Morris Minor Owners Club

I was talking to someone the other day about the poor heater in the moggy.
He said that a few years ago the "mini boys" used to put 2 heat exchangers in the heater box. Obviously coupled in tandem.
Has anyone heard of this mod and has anyone carried it out.
Yes I know you can get an uprated heat exchanger, at a price. Yes I did fit a hotter stat but that kept blowing my head gasket.

Well I don't know if you think this would help Ian, but I was thinking of (for the winter) making a scoop that fitted behind the rad on the drivers side out of an Osma downpipe collector cut down, and fitting the inlet pipe to that (instead of the grille inlet). Looks as if there should be enough room to get about 15 sq inches of area behind the rad without getting near the fan. The air would be drawn in through the radiator before going up the pipe thus pre heating it if you like. I haven't done it yet, just an idea at the mo. Seems like a cheaper alternative if it works?

DaveC wrote:The air would be drawn in through the radiator before going up the pipe thus pre heating it if you like.

The problem is it won't make the heater warm up any quicker from a cold start because the thermostat doesn't start to open until the engine's hot.

I too have tried fitting the end of the hose to the back of the main rad - I tried bits of wire and the like to no success.
If a proper piece was made up this would be excellent - you'd effecively have two heater matrices.
Whatever you do dont leave the hose open to the engine bay though - as if that werent obvious. You can always tell when mines fallen off the grill by the oil smell.

On a side note, can we assume you've already tried reverse flushing your standard matrix and checking the tap opens..etc..etc..?

That doesn't sound a bad idea at all Dave. I to have the inlet pipe fitted behind the top o/s corner of rad, secured by zipper clips, as per Dunketh. As he says doesn't make much difference on its own. But the collector may be a different story.

Well I have an old collector somewhere in my shed, so I might have a go in the next week or so, to see if it works. I'll post a pic

Yes - my inlet pipe can be slipped in behind the rad if necessary. Risk of engine fumes of course! Never heard of twin Mini rads - really don't think there is room for that. Mini fan+ motor is larger - and well worth fitting - and the Minor front panel transfers over to the Mini heater case - so looks same in the car. Also need to be SURE the little tap is wide open to allow max water flow round the heater. Years ago we used complete heater unit from 1100/1300 range of cars - now that really pumped out the heat - but engine has to be revving to keep enough water flowing - at idle it goes cold in no time.

People regularly use the later mini heater matrix as it is much more efficient - I've not done it myself so can't comment on the technical aspects.

Back flushing the heater matrix (or replacing it with new) can help a lot.
The 1098 Minor heater is severely limited in winter as it has to heat up far too much cold air. Another tip (it works) is to block up the external heater intake (to prevent sub sero temperature air getting into the heater) and remove the external pipe from the heater. Blocking the hose takes approx 4 carrier bags.
This only takes minutes to do, and allows the heater to recirculate the interior air, which then gets warmer and warmer until you can take eventually your coat off. If you need fresh air, there's always a window!
I drove a Minor with an interior circulating heater through the Pyrenese at -10°C in winter - it was warm enough even to demist the rear screen.

When the weather gets warmer, just unblock the hose and refit to the heater.

Well folks, I had a tinker this afternoon and fitted the modified collector
1 cut out, 2 heat bend the tab down, 3 finished article, 4 slacken top rad bolt off an push into place, 5 & 6 fitted. Will see tomorrow if it has any effect, it didn't cost anything, thats the sort of mod I like



I reckon it has about 25 to 30 sq inches of rad area
cheers
Dave

That looks very good Dave. Good pictures. Will await your test results with interest.

Thanks Ian. The weather warmed up over here today, although it has been raining all day. I'll give her a run tomorrow and report back, hopefully tomorrow will be colder

Brilliant !!! cross between scrapheap challenge & blue peter - cant beat free though
Cant wait to see what difference you find!

blue peter

No sticky tape required though

Looks great - should work fine once the engine heats enough to open the stat. I feel it's important to keep the fresh air tube open to ensure enough fresh air comes into the car. This greatly improves de-misting - and helps to keep exhaust fumes out!

helps to keep exhaust fumes out!

I'd fix your exhaust manifold joint if I were you!

The ram effect air intake hose was only added in ~1963. ~The earlier heater had a switchable internal/external intake but the external was not ram effect. Prior to that there was only internal intake to the heater, which worked well enough for the fist 15+ years of manufacture but didn't provide cold fresh air in summer (people used their windows - the quarter lights can be very effective at speed if you turn them 135°)

Cars in the 70's and 80's had a lever to allow switching between external and internal air intake - maybe they heard of the 1098 Minor trick of manually changing the heater to internally intake for winter.

A thought here - looking at Daves gizmo there, that elephant trunk looks just the right size for a PC case fan.
Would there be any advantage in putting a switchable one right there at the rad end? Could seriously improve the air through when the cars at low speed or not moving on a cold day.

Going to have a go at the Dave Gizmo once a suitable receptacle can be found to cut it from - don teven need cold air in the summer here

manually changing the heater to internally intake for winter.

Is this the screwdriver and scarf method Ray?

Would there be any advantage in putting a switchable one right there at the rad end? Could seriously improve the air through when the cars at low speed or not moving on a cold day.

Based on many discussions wrt electric superchargers I'd say no.
The fan will cause be more of an obstruction than benefit. Even the best PC fans are still rubbish.
I suppose you could do it with some kind of industrial unit from a garden vac or something?

Reason i mentioned PC fans was 2 fold. Recently got sent one to fix & sell for someone. its got some crazy fan on it - controlled by the pcu temp (i think), its silent when ticking over normally but when it kicks into 'turbo' mode I'd ate the airthrough with the mog heater fan or thereabouts.
Your right though Dunk about the obstruction bit, at speed there will be more coming through than the fan can shift hence becoming an obstruction.
thats maybe where 2 elephants & y joinrt might be handy - could boil and egg on the dash then

Hi All, for those that may wish to know I had a good run down the A12 today, and noted the following results.
Generally I was travelling at 50mph and the engine was up to temperature.
Readings taken at the heater 'CAR' outlet with the fan on.
The heater matrix was cleaned out a year ago.
Outside temperature today was about 60deg F

With the pipe to the usual grille connection:
Heater off: 60F
Heater on: 115F

Pipe to the rad scoop:
Heater off: 85F
Heater on: 140F

Seems to be a gain of around 25F (14C)

Cheers
Dave