Guest Andrew Terry Posted August 9, 2004 Report Share Posted August 9, 2004 Hi All, I've been the proud owner of a CP series TR6 for the last 5 months now and being no expert (my first classic) i'm still getting used to whats normal and whats not. I've noticed since I had the car that it generates a huge amount of heat from the transmission tunnel. So much so that even with the roof down the heat on the drivers left leg is towards unbearable. The car is behaving fine and not overheating, no exhaust problems etc. I'm starting to wonder if there is some undercarpet insulation that wasn't replaced when the car was restored. Is this sort of heat normal or does it indicate a problem I need to deal with? At this rate I won't need the heater in the winter! Thanks Andrew Quote Link to post Share on other sites
jean Posted August 9, 2004 Report Share Posted August 9, 2004 Andrew, original the 6 had a kind of thick cardboard tunnel covered with felt, mine still got it. This represents a reasonable isolation, but still radiates some heat into the footwell. As this gearbox cover deteriorates with time many cars have been equipped with fibreglass or metal covers and the isolating underfelt under the carpet is left away. The heat is mainly generated by the engine as the bulkhead creates a kind of ventury effect leading the engine heat along the cover backwards when driving. In addition you have the exhaust pipes passing just underneath I think there is nothing wrong with your car, beside the fact that it might be missing the isolation, what can be fitted easily. Jean Quote Link to post Share on other sites
Allan Jezzard Posted August 9, 2004 Report Share Posted August 9, 2004 Andrew, I agree with Jean but there is another possibility and one I'm sure others will relate to. Although the heater control on the dashboard may apparently be pushed fully in (i.e off), it is quite possible that the heater valve under the bonnet is still open. The problem lies with the thin control wire that has to push the valve shut. Original equipment might have been up to the job but most replacement wires are just not man enough. The answer is to open the bonnet and move the valve by hand, that is, operate it left to right, effectively pulling the wire through and at the same time closing the valve. As it's easier than stripping out the tunnel, you might try this first. Allan Quote Link to post Share on other sites
jean Posted August 9, 2004 Report Share Posted August 9, 2004 Very good thinking Allan, another problem on the heater/vent side is that the foam on the flap, sealing off the outlets, is often missing and even when selecting defrost a lot of air is circulated towards your feet Jean Quote Link to post Share on other sites
john.r.davies Posted August 9, 2004 Report Share Posted August 9, 2004 All, There has been a considerable correspondence about this problem with GT6s and Spitfires in the more torrid conditions of US Southern States, on the Totally Triumph Net ( http://www.totallytriumph.net/cgi-bin/dcforum/dcboard.cgi ). Sorry, I can't remember the exact reference, but there is a good search facility on the site. One idea that caught my imagination was to fit a length of ducting from behind the radiator grill to the arch of the bulkhead, directing cooling air into the gearbox cover, at least when in motion. It would not be beyond wit to add a fan in the intake to the duct. The thread(s) contain several other suggestions for insulation methods. Good luck John Quote Link to post Share on other sites
Guest ron Posted August 9, 2004 Report Share Posted August 9, 2004 Last month when I replaced the OD inhibitor switches I kept the cover off for a few hours till I was sure everything was OK, the amount of heat that comes off the gearbox and exhaust is incredible especially when the car is ticking over at traffic lights etc. The later MGBs have quite a good heatshield, but not very easy to copy, inside the tunnel about 1/4" away from it is an thin asbestos? pressing the same shape as the tunnel giving an airgap which acts as a very good insulator. My own TR has a heavy felt cover under the tunnel carpet which still feels quite warm after a long run. Ron Quote Link to post Share on other sites
Don Elliott Posted August 9, 2004 Report Share Posted August 9, 2004 Make sure that all the bolts holding the tunnel to the floor are installed and tight. Ensure that the joints are flat with little or no gap. If there are gaps, use a sealant that is used to seal window sills and sashes in your home for the winter. I use the easy peelable type so when I want to remove the tunnel sometime later, it will be easy to pull the sealant away. In its earlier life when I left the tunnel in my TR3A totally loose without any bolts, it was unbearable in the car just like Ron mentions above. Don Elliott, Original Owner, 1958 TR3A, Montreal, Canada http://mysite.wanadoo-members.co.uk/trebor/don3a_big.JPG TR Register Member since 1987 Quote Link to post Share on other sites
jemgee Posted August 9, 2004 Report Share Posted August 9, 2004 I agree with the heat output bit. My 6 had a loose cover over the speedo drive and i was treated to a funelled blast of hot air directly to the underside of the left thigh. Has anyone used the foil heat insulation over the cover and beneath the carpet/underfelt? Quote Link to post Share on other sites
Guest ron Posted August 10, 2004 Report Share Posted August 10, 2004 Mike I tried to stick it to the underside of the tunnel cover when it was off, but due to the rough surface of the fibreglass and oil contamination could not manage a secure job, but I think it's an idea that might be worth pursuing. Ron Quote Link to post Share on other sites
Goswell Posted August 11, 2004 Report Share Posted August 11, 2004 I agree with the heater valve issue, I definately have a summer setting to ensure the valve is fully off. However have you checked the rubber gaiter around the clutch leaver, if not fitted well will allow a lot of engine heat in. Also there is a captive nut just visible below the stearing column in the engine bay, that was missing a bolt on mine. Shot an incredibly hot jet of air on to my legs, bad news if you are wearing shorts. Quote Link to post Share on other sites
Guest Andrew Terry Posted August 12, 2004 Report Share Posted August 12, 2004 Thanks for your suggestions all, I will start taking a look around, I haven't had the carpet up but it doesn't seem well padded so it may be insulation. I will certainly check the heater and other bits but it definitley seems to be the tunnel and not the whole footwell. Andrew Quote Link to post Share on other sites
BryanD Posted August 12, 2004 Report Share Posted August 12, 2004 So has anybody got a fix for the heater valve problem then? Mine does it too - and it is annoying. I've replaced both the valve and the cable with new ones, but it seems that the new cables just aren't stiff enough to push the valve the last few degrees round to fully shut. I was wondering about fitting a weak spring to help things along a bit ... Quote Link to post Share on other sites
Guest ron Posted August 12, 2004 Report Share Posted August 12, 2004 Bryan I cured mine but it wasn't straight forward, the main cause of the problem is the aftermarket valves, at the time mine was acting up the MGOC had a stock of genuine NOS MGB valves, which although they mount differently from the TR6, the actual valve is the same, so I dismantled a NOS MG valve and built it onto the TR6 fitting and it has worked fine since. Don't know whether the MGOC will sell to people who aren't members but there's no harm in asking! Ron Quote Link to post Share on other sites
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