier by disconnecting the h/brake cable first and lifting it all clear of the hole, but I chose the 'disturb as little as possible' route, and managed to thread the wire through the hole in the lever and into the tubes pretty much blind and with no access for big fingers. Luckily I had a second h/brake assy around for reference so could work out what I needed to do without really seeing it. The key here was to know that the cable is not equal length, the longer side needs to go through the LEFT tube - don't get it the wrong way round!

bare hbrake assy.jpg

fitting heater control lever cable.jpg

Once the wire was threaded through and poking out of the right tube exit holes, as below:

cable exit from tunnel.jpg

I could then move back underside and finish the assy.

[MikeyC]

Next job, put the manifolds on (not forgetting the special nuts for the fixings that are only accessible through the heat exchanger holes, and first checking you have the correct length studs fitted for the flange size). Torque all fixings to 25Nm:

long and short manifold studs.jpg

heat exchangers fitted.jpg

Then can put the inlet air pipes on (don't forget to fit the hose clamps loose on the pipes before joining the pipes to the spigots!):

air inlet pipe lower.jpg

[MikeyC]

Next, need to turn attention to the orange heat exchanger to flapper box pipes (not forgetting that the special hose clamps used here are handed), fit these to the spigots on the heat exchangers and flapper valves. Apply some grease to the exposed control cable hopefully still hanging out of the tunnel tubes, thread it through the plastic guide tubes and through the special guide in the hose clamps. Close the ends of the hose clamp tube with the 2 rubber dust shields that allow only the cable to poke through. Attach the cable to the flapper valve by threading it through the M4 pinch bolt on the shutter assy, making sure the lever in the cabin is down, the valve to the cabin is closed, and incoming air from heat exchanger is venting to the engine bay.

exchanger connected to flapper valve and cabled.jpg

Check that the full range of lever operation gets you from fully closed to fully open.

Find some good roads and drive it lots, all warm and comfy, and enjoy the experience of that lever on the centre tunnel now actually doing something. Play with the vent shutters by your leg and the front screen fresh air mixer, and if you've previously plumbed in the rear window demisters, enjoy the marvel of warm air jetting out from the corners of the rear screen.

installation complete.jpg

After it's got good and warm and stopped smelling of VHT paint curing, bring it back in, check all fixings and cable operation and torque check manifold nuts. Job done!

[sladey]

Nice one! Thanks for sharing

[scalino65]

Many thanks indeed Mike for this. Very much appreciated. What could possibly now go wrong! Really quite a straightforward system. It would be so much nicer not to wear two jumpers, a flying jacket, long johns and a hot water bottle stuffed under my shirt...
In summary,

[hot66]

great post ... if its OK , I'll put a link to this thread in the 'how to ' thread