DTR - Project Recommission 1972 'Dolomite' Manual

[Mahesh]

Temps are running a bit high for my liking. I want to sort this now before tuning as that will make it worse.

Just been to Tunbridge Wells and back via the M25. Roughly a 150 mile round trip. When I left it was not hot, probably about 15 degrees, quite pleasant.

On normal driving the needle is about here, the electric fan kicks in and out happily. I'll add quickly that I did not take the photos

On the Motorway it is up here at an indicated 75-80, if I turn the fan off it will get hotter.

On the motorway I had to have the heater on full hot and the fan going to get the temp down to a reasonable level.

The car happily sits at motorway speeds, it climbed Reigate hill on the M25 with relative ease. It did get hot again, but cooled down the other side.

The radiator is new and a Sprint one at that. Cooling system is all in good health with no leaks now and a new water pump. Voltage regulator is new and the temp sender is Robsport.

Is there a way that I can test the gauge? Tony, you'd probably know this! I'm wondering if I do have a heat problem at all and the sensor and voltage regulator are just fooling me and making the gauge read high.

The other thing I may do is fit an Aluminum Rad, one of those Alicool ones with the fan mounts.

My Sprint does this after a coolant flush and refill, following the handbook method of not getting air trapped is awkward, Jonners method of taking off the filler bung and squeezing
the bottom driverside hose whilst the car is cold (and engine not running) always works for me.

Having said that, my thermostat seems to have developed a sticky spot and needs changing, only 9 months in the car and its failing, last problem I had was on the way to
Stoneleigh, the car was over cooling (as Martin put it), this turned out to be a dirty lead connection at the temp sender.

[James467]

I was just wondering if it was the thermostat.

I think its a standard one, going to pop to Whoppee and get another.

[James467]

Ooooh really bad judder in reverse now.

Probably prop centre bearing or engine mounts.

[MIG Wielder]

Temps are running a bit high for my liking. I want to sort this now before tuning as that will make it worse.


Is there a way that I can test the gauge? Tony, you'd probably know this! I'm wondering if I do have a heat problem at all and the sensor and voltage regulator are just fooling me and making the gauge read high.

Hi James, The 1-Line Management summary from the article I did for the mag; earlier this year is that if you add a 68 ohm resistor from the disconnected lead to the temp; sender, with the other end going to a good earth, with the IGN on , engine running and allowed to stabilise for a minute or so the gauge should read 1/2 way.
Let me know if you need a 68 ohm resistor (with the sad demise of Maplins ) and I'll put one in the post to you.

Tony.

[Carledo]

With a new Sprint rad and an electric fan, the car SHOULD be able to control it's temperature WITHOUT resorting to using the heater to help it! So SOMETHING isn't quite right!

Having said that, the engine is still new and may be tight enough to be running just a shade too hot in the current high ambients.

Also, using an electric fan allows you to run the engine comfortably at a higher temperature than an engine driven fan would. My own inclination here, is to mistrust the guage reading, you wouldn't be the first to be fooled this way and you won't be the last! Just cos you got the sender from Robsport, doesn't guarantee it's not the wrong one, they may have restocked! Try Tony's guage test first, it's the simplest and cheapest thing to do!

Nice wheel choice, Do the hubcaps come with them for that money?

Steve

[dollyman]

My temp guage was reading the same as yours today But putting the heater on and popping the bonnet did not bring it down any..... It's not been as high as that when at about 65mph. I will give it a look tomorrow and another run

Tony.

[James467]

I have another stat, sourced from the back room at my local motor factors! Thanks to the guys at Whoopee!

It's an old QH one and has the little hole in it. I'll change it then refill the system as per the late Jonners method. I then have a better stat and hopefully eliminate any air bubbles. I can then work from there.

Nice wheel choice, Do the hubcaps come with them for that money?

They do!

[sprint95m]

I would try another temperature sensor........



The early 1850 I had sat at just under half all year round, it had an 88 degree thermostat.
During the summer the heater was set to cold and the electric was unemployed.
Fitting a Saab radiator increased coolant volume by over half a litre but made no difference to the running temperature
(I won't fit another Saab radiator).
This car did have a proper header tank and Evans Powercool 180 though.

For my Sprint I will be going this way, 88 degree (remote) thermostat, Volvo header tank, Powercool 180, standard sized radiator,
280mm electric fan and a Stewart coolant pump (200 litres/minute).



Ian.

[soe8m]

I regularly do sell ir tempguns so customers can measure the exact temp.

Those few euro investments made a lot of, mainly British car, owners sleep again at night.

Check first if your temp problems are existing problems.

Jeroen.

[yorkshire_spam]

I regularly do sell ir tempguns so customers can measure the exact temp.

Great little gadgets! As soon as I can find mine (it's in the garage somewhere) I'll be checking actual temp against gauge.

[dollyman]

I have been looking for mine as well When i find it? I will take it out of the box and keep it the dolly.

Tony.

[James467]

I regularly do sell ir tempguns so customers can measure the exact temp.

Got one of them Jeroen, but I have a temperature problem, I can guarantee it.

Stat changed, filled using the Jonners method that I normally use. I also have a funnel and use that as a header tank as I squeeze all the hoses so I am 100% confident that I don't have an air lock.



Run down the M3 from junction 4a to 5 in 28 deg ambient heat, I deliberately turned off the fan and set the heater to cold it shouldn't need a fan on the motorway.

This is hot hot it got before I gave in and turned on the fan and heater to hot! Again, I didn't take the photo.



It then died coming up Beacon Hill, misfiring etc... so it must have got so hot that I got fuel vaporisation. Got the car to a safe place, let it cool down for 10 minutes and it was fine.

Next I'll check the gauge using Tony's method, pretty sure it's fine given what happened.

Then I'll double check the water pump cover clearance, I wonder if it's not tight enough and I'm getting a flow problem.

If that's ok then it's off with its head!!

[Mahesh]

You are too surgical James, are you sure like some surgeons,
that you haven't left a nut, bolt or forceps inside.

Might be worth removing the thermostat, replace the cover, undo the heater matrix hoses at the bulkhead and connect a hose (check if there's a hosepipe ban in your area first) and make sure you have good flow.

You never know, my heater matrix throws up some crud on every flushing, just waiting to get lodged somewhere.

[James467]

Good idea Mahesh

The other thing I forgot to mention, timing is 11 deg and I can't hear it pinking and it is fine around town.

So I don't think it's that causing the excess heat.

Steve, Jeroen, I'm running Optronic with Magnecor leads and that Bosch Coil NGK plugs with a gap of I think 30 thou. I wonder if the bigger bang in the combustion chamber caused by the wider plug gap, coupled with the slightly higher compression ratio is causing more heat under load at higher speeds?

[new to this]

James

Did you rebuild your original water pump,or buy a new one,only asking as there may be some bad water pumps around again

Dave