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Heater Unit Refurbishment


Paulfc
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Hi,

I currently have the heater unit out of the car and wondered if anyone can advise on any of the the following:

1. The heater blower seal and the seals to the water inlet/return pipes are perished. Having looked around I can't find replacements at the usual places and so am assuming they are no longer available. Can anyone please confirm this is the case before I start to make replacements?

2. Is it possible/practical/sensible to open the heater unit up? Having successfully performed and survived the multiple contortions required to remove it I just want to clean the thing up as much as possible before the repeat performance required to re-install it.

3. Does anyone have any recommendations for replacement air distribution hoses? Most of mine are torn so I'm looking to replace them all.

4. When removing the unit the heads on the bottom two bolts sheared off. I've got a little length on each and have tried a few ways to ease them off but I've not yet been able to budge them. I'm planning to gently heat them next but before I do I thought I'd ask if anyone has any suggestions on techniques/tools etc.

Many thanks,

Paul 

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Paul,

Not sure about the heater blower seal, but don't Rimmer list the inlet/outlet seals and air distribution pipes unless I'm miss-understanding what you're after.

Plenty of plusgas on the bolt remains - give them a good shock from side to side with a flat punch to break the rusthold; then leave them to soak as long as you can - then the heat. An easyout somtimes works, but on small bolts can often break and cause worse problems. Worse case is drilling out the remains for a helicoil or other thread repair.

Personally it's such a job to remove the box I'd be taking it apart to clean up and refurbish while you've got it out.

David

 

 

 

 

 

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  • 3 months later...

Hi

To slightly re-boot this topic. I have the Heater on the 13/60 removed and stripped to it`s component parts. Eventually It will be cleaned up tested and replaced in the car. However before I do all that, my recollection of the previous Vittesse was that these heaters are not exactly the most efficient devices!.

Any idea if they can be uprated?. and by what means?. According to the Haynes Bible too, the Rad cap is the later 13psi. up from 7psi on earlier ones, any Idea what that change was for?

Edited by PeteH
spellin
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The heater is very easy to open up, either just by removing the clamps (Smiths) or unscrewing the cover (Delaney-Gallay). There are two nuts underneath and one self-tapper to the top rear holding it to the car. If it's anything like mine, you'll find it full of dead leaves and Lord knows what else, so removing those has to improve performance.

You can fit the blower motor from an early Nissan Micra, no doubt those in the know will tell you exactly which model.

The rectangular seal to the bulkhead below the heater is not available from anyone; the round seal to the back is 'supposedly' available but the one I was sent turned out to be only the grey foam spacer which comes around storm drain pipes, it's not waterproof (in fact it holds quite a quantity of water) and never a great fit. Possibly better than nothing, although I'm not sure if they'll do more harm than good.

I've debated buying a sheet of suitable waterproof material and making my own using a sharp knife or scalpel; they can't be any worse of a fit.... 

DSCF4850.jpg.4dc1047e69147c6fed245a0a5700c58b.jpg

 

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Hi

Thanks. Do I take it that fitting the suggested Nissan Motor might improved the flow rate and or give a multispeed output?.

My study of heat transfer (many moons ago) would lead me to suggest that only a finite amount of heat can be transferred for a given area of matrix regardless of air flow. Which would suggest that a larger Heat exchanger would be desirable?. A source of suitable Gasket material, might be a Marine Engine outlet. We used product from "Lion Packing" a company once headquartered in Woking. To make all kinds of waterproof joints in my Merchant navy Days. The problem you would have going direct (if you still can) is they only supply large amounts. Soft Nitrile rubber might work?.

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You can make gaskets from sleeping bag rolls - heres a typical ink . You can also use the same 6mm foam for Gearbox cover gaskets - simply place the gearbox cover over the mat , mark & cut with scissors 

RE replacement blower , im just about to replace my Smiths Blower with one from a Nissan Micra - Heres an Ebay Link   If you are not in hurry they can be cheaper especially if they are not Buy it Now 

The Nissan Blower is bigger in circumference so a degree of fettling is required though my bench tests clearly demonstrated the Nissan was much more powerful due to bigger motor and bigger fan - Ill dig up a pic and post later. The fuse rating of the Nissan Bloer is 15amps so adding a relay to cope with the load 

NB - heres a Nissan Blower at a good price

Hope this helps 

Paul 

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Is that Smith's blower from a gt6? Or a Herald like in the link? I'm considering doing this myself as my demisters are pathetic in my gt6 and I use it daily so would like to have a bit more air flow through my vents

Also am I right in thinking that a single speed blower would run at 2 speeds if wired up with the standard 2 stage pull switch?

Thanks 

Dan

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8 hours ago, Danwedges said:

Also am I right in thinking that a single speed blower would run at 2 speeds if wired up with the standard 2 stage pull switch?

Unlikely. it would require the blower motor to be a 2 (or more) speed motor. You could conceivably use a Rheostat, to regulate the speed. but attention should be paid to the rating of the Switching, to avoid burn out.

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I know k11 micra have 3 maybe 4 speeds on their blowers so many a k11 blower unit would be okay to use with the gt6 2 speed resistor? I'll have to read into it more because if it could burn out it's a nightmare to get the heater on and out so i would like to only have to do it once if possible.

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Hi

As I remember, If there are 3 or more wires to the motor. it is likely to be a multispeed. However IF only 2 wires, then speed control is by the switching. There are 2 main ways to control speed one is by wiring in a series of resisters, each one giving a different voltage. But creating heat in the resistance in the process (part of Ohms law), similarly with "volume control" type switches. The other way is to include an electronic controller which switches the voltage on and off (pulsing) according to a dialled position, which gives the effect of speed change.

Getting More HEAT out of a Matrix can only be achieved by increasing the size of the matrix in some manner OR using a more efficient material in it`s constriction. The laws of physics apply I`m afraid. It being clean will obviously help.

The OP asked:- 3. Does anyone have any recommendations for replacement air distribution hoses? Most of mine are torn so I'm looking to replace them all.

What Dia? The flexible coated hot air ducting used in caravans is generally available?. But could be to large?

 

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11 minutes ago, PeteH said:

Hi

As I remember, If there are 3 or more wires to the motor. it is likely to be a multispeed. However IF only 2 wires, then speed control is by the switching. There are 2 main ways to control speed one is by wiring in a series of resisters, each one giving a different voltage. But creating heat in the resistance in the process (part of Ohms law), similarly with "volume control" type switches. The other way is to include an electronic controller which switches the voltage on and off (pulsing) according to a dialled position, which gives the effect of speed change.

Getting More HEAT out of a Matrix can only be achieved by increasing the size of the matrix in some manner OR using a more efficient material in it`s constriction. The laws of physics apply I`m afraid. It being clean will obviously help.

The OP asked:- 3. Does anyone have any recommendations for replacement air distribution hoses? Most of mine are torn so I'm looking to replace them all.

What Dia? The flexible coated hot air ducting used in caravans is generally available?. But could be to large?

 

Hi, the Nissan Micra K2 has 2 wires. Re your ? On air ducting . I used flexi hose pipe from an old hoover

Paul 

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The two speed motor in the Triumph Dolomites I had may years ago just had a big resistor to reduce the voltage for low speed, the motor just had two wires.

I have the setup in my Vitesse, can not say if there is more flow at high speed as fitted many years ago.

Regards

Paul

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10 hours ago, 68vitesse said:

The two speed motor in the Triumph Dolomites I had may years ago just had a big resistor to reduce the voltage for low speed, the motor just had two wires.

I have the setup in my Vitesse, can not say if there is more flow at high speed as fitted many years ago.

Regards

Paul

That would be in line with what I said earlier. Changing speed by using a Suitable resister. The switch would have 3 positions Off : Low (resister in series) : Full Resister Bypassed.

However the Physics of the heating, would require the increase of Heating surface area I suggested. A bit like the reverse of fitting a larger radiator to improve cooling on an uprated Engine.

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The corrugated heater hoses are quite restrictive to airflow too. Smooth wall ones would increase air flow. Or I guess ones with small ridges. 

But as already said the heater matrix will be the issue in that it has a maximum output. Unless you can increase the water temperature- winter thermostat fitted I assume?  Though that won’t change the power output of the heater. 

The formula for heat output is 

Heat transfer = (mass)(specific heat)(temperature change)

Q = mcΔT

c for water is about 4.2J/g/K and air is about 1

Q being in Joules. 

If instead of mass of water we use mass over time the result is in watts - which is more useful in this case. 

So the other way to increase the heater output is to pass more water through it. Though you then risk not being able to transfer the heat to the air if you increase it too much so the delta t will reduce. 

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When my GT6 was suffering from "cabin sauna", I experimented with small computer fans attached to the foot well vents, which did seem to boost air flow. But I couldn't find a way to attach them "discretely" to the system. (Wonderful stuff Gaffa Tape!) 

I like the smooth tube idea which I might implement, although messing with those pipes is always a pain. If my new plastic tunnel and heat resistant cladding are successful I may be joining the "cold cabin" club and need a heater refurb. Fix one thing, foul up another, it never ends. :(

db

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3 hours ago, Anglefire said:

The corrugated heater hoses are quite restrictive to airflow too. Smooth wall ones would increase air flow. Or I guess ones with small ridges. 

But as already said the heater matrix will be the issue in that it has a maximum output. Unless you can increase the water temperature- winter thermostat fitted I assume?  Though that won’t change the power output of the heater. 

The formula for heat output is 

Heat transfer = (mass)(specific heat)(temperature change)

Q = mcΔT

c for water is about 4.2J/g/K and air is about 1

Q being in Joules. 

If instead of mass of water we use mass over time the result is in watts - which is more useful in this case. 

So the other way to increase the heater output is to pass more water through it. Though you then risk not being able to transfer the heat to the air if you increase it too much so the delta t will reduce. 

I agree, The conundrum is the Physics. Heat transfer, relies on several factors, the finite size of the  Matrix being the arbiter. Improving air flow can even be counter productive in that the air mass has to be in contact with the heat transfer surface long enough to actually transfer the heat! Increasing the Air flow speed will reduce that "dwell" period too!.  Cleanliness both internally and externally will improve matters. but that is all.

 

A thought?. Is there enough space in the Casing to insert a second Matrix?. Will have to take a look I think. If The makers of the (expensive) MGB item have done it?.

 

Pete

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Water temperature makes a significant difference. A faulty thermostat in my modern with the gauge only getting up to 1/3rd made the ventilation luke-warm. You could try a hotter thermostat - in winter when you need it! The other thing is, is there a significant temperature drop across the heater water inlet-outlet? If so, a small pump to increase flow might help. I believe a number of modern cars have these.

Cheers, Richard

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Quote

According to the Haynes Bible too, the Rad cap is the later 13psi. up from 7psi on earlier ones, any Idea what that change was for?

The extra psi increases boiling point and helps control localised nucleated boiling.  I have been told that the change came when the quality of the heater hoses improved so that they didn't burst.  I believe moderns use 20 psi or more.

C

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My BMW runs at 100'C - according to the gauge, so if you assume 15psi  the boiling point is about 121'C - 20psi about 126. I'm guessing around the cylinders it could be quite a bit hotter so more volume and nearer the boiling point so I'd have thought 20psi is reasonable for moderns

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Hi , removed the Smiths Unit from my Vitesse Mk2 today and fitted a second hand Nissan Micra K2 fan - The Micra fan is much larger than the Smiths so the hole needs opening up. I used a paper template and drew a circle  14.5cms diameter , laid over the existing hole and sprayed primer showing the area to be cut. I found the easiest way was using an electric jig saw - 

heater3.thumb.jpg.f11bc8f44612db4d47036f03879fc577.jpg

 

 

For interested parties who wanted to see the Smith's box  interior here are a couple of photos 

heater6.thumb.jpg.e1e56ac12068c35faddc667181e2cd7a.jpg

heater7.thumb.jpg.8029a360e3e3800214c39d4f68338562.jpg

The above photo show the Heater Matrix in the correct position blocking off the inlet and outlet air flow . 

There are 2 cables coming out of the Nissan blower Blue White & Blue Red - The Blue Red being positive 

heater8.thumb.jpg.1f6e40c4f75c8c7ec98ca3d83cceb1e2.jpg

I tested the Blower on the bench and it was very effective much more powerful than the Smiths version - Though the principle is that air is sucked in from outside & blown through the Heater Matrix with  reduce the air flow , so a clean Matrix is important - 

I plan to use Hoover piping to connect to the demisters , whilst the hoover pipe has some ribbing its no where as ribbed as other convoluted piping - Unfortunately the PO didnt fit the demister unit which sits under the dash and the connection was from the air distribution box to the demister aperture was done with 2" white plastic plumbing pipe - At the windscreen end the pipe had been heat crushed to create some pressure to demist - Needless to say this was pretty much ineffective - Now fitting the demister units which unfortunately mean the dash has to be removed - Unless somebody knows an easier way   

 

Paul 

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