Morris Minor Owners Club

Now that the weather is turning much colder how many of you block off part of the radiator to run warmer ? What are your parameters eg only when it below say 5C and what part and how much do you block off ?
Interested to hear from you ?

I’ve honestly never had a need to do this - with a thermostat working correctly, all the Minors I’ve owned over the years have warmed up quickly and maintained normal temperature without needing to blank off any of the radiator.

I had to use a "muffler" once many years ago on a 1964 2-door saloon, which I don't have any-more.
Turned out the problem was a silted-up heat exchanger core!
I do happen to have 2 period-correct grille muffs, which I keep in the house - just-in-case.

George.
P.S. In the early 70's I had to insert a hardboard peg-board off-cut behind the grille of my 1967 Singer Vogue Estate car, to get it to warm up.
I then forgot about this modification and when the weather warmed up, the car over-heated!

My only concern would be if it would cause any overheating issues or not

With a well-maintained cooling system a muff would be advantageous. Keep the two fold-back vent strips fully open to begin with and do not block it off completely. Fit a thermostat of around 86 or even 88 degrees (the late bmcecosse was a great advocate of a winter and summer thermostat). Keep the cooling fan on the engine as it provides much-needed airflow when stuck in traffic. In a nutshell you will have to experiment with the muff until you find the position which works best.

JOWETTJAVELIN wrote: ↑Fri Nov 27, 2020 10:03 am In a nutshell you will have to experiment with the muff until you find the position which works best.

Mmmmm.......

I had a 12 inch wide piece of sheet aluminium that slipped between the radiator and the top rail for a quicker warm up in winter. I only had a short distance to drive to work though.

Radiator mufflers were in common winter use when most cars didn't have thermostats. An engine which was designed to be adequately cooled by thermo-syphon in high summer would tend to run too cool in winter. A diligent driver would manually fine tune the amount of muffler by keeping a close eye on the temperature gauge. All Minors except the non-water pump versions of the side valve have thermostats, so no hot water should be diverted through the radiator until the working temperature is reached, and no overcooling should take place. Muffling should therefore be unnecessary. The only application I can think of is if you were using a vehicle intermittently in cold weather and wanted to retain as much heat as possible in the engine compartment between trips.

Edward1949 wrote: ↑Tue Dec 01, 2020 1:07 pm Radiator mufflers were in common winter use when most cars didn't have thermostats. An engine which was designed to be adequately cooled by thermo-syphon in high summer would tend to run too cool in winter. A diligent driver would manually fine tune the amount of muffler by keeping a close eye on the temperature gauge. All Minors except the non-water pump versions of the side valve have thermostats, so no hot water should be diverted through the radiator until the working temperature is reached, and no overcooling should take place. Muffling should therefore be unnecessary. The only application I can think of is if you were using a vehicle intermittently in cold weather and wanted to retain as much heat as possible in the engine compartment between trips.

Completely agree!

Ditto.... Totally agree.

I'm a sucker for some period accessories so did track down an "original" BMC one a while back - leather with the two flaps.

The one time I put it on, with flaps open, I nearly cooked the engine in traffic and had to pull over to take it off!

There might be need for one if your thermostat has been drilled to allow some flow when it's closed and the engine never heats up, or it came like that as some apparently do, even with jiggle-pins in for some reason or other.

Just dug out my radiator blanks which I've used for many years (but not much this year!) and I hope they may encourage our our original questioner, Mr djk3816.
Unlike Edward 1949 and Geoberni I'm certain blanks are useful, definitely at low temperatures and especially if you're using your heater (as I suppose you will). I've capillary gauges for both water and oil (both checked against quality mercury thermometers) and I've found that frequently below air temps of 10C and definitely below 5C my 85C thermostat doesn't open if the conditions are such that I'm restricted to not much more than 40 mph (narrow lanes, mist, shopping traffic, etc). In those conditions the heat loss from the block and the heater is sufficient and a radiator is hardly necessary. Worse still, the oil temperature struggles to get above 30/40C even on relatively long shopping journeys of say 20 miles. My solution is the blanks below.
These slide down in front of the radiator behind the steel cross piece that ties the wings together and are made of 4mm thick hardboard. (They've lasted well but it's not a good material when subject to rain, etc and I've always intended to replace them with sheet plastic or aluminium.) As you can see they've circular holes that line up with the radiator fan so that if I get stuck in traffic the fan can keep things cool. The blank on the right has a 12 inch diameter hole, the same size as the fan, and is for general use esp below 10C, and that on the left has a 10 inch hole for snaps below 5C - but I strongly recommend a water temp gauge if you use this latter blank for long or faster journeys. These blanks pull the oil temp up by about 10C (not enough really) and assist in preventing mayonnaise forming in the front timing cover.
Note that my blanks don't have a hole for the starting handle. Have a Happy Eczema from MikeN.

I remember driving over the M62 one year in February to the Manchester Bus Museum rally from Leeds, the car never got warmed up. It convinced me to use a blank in front of the radiator when driving the car in lower temperatures. I also remember a couple of cars on show also had period radiator blanks fitted too.

This shows the factory optional radiator blind for later cars. This has a pull cable with a lock so you can adjust how high the blind gets pulled up, against a spring. Rolls back into the little holder at the bottom of the front edge of the radiator.

Mmm, that's exactly the arrangement I came up with many year ago on a Rover that I owned and which persisted in running far too cool on the mostly short journeys to which it was subject. In my case however, I bought a small roller blind (sheet plastic rather than cloth) from B&Q or somewhere similar and fitted it as shown above, with the inbuilt ratchet mechanism locking it at whatever height I pulled it up to and the (also) inbuilt spring ensuring it returned to the fully open position (or, for that matter, anywhere in between). Worked well.