330 GTC heater ducting

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Fasthound330
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330 GTC heater ducting

Post by Fasthound330 »

I am replacing all of my flexible heater ducting/hoses and have some questions for other 330 GTC owners.

As currently configured, there is a 4”-to-3” metal reducer connected to the blower exhaust (forward of the wheel well) which then is connected to 4”/100MM flex hose that is routed above the tire in the wheel arch and then connects directly to the heater box behind the wheel well. Wouldn’t it make more sense to reverse that so that the hose coming off the blower was 3”/80mm which would then run above the tire (with more clearance than a 4”/100mm hose) and then use the reducer to connect the 3”/80mm hose to the inlet of the heater box? How are your hoses/ducting set up on your car?

Also, the small hose/ducting that goes to the defrost vents appears to be approx. 1-7/8” inside diameter which is about 48mm. I can find 45mm black canvas hose, but haven’t found any 50mm hose which I think would be a better fit? Any thoughts? Currently on the car, one side had very misaligned flanges and someone just used duct tape (ugh!!!) to form the ducting/hose and on the other side it appears to be original ducting/hose and it is rather holey and deteriorated badly. And thus the need to insert some replacement ducting/hose pieces, and as long as I'm in there, may as well replace it all.

I’m also cross posting this on FerrariChat.

Thanks for any advice or thoughts.

Kevin
1967 330 GTC s/n 9911
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Re: 330 GTC heater ducting

Post by 330GT »

That's exactly what I did on my 330 GT for exactly the same reason.

Regards, Kerry
Regards, Kerry
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tyang
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Re: 330 GTC heater ducting

Post by tyang »

Hi Kevin,

Although the correct hose usually has to smashed flat to clear the top of the tire for suspension movement, using the smaller hose will work better. It all depends if you want it to work, or if you want to show the car, provided if the judges even look up inside the wheel wells! Good luck.

Tom
'63 330 America #5053
Fasthound330
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Re: 330 GTC heater ducting

Post by Fasthound330 »

Ok, so here is my dilemma:

The exit from the Smiths blower is 83mm or 3-17/64” outside diameter

The current metal “reducer” is 87mm or 3-27/64” outside diameter on the small end. The inside diameter of the small end is 83mm or 3-17/64”

The large end of the reducer is 102mm or 4-1/64” outside diameter. The inside diameter of the large end is 99mm or 3-29/32”.

And the intake of the heater box is 100mm or 4” outside diameter with an inside diameter of 98mm or 3-55/64”

And while I realize one can “force fit” pieces and cut slots in the metal to expand or shrink the diameters, I’m wondering what SPECIFICALLY others have done?

When I received the car, the reducer was attached to the output of the smiths blower and then a 4” diameter duct (not original black coated canvas) was attached to the large end of the reducer and ran over the tire to the 4” intake on the heater box. And it was flattened (based on damage, I would say it was flattened by the tire) in the middle down to approximately 3” outside thickness. And thus why I want to use 3” ducting.

But given the various diameters of the intakes, outputs and reducer, I don’t see how I’m going to fit a 3” ID flex duct without some cutting and squeezing or expanding the metal parts and then using metal duct tape to ensure no significant leaks. I hate having to use tape as part of the solution, but I don’t see another way short of having a new reducer manufactured?

Kerry, do you remember the manufacturer of the ducting you used? And did you end up using a lot of duct tape to make all the fitting work? I’d ask for photos but I don’t want to ask anyone to take off a wheel and fender liners for photos.

I have no desire to show the car for judging and so originality is not a concern.

I’m probably over-thinking the problem…wouldn’t be the first time.

Cross posting to FChat as before.

Thanks.
1967 330 GTC s/n 9911
Fasthound330
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Re: 330 GTC heater ducting

Post by Fasthound330 »

BTW, I’ve spent a lot of time on various sites trying to find a suitable 3-1/4” ID duct as that would solve the problems with blower output and reducer diameters. No luck.
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Re: 330 GTC heater ducting

Post by 330GT »

Fasthound330 wrote: Thu Mar 03, 2022 2:46 pm ...
Kerry, do you remember the manufacturer of the ducting you used? And did you end up using a lot of duct tape to make all the fitting work? I’d ask for photos but I don’t want to ask anyone to take off a wheel and fender liners for photos.

I have no desire to show the car for judging and so originality is not a concern.

I’m probably over-thinking the problem…wouldn’t be the first time.

Cross posting to FChat as before.

Thanks.
Sorry, but it's been too many years to remember. A good marine supply place usually has a wide range of flexible ducting. Grainger might also be a possible source. I don't remember having to use any tape though.
Regards, Kerry
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