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Isolating switch

Imported from years of club emails (sent round Graeme Oxley's Stag Forum email list). Names, dates and details may be incomplete or wrong. If you spot a mistake, please let us know and we'll fix it. Got old Stag emails, from before 2017 or on a subject that isn't here yet? Forward them to mail@triumphstag.info and we'll add them to the archive.

Graeme Oxley

11 Sep 2017, 5:02am

I have been having issues with the starter motor on my 2.5PI not working properly. This has been a problem for a couple of months now. Last Friday it failed to start and I called the RACV. I then decided to have one last go and lo and behold it started and I went straight home and put it on ramps. The RACV tow truck was cancelled. One of the checks showed that the cable from the battery to the starter motor had become loose but still firm. I thought that I would clean the battery terminals and cable clamps. On the negative terminal I have a isolator switch. Before tightening the cable on the starter motor I unscrewed the green knob. Once tightened I notice that the LHS engine mount was broken and the RHS was starting to fall apart. I guess after 300000 kms they were allowed to fail. Luckily I had 2 new mounts in my shed. Whilst cleaning the isolator switch I noticed the connection had shown signs of contamination or electrolysis and was black and not a clean brassy look. I disassembled the switch and cleaned it up on the pedestal drill with a wire wheel. The battery was new and had a green light in the battery window indicating it was fully charged. I was blaming the starter motor as the culprit. It was replaced by a second hand unit in 2002. A replacement Hi-Torque Starter Motor from Castlemaine was going to be $375. Since cleaning the isolating switch the car now has full battery positive and the engine fires up beautifully. If you have one of these isolation switches pull it apart and clean it thoroughly. The mating surfaces should not be a black colour. I have had my1975 2.5PI since May 1996 and has covered 683000 kms. Engine is at TR6 spec and has a manual od gearbox. This is a facelift car car and the original engine had the HP dropped from 132 to 125 BHP. It is now at 150 BHP I replaced both engine mounts on Saturday morning

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