What is heat backdate

[Terry Grillo]

Hello all,
I've been working on my SC's heat system and have it working pretty well. Without the blower in the engine compartment turned on, I get plenty of heat. I drive the SC all the time, and I live in the Sierra foothills of N. California, so during winter heat is necessary. I've removed the useless AC and now I think I'd like to remove the heating contraption on the other side of the motor. What does backdating the heat involve?
Thanks,
Terry

[pplkook]

Search - heater backdate
Pelican Parts Technical BBS - Search Results
What is it? Basically removing everything in the engine compartment so the only way you get hot air is due to the engine fan.

I did it to my Carrera, so I don't know the specific of a SC.

-jack

[KNS]

You'll be removing the blower motor and associated hoses. If you're getting plenty of heat now with the blower inop, you'll have the same if not more heat with the backdate. I backdated my SC and it was worth it. You will need some engine tin as well.

[SpeedracerIndy]

Here's what it looks like with everything removed and backdated.



You have to remove the blower, and both block off plates next to the fan and replace them with parts from an older 911. There are some 930 parts that will work too. If you search there are plenty of threads that outline all the parts you'll need.

I can roast my toes on the coldest day, but you have to keep the RPMs up without the blower there. In the past I had half backdated it. I left the blower but removed the hose over the top of the fan. This gave me forced air from the blower to the drivers side of the car, and heat from the engine fan only to the passengers side. It was a good compromise of looks with forced heat. Since I don't drive it in the winter at all, I just yanked it all out for simplicity. So much easier to work on the engine now.

[Terry Grillo]

Thanks all. Speedy, your engine bay looks very clean, with clear access to all the important bits. Mine will now, too.
Terry

[dshepp806]

Will the backdating eliminate the cooling fan up top (on a Carrera)?

Just asking?

Doyle

[KNS]

dshepp,

If you mean the blower motor and duct work on the upper/left side of the engine compartment - yes, it will

[tcar]

Originally Posted by dshepp806

Will the backdating eliminate the cooling fan up top (on a Carrera)?

Just asking?

Doyle

That's not a cooling fan. That's the heater fan.

It will eliminate it and the only heat fan will be the big 11 blade fan on the engine.

If you need a lot of heat, like if it's really cold, you have to keep the engine revs up to get heat... won't do real well just idling.

[Bob Kontak]

The engine tin parts from aftermarket sources - including Pelican - do not always fit perfectly. However, when you are done and it looks like Speedracerindy's you won't mind the hassle of a little tweaking to get the parts to fit.

[Craig_D]

Here's my recent heater backdate completed. I've also upgraded the standard '78 SC headers/heater boxes with SSIs which appear to have more air volume around the headers and deliver serious heat up front. I don't know what a heater backdate would be like with standard headers/heater boxes..

[Craig_D]

Oh, and here's the "before" picture:

[tcar]

Note, he's pulled the A/C out too.

[RoninLB]

my old tin duct rubbed with the dizzy cap. A hammer on a piece of round wood like a broom stick pounded out clearace. I don't know anything about the new repo aftermarket ducts.

red is mine, the other isn't

[Craig_D]

I did have to hammer my left side duct to get adequate clearance for the diz. I like the safety wire on the diz clamps Ronin! I'll do that tomorrow.

Cheers,

- CraigD

[dshepp806]

I thought the fan up top would be to assist with cooling the engine in a high heat situation, trigger by a temp sensor of sorts? Even heard stories of this blower running after the car is turned off in order to assist with cooling the engine down (again, driven by the system sensing a high temp condition). Not true?

Thanks,

Doyle