68 replies to this topic

[Earwax]

Good sleuthing skills and persistence!!!!   

 

Just a mention - if your heater matrix is still lots worse than your lovely clean radiator - you will eventually add some of the not so good stuff into your system again.

 

I think neglect is a bit of a harsh word for you or the previous owner. It is fairly common for the matrix to have stuff settle.  If you can plumb around it  I would by pass the heater loop for a few runs - you will get a feel for the cycling efficiency of the pump/rad without the further variable of the heater.  You will also be more sure of if and where a leak maybe. ( for me without different radiator hoses laying about = i would just pop the input and exit hoses off the heater and join them in a loop with barb connectors , a small length of heater hose and some clips and just tie it out of the way ( as I said temporary only.) Good luck and enjoy your summer weather

[mullet]

Hi all.  Some good news.  Again pretty warm day here, but cautiously took the car out in city driving, then some faster roads.  First with internal heater on (just in case), then without.  Eventually onto country roads going up to 80kph/50mph.  Although the needle did creep up about 7/8th of the way to the H at one point due to hitting numerous redlights, there was never any hot engine symptoms, like spluttering and sudden reduced power and acceleration.  On a 25 degrees day, I guess getting close to the H isn't to be unexpected?

 

The internal heater had a couple of drips overnight before this test.  But seems to have sealed itself somehow.  It was blowing ROASTING and take that as a good sign.

 

I still would like the engine tuning looked at (hopefully shadowing someone) and I alreadybhave new gaskets for getting the carb out and totally cleaned up.  I say this as I think it still lacks acceleration, yet I don't think this is heat related.  Just carb/tuning.

 

I want to take it out for a longer drive with proper hills and onto the motorway too, to be completely sure.  If successful, I will summarise all I did as a list in the hope it helps others.  Couldn't have done all this without such an excellent community here.  THANK YOU!

[cal844]

Change the heater matrix, for the cost of an all metal unit it's worth doing, thus you know it's right

[mullet]

Change the heater matrix, for the cost of an all metal unit it's worth doing, thus you know it's right

Thank you.  Do you have a link for the all metal version please?  I think my problem might be because the inlet plastic tube is a bit out of shape.  I wouldn't mind something of better quality, especially if the leak returns.

[mullet]

Hi all.  Mild day here.  The test went well until motorway driving.  Getting to about 100kph/60mph the needle was close to H.  Put the internal heater on to help.  But then the car started to kind of shake like I had a flat.  Turned off the motorway.  I didn't have a flat, so was the symptom of this overheating again and I spluttered it to a carpark t cool.

 

With each step I take (new calorstat and then new pump) I get better performances and I am confident now for short city runs.  But the problem hasn't gone entirely. 

 

Am I now looking at a new radiator?  I am not even sure where I can get one tested around here, but with that cost only for the radiator to possibly be defective means I am willing to buy a new one.

 

I've read about better performing radiators, but at the same time I don't want to "hide" a problem when I guess the original type should be coping.  I'd feel like I am papering over the cracks if I get something other than the original type.

 

New rad then?  Or something else to try?

[imack]

Ignition timing correct throughout the rev range?

[mullet]

Ignition timing correct throughout the rev range?

I honestly don't know, but I expect this is not a finely tuned car.  I am good at following instructions, learning and getting stuck in and coming out the other side a competent amateur mechanic on the thing I just did.  But I am yet to find a really good youtube type video of tuning being broken out for a layman to understand, with non-technical terms to boot.  Any good video links out there?

[imack]

Retarded timing, siezed ignition advance or very wrong advance curve could cause over heating.
Check out AC Dodds videos on YouTube. Plenty on distributors, ignition timing and general ignition systems. Also carburettor tuning.

[tmsmini]

Somerford has the heater matrix:
https://www.somerfor...ose-connections

[tmsmini]

Wrong one, this should be your year:
https://www.somerfor...heater-84-to-92

 

Somerford has the heater matrix:
https://www.somerfor...ose-connections

[Earwax]

Are you sure you aren't losing coolant?   A sad possibility  for engines running roughly when hot , is a warping around the head or manifolds. As above -retarded timing can really heat up things. If you had access to the tools, I am sure you could diagnose further- but compression tester , dial in timing light, possible leak down tester for valves and even a pressure pump to test the radiator cap would be nice to have on hand to truly get to the source of this problem.

[Icey]

The heater, cooling system stuff is likely a red herring. Poor quality/old/corroded/clogged rads and heaters will cause warm running but unlikely to result in an engine so hot it won’t run.

I suspect it’s either very lean or the timing is way out at the engine speeds/loads you’re only reaching when at speed.

[cal844]

'68-84

https://www.ebay.co....:Bk9SR_KIwLH0ZQ


84-92

https://www.ebay.co....:Bk9SR_KIwLH0ZQ

[mullet]

The heater, cooling system stuff is likely a red herring. Poor quality/old/corroded/clogged rads and heaters will cause warm running but unlikely to result in an engine so hot it won’t run.

I suspect it’s either very lean or the timing is way out at the engine speeds/loads you’re only reaching when at speed.

Thanks Icey.  I found someone who still uses facebook and there's a fairly local group of mini enthusiasts.  She's asked if anyone can direct us to someone good on timing.

[mullet]

Are you sure you aren't losing coolant?   A sad possibility  for engines running roughly when hot , is a warping around the head or manifolds. As above -retarded timing can really heat up things. If you had access to the tools, I am sure you could diagnose further- but compression tester , dial in timing light, possible leak down tester for valves and even a pressure pump to test the radiator cap would be nice to have on hand to truly get to the source of this problem.

Hi Earwax.  I have monitored the coolant.  Losing about 5ml/day and seems like the pump bolts need just a fraction of a turn each (damn it!).  I can see it's slightly wet right there.  Unless it magically seals itself (these things can happen, right?), it looks like the whole rad etc will need to come out to reach these bolts.  At least I am now well versed in how that's all done now.  I don't think this minor leak is causing the heating.  I'll hold off taking rad out again in the hope my friend's facebook "timing SOS" post gets a response.  If the timing is well adjusted and the rad is now the main the culprit, I'll deal with the leak then.