replacing hot air ducting

[bonefish635]

After a cold drive yesterday I decided it was time to replace the worn out ducting bringing hot air from the heat exchanger into the cab. Last time I was underneath I could see it was in poor shape. I looked at the old posts about it but noted a difference between the stated tubing diameter needed and what I think the manual is telling me I need.

Basically, the older posts (2008) suggested 20 feet of 3" (75mm) tubing was all that was needed. From the book it looks like: 500mm, 400mm and 1100mm of 70mm diameter ducting; 250mm of 75mm diameter; 250mm and 440mm of 50mm diameter and lastly 420mm and 800mm of 42mm diameter (ignoring for the moment the warm air feed to the carb intake).

The tubing I had in mind was this: http://www.ebay.co.uk/itm/140671550957? ... 1423.l2649

It'll handle up to 300'F apparently and I can't imagine the air temperature downstream of the heat exchanger is anything close to that. Am I OK at that temperature rating do you think?

Do the guys who re-ducted their steeds back in 2008 disagree about the diameter's actually needed? It'd be a lot cheaper for me to order a single length of one diameter.

Any thoughts?

Tony

[krick3tt]

I did reduct the in cab tubing but left the old stuff alone for now. I did wrap the ducting from exchanger to the front with fiberglass. The same stuff to wrap hot water pipes
that is foil coated about 3 to 4 inches wide. Made a world of difference getting hot air to the cab. I also put the blackout tarp down in the winter to keep the heat in the cab.

Measure the diameter of your pipes and order what fits. Always a bit more length than you need is good.

[westernair]

I just took all mine off and brought it in to an industrial supply house.
I bought all the pieces in high temp orange aircraft ducting for about $80.

[audiocontr]

Seems like a great price!

[mm58]

I bought all the pieces in high temp orange aircraft ducting for about $80.

The orange aircraft stuff goes by the name "SCAT" (single wall), and the double walled is called "SCEET"

[bonefish635]

I looked up the SCAT and SCEET stuff before posting, since that was on an earlier thread. No suppliers over here (Scotland) but similar products available (not in funky orange though).

I'll let you know how this stuff works. After ordering it, I now worry it might be less flexible than the original and that could be a problem. I'll keep you posted.

Tony