40 replies to this topic

[68+86auto]

What’s the perceived advantage of running a hotter thermostat?

They are designed for better fuel economy. 74 degrees was good for leaded fuel.

I think that there is a lot of misconceptions about thermostats.If you are overheating then the thermostat value has no effect.Hotter thermostats were used in colder weather to help the engine run hotter before introducing the radiator.If you had masses of cooling which could reduce the water temperature below the stat value then it would have some effect,unlikely in a mini.The restriction value of the stat is more important.
This is my understanding and could easily be incorrect and I will embrace education if so.Steve..

That's my belief too. It would probably have some effect but it won't solve anything.

[Ethel]

The hotter the water, the more heat it can transfer to the air.

 

It is counter intuitive. The flip side is it'll be that bit harder to take the heat from the cylinder head in to the water, but the combustion chamber will be way more hot than the water, than the water is hotter than the air. Air also has far lower heat capacity than iron or water.

 

 

If the radiator hasn't got enough cooling capacity it's going to overheat regardless of the thermostat value. A 74 degree stat will just give you a bit more headway than an 88. So if you're lacking cooling capacity it will take a bit longer to boil over when you go beyond the radiator's capabilities, say on a long uphill thrash.

 

 

Lead was added to petrol, in part, for its anti knock properties. It should be able to run hotter, but the octane rating encompasses that anyway. If it came with a lower rated thermostat it was likely also a low compression engine intended to be run on old fashioned 2 Star (90 octane). 4 star was 97 octone, today's low fat juice ranges from about 87 to 93.

[PACINO]

Hi everyone! Thank you all for your responses. Nothing, I haven't achieved anything. I can't get this machine to not get so hot.

Yesterday I didn't stop doing things to the car:
- First, I removed the thermostat cover and although this thermostat was installed in the engine rebuild, I changed it for my usual one, German, also 74 degrees.



- Second, I adjusted the valves but they were all good (0.30). *Here I noticed something important. When turning the wheel, with fourth gear engaged to spin the engine, it was going "very hard." I did it with the spark plugs removed obviously. I think there is compression there, or the double timing chain is too tight. I have never needed so much force to turn the engine.





-Third, I changed the oil for a better one. This one only had 30km, but I was suspicious that it was the right one. In the old one I found some paste sediment like a rubber, but nothing metallic. A little too much black color being so new, I think.




- I also changed the curve on my 123Ignition to "6" as Ac Dood recommends.



- In the morning in the garage, they had replaced my radiator with the one I bought at Minispares with two super cores that Gavin recommended to me. Also new antifreeze (50% organic).




Nothing has changed. The engine gains temperature within a minute of being turned on. And without fresh air from the front, the needle goes beyond 90 degrees quickly. In 5 minutes stopped it reaches 84º. Before rebuilding the engine, this never happened.

*At the end of the video, when I turn the key to turn off the engine, it seems to "auto start" and wants to revive.

https://youtu.be/tj_...dffsDdH_JQ3JON9

This was today on the road when I was going to pass the M.O.T. I got it at last. They don't look at the engine temperature there. They don't care about that.

https://youtu.be/Xrk...9rrNUXrzvL9vFrd

[timmy850]

Is your temperature gauge reading accurately?

 

What idle timing did you set the distributor to?

 

Is the coolant system bled properly? If you have a heater is it blowing hot?

[68+86auto]

You need to check the idle timing. It could've saved you a lot of time and money.

[Earwax]

hi PACINO  . Well done on getting her on the road and MOT.  I am afraid to say it looks like you are checking anything and everything to 'find ' the reason for overheating but possibly not doing it in a methodical manner and in a manner where you can hopefully check and then cross certain items off your list before moving on. 

 

I say this because although you have checked the curve on the 123 ignition , you have not cross checked that it is indeed firing at the numbers advertised. (eg 10BTDC at idle- this is just an example not actual)  As 68 auto has advised, please double check timing - ( I would do timing at idle 2000, 3000, and maybe 5000 rpms)

 

Secondly - some of the  things that you have crossed off your list may still be possible culprits. In the picture of your thermostat , I can see where the alignment of the fan inside the cowl is off - the fan has been grinding itself clear or maybe you have just moved the cowl trying to get to things?-  this does happen and i have been guilty of letting the plastic fan resize itself a little - but I then double check alternator belt wasn't slipping. 

 

I might also ask others to look at how far the plastic  fan is under the cowl ?   

 

Some other checks were great follow up for installing a new motor but again may still need keeping an eye on.

 

For the oil - this is the one time in the life of the motor that you almost expect to see fuzzy small metallic bits - this is also why a break in oil without many additives is important. Break in oil and  engine loading greatly assist running in the pistons and rings especially - so again good timing and no overfueling are important. So at 30 kms on a road car I wouldn't be changing to a high ZDDP oil yet.

 

A tight engine , is definitely a possible source of heat - and the temperatures and speed of the heat build up are concerning ( again check the temperature gauge /sender . Best of luck , and hopefully many many trouble free kms to come. 

[PACINO]

Is your temperature gauge reading accurately?
 
What idle timing did you set the distributor to?
 
Is the coolant system bled properly? If you have a heater is it blowing hot?

Hi Timmy! The temperature sensor is the original, and it always worked well. The heat gun (although it's cheap and made in China, it says the same thing. Between 84º
and 90º pointing to the corner of the cylinder head).
Regarding your second question, I don't understand it well using the translator. Idle speed is between 950rpm and 1000.

The coolant system I suppose is clean. The radiator is new. But... I didn't drain it, I can't say for sure. I didn't like this last garage where I left the car to solve the problems to obtain the M.O.T. They didn't want to touch the dizzy. Therefore they didn't do the timing set.
The heater control works fine (it's new). If you open it when the engine is so hot, NOTHING happens. The temperature does not drop.

Cheers for your help!
Luis

[PACINO]

You need to check the idle timing. It could've saved you a lot of time and money.

68+86..., I tell you the same thing as I told Timmy. In the workshop they did not want to configure the distributor (They neither know nor want to. They are incompetent. Here we say "botched".
* What I can say is that I drove the car today and it did NOT get that hot. I think the mixture was a little bit lean, and it has improved a lot.

I must also say that this country is suffering the biggest heat wave of the year. And although I live in the north, the heat is great.

[PACINO]

hi PACINO  . Well done on getting her on the road and MOT. 

Earwax, thank you a million for your extensive and complete response, like the one you gave me the other day.
It's a pleasure to find people like this on a classic car forum.
-First I will tell you that the fan housing looks like this, off-center, because I had to move it a little to be able to release the thermostat cover. Everything ok.
-You are absolutely right. You should already know what degrees the engine is tuned to. But I don't have a strobe gun (I think I'll buy one soon), and these sons of bitches from the last workshop didn't want to do it either. (I don't think they even know how to do it).
-This second oil that I have put in the new engine is a little better, but its ZDDP level is very low.
I've got a 5L container of Valvoline R1 at home, I haven't used it for now, until the engine has more kms.
-I have returned to the curve that I have had in recent years. "B" curve, because the "6" the engine did not stretch and acceleration was poor on the highway.

Here you have a friend for whatever you need.

Luis

[timmy850]

 

Is your temperature gauge reading accurately?
 
What idle timing did you set the distributor to?
 
Is the coolant system bled properly? If you have a heater is it blowing hot?

Hi Timmy! The temperature sensor is the original, and it always worked well. The heat gun (although it's cheap and made in China, it says the same thing. Between 84º
and 90º pointing to the corner of the cylinder head).
Regarding your second question, I don't understand it well using the translator. Idle speed is between 950rpm and 1000.

The coolant system I suppose is clean. The radiator is new. But... I didn't drain it, I can't say for sure. I didn't like this last garage where I left the car to solve the problems to obtain the M.O.T. They didn't want to touch the dizzy. Therefore they didn't do the timing set.
The heater control works fine (it's new). If you open it when the engine is so hot, NOTHING happens. The temperature does not drop.

Cheers for your help!
Luis

 

 

My question is:

When the engine is idling, what is the timing reading on the strobe?

 

According to the instruction manual, 123/Mini curve 6 gives a total 20 degrees of advance at 5000rpm

 

This means to get decent performance you'd want to have your idle speed timing around 10 degrees. 

[PACINO]

Hi Timmy, thanks for explaining it another way. Now I've understood you Well. I can't answer that question. So far I haven't used the strobe gun. On August 27, I've an appointment in a good workshop to check the engine and the timing set. This places ís specialist in electrical/electronic issues.

I believe that if the dizzy is not at its correct point, it is very close. Now I'm using curve "B" again. With curve "6" it is worse.

Thanks a lot Timmy!

[timmy850]

Setting the timing is fundamental to tuning the engine. Learn how to use a timing light and set it correctly before you use the engine again

Curve B gives 22 degrees of total advance, which is more than curve 6. It’s even more critical to get this correct

Curve 6 would need an idle setting of approx 8 degrees for safe operation

[PACINO]

You are absolutely right Timmy! In the first workshop, where they fitted the engine (that was made by a specialist), they should have done the synchronization. But I had so many problems in that place... I had never been treated so badly before. Only I'll say that they didn't adjust my brakes (I had to do it at the other garage).
I've spent a lot of money on this whole project. In September I'm going to buy a strobe gun to have myself. Thank you for giving me the degrees of advance for curve "B".

[PACINO]

Hi everyone! I continue observing things. I find this very curious: After 10 kilometers, I get home, the water temperature is 100º, I open the heater, and the air that comes out towards feets is completely 'cold'. I don't understand this. The controller is new.

[Quinlan minor]

There will be an airlock in the heater pipe.
Open the heater valve, disconnect the hose taking the hot water to the heater, top it up with a watering can, thumb over the end, quickly reconnect.
Run the car and see if you get heat.
If not, once it has fully cooled down, repeat the procedure.