11 replies to this topic

[Minigman]

I have a 1960 mini, running a re-cored original radiator with the original metal 4 blade fan on a 1098 tuned engine . It’s ok up to about 55mph even on a hot day but it does tend to struggle at motorway speeds causing me to slow for a few minutes.

Thinking of fitting a 2 core rad and retaining the 4 blade fan for period look and the lovely fan sound.

Any thoughts or better suggestions please?

Edited by Minigman, 25 September 2025 - 01:50 AM.

[mab01uk]

Add an expansion tank would be my suggestion. The ADO16 (BMC 1100/1300) expansion tank and strap was always a useful mod and cured many of my Mk1 Mini overheating problems. They were easily found in breakers yards back in the day but do come up for sale on Ebay, I mounted mine up on the bulkhead but on the ADO16 the tank was mounted low down at the bottom of the front panel. They don't rely on gravity it's the syphoning effect that makes it work. 
Reading books about the BMC Works Minis recently it seems they did the same but mounted the ADO16 expansion tank in the passenger foot well. The ADO16 and other BL cars like the Landcrab, MGB's, Rover SD1 etc plus some Mokes also had them in various different sizes but later went over to white plastic tanks which were not as sought after as the early copper/brass tanks which could be polished up!

I guess the Mini never had an expansion tank fitted in BMC/BL production (until the Rover Cooper had a plastic tank hidden under the front wheel arch) due to cost and space issues.

These below are the later similar plastic expansion tanks (taller in shape than ADO16 version) as fitted on Minis from the Rover SD1

 

Edited by mab01uk, 15 September 2025 - 03:51 PM.

[JXC Mini GT]

Both of the photos above are of my Mini's, the top one was fitted to a Mk 2 Cooper S and is quite a tight fit and requires the washer bottle to be relocated, the 2nd photo is of my Mini GT where there is a lot more space in the engine compartment to fit them in.

[Steam]

It would be worth while checking for other overheating issues as well. There may be an underlying problem causing the overheating. I would look at the rad cap amd the themostat first.

Edited by Steam, 16 September 2025 - 11:44 PM.

[68+86auto]

Two things that I always say...

Why do you say it needs more cooling? What temperature does it get to? A lot of people start worrying before it has even got to operating temperature.

 

 

IF it is in fact getting hot, Have you checked the timing and fuel mixture throughout the RPM range? Not just at idle or a single speed. If either are out it will cause heaps of additional heat and potential engine damage.

[nicklouse]

At that speed it should have no problems.

 

timing. Mixture and maybe a good intense internal clean out of the water ways.

[Minigman]

At that speed it should have no problems.

timing. Mixture and maybe a good intense internal clean out of the water ways.

Newly built engine which was flushed before rebuild, set up on rolling road, DM2 rebuilt dizzy recurved by H&H Ignition.

[Minigman]

Two things that I always say...

Why do you say it needs more cooling? What temperature does it get to? A lot of people start worrying before it has even got to operating temperature.


IF it is in fact getting hot, Have you checked the timing and fuel mixture throughout the RPM range? Not just at idle or a single speed. If either are out it will cause heaps of additional heat and potential engine damage.

It needs more cooling as it reaches 230 degrees F at high speed. All set up on rolling road etc.

[Minigman]

Add an expansion tank would be my suggestion. The ADO16 (BMC 1100/1300) expansion tank and strap was always a useful mod and cured many of my Mk1 Mini overheating problems. They were easily found in breakers yards back in the day but do come up for sale on Ebay, I mounted mine up on the bulkhead but on the ADO16 the tank was mounted low down at the bottom of the front panel. They don't rely on gravity it's the syphoning effect that makes it work.
Reading books about the BMC Works Minis recently it seems they did the same but mounted the ADO16 expansion tank in the passenger foot well. The ADO16 and other BL cars like the Landcrab, MGB's, Rover SD1 etc plus some Mokes also had them in various different sizes but later went over to white plastic tanks which were not as sought after as the early copper/brass tanks which could be polished up!

I guess the Mini never had an expansion tank fitted in BMC/BL production (until the Rover Cooper had a plastic tank hidden under the front wheel arch) due to cost and space issues.

These below are the later similar plastic expansion tanks (taller in shape than ADO16 version) as fitted on Minis from the Rover SD1

Thanks for the suggestion. I do have a spare one off my Midget I could try. Will fashion a bracket of sorts and give that a go.

[68+86auto]

All set up on rolling road etc.

 

Does said rolling road actually know what they are doing? Why didn't they recurve the distributor?

[Minigman]

Been race prepping engines for 40 years so I’m sure they know what they’re doing. Never had an issue with any of my a series powered cars set up by them in the 20 years I’ve been a customer.

The dizzy doesn’t need recurving by them because it’s already been done by H&H.

All set up on rolling road etc.

Does said rolling road actually know what they are doing? Why didn't they recurve the distributor?

Edited by Minigman, 25 September 2025 - 01:08 AM.

[Lplus]

You could try blocking or restricting the bypass between head and water pump to increase the volume actually flowing through the radiator.  In the same vein, ensure the heater tap is shut off unless the heater is actually in use to take heat out of the water.  Leaving the tap open but the heater air vents shut simply allows even more hot water to bypass the rad.