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My slightly modified TR4 still runs a bit hot.

Under normal driving it's running right at the top of the normal range on the gauge and I verified this as about 85 degrees with a digital themomometer.

Thing is when I star giving it some welly it starts to get much hotter quite quickly and, although it's never boiled, get quite high up the gauge.

I've tried all the usual stuff and the block is so clean you could eat off it. The electric fan is operational and working in the correct direction.

I'm considering fitting an oil cooler to help dissipate some heat and modifiying the rad duct so it doesn't have the gap at the bottom of the radiator.

Any other ideas?

 

Paul

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Hi Paul,

 

Do you have a sleeved thermostat or a restrictor in the bypass hose? Many folk say water escaping down the bypass can be a problem.

 

Also, does it get any better if you put the heater on - and the heater fan (unpleasant to test if it's a hot day, but if you have the top down and least it's only your feet getting hot ;-))? If so, that might point to inefficiencies in the radiator. For that matter, when the engine is running hot, are there any cool spots on the rad?

 

And I'm assuming from all the other things you've been through over time that you have a good flow if you open the block drain tap? If not, that can point to bad flow around #4 cylinder, another thing that can drive high temp.

 

For some reason, and I truly don't know why, mine seems to run cooler if I switch on the manual over-ride for the electric fan - even though the thermostatic switch kicks in fine. I don't understand that, I have to say - but in the heat that we've had around here this summer, it's been useful!

 

Good luck!

 

Tim

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Hi Tim.

I have a sleeved thermostat and the bypass is partially blocked. The rad is new, as are all the hoses and inside the block is sparkling clean.

Running the heater fan and electric fan stop the temp rising anymore but don't bring it down. It's been hot here (35 ish) so I tried running at night when it's much cooler and the result was the same.

It's no huge drama as its not boiling, and if I keep it around the speed limit it's fine. I'm just not a fan of bimbling around at 55 mph!

Paul

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Did you pull the sleeves out to clean the block from inside?

 

I occasionally get totally blocked blocks from USA where nobody had ever used coolant but just water and the chalk did block it then.

 

Chees

Chris

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Hi Paul,

I read that you have ascertained the temp to be about 85C - how was this achieved.

Some of the non-contact thermometers require a particular surface preparation to read correctly (often a piece of black tape works well)

Have you tried putting the sender in a pan of hot water and seeing what happens (using an immersion thermometer)

The electric temp gauge runs off the voltage stabilizer is this giving out 10V.

Although the rad is new try spraying water mist onto the fins and see where is evaportates the slowest; there may be an internal blockage.

 

Roger

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My thermostat is a 65degree one and seems to open around the correct temp according to the digital thermometer and the gauge.

The block was cleaned with a dremmel tool when I replaced the liners.

I'll try a different sender unit, but the gauge and digital thermometer agree, so it's unlikely they are wrong.

I'm wondering about the water pump. It's also new, but I'm starting to wonder if it just can keep up under high revs.

Mixture is if anything a little rich, and the timing is ok. I don't think it's too advanced as there is no pinking even in top gear at WOT on hills. I'll try and back it off a couple of degrees and see if that helps.

My other thought is that the airflow to the rad is being restricted by my pusher fan. Its a 12 inch model and the motor in the middle seems to cover a fair bit of the rad. I realize it's clutching straws, but I'm going to pull it off and see if there is a difference.

 

Paul

 

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The other option here is that the engine is running in. It will run warm till it has bedded in OK.

Certainly check timing and mixture.

This could be egg sucking time.....sorry if it is.

Are you double dog sure the spark is happening at the right time - If you have had the timing pulley to bits it could be way out.

Do the simple physical check like piston at TDC on No 1 with the plug out and check this with the timing mark position on the pulley.

 

Do you have card board duct to funnel the air from the grille into the radiator?

 

What is your ambient temperature?

 

Cheers

Peter W

Edited by BlueTR3A-5EKT
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Cheers guys.

I'm failrly sure the timing is bang on but will check anyway.

The duct is in place.

The ambient temp here is high at the moment and mid thirties is not unusual, but at night the temp is down to about twenty and the engine temp is the same.

It could be running in still, but I've done 2000 miles in it now since the rebuild, so should be starting to slacken off.

I think this winter I'll fit a new water pump housing and a new pump to see f it improves things.

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My slightly modified TR4 still runs a bit hot.

Under normal driving it's running right at the top of the normal range on the gauge and I verified this as about 85 degrees with a digital themomometer.

Thing is when I star giving it some welly it starts to get much hotter quite quickly and, although it's never boiled, get quite high up the gauge.

I've tried all the usual stuff and the block is so clean you could eat off it. The electric fan is operational and working in the correct direction.

I'm considering fitting an oil cooler to help dissipate some heat and modifiying the rad duct so it doesn't have the gap at the bottom of the radiator.

Any other ideas?

 

Paul

 

 

HI

So far as I recall the TR4 should run at nominal 185F which in Celsius is 85. This corresponds to a vertical needle /mid range on a properly functioning/adjusted gauge. So if your dial is over reading at normal temperatures it is likely to be over reading at least the same amount, more, at progressively higher temperatures. So your engine may not be as hot as indicated.

An oil cooler will suck more heat out, but could give you over cooled oil in winter.

As well as considering airflow under the bonnet/hood what about outside? Are you running with big lights in front of the grill or similar?

Finally by coincidence when talking about cooling on a friend's highly tuned MGA the other night my mate observed that some performance cars and highly tuned rally cars have two smaller electric fans in place of one, one is set at a lower temperature than the other. This was a data free discussion as we didn’t know the switching temperatures or if the two smaller fans had the same or greater capacity than a single one, so our conclusion was it would be interesting to try and see what happened……

 

Mike

Edited by MikeF
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Hi Paul,

some of the water pumps are not too good. The uprated ones less so. The standard pump should do the buisness. Make sure it sits in the housing correctly.

TR4Tony does a good uprated pump.

 

Roger

Edited by RogerH
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Hi Paul,

 

For some reason, and I truly don't know why, mine seems to run cooler if I switch on the manual over-ride for the electric fan - even though the thermostatic switch kicks in fine. I don't understand that, I have to say - but in the heat that we've had around here this summer, it's been useful!

 

Good luck! Tim

 

Hi Tim

 

Heat soak (IMHO). If you can manually turn on the fan you obviously haven't hit the thermo switch point yet but what you are doing is cooling the engine before it builds up heat. Once the engine is hot and 'heat soaked' it takes much longer to pull the heat down, especially in traffic with no natural air flow. I always switch the fan on manually if I spot traffic up ahead

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I also found my newly rebuilt engine ran hotter, high torque cam and higher compression did not help. My fan is 12 inch but is a puller. And has a shroud which covers the full width of the rad. Since cleaning the rad with Fernox and fitting a 76 deg stat it now runs at the lower end of the normal band. High ambient temps here are mid 20s, have you considered fitting a larger fan say 16 or 17 inch as a puller, should take about the same amps but stay on for shorter time.

 

I worked at the Ford Tractors for many years and as tractors are slow moving air flow is a probem, and much time was spent designing puller fans which were fully ducted and the sides of the ducting were sealed with expanding foam tape. These types of installation are far more efficient.

Edited by potts4a
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Some interesting ideas.

I'll have a fiddle when I get home (camping in Banff national park) and report back.

I think the oil cooler might be the way to go even if the engine isn't running as hot as I thought.

I don't drive the car in winter here for two reasons, the gravel they put on the snow trashes the paint and the standard of driving of the locals leaves a lot to be desired, particulary on the snow! So over cooling of the oil won't be a problem.

Cheers guys

 

Paul

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We are that. Been hiking around morraine lake today. Very nice. It's only four hours from home so we come here quite a lot.

If I can solve the few issues with the TR that are left, I want to drive it over here soon.

Paul

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Camping in Banff National Park? At least you are looking at some of the most wonderful landscape in the world whilst you ponder your problem!!!

 

:)

 

You can wrap the oil cooler radiator in aluminium (aloominum for colonial speakers) foil as used in the kitchen for baking.

 

I made up a clip-on piece of plastic to cover mine years ago, a copy of the Leyland ST item offered to BL performance vehicles like MGB. I think they have been remade by Anglo Parts of Belgium or one of the Mini specialists. link http://www.somerfordmini.co.uk/eshop/index.php?main_page=product_info&products_id=5883

Be sure to tell them what size oil cooler you have, 10, 13, 16 row etc

Cheers

Peter W

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An oil cooler is nice perhaps, but it is not the ultimate answer solving your overheating problem. My money is also on the quality (or: the lack of) of the waterpump.

Secondly, try another volt stabilizer: these are sometimes the reason gauges are misreading. I don't think it is the problem here but it is a 10 quid solution. A lot cheaper than an oil cooler and less hassle to instal.

 

An oil cooler looks nice but there is one problem, often overlooked: one flying stone through the rad and you are out of business. So, when investing into an oil cooler, be sure you mount a proper quality mesh in front of the oil rad!!

 

Menno

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Hi

 

My TR4A had an overheating issue, What I found that when getting hot it would discharge into the radiator overflow bottle reducing the volume of water in the system.That made the car prone to more overheating. So eventually I fitted an extra expansion tank and piped it into the return of the heater. The extra 1,5 ltr takes over from the header space of the radiator and helps to keep the radiator it self nicely toped up.

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Been on the beach for the last two days. Scorching hot overhere in Holland - gives me time to think about this cooling matter. My old Saab 96 is keeping its cool pretty well, but these old beasts tend to overheat as well. Under the same condition as yours: at speed. 9 out of 10 times, it's the waterpump that's giving up. ( the 1 out of 10 remaining is a clogged up rad). Again, I would like to suggest that you search in that direction.

 

Menno

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