stussysoil Posted April 23, 2008 Share Posted April 23, 2008 On mine the only connection to the expansion tank is 1a/1b with 1b connecting to the bottom of the expansion tank. The expansion tank then has a pressure release cap and a pipe that allows any excess coolant if temps get too high to drain to road. On mine 3 is the sensor for the water temp gauge and 2a does not go to the expansion tank. It does not look like the cap on the expansion tank is the sprung pressure release type? I reckon the tank should have some fluid in but stand to be corrected Chris Quote Link to comment Share on other sites More sharing options...
Hammy Posted April 23, 2008 Share Posted April 23, 2008 Mine is slightly different again. I have a pressure cap near 1a and the the pipe 1a goes to position 2b . The top of my header tank (4) is vented, by way of the Non pressure cap on it and there is no other pipe connected to it. The different position of the pressure cap on mine and sussys shouldn't matter IMO. The pipe 2a is usually linked to the heater with the other connection from between the carbs on the manifold -if you look at my WWW you can work this out. ( the two heater connections are the drivers side of the header tank) I am aware of a variety of setups, yours may be a copy of something found on more "modern " cars - hopefully someone can clarify better. Is it causing a problem ?? Is the caps near 1a a pressure cap ?? Yes I expect 3 controls the fan -which should only come on when the car is stuck in traffic, not when driving around normally ! Quote Link to comment Share on other sites More sharing options...
minisweeper Posted April 23, 2008 Author Share Posted April 23, 2008 In the past I've usually known the fan to come on at approx 100C when sitting around - is this about the right temperature? I dont really know whether the set up's causing a problem - it will overheat quite easily if running at low speeds 0-30 for any length of time. Cruising at 60 it will drop to the mid 80's which seems about right. I don't have a heater on mine as you may have guessed - I assume the entry point at 2A is the inlet to the water pump which then shoves the water through the block and back up to the top? If so is it possible that water/steam is being passed down pipe 1 into the expansion tank, then falling back through pipe 2 into the inlet and therefore being pumped back through the block warm? Presumably this wouldnt exactly help with cooling? Also, you cant see it on this photo, but slightly below the turret @ 1A I have a small metal plate with a wire clipped onto it - I assume this is the temperature sender? Quote Link to comment Share on other sites More sharing options...
Hammy Posted April 23, 2008 Share Posted April 23, 2008 The wire you describe is the temp sensor for the gauge. You might be right: A check for "short circuiting" would be to see if there is any flow through the header tank whilst the engine runs -it may well be shorting circuiting the pump making it less efficient and causing overheating at lower engine speeds. The other possibility is the water pump isn't pumping due to damaged impellor. Might be time to re think the pipework ? using one of the setups previusly mentioned ( which mimic the installations you see in the haynes manual) , have a good flush out, take the pump off and check it, put a new stat in, while you are in there, and away you go. You have the same radiator as me so that should be ok. Mine will hold a steady 80 deg in normal road usage whatever the speed/revs, with the fan needed in stationary traffic. Temp gets up to 90 ish on the track- I expect the rad is not big enough for this treatment tho ! Heater is nice too Quote Link to comment Share on other sites More sharing options...
blankczechbook Posted April 24, 2008 Share Posted April 24, 2008 check that the top up cap holds pressure and releases it if needed... if this doesnt seal then your whole current system will boil easily. usually the thermostat housing has the working pressure relief cap with the little hose blowing off the pressure to the top up tank - and then sucking it back as it all cools - so it needs to connect to the bottom of the topup tank. - the little topup tank hose vents to the road... the extra hose was for inlet manifold/automatic choke on these cars - but as thats no longer there i'd loose the bigger pipe - cap it off by the water pump. Quote Link to comment Share on other sites More sharing options...
minisweeper Posted May 6, 2008 Author Share Posted May 6, 2008 Ok. I've taken it all apart today and given the whole block a good flush through with a hose (lovely messy job for a nice sunny afternoon!) I've got a new 82C thermostat from Burton Power to put in. Where's the easiest place to get a gasket from? And what can I use to cap off the large pipe? And how can I connect the small pipe to the big end of the expansion tank? And what sort of pressure release cap should I have? Cheers!! Quote Link to comment Share on other sites More sharing options...
blankczechbook Posted May 7, 2008 Share Posted May 7, 2008 on the thermostat you already have a pressure cap by the looks of it... then how about cut the existing length of hose down - and blank it off with a bolt ( big bolt with the threads cut off leaving the smooth shaft for the hose to clamp onto...or a copper pipe blanking piece.. or a cork ) the expansion tank little pipe will now vent to fresh air - so run this pipe downwards to vent to the road. Quote Link to comment Share on other sites More sharing options...
minisweeper Posted May 7, 2008 Author Share Posted May 7, 2008 But if you're saying I should take the pipe 1A to position 2B, how will I connect it? They're considerably different in size. I assume I can get some converter and it's probably a very stupid question I just haven't had chance to investigate Halfords/SAS yet. Also if I vent to air from 1B wont that completely release pressure from the system and lower the boiling point/etc? Quote Link to comment Share on other sites More sharing options...
minisweeper Posted May 17, 2008 Author Share Posted May 17, 2008 Right miserable weather has encouraged me back into the garage and I've done some tinkering.. I'm pretty sure I've reached a reasonable conclusion as to why it was overheating as follows: Hot water has been coming out of connection 2C from the engine block, presumably this would normally then be taken to a heater exchange where it would cool down, however as I dont have a heater fitted this doesnt happen. Therefore it then flows into the water pump still hot at 2A and gets put back through the engine still warm. To make matters worse, hot water can also flow out of 1A, into 4, out of 2B, and back into 2A. Is all this sane and correct? Am I right in thinking that since I do not have a heater I should be blocking off both 2A and 2C? Do I then connect 1A to 2B as previously suggested and vent 1B to road? Thanks! Quote Link to comment Share on other sites More sharing options...
pikeyboy Posted May 18, 2008 Share Posted May 18, 2008 yep my x flow was rigged up like this and worked fine. I've recently removed the header tank as you dont really need it. Capped off the water pump feed to it and the feed from the thermostat housing is now vented over board. I've fitted a normal rad cap (well a stant lever type) to it and bled the system. are you sure theres no air in the system allowing it to boil up? Quote Link to comment Share on other sites More sharing options...
minisweeper Posted May 18, 2008 Author Share Posted May 18, 2008 When you say 'like this' do you mean as i've suggested i change it or how mine is now? There's tons of air in the system at the moment cause it's in bits I'll be sure to fill it up slowly when I'm done though to try and avoid any air gaps getting in... This is what my cap above the thermostat looks like - is it the right kind? Quote Link to comment Share on other sites More sharing options...
stu999 Posted May 20, 2008 Share Posted May 20, 2008 Cap on thermostat cover = yep 1B should be connected to 1A. Venting 1B to the road will mean the system will no longer pressurise, as this is currently under the prssure side of the system. Where is 2B currently connected? IMHO it should ideally be 'T'd into the bottom hose if possible. Quote Link to comment Share on other sites More sharing options...
minisweeper Posted May 20, 2008 Author Share Posted May 20, 2008 Numbers are pipes and letters are connection points Therefore 1A is indeed connected to 1B, and you agree with my 'no pressure' assumption. 2B is connected to both 2A (the bottom hose, I assume?) AND 2C (it has another T in the pipe) I think this is where the problem lays - presumably hot water is coming straight out of the block at 2C and falling straight back into the pump at 2A and therefore there's no actual cooling going on? Would you say I connect 1A to 1B and 2A to 2B then block off 2C on the basis I don't have a heater? Quote Link to comment Share on other sites More sharing options...
stu999 Posted May 20, 2008 Share Posted May 20, 2008 Well, nothing to lose at this point... Quote Link to comment Share on other sites More sharing options...
minisweeper Posted June 3, 2008 Author Share Posted June 3, 2008 I'm back again! Cheers once again for your time tonight Chris - didnt quite realise how late it had got!! Hope the wife wasnt too upset and the storm hasn't kicked in! For the rest of you...here's basically what we did: Until now the leads have been connected 4 3 1 2 with 4 at TDC (and it's run on that) Took the dizzy cap off to check the rotor and then swapped the leads to 1 2 4 3 as suggested by the Haynes (180deg out from where it was but there's definitely no room to spin the dizzy cap 180 degrees as the carbs get in the way) Turned it over in both situations and no luck. Sounded a bit better (to Chris's trained ear) with the 1 2 4 3 set up but it's not run on that before so I'm a bit confused. Chris was slightly puzzled by my cooling set up which may or may not be right but I dont think that should prevent it from firing..? We're both pretty confused though. Any more clues what it might be or is it time to dig deep and take it to see the bogg bros? Quote Link to comment Share on other sites More sharing options...
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