RichardS

Yes, I agree that people who remove the thermostat in order to cure an overheating problem are failing to understand the physics involved. However, where there is no thermostat fitted at all, one might as well fit the cooler range variant. The radiator does appear to have rather "coarse" horizontal fins rather than the the finer vertical ones that I'm more used to seeing. Is it possible to have the existing rad re-cored with the finer fins etc or is it cheaper to just buy a new rad built to a better design if such a thing is even available? Richard

The rad appears to be fairly new and appears to be getting hot across its entire surface. Unfortunately, unlike most other rads I've worked on, the top of the matrix is not really visible. I've seen rads in the past where you can actually see that some tubes are blocked. It might be the case that the rad itself needs to be overhauled but, to be honest, the only costs so far are my time and I don't mind that but if these cost-free mods don't do the trick then I'll remove the rad again. I could try pouring diluted hydrochloric acid into the inverted rad as that's something that seemed to make an improvement when I tried it in the 1970's but it's not without it's implications and might still not clear blocked tubes. Richard

Thanks to those who have provided details of the forward cowling. I will be able to fabricate something similar and possibly even more extended with the sheet I have left over from the fan cowling. I realise that it's more of a forward movement thing but, thinking about it, if the car arrives at a traffic jam with a lower temperature of coolant then it should provide a bit more headroom for the time at idle in the jam. Richard

Yes, the Kenlowe does have its own casing/cowling but I've removed the electric fan so the cowling has now gone. Richard

Thanks to all for the helpful comments. When I got the car it had no thermostat fitted and a lot of blockages in the cooling system. I fitted the lower temp option thermostat which I think was 75 degree and have drained and back-flushed the system several times. I dug out some total blockages with long pieces of stiff wire! All the passages now seem to be clear and water pours out of every spigot and the block drain. When I fully drained it yesterday there was no crud at all but I still flushed through with the hose pipe so I'm confident that the system is clear. I do not have any cowling in front of the radiator. Perhaps that was removed to fit the electric fan? As has been pointed out, a front cowling would probably only affect cooling whilst moving but if anyone has a photo of what I'm missing I would be very interested. With a 75 degree thermostat, I would expect the gauge to stabilise in the lowish 80's if the system if the cooling is able to keep pace with heat being generated and, sure enough, that seems to happen now as long as the car is moving. I suppose that I'm used to modern cars which run at the same mid-range temp under every condition. I have a V8 Jaguar which only has electric fans and you can leave it all day at idle and the fans will never even start as the capacity of the massive radiator is able to dissipate all the heat being produced by the engine without any forced airflow. The GT6 is clearly a very long way from that level of cooling performance but I was hoping that my ducting would maintain the lowish-80's equilibrium position. The number plate is partly covering the air intake but, as with the front cowling, that's presumably not affecting the stationary situation? I can see that I will need to do some more testing. I didn't try it today but I suspect that if I had turned on the heater and possibly the blower the extra cooling might well have pulled it back down although in today's weather that would not be a pleasant experience. I used to have a 1960's Vauxhall Victor and that used to overheat in the summer so I disconnected the air duct pipes so it would blow hot air into the engine bay and that always kept the temp within the normal range. However, that's not an option with the Triumph because the matrix and blower are in the cabin rather than in the engine bay. I'll report back when I've done some more testing on a longer run. Thanks to all Richard

My GT6, as purchased last year, was fitted with a blue plastic 8 blade fan and a Kenlowe electric fan but had no cowling of any sort on the back of the rad. The engine also has a high-performance cam fitted by the previous owner so I suspect it is generating a little more heat than standard. I fitted a lower temp thermostat and an accurate temperature gauge and found that on every trip, even in cool weather, after a few minutes at dual-carriageway speeds it was necessary to turn on the electric fan as the temp gauge only remained at the stable thermostat-controlled temp of about 83 for a few minutes in hot weather and a bit longer in cool weather. I was sure that the engine fan was not working efficiently as it was well away from the rad and was not being helped by the electric fan when it was not turned on. I have therefore fired up the MIG and produced the cowling shown in the photos which totally encloses the fan. As soon as I started the engine I could see that something had changed because the electric fan blades started spinning as a result of the airflow. The electric fan did not do this before I fitted the cowling so I was feeling positive and went for a drive with the electric fan still in place. This was yesterday and today so high 20's around here. Things were better and as long as the car was travelling at 60 or 70 the temperature held at 83 but once I turned off the dual carriageway the temperature started to creep up and turning the Kenlowe on brought it back down which suggests that the system was at its limit. I removed the Kenlowe and tried again today. The results are much better in that during the entire run the temp was stable at 83. However, I did not meet any traffic jams so was never stationary so when I arrived home I just let the engine idle to see what happens. Sure enough, after about 5 minutes the temp started to creep up again and reached 90 after 10 minutes before I switched it off. I was hoping that it would hold a steady 83 at idle even after a good run in hot weather but it seems not to be. Any advice about whether I am striving for the impossible would be helpful, along with any further ideas. Thanks Richard

That's interesting. I'll have a look through the "cooling" threads. I've cleared a huge amount of crud from the coolant pipes by back-flushing the entire system from the back of the block and rodded out some waterways which were completely blocked. At the moment the heating is such that it appears to hold steady during this hot spell if the heater valve is open so I feel it's not far away from being competent ..... but as soon as I shut the heater valve (which is essentially if one is to avoid heatstroke!) the temperature starts to creep up. Maybe that's just how it is. Richard

You're right about that Nigel. I still can't leave stuff along until I know exactly how it works. It drives my Wife mad as she thinks I should just accept that if stuff works, it works. 😊 However, I did use white spirit as that seems a bit less volatile than petrol but I did use a long pipe just to be on the safer side. I'm still going to make that visit once I'm sure that she can make a longish journey without problems. The one problem I still have is during this hot weather I can see that the cooling system will not hold steady at 85 degrees as it does in cooler weather. She's not exactly overheating but , to my mind, the performance of the cooling system should not be so marginal that ambient temperature affects the cooling ability, although I might be on a losing battle with this. Richard

Right .... in the interests of science I've conducted a few experiments with surprising results! I took a new filter exactly the same as the ones I have fitted. There is no dip tube in these simple filters. The entry aperture is in the very bottom of the cylinder and the exit aperture is in the very top. I attached a clear plastic tube to the exit spigot so I could suck, and, with the filter held vertically, dipped the bottom spigot into white spirit. I then began to suck gently and the liquid started to rise in the cylinder. However, the filter acts like a wick and you can see the liquid wicking up in the filter material ahead of the level of the liquid. By the time the level of liquid gets about half way up the filter, the wick level has reached the top of the filter and, as soon as that happens, liquid starts to rise up the exit spigot and into the clear tubing. It seems to defy logic but it is what it is. Inside the cone of filter material, it must be full of liquid even though the actual level of liquid outside the cone is only halfway up the container or lower. It doesn't matter how hard I suck now. The level stays at about half way in the cylinder and liquid continues to exit from the top. A mouthful of the stuff now becomes a clear and present danger! The really surprising thing is that if I stop sucking and just leave the end of the plastic tube in the air and leave the bottom end of the entry spigot in the liquid, the level stays the same in the filter i.e. the liquid does not run out even though the top end is at atmospheric pressure. What is more, if I lift the end of the entry spigot out above the liquid, nothing different happens. The filter just sits there half full of liquid. The filter material acts like a non-return valve which I never expected. I can obviously blow the liquid out quite easily but, now that the filter is wet, when I start to suck again the liquid starts to come up the exit pipe almost as soon as the liquid touches the bottom of the filter material. It is now behaving exactly as in my photo above. I can tip the filter right over on its side or leave it vertical but it makes no difference .... as soon as the liquid reaches the filter material it starts to exit from the top. However, this doesn't work the other way. If I reverse the filter the other way up and such through the bottom end, then the level rises right to the top of the housing before it starts to appear in the plastic tube. If I stop the suction, the liquid simply runs out of the filter as you would expect and it drains completely. The filter material seems to behave differently in each direction. If you want the filter housing to be full, the only way to achieve it appears to be to mount the housing the wrong way round. In theory, I guess in would be possible to fill the housing inverted and then quickly connect it up the right way around whilst it's still full. However, those bubbles which seems to come into my filter from the bottom with the new fuel would presumably just re-establish the air gap again? Anyway, where does that leave us? I suppose with the confirmation that having the petrol near the bottom of the filter housing is not an issue as the inside of the filter cone is full of fuel which is why the engine never seems to suck that air bubble through into the float chambers. I'm still non the wiser about where the bubbles in my incoming fuel are coming from. The research will continue! 😉 Richard

I did look at the old filter and couldn't see a dip pipe. However, I'll go and have another look. Richard

Is there a way of doing that? You could do it will my old British motorbikes as they had a tickler but I didn't think that Strombergs had such a device unless simply opening the choke valve on the side of the carb will do it? Richard

It's been driving me mad ever since we bought the car, so much so that I changed the filter in a bid to put an end to it. 😕 We were both trained in chemistry/physics and there must be a scientific answer to this conundrum but I'm damned if I can work it out. Richard

I did wonder that, but surely the vapour would be sucked through the pump along with the fuel and the air gap would clear? When I disconnect the pipe at the top of the filter, it's fuel that comes out because of the height of fuel in the tank. Why does the vapour not come out first followed by the fuel? There must be an answer to this, surely? Richard

It is almost vertical but the air gap only vanishes when the car is left standing and then appears again as soon as the engine starts. I did try holding it both vertically and horizontally with the engine running but it made no difference. I can't believe that so much air is being sucked in from one of the four joints hose before the filter (it can't be due to anything after the filter) but that petrol will not leak out. Petrol is famed for finding the tiniest crevice to squeeze through that there would have to be some weeping at least but I checked the whole line and can't find anything at all. I just can't figure it out. Richard

The photo was taken with the engine off, although it had been running a few seconds earlier and it looked exactly the same when it was running. The fuel tank is actually full at the moment so the level is higher than the filter assembly. Any siphoning would actually serve to fill the filter rather than the other way around, although it can't actually do that because it's a sealed system, of course. Richard

Another puzzling issue with my GT6. All advice welcome. 🙂 I don't think that this is actually affecting the running of the car but it just doesn't seem right. The photo below shows the filter on my engine. This is a new one which I fitted a week ago because the original one was always full of air so I thought that it was faulty. However, as you can see the new one behaves exactly the same as the old one! You can see that the fuel only just covers the bottom of the filter, even though the filter outlet is right at the top of the filter and there is no dip--tube inside it. This photo was taken after a run yesterday. Occasionally, after the car has been left unused for a few days, the fuel level does creep up inside the housing and almost reaches the top. However, if I manually operate the fuel pump, then bubbles of air (I assume it's air?) come in at the bottom and the fuel level in the filter rapidly drops down again. Similarly, if the level has crept up, once the engine starts, more bubbles come in and the fuel level always ends up right at the bottom again. This happens whether the tank is full or empty, and when it's full the fuel level is actually above the level of filter. It's probably around the filter level even when tank is low. If I disconnect the line from the top of the filter then fuel, not bubbles, comes out of the top driven by the head of fuel in the tank. I would have expected the air to be driven out first but it isn't. There is a short length (a few inches) of rubber fuel line running from the bottom of the filter to the end of the metal fuel line. This metal line then runs along the chassis back to the bottom of the fuel tank. There is another few inches of rubber hose where the line goes above the rear axle and then it's metal into the tank fitting. There are no fuel leaks anywhere along this line. The car is kept in a garage and there is no smell of petrol. I cannot understand where the air bubbles in the fuel are coming from and why the fuel pump is not removing the air gap at the top of the filter housing and filling the filter with fuel. The more the engine runs, the emptier the filter housing becomes. It only starts to fill when the engine is not running for a few days. Can anyone explain to me what is going on? Many thanks Richard

It did come with pancake filters but I've left the original twin filter thing in place. It doesn't have the two pipes running to the front but they are in the box of parts as well. Richard

The temp compensators are present and they do work but they are blanked off at the air filter flange. That's interesting about the size. The special tool from Rimmers is quite a loose fit whereas my 1/8th key was a tight fit so I assumed that the Rimmers tool was 3mm. If it's supposed to be 1/8 then I reckon that the Rimmers tool is being manufactured slightly undersize. The little washer is up inside the housing as both carbs are only 1/2 turn from fully rich and a level washer is about 1.5 turns from fully rich. However, my engine is running it's plugs at the right colour and the revs don't drop when the slide is lifted by a few mm so it feels right. It might be that the tuning parts fitted to it are demanding a slightly richer setting. However, I'll do another plug chop when everything has settled down. Richard

Right, I took the diaphragm assembly out and, after a lot of to and fro-ing a bit at a time whilst squirting easing oil into both ends, I managed to get the needle out from its housing. I ditched the proper carb adjuster and used an 1/8th inch Allen key as that was slightly larger than the proper 3mm adjuster and gave better purchase. I can't see anything actually wrong with the two threads ... they were just impossibly stiff. I've greased the threads and now it moves smoothly through the full extent of its travel. In future, I might give them a workout a couple of times a year just to keep then running free. Anyway, it's now set a 1/4 turn richer like I did with the rear carb yesterday and I took her for a test run and, (even in this extreme heat!), she pulls smoothly through the revs. However, she's comfortable at around 75mph actual in OD which is fine for me. The needle is a B5CF which I think is right for my carbs. However, I now have another puzzle concerning the fuel filter but I'll put that in a new thread with a photo. Thanks to all Richard

Many thanks for the helpful information Rob and Pete ..... I'll take it apart tomorrow and see what's going on in there. Richard

It seems that every day means a new surprise with the GT6. After much testing I decided that I would try and richen the mixture a little. First thing I noticed is that the two little cutouts which are held by the adjuster tool are positioned across the engine bay in the rear carb whereas the cutouts on front carb run along the length of the car. I would have thought that the little flaps on the diaphragm would mean that the cutouts would always be orientated the same way unless the metal tube itself is assembled by Zenith with a random orientation. Are the different orientations normal? Secondly, I wound the rear carb adjuster fully clockwise and it was exactly one turn before it was fully home. I then backed it counterclockwise 3/4 turn to give me a 1/4 turn enrichment. However, the front carb adjuster appears to be jammed virtually solid such that I can't turn it either way. After a lot of rocking it to and fro I managed to turn it a 1/4 turn counter-clockwise and then clockwise through the original position to a 1/4 turn richer. I have left it there without finding the actual number of turns out it is because I'm worried that something is going to snap. The end of the brand new adjuster tool definitely looks the worse for wear after this first usage. 🙁 It seems inevitable that I'm going to have to remove the diaphragm to find out what's going on but I'm just wondering whether seized adjusters are par for the course? Many thanks Richard

I've just fitted this Woolies stuff and it's better than what was on there already and far better than the Rimmer's stuff which wouldn't allow the boot to shut. The panel gaps are still not as good as I would like but it's an improvement on when I bought it. Richard

I've spent days shimming and drilling my GT6 hatch to try and make it fit correctly down the driver's side and finally managed to get a reasonable alignment ... and then changed the cracked old seal for a new Rimmers one only to discover that its shutting days are now over. I've put the old seal back on again as it's clearly a smaller profile than the Rimmer's one. For the moment I've decided to leave it alone and move onto something else but I will certainly investigate the alternatives mentioned above in due course. Richard

Dontcha just love internet forums? 😉 Richard

I'm even more confused by this speedo issue. We removed the speedo drive unit from side of the overdrive because it was leaking gearbox oil. The oil seal on the pinion shaft was completely shot so we replaced the oil seal and, whilst we were at it, replaced the speedo drive cable as the old one had several fractures in the outer casing. We did not touch the speedo itself other than unscrewing the old cable and screwing in the new one, all done from behind the dashboard with the speedo still fixed in position. When we took the car for a test run, rather than reading 20% fast, the speedo now reads only 10% fast, which is acceptable and can be lived with. However, I do not understand how putting in a new seal and a new drive cable can reduce the speedo reading by 10%? I would have understood if it was now over-reading even more ..... but less? Richard