Pre-heat hose on MFI - Inner and outer?

[SIMI BOB]

The two hoses, as called out in the PET, are as follows. Inner hose: 901 110 295, 28 x 560, paper, alu, paper. Outer hose: PCG 110 296 00, 34 x 550, paper, alu, paper, although it is supposed to have a shiny plastic like finish (see photo). The problem here is that the port on the MFI pump is about 24.75mm, and the tube on the other end is about 25.25 mm (I just measured both on my motor sitting on the ground next to the car, 69S). So the inner pipe is called out as 28 mm inner dia, and when you tighten the hose clamp there is a 3 mm difference in the diameter of the two parts, so the hose wrinkles up and leaves a propensity to rip at that point. There is another hose that is 25 mm dia, VW P/N 211 255 359. It is a very tight fit on both ends, but this keeps the hose from bunching up at that point. I think this is an advantage, and what I will use. Please note that the inner hose shown is longer than needed, and will be trimmed upon installation.
Bob B

[garycox]

Thanks for that Bob. I have a 69S, my experience is like yours. I will try the VW part. Much appreciated.

[Einspritzer]

Bob, thank you. You're measurements are spot on and to what I have on the 69E. I've ordered the VW part, which was only $8 for a 1,000mm length section. My current hose is 3mm oversized and has cracked and split at the ends as you described.

[SIMI BOB]

Just one more thing. Because the VW hose is a tight fit on the metal tube on the shroud, I took a needle nose pliers and flattened around the perimeter of the end of the hose to make it a little easier to slide on the tube. Thanks for the replies.
Bob B

[G69]

I have seen that shiny looking hose and I'd like one. Where did you get it?

Thanks

[SIMI BOB]

G69, I think Roger Birsch replaced that hose on my car back in 1975, when I took it into Scientific Auto in Pasadena for a service. Now you know how old I am. The car was parked soon after that, and the hose looks like new.
Above part number (PCG 110 296 00) at Stoddard, $17.00. Sierra Madre Collection has the part number for $11.00, but can't tell if it is the shiny one. Call to confirm (1.888.986.4466). Pelican has it for $12.50 and the picture shows the glossy tube, and this is probably the proper one because they sell another one that is only $5.00 and the picture is just a black paper tube.
Bob B

[Simonjjb]

I have seen that shiny looking hose and I'd like one. Where did you get it?

Thanks

Porsche sells them PCG 110 296 00 - I just got one

[Frankr]

Porsche sells them PCG 110 296 00 - I just got one

Or you can just use the mechanical gizmo. It always works. Plenty of fuel for cold start without the fire squirters.

[G69]

What I got in the mail today is not going to work out. The inner hose looks too small to fit the nipple on the engine tin and the outer hose is far too big (if it is for insulation) to prevent a cool breeze from compromising the heat transfer to the injection pump thermostat.

I remember this dance from years ago and I have a real Rube Goldberg setup of shims made from a beer can and other mess. Its hidden but a real challenge putting back together when I remove one end or the other.

With deference to Frankr I know the importance of this hot air calibration for the MFI pump and have often wondered if my SSI heat exchanger's stainless steel construction hampers the original design since stainless steel is a lousy conductor of heat. If you notice a change in idle after a nice long run you are seeing the effect of a (finally) fully warmed up injection pump.

I tried Porsche classic and there is no return from the part numbers.

I'll call Stoddard and Pelican tomorrow and see if they can help.

I'd pay $50.00 for a well designed insulated hose that would fit the engine tin and MFI pump both- I'm surprised no one has designed one.

Any more input is much appreciated.

Thanks!

[SIMI BOB]

G69, Please allow me to amend post #11 above. The sizes of the hoses was not taken from the PET, but from various vendors (sorry about that), so please let me tell you what you need to get. The inner hose needs to be 25mm inner diameter and 28 mm outer diameter (weather it be OEM Porsche, aftermarket or the VW number I give above). The outer hose, PCG 110 296 00, needs to be 29mm inner diameter and 34 mm outer diameter and also finished with shiny plastic. That is what I have, and u can see by the pic that they are perfect for the job, with only 1 mm separating them.



Can u please give the dimensions of the hoses you got and where they were purchased from?

The problem here seems to be that the various Vendors don't tell you if their measurements are ID or OD.
Pelican describes them as 28 x 560 and 34 x 550. In their picture this looks like the shiny hose and is $12.50. As you will see below, this is the proper hose.
SMC describes them 28 x 560 and 34 x 550, same as above. Interesting because the inner hose should be longer.
Stoddard calls out 25 x 580 and no description for outer hose. On their web site, this looks like the right hose with shiny exterior.
Stoddards price for the outer hose is about $17, but unfortunately the inner hose is almost $23, so I would get the VW hose I described above for $8 or so.
Bob B