6 replies to this topic

[cal844]

Hiya folks, me again!

1980 Clubman Estate with a 1994 Italian Job specification 1275 engine and manual box on 10 inch wheels.

The guage cluster is the 2 guage pod fitted as standard to the 1980 CE, the temperature sender and the auxillary belt pulleys fitted to the engine is the standard one for the 1994 engine (afaik)

So my Estate runs hot (just under the red on the guage) at an indicated 55mph, but if I drive at approx 53mph the car will sit on the N mark of the guage all day, regardless of load. Also if i get it to run hot, back off to 53mph and run the aux and heater matrix fan the engine cools back to half mark on the guage.

I tested the temperature a while ago with a IR gun and the temperatures seemed within limits (tested at the water pump, either end of the head and top and bottom radiator tanks)

I think the water pump is a press fit impeller type (could that be all the difference?)

I know the belt is adjusted well enough as I can't force it to slip on the pulleys.


Apologies for the long post but thought I'd put a list of things I've tried and tested.

Thanks in advance

Cal

[Spider]

That's only a small difference in speed for a big change in temp.

 

What revs are you doing at these speeds?

And, what's the Distributor Curve ?

 

Apart from running temp, does the car perform more or less the same ?

 

I'm just wondering if at those speeds it's on the cusp of going from Primary to Secondary Curves, with the Secondary being out ?

[cal844]

That's only a small difference in speed for a big change in temp.

What revs are you doing at these speeds?

And, what's the Distributor Curve ?

Apart from running temp, does the car perform more or less the same ?

I'm just wondering if at those speeds it's on the cusp of going from Primary to Secondary Curves, with the Secondary being out ?

I'm unsure of the revs as I don't have a rev counter installed, at a guess I'd say about 3k... the gearbox is a DAM5626(totally standard from the factory)

I can run the engine number through the Guessworks decoder if needed to get the diff ratio and plot the speeds if needed.


Distributor is a 65DM4 (factory electronic distributor) the timing is ok going by ear (for pinking, the engine doesn't 'run on' either)

I assume when you state primarg and secondary curves you mean the dizzy weights or springs are sticking? (Apologies if I'm totally wrong here)

[cal844]

Double post but I've just been to check the dizzy to see if I can find out more.

The car has a DAM5626 standard box( circa 1993, on 145/80/10 tyres 3.105 diff ratio according to Guessworks)

I have found a sticker under the vacuum bell on the dizzy

65 DM4
NJC10038 2026
42535A 4892

Is this any use?

[Spider]

It maybe a Red Herring however perhaps have the distributor tested to be sure that it's working as it should in regards to the curve.

 

Another thing is that is it really running that hot ?  As I mentioned and from your observations, it's strange that such a small change in speed can have such an effect. Where I'm going with this question is I have heard of two guys (so far) that had similar peculiar 'overheating' issues and it turns out at certain speeds a draft would waft over the Voltage Stabaliser and give funny readings as it's output voltage changed. If it's a Solid State Reg, I doubt this would occur,

 

So, if you can lay your hands on a Mechanical guage, only to test with, it might be good to confirm what you are seeing.

[Cooperman]

Before doing anything further, check what the actual operating temperature is.

The temperature gauges in Minis are notoriously inaccurate. I had one in a Cooper 'S' which would go 'into the re' as soon as I started to drive it at all hard. In the end I bought a capillary-type mechanical gauge kit and found the temperature to be entirely normal at all speeds and revs.

[cal844]

I will use my IR gun when i get a minute (it will probably be Wednesday before i do, I will update with my findings asap as my eurobox is in for an MOT tomorrow) , I've taken the car on a 50 miles run today (basically from my house to the forth road bridge then home once id had a cup of tea)

surprisingly the car sat at and indicated 60mph ( probably 65 as the speedo drive is geared for 12 inch wheels and is worn, the speedo fluctuates by 5mph either way from cruise speed when i lift off) all the way to the FRB (mostly downhill, with 20 miles as motorway, then used the motorway home again to add extra load.)
The temperature sat at normal all the way to my tea stop, then on the first steep hill coming home, the temperature shot up and stayed there, only dropping slightly (still over 3/4 guage) when I wimped out and put the heater matrix fan on.

I should also add that the engine has been drilled and fitted with a DSN Retrosport heater take off ( I'd fully flushed the head from the thermostat end to remove the drilling swarf.) Water pump is only 2 years old.

Edited by cal844, 22 July 2019 - 07:56 PM.