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Robin Hood Series 3 Overheating


Joner31
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Hi

 

I have just purchased my first kit car but there are a few issues, the main one is the engine overheating.

 

The engine is a 2.0 pinto with a twin choke webber carb.

 

At present there is a fan mounted to the back of the radiator, this seems to be set so it draws air through the radiator (e.g sucking). I believe that fans should blow so is this incorrect at present.

 

I am looking to replace the radiator and fan with the biggest one possible and am wondering if anyone knows what Would be the best cooling set up to go for.

There is no header tank on the system and no heater matrix on the system either so thinking the bigger the radiator the better.

 

I am going to be replacing the stat aswell with a 89 degree stat and also getting the engine set up correctley, as at present it is not running quite right which i understand may contribute to the engine running hotter than usual.

 

all help appreciated.

 

Thank you.

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Thanks CMA,

I assume for the fan to also work in a sucking manner it needs so be sealed to the radiator so it pulls air though it and doesn't just move air from around it which mine doesn't I have a few pics if that will help?

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Thank you, im sure i will enjoy and learn some good ideas on here.

 

I will look into doing this and see how this improves the situation along with the other options.

 

Do you know what would be the best size radiator to get if i were to replace it.

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One that fits inside your chassis, on an angle top sloping backwards.

Lower t stat might help cooling as it will circulate the coolant quicker.

Two other important jobs.

Make sure the sides, top and bottom of the radiator is sealed against the nose cone forcing the air through it.

Make sure the space in front of the nose cone does not restrict the air flow. ie, horns, ignition coil, air filter box.

Should be no real need to put gaps under the bonnet rear joint or louvre sin the bonnet.

If they are needed, just a couple of rows towards the rear of the bonnet should easily do it to relieve any pressure build up of hot air.

Water still gets through them no matter what way you face them as you are not all way moving.

Water and electrics do not get on well together.

Yes Andi and co, I'm back on the forum at silly o'clock again. 😀😬

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Is it actually overheating, do you have a temperature gauge fitted and what does it show?

You say there is no header tank, I take it you mean an old fashioned expansion tank and not a modern header tank with a pressure cap. If it's the former you may just need to fit an expansion tank/bottle to catch the water that is ejected as it heats up and this will allow it to be drawn back in as the engine cools.

Check the basics first before splashing out on a new rad, is the fan belt tight, is the cap working properly, if you fit an expansion bottle make sure you have the rad cap with the two way valve to allow the coolant to be drawn back into the rad - capri or cortina one will be correct, you can remove the stat and back flush the system to remove any crap, fit a lower rated stat if you feel it will help and refill with correct mix of water and antifreeze

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Hi Steve thanks for the info mine has a temperature gauge in the dash and it just slowly goes all the way up to the red even with the fan on all the time.

Thanks for the pic mine is mounted behind the suspension not in front which I think may also be contributing to the over heating

Edited by Joner31
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but is it actually boiling over? Although it's going into the red the gauge and sender might not be a matched pair.

Some expansion is normal hence the vessel to catch and store it til the engine cools, but if it's actually constantly boiling then you have an issue that need resolving.

 

I have a 280bhp turbocharged engine and a medium size radiator that copes with all the associated generated heat and during 135 miles of driving in the heat yesterday the temperature only reached 90 degrees while sitting in standing traffic and then the fan cut in and did it's job, so a massive rad isn't always necessary.

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There are several reasons for overheating. You have hit on one but you may have more in your car. Fans must be 1/2 inch or less from rad core. Efficiency drops rapidly if it's further than that. So move rad or fan so they can be together. Shroud round the outer edge of the fan also helps. Shroud must be a close fit.

Retarded timing or weak mixture also contribute to overheating. Thermostat is less important if it works OK. It only adjusts flow rate proportional to temperature. Your car should have been built with excess cooling capacity. If not then it will still boil even running without a stat.

So pay attention to increasing the cooling capacity. Cold air in. Minimal grill. All air ducted through the rad. Fan close to rad, shrouded round its edge, efficiently aiding air through the rad. Room for the 'used' air to escape. Rad big enough. No air locks and rad self bleeding of air and kept full at all times with header or piped overflow.

 

Nigel

 

ps Choose a stat that is designed to run your engine at its ideal temperature. Lower is not better.

Edited by Longboarder
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OK much of above is spot on but ------- 82 is best stat for a pinto !! available all over -- is temp gauge wired correctly ==if you change the rad go for a mk 1/2 rs 2000 alloy one it fits and is much more efficient--- ventilation of under bonnet hot air is very important ,side panel and bonnet vents help greatly-- I ran a 2.1 for 13/14 years and it had almost all the mods mentioned for the last 3/4 years with no trouble. The alloy rad is available on Ebay ,I paid around £125 delivered but its a few years go i ran 2 x 7 inch fans between rad and engine . by the time I finished I had approx 145 bhp at the crank and a very nice drive able car get in touch if you want any more info :crazy: mick

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Your problem might not be the rad at all. My 3A has the rad positioned upright behind the shocks and the front cross member. Its been like this for the 14 years i've had the car with no over heating problems. Are you sure that all the water galleries in the block are free from dirt and sludge etc? Also as Mick touched on earlier, the air not only needs to get in through the rad its needs to get out from under the bonnet. All you can do is work through things one at a time. We've all been there for one reason or another, keep asking questions and someone will answer. Also someone local to you may be willing to give hands on help. It's that kind of club.

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We believe that the clock is from an escort possibly a sierra and assume everything is working correctly. We are going to fit an external temperature gauge as well just to clarify that the dash one is ok. I also have a 82degree stat now tp fit.

 

The bonnet already has louvers cut in to relaese the heat from the engine bay. I think we will move the radiator to the front first infront of the suspension and duct direct into it sp the airflow goes through it before changing the radiator.

 

Richard with regards to the expansion bottle in your pitcure, is this from a VAG group vechicle and does the pressure cap on that act as a pressure cap for the whole system so the one on the radiator is just a sealing cap.

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Lots of information there, but let's get things in the right order.

 

FIRST thing, is the temp sender the correct one? Ford make 5 different temp senders, each for a particular set of clocks, so if you have the wrong sender, you have no chance of it reading correctly. Ford senders are colour coded. (this is a Ford sender with a green marking. there are, black, brown, white, orange as well).

 

DSCF0258%20Copy_zpspjsvadqq.jpg

 

You need to know which car your clocks came out of, or alternatively if they are aftermarket clocks, you need to get a sender to match them

If you find that you have the correct sender, then change it, put a new one in anyway. the wrong sender will give incorrect readings.

 

Fans & Radiators.

 

you say that the fan pulls? We all assume that it then pulls the air from the front of the car, through the radiator then through the fan itself? If so, this is correct.

 

In the days of the Mk3s & 3A's. RH was including a fan in the kit, but it was a piece of crap, it was actually a pusher type fan, but you wired it so that it became a puller. Basically the blades are formed incorrectly to pull efficiently, check this.

 

The radiator that you have, is the basic single core cortina radiator, it is just about adequate for the standard pinto RH for Normal driving.

 

You want as much of the air that comes in through the nose-cone to go through the radiator, you need to stop it from going around the radiator by blocking off the gaps, or fitting a cowl.

 

A 82ºc thermostat will allow water to flow from the engine to the radiator earlier, but will only delay overheating if the radiator & fan etc are not doing their job good enough.

NOTE; The thermostat for the pinto can be fitted the wrong way around, see here; http://nw.rhocar.org/thermostats.htm

 

The Mk 3 is a monocoque design, and the engine floor is mainly covered unlike the 2B which is open, so you need to think about assisting the airflow by getting that hot air out from under the bonnet, most of us did this by fitting louvers into the sides of the bonnet, these are mine,

 

 

DSCF0256_zpste9br54r.jpg

 

But check out these louvers, much nicer IMHO; http://nw.rhocar.org/parts2.htm

 

Now you need an overflow bottle, and a double acting radiator cap (13lb)

 

This is a double acting cap, as the pressure builds up, it will release water to the overflow bottle, as the water cools down, the 2nd valve opens and the vacuum sucks the water back into the rad. It's therefore better if you can get one with a rubber seal around the main fitting face as well as under the spring. 9the one in the pic doesn't have that seal)

 

P1030132_zps8tvypvmq.jpg

 

You then need an overflow bottle where the leak off pipe from the rad goes to the bottom of the bottle.

 

I would suggest that you wire up the fan as per this diagram, I DO NOT recommend relying on a switch on the dash that can easily get forgotten.

 

(Drawing also here; http://nw.rhocar.org/fan%20wiring.htm

 

fan%20wiring_zpstmntzze7.jpg

 

As many of us have mentioned, you need to block all escape routes for the air coming through the nosecone, make it so that it HAS to go through the radiator. This is my setup now. 82ºc thermostat, remote switch in top hose at 93ºc, wired as above. the car will run all day at 82ºc providing vehicle speed is over 40mph. but temp never gets higher than fan setting.

Note the gap over the top of the radiator is blocked off .

 

DSCF0260_zpsoptnx5sy.jpg

Edited by Big Jim
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99% of systems will work fine with just an over flow bottle and the correct rad cap, mine on the other hand, maybe because I had to mount the overflow / expansion bottle so far away from the rad, it just wouldn't suck the water back into the rad when it cooled, I got around that by fitting a normal 13lb double acting cap on the rad, but with a 2lb cap on an old Rover expansion bottle. which then helps by pushing the overflowed water back into the rad.

 

YOU SHOULDN'T NEED TO DO THIS. just showing you that there's always an answer.

 

DSCF0261_zpspzqx9yge.jpg

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