Morris Minor Owners Club

hi all i wondered if you can tell me the piece i circled blue,why was this blanked of on some cars with a black piece of plastic in stead of having the pipe through the engine bay[frame][/frame]

Im guessing cheaper models without a heater fitted??

Its not plastic, its a metal blanking plate but the purpose of fitting them is unknown to me i'm afraid!
All i know is that i have one fitted to my pick up to get rid of that horrible hose!

I would imagine that in some export markets the heater was an optional extra. That type of car was probably chosen for visual clarity of the mechanical and electrical componants of the engine bay.

what exactly does the heater pipe do

It's for the fresh air intake pipe for cars around 63 onwards fitted with the optional heater.....

is there anywhere else i can put the pipe as it gets in my way in the engine bay

You could always cut a big hole in the bonnet and fit a ram pipe

lol i dont think so

Yes, it blanks off the hole where the fresh air hose should go. If you don't have fresh air the windows will fog up. I well remember hurtling down Canadian highways with one hand on the steering wheel and the other employing an ice scraper so I could see where I was going!

Darrell McDonald

i just took it off, and never got round to replacing, makes the engine bay look messy

Early Minors had 'optional' heaters
next they had heaters with internal intake only.
after that they had external and internal air intake, switched by a big flap
finally they had the external pipe - where the air is forced in more as your speed increases, but without the internal intake option.

The external pipe came online for UK saloons and Trav around '63 with a slightly improved heater*. When they did this version, it was better in most conditions and in theory it allows cold or hot air in. At speed you get much more air flow than by using the fan motor on its own. However on REALLY cold days (-10 and below) the heater isn't strong enough to heat all the cold air that can pass through the heater. When the cars get older the heater output reduces as the matrix starts to get clogged and furred up so with a poor matrix, the air will still be cold when it isn't sub zero.
The fix for that is to block the external pipe and remove the end from the heater - this changes it to an 'internal intake'. On the penultimate version this was possible without such hassles.

External air does not demist the windows - but can be a factor!
The windows mist up if the relative humidity of the internal air is high and the glass is colder than the air. The air by the glass becomes cold and the relative humidity is therefore increased. Towards and at 100% rel-hum the water can't be held by the air and comes out as condensation (mist on the glass).
Therefore to prevent condensation:
increase the heat of the glass (i.e. the air inside of the car needs to be hot enough to warm the glass sufficiently)
maintain a low relative humidity of the air in the car (chuck out any passengers who are breathing! / raise the air temp / introduce air that has a lower humidity**)

**thats the bit where external air can help, but if it prevents the car getting warm enough then you won't win the battle as it requires a balance of temp and humidity. Using an internal intake heater works really well if it's very cold outside - butg only if the heater is any good! Mine melted the ice on the rear window in 15 minutes when travelling over the Pyrenees and the Atlas mountains one winter
* LCVs and export cars can differ from saloons depending on market and even vary by individual order.

sorry - it's been another annoying week at work and it's only Tuesday, so it must be time for some technical pedantry.

There is an oft used modification to move the intake position for the 'elephant trunk' to behind the radiator - at the top. Thus in v cold weather the air is pre-heated by the rad before passing into the car heater. It helps - slightly. I would urge you to fit a new 'trunk' - it will be quite tidy and does help to keep the car 'fug' free and to keep fumes out. As Ray says - it's all down to humidity levels - and the fresh-air passing through carries away some of the moisture. It also (slightly) helps to prevent draughts coming IN to the car around the door/window frame seals. To avoid the 'messiness' in the engine bay the Mini used a trunk that ran within the front wing - with two right angle bends - one in the front wheel well at the inner wing and the other at the inner wing just before the grille. You could fit the parts from a Mini - but it's a load of work for frankly very little advantage.