330 GTC heater ducting/hose

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 tomyang.net.

Thanks for any advice or thoughts.

Kevin

 

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?

I’ve spent much time on various sites looking at options for ducting sizes, but haven’t found anything suitable with an ID of 3-1/4” which would be perfect.

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 Tomyang.net as before.

Thanks.

 

Thanks!

 

Thanks