Triumph TR6
Nigel’s TR6 takes two steps forward, then one back
The TR6 is running well but inevitably it’s built up a few little niggling jobs for me to attend to. The valve clearances need checking, the speedo needle has developed an erratic twitch and there’s an irritating rattle from the exhaust at low speeds.
I began with the shaking speedo. Usually such problems are caused by a sticking drive cable, so I dived under the dash and disconnected the cable from the back of the speedo head. After pulling the top of the cable through the bulkhead into the engine bay, it was easy to withdraw the inner cable. I gave it a good wipe then oiled it sparingly, as too much oil risks gumming up the speedo head. With the inner cable slipped back into place, everything was soon reconnected.
A quick test run showed the speedo was no better, with the needle waving wildly at 30mph. Almost certainly a new cable would be needed, but I didn’t want to go to the trouble of stripping out the interior of the car to get to the far end of the cable – well not yet, anyway.
Rattle and hum
The next job on my list was the exhaust rattle. When pulling away, tacho showing about 1000rpm, there was a rattle from the exhaust. Waggling the tailpipe by hand caused the same unpleasant noise and it seemed to be coming from the silencer. Car safely secured on axle stands, I ventured underneath. The silencer was hanging correctly between the rear chassis extensions and wasn’t knocking on anything, so I figured the rattle might be caused
by loose baffles inside the silencer. Clamps and mountings undone, I wrestled the silencer from under the car. Standing and shaking the silencer enthusiastically produced a bit of a sweat but no untoward noises. Clearly the problem must lie elsewhere. I worked my way forwards along the rest of the system and soon found a likely culprit. There’s a bracket intended to secure the centre pipe to the overdrive mounting bracket, between the chassis rails. The bracket had sheared and waggling the pipe made the same rattling noise.
That’s good news and bad news. Good news in that I’d now found the cause of the problem, but bad news as the broken bracket is hard to access. I removed the rest of the system, all the way up to the manifold. But I still couldn’t get to the remains of the bracket. The answer? Same as the speedo cable… strip out the inside of the car.
With both speedo and exhaust still to be fixed, I took the plunge. After taking out the front carpets and passenger seat, I removed the auxiliary instrument panel from the centre console then the console itself.
Finally I undid the bolts that hold down the gearbox cover, which grudgingly slid out from under the dash. The end of the exhaust bracket was now in reach but running out of time, I’ve left that for another day.
Last, with the speedo cable disconnected I attached an electric drill to the bottom of the cable. Spinning the cable gently anticlockwise with the drill got the speedo up to 30mph, still twitching like an angry wasp in a beer glass. I retired indoors, put on the kettle and ordered a new cable.
The final job was to retorque the cylinder head nuts and then reset the valve clearances. All the clearances had closed up by 5-6thou, confirming the gasket had compressed further. I reckon that proves why retorquing head nuts is important.
When the new speedo cable arrives, I can finish that job and I’ll get the welder out to repair the broken exhaust bracket.
‘The speedo cable was twitching like an angry wasp in a beer glass’