I am getting a problem with overheating which now the summer is coming is going to be impossible.

I have just spent 4 years building myself a new house,so cars have been left on the shelf. Before I laid the old girl up she was always running far too hot,and nothing I did seemed to do any good.I removed the rad., made up a jig to continuously run rad. flush through it . I have checked the timing,so she is not running too retarded. There are no leaks or head gasket problems,but after a few miles in even reasonable temps.(say 8-10 degrees C) she is boiling away like billy-o.

I think the rad capacity isa bit small,and of course thermo-syphon is not the best of circulation methods,but it shouldn't boil up the way she does. The fan could be an inch or so bigger (she has a lovely cast ali.one) but we are talking bigger problems than a fan with an inch greater diameter could sort out.

Do you have any words of wisdom on this? I have been thinking how to put a water pump on her,but it doesn't seem to be very easy,to put it mildly.How about an electric fan,but where in heck would you get 6V one of those? Has anybody come up with any solutions to this before?

Mike, Just a thought?

Are you certain the rad is OK?

Might be worth trying another one to eliminate.

I presume its a standard rad in the standard position?

Steve.

Presumably you have also checked that the block isn't clogged up with grot?
Demon Tweeks list an (expensive)electric water pump that runs on 4-14.5V. I have known impecunious special builders use the water pump off a Hoover twin tub. Could be hard to find.
GPR list a cheaper electronic pump (no voltage stated) suitable for "small motorbike engines". Good luck.

Regards, Stuart

Firstly by reputation a7s don't really run hot. The thermo syphon system works well and there is enough water.....so I'm thinking aloud. First have you the right fan blade . That is ,does it SUCK air through the rad ? The early cars had the fan blade driven off the bottom pully so they rotated the other way. ,so obviousely the pitch is the otherway. It has been done,I.E.. Fitting the wrong blade!. So if you have the wrong one it would BLOW ais forwards through the RAD.. So, if it is right ,next thing is to fit a 4 bladed fan . they were fitted by the factory for Export models.They are available.I think that what you
have done to the rad. is fine. As the problem is hisoric the 4 bladed fan is a must . But it is worth back flushing throught the block via the side water branch. If a car has been laid up ,with water in, and as you don't put anti -freeze, the side branch some times degrades on the inside , and I had experience of them being blocked by "Gunge"if left for some time.Don't remove it unless you have to . Can of worms! let us know how it goes. Mac

I agree with Mac but as this is a long term problem I would be inclined to consider an engine out - block off - manifold off - core plugs out, and then make sure that all the waterways around the block are clear both in the block and the head. The back cylinder, No 4 , is the most suspect in that the water has further to travel and can turn to steam causing a 'boiling' effect when the rest of the system is running OK.

While the block is off I would also check that I did not have any cracks in the block allowing hot gasses from engine combustion to enter the water system.

Finally there are products on the market that make the water 'wetter' and allow a better heat transfer from block to water, these help systems used in hot climates.

Lucky you to be in a hot climate !

If the problem isn't simply the wrong fan blade, then I'm sure the solution lies down the path suggested by Malcolm. The "can of Worms" indicated by Mac is the likely discovery of broken/corroded webs which take the fastenings for the water manifold. I suggest using a nut splitter on the nuts holding it on, or sawing off the bolt heads if bolted. You can then apply plus-gas or whatever to help ease out the stubs.
When fitting a new manifold check the mating faces very carefully. Filing/lapping will be needed.
There are various dodges for getting around poor webs and/or their threads. I like the Australian solution of fitting a modified manifold with 4 off holes taking 3/16" stainless steel studs. I did this mod successfully a year or so ago. Be interesting to see if Bill Sheehan also thinks this is a worthwhile solution. If you have a contact in the Victoria Club they may be able to procure one for you.
Best of luck, Ron

Another thing to try (which makes an absolutley huge difference) is to make sure you have the correct top fan pulley as there are two different lengths for the coil ignition cars.

It all comes down to when austins changed from three to four speeds, moved the engine forward relative to the engine mounts to get the gearbox infront of the front chassis cross member. This made the fan touch the radiator so they shortened the pulley. Still with me?

There are hence two different versions of the pulley, one where there is roughly 1/4 - 3/8" between the surface the belt runs on and the back of the fan and one that is about 1/2" longer - dont hold me to the lenghts i have none around to measure.

In any case the fan blades should be about 1/2" or a little less from the rad but you must have the right combination of crankcase, fan pulley, and radiator mounts to achieve this. Also make sure the bush the fan runs on is not worn out and doesnt have too much end float or the fan will move and hit the rad with obvious consequences.

Regards
Rob

For what its worth, I had a similar problem. Having removed the rad and flushed it no end of times with the garden hose, poked about a bit inside the side water branch and got some (but not that much )debris out I then stuck said garden hose in the top hose (which is the reverse of the circulation flow)

To cut a long story short, I think I identified my problem as caused primarily by a constriction in the bottom hose. A straight line between the side branch and bottom rad outlet is obstructed by the dynamo. My hose was slightly kinked to pass round the bottom of the dynamo in a curved fashion because the hoses are supplied straight.

I replaced with flexible hose and all seems well.

Good luck

Mike has just mailed me from Portugal to say that he has done EVERTHING we suggested and he went on a rally and it boiled dry! have WE any ideas?

What exactly is Mike's car? Is it a 'special' or a production model?. My 4 speed box managed the 25 km climb up to the summit of Mont Ventoux the other day, most of which was in second gear due to the severity of the gradient. After a round trip of 200 miles she had spat out about a teacup full of water, and never boiled once. The temperature was about 25°C. Granted, not summer in the Algarve but much warmer than the UK it was designed for.

Sounds to me that there is something seriously wrong somewhere, either a blockage, a leak, or something non-standard that's causing the problem.

A normal thermo-syphon system holds more than enough water to prevent boiling except under extreme conditions. If it's a special, has this car got a rad that's too small or perhaps mounted too low in relation to the block to allow the thermo-syphon to work?

Just a thought.

RR asks a good question, I ran my RN for years without a fan belt and the only time it would overheat was when stationary in traffic. These days I use the car less for commuting and more for Austin 7 events, such as Malcolm Parker's Penine Run which sets out to find every 1 in 4 hill in the area for which a fan is required. This problem sounds like a serious restriction in the water circuit. Dave

Reckless, It,s a saloon.. bog standard.

In that case, there's something wrong somewhere!

A thought struck me regarding this particular problem. As Dave Mann says, there must be a serious circulation problem somewhere as a Saloon set up is more than capable of keeping the engine cool (apart from real extremes). However, before you start stripping down the engine, how old are your top & bottom hoses?

The problem of an old bottom hose going soft and then being obstructed or flattened at the point where it passes under the dynamo is not uncommon, and I have experienced in times gone by, the separation internally of a hose which from the outside appeared OK. If the inner wall has collapsed or separated it could be acting like a flap valve & preventing the water from going round as it should. The use of a new, convoluted hose should solve this problem.

If, however there was water freely circulating through the block with a hose pipe connected, I would be tempted to consider the suggestion made earlier that the is a build up of rust etc around one of the cylinders which is causing it to overheat and boil the water around it.

Never use convoluted hose it looks ghastly,what about timing too retarded?

Mrs Rekkers isn't what you'd call a looker, but she goes well enough!

If I had a choice of an ugly bottom hose or a seized engine I think I know what I'd pick.

just got a call fom mike. Having done everything we collectively recommended, still no good. Well, He has found the problem.! The bottom fan pully had a hairline crack in it.(not without precedent) But When the engine was ticking over it "Held" so was turning the blade,so was not evident. When hot and driving it was slipping. This was found quite by chance. Ureka!

Lets hope when he has fitted the new pully he does not have the fan belt to tight, it does not have to drive a water pump or anything else, just turn the fan pully, so there's room for 'slack', and thus save the pully bearing.

Sandy