X-changer Heater Tubing - maybe dumb-a$$ed

[Hawkeye's-911T]

I would very much appreciate any input on how to 'smoothly bend/curve' this heater duct tubing for a 1970 911 (from the heat exchanger outlets to the flapper valve inlet) without having it form a kink. It is quite stiff & doesn't lend itself to being curved very easily - at least by my initial tentative attempts. A search yielded precious little info on this topic.

Any suggestions before I really start messing things up with the proverbial 'BFH' approach? I realize there will some trimming to be done during installation.


Thanks in advance & Cheers
JB

[EC900]

One trick or method actually, to bend tubing is to insert a barrier on the inside to prevent kinking. Small copper for instance there are inside diameter sized flexible spring inserts that create shape contours. .

For the flex aluminum-paper hoses, try and find a foam “pool noodle” that will fit inside the hose as close to same diameter the better. A tight rolled towel may do the trick too.

You also can try to make a plywood board jig and lay the hose out. Screw down some strategically placed wood stop blocks to hold it as you form the next bend or shape in the directions you need. Sort of snakes around the blocks in a general shape and tweaking once ready to install.

[Hawkeye's-911T]

Hey EC900
Apologies for not getting back sooner. The "pool noodle" thing looks to be the best solution.
Thanks & Cheers
JB

[ed mayo]

The correct hose has the supporting wire coils closer together and will make tighter bends.

[nickelplated5s]

Got mine from our host, fit perfect. You can get the fancy clamps for the boxes there too.

[Hawkeye's-911T]

Hi Ed

Your comment on the spacing of the reinforcing or supporting wire coils in the tubing raises an interesting point. The PET lists the tubing in question (PP#930-211-622-01-M127) & is supplied by our host as: “Hot Air Hose” - from heat exchanger to heater control box.

The tubing I received is as per the photo. I totally agree with you the coil spacing in the supplied hose does not allow for a tight bending radius. I’ve tried the using the ‘pool noodle’ method suggested, as a mandrel of sorts to try to facilitate a smooth tight curve. My initial attempts result in a rather ugly & lumpy curve – to say the least.

I shall have to live with this as the tubes list out at ≈ $90 CDN each. This reply may qualify as ‘heads-up’ for those considering purchasing this particular part.

Thank you all for your input - much appreciated
Cheers
JB

[76FJ55]

if you look at the PP part numbering system, you will notice that last dash number (-147) in your post designates the supplier. in this case it represents a random German manufacturer, so not necessarily the same configuration as the Porsche (OEM) part, but supposedly a viable substitute. I do buy the aftermarket options with many of the parts I get, but if you are having difficulty it may be worth the extra $30 to get the Porsche part for this application.

[john walker's workshop]

Scat hose from Aircraft Spruce is the go-to.