[Jacques Reed]

Good Day,

I decided to re-do my radiator inlet pipes on my F15-A. I had them made up years ago at an auto exhaust system shop but there were two things wrong with them.

The pipes were done on a typical exhaust shop pipe bending machine which bends by the crush bending method. This results in the pipe not being round shaped at the bend. The machine was also not capable of making a CLR (Center Line Radius) as short as the original pipes. The larger CLR, and distorted pipe at the bend, meant that in order to have a round pipe at the clamping area at the head, the pipe had to extend further than the original. This now causes misalignment with the inlet pipe on the radiator which is angled 60 degrees to the radiator core. If you chop off some of it, you are now clamping the hose on the bend at the distorted part of the pipe. Neither solution is very good.

I read about mandrel bending of exhaust pipes and thought that would be the way to go. The mandrel inside the pipe during the bending operation keeps the round cross section shape and tighter bends can be performed. Exhaust pipe, 1-3/4” diameter- same as the radiator pipes, could be mandrel bent to a CLR of 1-1/2 times the OD. In this case a CLR of 2-5/8”. Laying off that radius, and the pipe inside and outside radius on a piece of paper, it was a perfect match to my original pipes- Bingo!

To get them bent however, proved problematic. Most shops wanted $150 just for the set up cost of the machine. Then there was the labour cost of bending at $30 each plus materials. Some also wanted me to pay for a full length of tubing even though they could probably use the left over for other jobs. Some wanted a minimum 30 pieces produced.
It was looking like it was not going to be economically feasible.

I found an exhaust system supplier that had off-the-shelf elbows, mild steel, mandrel bent 60 degrees, 2-5/8” CLR, and best of all, reasonably priced- $14.40 each. I approached them to make the radiator pipes by just making the long leg the correct length and I would cut the short leg to fit. They claimed they would still have to reset the bending machine with the aforementioned setup costs. My skepticism arose, 60 degrees is 60 degrees on any length tube, but maybe it was true?

Back to the drawing board:
I thought why not use the off-the-shelf elbows they sold, and attach them to pieces of 1-3/4” exhaust pipe? As luck would have it, the wrong crush bent pipes were just long enough on the straight section to graft onto their elbows. I had a piece of 1-5/8” diameter exhaust pipe leftover from my tailpipe which fits nicely inside to make joiners.Two pieces of 1-5/8” exhaust pipe 2” long each made the joiners.

So for a reasonable cost I have two radiator pipes that are close to original, in design and appearance, and as an added bonus, are made of tubing with 1.8 mm wall thickness instead of 1.2 mm thickness as measured on a good original pipe. They will outlast me for sure. Will weld them up this week and job done.

Before this, I spent some time scouring around the net for repros or NOS pipes with no success. The part is not unique to Ford CMP’s and would have been used by commercial vehicles also. I was surprised no one produced them but then again, restored cars far outnumber restored trucks.

I am sure many other methods would also work such as using flexible hose, modifying Ford repro hoses, etc. This is just my method to replicate originals which may be of interest.

Cheers,