4 replies to this topic

[Villehaseo]

Hi everyone,

Long-time reader from Finland here! I’ve been lurking on the forum for a while, but I’ve finally hit a cooling puzzle where I could really use some advice and thoughts from the community, so I decided it was time to make my first post.

 

First the car info 1977', 1340cc, HIF44 carb, Kent 286MD cam, 1.5 roller rockers, 123ignition.

 

The problem currenty is that during the summer, as ambient temperatures rise, I notice that the temperature difference between cylinder 1 and cylinder 4 increases. I’ve been planning to address this for a while now, mostly as a preventative measure to ensure even cooling and prolong the engine's lifespan.

 

Right now, my coolant flows from the heater tap on the cylinder head, through the cabin heater matrix, and back into the bottom radiator hose (just before the water pump) as it usually does on Minis.

To keep this cooling loop active for the back of the head, I have to keep the heater valve open.

The obvious downside is that during hot summer days, ram air constantly forces warm air into the cabin through the heater, making it pretty warm to drive :)

 

I am considering two different ways to bypass the cabin heater during the summer while keeping the head cooling intact:

 

• Option 1: Disconnect the cabin heater completely for the summer and route the hose coming from the heater tap directly into the bottom radiator hose return.
• Option 2: Install a sandwich plate at the thermostat housing (arranged as: head -> thermostat -> sandwich plate -> radiator top outlet). I would then route the hose from the heater tap directly into this sandwich plate, forcing that hot water from the back of the head to go through the radiator. For the summer, I would block off the cabin heater lines, and then easily swap them back before the cooler autumn weather arrives.

 

What is the best route to take here?

I know race cars often route the heater tap line directly to the radiator setup to improve head cooling, but I haven't been able to find any ready-made kits or specific guides for this.

Any thoughts, advice, or alternative ideas on how you’ve tackled this would be highly appreciated!

 

Thanks in advance for the help!

 

[timmy850]

You can buy a 4 port heater valve and install it before the heater.

In the “summer mode” it bypasses the heater core and send the the coolant back
In the “winter” mode it sends coolant through the heater core

One example with 5/8” outlets
https://www.amazon.c...d/dp/B0DCK2DHZ9

[Icey]

You can buy a 4 port heater valve and install it before the heater.

In the “summer mode” it bypasses the heater core and send the the coolant back
In the “winter” mode it sends coolant through the heater core

One example with 5/8” outlets
https://www.amazon.c...d/dp/B0DCK2DHZ9

You can buy electronic version, I have one that was used on a Ford Ka; wired in with the heater fan so it’s in by-pass unless the fan is on.

[Ethel]

Black Cabs (London Taxis) have such a valve, Ford used a similar electrically operated valve on the Fiesta, Transit....

 

 

The later Minis, with thermostat sandwich plates, have a flow restrictor in the heater bypass hose connector. A diverter/bypass valve is a simpler solution, ensuring you'll always get full flow, with or without the heater.

[Earwax]

Hi Villehaseo

 

Just to give you a slightly different perspective. 

 

Are you trying to solve a problem that is not a problem? 

 

What measure makes you sure #4 cylinder is hotter?

 

Does your car actually run hot at all - or is it more about the cabin temp.?

 

 

If it is cabin temp related, then Timmy"s suggestion ( or similar) is the go.

 

If the 1340 in the wrong set of conditions ( hot summer, traffic, extended runs or whatever) is testing the cooling limits of your system then it is worth just uprating the systems heat dispersal-

 

 

Some possibilities:

 

Alternator pulley size,  position of fan within the radiator shroud, type of fan, condition of radiator core, built up gunk in cooling system

 

 

For me - in a hot environment ( Northern Australia- so maybe totally not applicable for you?) the biggest overall aide for the cooling system apart from clean routes was to slightly increase the total volume of water. ( So the lines to the heater matrix plus matrix itself might be worth 200 mls or more - I personally go for an auxiliary tank instead of a heater (dont need a cabin heater in the tropics - so basically plumb the aux tank on the same line after cylinder 4 but put it in the engine bay.)  I actually found for my 1310 that that solution didn't allow the car to fully warm up - ran too cold unless stuck in traffic)

 

Note all these 'things' are just aiming for overall better cooling.  If you really think that cylinder 4 heat is the issue then dry decking works a treat - but is a lot of hassle