Iain T Posted May 13 Report Share Posted May 13 I've been thinking about this for some time. I've lowered my radiator to effectively clear the bonnet and to clear my 6-3-1 manifold I have a couple of spacers under the engine mounts. All this makes me wonder how can the water effectively circulate around the head. Has anyone fitted a small expansion tank high on the bulkhead? I think it just requires a blanking cap for the radiator and hose from the overflow pipe to new tank and one from the tank to the lower rad hose via a Tee piece. As to size I can fit a 100mm diameter x 200mm high which again I think is adequate if half filled to allow for expansion. Iain Link to comment Share on other sites More sharing options...
johny Posted May 13 Report Share Posted May 13 The above thread has some good photos of a modified cooling system however in your case I think the coolant will still circulate around the head with no problems. Its pumped and any air will be flushed out the same as it is from the heater (the highest point in the system). If you did use the rad overflow pipe obviously it and the tank would have to be rated for system pressure. Then the rad blanking cap would have to be removable to allow filling of the system in a reasonable time and also pressure seal against the top lip of the of the filler something that it isnt originally designed for. Also the size of the expansion tank is important as it has to accommodate the increase in volume of coolant on warm up which compresses the air pocket to arrive at the correct system pressure.... Link to comment Share on other sites More sharing options...
Iain T Posted May 13 Author Report Share Posted May 13 16 minutes ago, johny said: you did use the rad overflow pipe obviously it and the tank would have to be rated for system pressure. Thanks for the link. That is a concern and my long term fix is to have the radiator modified, I have already spoken to a local radiator specialist regarding the work. My current radiator is a Bastuck and I need to take a look as to the overflow pipe attachment. Personally I don't like the Triumph setup and would like to improve it. Iain Link to comment Share on other sites More sharing options...
johny Posted May 13 Report Share Posted May 13 The 1600 vitesse actually came with a head tank mounted above the manifolds. Its rad was also different with no cap and an additional large bore connection on the right top corner. I think Triumph initially worried about having the radiator lower than the heater so used that design until realising that there was no problem and a vented system would work... Link to comment Share on other sites More sharing options...
johny Posted May 13 Report Share Posted May 13 here it is if you havent seem one... 1 Link to comment Share on other sites More sharing options...
Nigel Clark Posted May 13 Report Share Posted May 13 If I've understood, I believe the issue is really to ensure that all air is bled from the cooling system, when the filling point and/or venting point is lower than the highest point in the system. How about installing a plug in the thermostat housing? With the car raised at the front, this could be used for final filing, and for bleeding air. The radiator pressure cap and origial expansion bottle should still work as intended. Nigel Link to comment Share on other sites More sharing options...
Iain T Posted May 13 Author Report Share Posted May 13 (edited) 25 minutes ago, Nigel Clark said: How about installing a plug in the thermostat housing? With the car raised at the front, this could be used for final filing, and for bleeding air Nigel that's still an option I'm looking into. I had a TVR3000M that had terrible overheating issues and the radiator was very low and no expansion tank. A bad design I prefer the tank to be higher than the thermostat housing. Iain Edited May 13 by Iain T Link to comment Share on other sites More sharing options...
Steve P Posted May 13 Report Share Posted May 13 I should have shown you mine at SEM yesterday, on my 2.5 Vitesse I have a tapping into the thermostat housing with a small diameter ali pipe running along side the rocker cover into an Ali tank mounted on the bulkhead, that pipe goes into the top outlet and then there is a bottom outlet with a hose that goes into the heater junction. This circulates better around the top of the head. I have an Ali rad as well. In the boiling heat of yesterday leaving SEM in the damned M25 diversion traffic it only went to 3/4 on the gauge, my feet were on fire though from the bulkhead temperatures. Steve Link to comment Share on other sites More sharing options...
johny Posted May 13 Report Share Posted May 13 But in a Vitesse surely the heater is the highest point and that clears air ok, well mine does once Im driving and I operate the heater valve a few times... Link to comment Share on other sites More sharing options...
Iain T Posted May 13 Author Report Share Posted May 13 15 minutes ago, johny said: But in a Vitesse surely the heater is the highest point and that clears air ok, well mine does once Im driving and I operate the heater valve a few times True although i never open the valve as it's always hot in the cabin. I like the 1600 set up better. There can't be water in the heater matrix or coolant would come out of the radiator filler when opened? Link to comment Share on other sites More sharing options...
johny Posted May 13 Report Share Posted May 13 As you undo the cap any excess should run into the reservoir via the over flow pipe.... Link to comment Share on other sites More sharing options...
johny Posted May 13 Report Share Posted May 13 Our system is the same design as that used in all (?) motorcycles because they also have a problem with the location of a high point sealed system expansion tank. Link to comment Share on other sites More sharing options...
Iain T Posted May 13 Author Report Share Posted May 13 1 hour ago, Steve P said: should have shown you mine at SEM yesterday, on my 2.5 Vitesse I have a tapping into the thermostat housing with a small diameter ali pipe running along side the rocker cover into an Ali tank mounted on the bulkhead, that pipe goes into the top outlet and then there is a bottom outlet with a hose that goes into the heater junction. This circulates better around the top of the head. I have an Ali rad as Steve, my system with the electric fan also coped well with the traffic I just have an issue with Triumphs design. Can you take a couple of photos to see how you've plumbed it into the heater pipe. I did like your Vanden Plas version of our cars! Cheers Iain Link to comment Share on other sites More sharing options...
johny Posted May 14 Report Share Posted May 14 12 hours ago, Iain T said: True although i never open the valve as it's always hot in the cabin. I like the 1600 set up better. There can't be water in the heater matrix or coolant would come out of the radiator filler when opened? The other thing Iain is that the heater once filled shouldnt drain unless the system is emptied. You should make sure its filled and open the heater valve once in a while to avoid corrosion and sludge in the exchanger👍 Link to comment Share on other sites More sharing options...
Iain T Posted May 14 Author Report Share Posted May 14 6 minutes ago, johny said: The other thing Iain is that the heater once filled shouldnt drain unless the system is emptied. You should make sure its filled and open the heater valve once in a while to avoid corrosion and sludge in the exchanger👍 I did open the valve on filling after a coolant change last year. When I first bought the car the coolant system was full of sludge due to mixing oat and iat antifreeze. I'll raise the car on by ramps and open the valve and check the levels. I have had a few minor leaks in the system which I've now sealed and noticed the overflow bottle now works whereas before the system wasn't pressurising enough. Iain Link to comment Share on other sites More sharing options...
Firefly Posted May 14 Report Share Posted May 14 Be careful if you use the original vitesse tank that sits along side the rocker cover, its joints are soldered and only good for 7 PSI. Running at 14 or 21 PSI will rupture the joints, ask me how I know. I have used a Volvo headed tank on my GT6 engined MGB, (£25-£30 brand new) which is see thro` plastic, i.e. check level without removing cap. I have attached a picture and hope you can see how its plumbed in. There must be a 3mm dia. restriction in the return (already fitted in Volvo tank) line to the top of the header tank, otherwise hot water will circulating thro` the tank not the rad. The bottom out let of the tank is connected to the inlet to the water pump. This is of course how modern car cooling systems work. Mac. 2 Link to comment Share on other sites More sharing options...
johny Posted May 14 Report Share Posted May 14 Lovely Mac! If only our cars had space like that😞 'I'll raise the car on by ramps and open the valve and check the levels. I have had a few minor leaks in the system which I've now sealed and noticed the overflow bottle now works whereas before the system wasn't pressurising enough.' Yes Iain its quite hard to achieve but the real test of a good system is that the overflow pipe stays full even if the car has been laid up for a while (as long as its end is covered by coolant in the overflow bottle of course)... Link to comment Share on other sites More sharing options...
Iain T Posted May 14 Author Report Share Posted May 14 33 minutes ago, Firefly said: Be careful if you use the original vitesse tank that sits along side the rocker cover, its joints are soldered and only good for 7 PSI. Running at 14 or 21 PSI will rupture the joints, ask me how I know. Cheers for that! So to fit I'll have to get the radiator modified. Aaron rads have already said they can blank off the top and fit a pipe in the side for the tank hose. I'll have to think about diameters or it'll take hours to fill the system! As you say the other hose from the tank should go to the bottom rad hose which is the inlet for the pump. Iain Link to comment Share on other sites More sharing options...
Firefly Posted May 14 Report Share Posted May 14 Johny Its not only more spacious under the bonnet, its the inside too. I`m a Triumph man thro` & thro` having been employed by them all thro` the 70`s. Love the look of the GT6. but being a 6 footer, it was just too tight a fit, but had to have that lovely 6 cylinder up front. Going back 6 months do you remember we had a discussion about the timing of the GT6, I and other found it performed running 16 deg. advanced. When I brought the Stag out of winter hibernation I tried the same. No no no, it was very unhappy, and had to return it to book setting of 12 deg. They both run similar compression ratios, so am wondering if its to do with the shape of the combustion chamber as the Stag is wedge shaped, or whether the valve timing is different giving better or worse scavenging. The jury is out on this one??🤔 Mac. 1 Link to comment Share on other sites More sharing options...
Iain T Posted May 14 Author Report Share Posted May 14 8 minutes ago, Firefly said: Going back 6 months do you remember we had a discussion about the timing of the GT6, I and other found it performed running 16 deg. advanced. When I brought the Stag out of winter hibernation I tried the same. No no no, it was very unhappy, and had to return it to book setting of 12 deg. They both run similar compression ratios, so am wondering if its to do with the shape of the combustion chamber as the Stag is wedge shaped, or whether the valve timing is different giving better or worse scavenging. The jury is out on this one??🤔 Ma Thread drift yeh... I had my Vitesse at 17 degrees but last weekend found it was pinging on acceleration at higher revs. I've knocked it back to 13 degrees but haven't tested it yet🤞 Back to thread I think the plugged second temperature sensor adaptor threaded hole is for an air bleed. Before I jump in I'll get a bleed valve, I note Merlin sell one, and see if there's any air in the system. Iain Link to comment Share on other sites More sharing options...
Firefly Posted May 14 Report Share Posted May 14 Sorry Iain.........to slow to do any drifting now. The beauty of fitting a header tank, so long as you haven`t a serious leak, is that the system is constantly bleeding any air into the tank, so keeping your engine and rad full of coolant. The problem as you probably know, that the slightest air leak will prevent fluid being drawn back from the low down expansion bottle. and it continue to do this till the bottle over flows and your engine over heats. the system may be water tight but not necessarily air tight. Every one knows a Stag overheats, I fitted this system to that 15 years ago and then had to change the thermostat to 88 deg. to keep the engine running warm enough. Well worth fitting a header tank in my view. Mac 1 Link to comment Share on other sites More sharing options...
Iain T Posted May 14 Author Report Share Posted May 14 3 hours ago, Firefly said: Well worth fitting a header tank in my view I have to agree it just good engineering practise plus it adds an extra pint or two to the coolant system. Iain Link to comment Share on other sites More sharing options...
Firefly Posted May 15 Report Share Posted May 15 Iain, another very important advantage with a modern tank, is most have a float switch built in, and a warning buzzer can be installed under the dash. In fact only last winter the GT6 engine was saved by this, when the Chinese rubbish water pump seal let go. As Johny pointed out there is more room in the engine bay compared to the Vitesse. So if it helps the size of the one I have fitted is off a Volvo 940 (dims are mm) 210 long X 125 wide X 130 high from the top of filler cap to bottom of tank, you will need a further 65 ish to connect to the bottom tank outlet. Also a Volvo 850 tank may suit 160 X 160 X 130 high from top of cap to bottom of tank plus fitting of outlet connection. If this is of any help the company who supplied the tank is called “Parts for Volvo” if you google that it should come up, and select the coolant section on the left hand menu. Mac. N.B. the 240 & 740 tanks do not have float switches. Link to comment Share on other sites More sharing options...
Iain T Posted May 15 Author Report Share Posted May 15 (edited) Mac thanks very much for the detailed information I'll search. I think the only reasonable site for an expansion tank is next to the clutch MC. It high enough and the right side of the car. As to water pumps I had a shortened hybrid one made by EP Services so I could squeeze in a large electric sucker fan. Hopefully the pump will last🤞. Measuring the limited room I can easily fit a 100 diameter 200 tall tank which has a 6mm return to the radiator and a 15mm outlet to the radiator lower hose. Capacity is 1.4 litres but I'll only fill to 3/4 full. I'll use the original 13lbs cap. I've found a nylon T piece adaptor for the lower hose. It will require the radiator modification but that's no problem for Aaron Rads to do. I'll also have to fabricate a bracket to hold the tank but fortunately have two unused M6 rivnuts on the bulkhead I can use. No low level warning light but as you know it's a tight squeeze putting a 6 pot in a Herald.... Iain Edited May 15 by Iain T Link to comment Share on other sites More sharing options...
johny Posted May 15 Report Share Posted May 15 You might need to experiment a bit with the level in the tank. According to my calculations our system coolant expands by about 0.25L on warm up and with a tank that'll be slightly more so the air space in the tank needs to be double that volume to give a pressurisation of approximately 15psi... Link to comment Share on other sites More sharing options...
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