Heating.

[the councillor]

i was wondering where they tend to fail first? the inner or the skin?

i think this is one of the great urban myths / legends / conspiracy theories of the air-cooled vw 'scene' :|

*common knowledge* (the same common knowledge that states that welded spindles are unsafe, and smart car tyres are unsuitable for type 2s, and so on and so on) decrees that in the majority of cases, people purchase 'new' beetles and buses, drive them home, end up stinking of petrol and assume they're being gassed.

it has therefore passed into the lexicon of air-cooled ownership that heat exchangers rot from the inside out, and that the 'j-tube' bit of the exhaust is the first to go, allowing noxious fumes to escape from the actual exhaust part of the system, where it is carried forward by the rest of the air in the 'heating' system and blown out at the driver and passengers.

cough cough etc. etc.

is this true though ? i must admit that i just go along with it, despite having possibly half a dozen sets of knackered old heat exchangers i could biopsy... if only i could *be arsed*.

isn't it more likely however that it's the outer part of the heat exchanger that corrodes and fails first, therefore allowing spent exhaust gases to be sucked back into the system through any holes which may have been caused by corrosion or just haphazard working tolerances... let's face it, i wouldn't want to go to sea in a boat made by the same people who assembled some of MY heat exchangers... they're not exactly 'air-tight' by anybody's standards... and with the low pressure area at the rear of the vehicle just willing the spent exhaust gases back under the bus, is this not a more believable hypothesis ?

that said, beetle heater channels rot from the inside out, and they built 20M of them, so maybe the VW engineers were as *arsed* as me when it came to heater longevity :roll:

 

[Clem]

Indeed, the internal tubing is pretty thick stuff whilst the outer skin isnt, and the inner part should be generally blast furnace hot, so not so prone to condensation?
Also if the inner tube 'is' shot you'll be backfiring and banging with all the system running pressure being screwed .... I reckon?

Get the system sealed as much as poss, and live with it, are my thoughts.

 

[Tofufi]

I found some spare time yesterday after stripping my van engine down... so I took the time to play with the heat exchangers I had lying round.

Genuine Vs repro...

You can see the genuine one has had better days.

But just look at all the fins!

I removed the outer casing with the hope of fitting the skin from the repro one. However, it might not work - I've been told previously that it won't fit as the fins in the genuine ones are so much larger. We'll see when I can find my drill!

 

[Guest]

hmmmm interesting pics which confirms then, that, if you can be bothered the best solution is to take the inner and replace the outer skin with new if your exchanger goes... :wink:

Councillor? have you ever watched "Deadwood"?, you remind me of EB Farnum on it, hes a bit of a wordsmith too

 

[woodslat]

Since my area doesn't have much in the way of corrosion, I see failure mostly on the outer skin, as well as rust in the connection into the muffler. The skin failures are usually due to it rattling itself to bits, and blows out around where the pipe comes out to attach to the cylinder head. I see the fins blast through the sides often as well. Are the Dansk heater boxes no good?

 

[Nic B-C]

The outer skins are transfereable and they usually rot either on the skins or the pip inlet to the tailpipes

 

[Tofufi]

I've spent all day transferring the skin from the repro one to the good one.

Seems to work, but it'll be a few days before my engine is in and running, I'm doing a few other jobs while it is out.

 

[Evilben]

I have used ones from a CT 1600 engine, the one year only engine from a type 25, GSF have loads i know use to work there :!: they use to sell them really cheap, just takes a bit of work cut them down at the front and block off the pre heats at the back. oe spec heater boxes at very little cost

 

[Tofufi]

I finished re-skinning my heat exchanger today, gonna pop it on the van, wrap it and all the other pipes in heatwrap, and see how warm it gets

 

[ground hugger]

Hi
the pipe that runs under the van ,does it have to be metal
or could you put a plastic tube in place of it:?:

 

[cunning plan]

Hi
the pipe that runs under the van ,does it have to be metal
or could you put a plastic tube in place of it:?:

Good point, if its metal, surely its like a radiator, radiating the heat out of the pipe. A plastic pipe with modern insulation must work better right?

 

[baron]

wow, props to tofufi for the pics, excellent stuff

for what it's worth, i get fantastic heat from my repro exchangers, even bearing in mind that i have a deluxe which also has rear heat vents under the back seat.

my exhaust is a empi 4 into 1 header

never done anything to the system beyond the engine bay, aside from remove a pencil that had fallen into the drivers side vent and was blocking it

 

[Tofufi]

wow, props to tofufi for the pics, excellent stuff

for what it's worth, i get fantastic heat from my repro exchangers, even bearing in mind that i have a deluxe which also has rear heat vents under the back seat.

Enough to make you want to wear a T-shirt when driving on the motorway in winter?

Mine were not that good before I swapped the repro heat exchanger inner for a genuine one... but It was warm enough (with one gen, one repro) to happily just wear a good jumper. Now, I've heatwrapped the genuine heat exchangers, and I will try to fill in any joins, so hopefully it'll be even warmer

 

[Tofufi]

Quite frustratingly... my van is no warmer with two genuine heat exchangers than 1 genuine, 1 repro. If anything, it seems colder (warms up faster though).

There seems to be a much smaller flow of air, so I'm guessing either the genuine heat exchangers restrict the flow too much, or I've cocked something up and left one of them 'shut' or something

I'm not gonna find out now, however... it's torrential rain out there - not fun for 80 mile journeys in EBs...

 

[Tofufi]

Quite frustratingly... my van is no warmer with two genuine heat exchangers than 1 genuine, 1 repro. If anything, it seems colder (warms up faster though).

There seems to be a much smaller flow of air, so I'm guessing either the genuine heat exchangers restrict the flow too much, or I've cocked something up and left one of them 'shut' or something

I'm not gonna find out now, however... it's torrential rain out there - not fun for 80 mile journeys in EBs...

Just to add to this today, I just went out there now and checked... and I had only one of the heat exchangers open (doh ). I've opened the second one, so I'll let ya all know how well it works. I don't expect to drive it anywhere for the next month or so though...

Still, as it is my only working car I do expect some form of heating from it

Anyone else checked out their heating and improved it at all?

 

[Benyon]

I am in the process of...

Currently have no heat exchangers, bought a pair of repros from Rocket and found a bargain pair of OGs on ebay which I have to collect, but as yet haven't installed anything. Drove back from my mum's (100miles) tonight without any heat, by God it was cold!!

Once I get them all together will look at how to make the best pair then give em a coat of VHT paint and get em on the van! TOASTY - or so I hope!

 

[baron]

Enough to make you want to wear a T-shirt when driving on the motorway in winter?

Mine were not that good before I swapped the repro heat exchanger inner for a genuine one... but It was warm enough (with one gen, one repro) to happily just wear a good jumper. Now, I've heatwrapped the genuine heat exchangers, and I will try to fill in any joins, so hopefully it'll be even warmer

maybe not a tshirt, definately a jumper though

 

[Benyon]

I found some spare time yesterday after stripping my van engine down... so I took the time to play with the heat exchangers I had lying round.

Genuine Vs repro...

Is that genuine one a beetle exchanger? Or more to the point, are these Beetle exchangers:

 

[Tofufi]

My genuine one was a beetle one - the only difference is in the flap mechanism to control the air flow. I've just cable tied mine in the 'open' position for now as my cable tubes are blocked anyway.

The beetle heat exchangers have the large lever system like the top h/exc in your pic. They will fit, but you will need to modify the opening mechanism to get them controlled from the dashboard.

 

[aogrady]

My genuine one was a beetle one - the only difference is in the flap mechanism to control the air flow. I've just cable tied mine in the 'open' position for now as my cable tubes are blocked anyway.

The beetle heat exchangers have the large lever system like the top h/exc in your pic. They will fit, but you will need to modify the opening mechanism to get them controlled from the dashboard.

Hi!

How do you modify them? You have the same problem as me, mine are tied open - bloody hot - just can't connect them to my cables, so how do you go about that? Wouldn't mind, but my cables are working fine at the dash end/and HE end - wish i could connect them!

Alistair