Heater Transfer Pipe Replacement

[Dr-G]

'64 S1 4.2 Coupe (external vacuum pipes).

All, is there a "how to" for replacing the inner bulkhead heater transfer pipes?

Mine are original, and looked OK when I rebuilt the car 20 years ago. However, during preparing the car for the road after a 16 year lay up, I have a nagging feeling that they really should be replaced (coolant under the 4TR unit and under the wiper adjustemnt knob, with no obvious source). I know that's not proof of a leak within the bulkhead, but I just know at some point there will be an issue.

Is it a "windscreen out" job in a coupe?

Thanks.

[bitsobrits]

I replaced mine without removing the front screen, but I did have pretty much the entire dash, wiring loom, and steering column out at the time. I also had the wiper motor out as I recall, allowing me to move the wiper mechanism out of the way.

It was a real challenge, but I replaced the tubes with stainless items, and now have no worries for the rest of my ownership at least.

[Gfhug]

Attach pieces of string to the old one, then attach to the replacement to help guide into place.

Geoff

[Dr-G]

I replaced mine without removing the front screen, but I did have pretty much the entire dash, wiring loom, and steering column out at the time. I also had the wiper motor out as I recall, allowing me to move the wiper mechanism out of the way.

It was a real challenge, but I replaced the tubes with stainless items, and now have no worries for the rest of my ownership at least.

Thanks.

Did I read somewhere that stainless tubes are prone to cracking? Not sure if there's any real-world evidence of this.

[Allrand]

Had mine made up with copper pipes, can't see any problem with that, I've used copper for the Mk7 heater pipes for 40 years with no problem.

[bitsobrits]

Did I read somewhere that stainless tubes are prone to cracking? Not sure if there's any real-world evidence of this.

Don't believe everything you read, unless you read it on the internet

There is no reason why properly made stainless tubes would be prone to cracking in this application as they are solidly mounted and only dealing with 7-14psi depending on the car spec. Mine have been in place since about 2005 and should outlast the rest of the car. They did come from John Farrell, who made excellent parts.

[Dr-G]

Thanks all.

Today my cheap Amazon special boroscope arrived (for a home DIY job). I had a quick look at all the pipe flanges inside the bulkead and couldn't fine any sign of leaks at all, so I guess I'll leave them well alone until there's a problem.

I think it's probably time to just drive it and see what happens...

[politeperson]

If it does leak you can just blank off the heater pipes until you are in the mood.

Who needs a heater in the summer anyway?

I have replaced the pipes with the windscreen in situ. You need small hands. However, the engine was out. I do not see how you could get to all the rivets with the engine in place.

[Dr-G]

If it does leak you can just blank off the heater pipes until you are in the mood.

Who needs a heater in the summer anyway?

I have replaced the pipes with the windscreen in situ. You need small hands. However, the engine was out. I do not see how you could get to all the rivets with the engine in place.

I guess you could solder nuts on the back of the pipe flanges and use screws in stead of rivets?

Presumably since the heater valve is on/off, if there was a bad leak during a trip, the pipes from the engine (water pump & manifold) could simply be plugged at their flexible bulkead ends, and the others left to drain externally? A couple of metal or plastic plugs for this purpose might be a good thing to put in the tool kit?

Thanks.

[politeperson]

You just need to join the two water pipes together before enter the bulkhead around the inlet manifold to blank off the heater pipes, in effect you are connecting the water pump to the inlet manifold.

[Dr-G]

You just need to join the two water pipes together before enter the bulkhead around the inlet manifold to blank off the heater pipes, in effect you are connecting the water pump to the inlet manifold.

Wouldn't it be easier to carry two plugs rather than a long flexible hose?

Or are you saying one of the existing hoses can be reoved, and the remaing one bent around and secured to where the first was attached?

Thanks.

[politeperson]

Their is a heater pipe that runs underneath the inlet manifold from the water pump to the bulkhead. Undo it at the bulkhead pipe union.

Undo the inlet manifold heater pipe at the back of the engine. This is very close by.

Reattach the pipe form the water pump to the inlet manifold you have just undone.

That will bypass the heater, valve and all the pipes inside the bulkhead.

[Dr-G]

Their is a heater pipe that runs underneath the inlet manifold from the water pump to the bulkhead. Undo it at the bulkhead pipe union.

Undo the inlet manifold heater pipe at the back of the engine. This is very close by.

Reattach the pipe form the water pump to the inlet manifold you have just undone.

That will bypass the heater, valve and all the pipes inside the bulkhead.

OK thanks. So no additional pipe required.

[paydase]

This is exactly what I did when I saw the rusted condition of my heater pipes.
It was to be a temporary fix ...that is now lasting

P1150184.jpg (249.8 KiB) Viewed 1123 times

[Series1 Stu]

I fitted copper transfer pipes in my 3.8 coupe when the shell came back from paint. It was an easy job because it was just a shell. I looped some thin rope through the pipes and passed them around myself so that, by leaning back while standing between the engine frames, I could keep the flanges pulled up against the inside of the bulkhead while I rivetted through the outer plates. That made it all so easy.

The problem came when I was plumbing up the engine and it became obvious that the copper pipe poking out of the bulkhead was too short to give a good purchase for the pipe clip. This resulted in the copper pipe distorting and causing a coolant leak.

I found myself replacing the pipes with stainless steel items, made by Dave Kerr. I'm not sure which grade of stainless he used but I think it was 316, which is less prone to stress corrosion cracking although a decent antifreeze/inhibitor will reduce the risk further. They fitted much better than the shop bought copper items too.

This time, the job was so much more difficult with the engine in the way so I had help to keep tension on the ropes. I did manage to get the riveter in but I'm not totally happy with the result. I will have another go if the cylinder head ever has to come off.

Regards

[Dr-G]

Thanks all.

[rfs1957]

My modest contribution to this debate might be this.

Firstly, I'd encourage anyone doing this to spend more time (than I did) in doing dry-runs prior to starting riveting, as getting the integral backing plates good and parallel to the shell whilst achieving the correct centre-to-centre distance can be quite tricky - and I was only re-fitting a set of copper ones that had been in the shell for 30 years.

Secondly, make sure your rivet gun nose enables you to get into the limited space there is around the pipe, mine required some surgery plus a 9mm spacer to create a fake nose.



Thirdly, I'd query whether 1/8" rivets might not, in some circumstances, and according to how accurate the hole-drillings are, be a bit lightweight. I originally used 1/8" (3mm ?) but was caught out on one pipe where the back-plate had been drilled slightly askew, and the PO had ended up drilling ovalised-holes ; when I put some serious thrust onto the protruding pipe, whilst fitting hoses, that one gave way slightly.



So with the initial 1/8 rivets still in place, I redrilled ALL of them one by one and used 4mm rivets instead, which is an essentially imperceptible change, visually, but which reams out the holes in all the sandwiches and then applies a much more satisfactory clamping effort.

(This shot is 4mm, the other three are still with 3mm)

I can see in Jag-Lovers that this has been mooted by others, some of who actually thread the back-plates and screw the escutcheons into place.

Now, here's a question for everyone, well TWO actually.

I've never been comfortable with the un-swaged ends of these heater pipes on the bulkhead ; Jaguar made the fittings on the heater itself with swaged-ends, to stop the hoses pulling off, but the bulkhead pipes are just straight, presumably to reduce the size of the holes and anchorages on the bulkhead.

If there had been room for the tools, I'd have been tempted to swell the orifice with a swaging cone, just to give it a bit more of a mechanical grip once the Jubilee clip is in place, even if meant the next guy needs to cut and change the heater pipes to get them out.

Do these hoses ever pop off ?



Question two, is the alignment of that top hose always as uncomfortable as mine appears to be ? I cut the pipe as far as I dare on the heater end, but still it's not visually satisfying and looks like a design cock-up, by about a half-inch.



PS Who made all the neat stainless fittings, like those pipe-escutcheons, on my car ? Guess same guy who did the SS throttle linkage, the SS main hood pivot anchorages, maybe the SS hydraulic bottle brackets. Anybody know the source ? It would have been circa 1989. A very talented chap, anyway.

[Allrand]

Hi Rory, yes those heater pipes are awkward. I'm surprised your pipes out of the heater are swaged, mine aren't & popped off. I soldered on some brass plumbing ferrules but haven't reconnected them yet, I've left the heater bypassed.

[rfs1957]

Not the best shot, but had this from pre-restoration.



Am off to see an air-conditioning mate tomorrow, these things are called spin-swagers, designed for copper-pipe junctions, I reckon I can get the beginnings of a lip on the pesky bulkhead pipe stubs.



I may yet be glad of those stronger 4mm rivets ...........

[paydase]

Mines also unswaged on the heater box.
Maybe the stiff turn (and strain) on the hoses in that tight space was supposed to help in not popping off?