stillp Posted August 12, 2016 Report Share Posted August 12, 2016 Out for a run in the 4A today, car was running fine but I suddenly heard a grinding noise, and smelt 'something' hot. Smelt a bit like clutch lining, but the car was driving alright. Popped the bonnet and couldn't see anything, so decided to head back home, very gently. The noise had gone when I restarted, but a few miles down the road the ignition light came on. Under the bonnet there were small particles of metal everywhere, but mostly around the dynamo, so out it came. The sintered bush at the brush end of the dynamo had gone oval by about a millimetre, and the rotor had been rubbing the stator segments. The commutator is chewed up, all the solder has melted, and the insulation on the rotor is worn away over about half its length. I'm assuming the bearing had run dry - can't remember when I last oiled it. Pete Quote Link to post Share on other sites
Graham Harris Posted August 13, 2016 Report Share Posted August 13, 2016 That will happen if the fan belt is too tight. Graham Quote Link to post Share on other sites
Richardtr3a Posted August 13, 2016 Report Share Posted August 13, 2016 Bad luck. I have had a noise from the bearing and gave it a bit of oil. Later it stopped charging and the oil was too much and had crept up to the brushes. I always carry a spare now I hope you get it repaired as the new ones are of doubtful quality. I tried several companies before finding Cox Automotive CV9 2QZ 01827 718484. They are very good at Control Boxes as well and I keep a small supply in case they retire. Good luck, Richard & H. Quote Link to post Share on other sites
Motorsport Mickey Posted August 13, 2016 Report Share Posted August 13, 2016 Get into the habit with a dynamo, check your oil in the engine and before you wipe the stick just touch it on the bearing end disk with the hole in. Drop of oil departs from the end of the stick onto the plate and thence into the sintered bush, just the right amount. Mick Richards Quote Link to post Share on other sites
JeffR Posted August 13, 2016 Report Share Posted August 13, 2016 Hi Pete, I think you're talking about a problem with the front bearing, not the bush at the rear, near the brushes. I had a similar problem with the dynamo on my TR4 on the journey up to IWE this year. The front bearing seized solid when I was on the motorway but not before destroying several segments on the commutator.and the brushes which I had replaced only 6 weeks earlier. Fortunately for me, even with a seized dynamo the fan belt had continued to turn the water pump, keeping the engine at normal temperature for the remaining 150 miles to Lincoln. On arrival the local Lincs Group assisted me in obtaining a rebuilt unit from Rimmers - well done and thank you chaps. My concern, on reflection was that I had fully rebuilt this dynamo, which was original to the car, about 20K miles previously including changing the front bearing - so my question ultimately concerns parts quality. These days I buy all my bearings from recognised quality brands. Cheers, JEFF Quote Link to post Share on other sites
stillp Posted August 13, 2016 Author Report Share Posted August 13, 2016 Jeff, I think there must have been some wear on the ballrace at the pulley end, or the rotor couldn't have put any significant side load on the bush at the commutator end, but the ovality is at the commutator end. Pete Quote Link to post Share on other sites
stillp Posted August 13, 2016 Author Report Share Posted August 13, 2016 Get into the habit with a dynamo, check your oil in the engine and before you wipe the stick just touch it on the bearing end disk with the hole in. Drop of oil departs from the end of the stick onto the plate and thence into the sintered bush, just the right amount. Mick Richards Mick, I always used to do that with previous cars, but the dipstick and the dynamo being on opposite sides of the engine mean I have to walk round the car and the oil drips off the dipstick, so I've rather lost the habit with the TR. Pete Quote Link to post Share on other sites
stillp Posted August 14, 2016 Author Report Share Posted August 14, 2016 What was I thinking! Of course, the bearing at the pulley end is also a sintered bronze bush! Anyway, a new dynamo from TRGB and it's working fine. Pete Quote Link to post Share on other sites
stillp Posted August 18, 2016 Author Report Share Posted August 18, 2016 I might have spoken too soon! After an interesting evening at the Langton garden centre car meet, where there were some very interesting cars including a 6 from Leicester Group - sorry, I've already forgotten your names - on the drive home with headlights on, the ammeter was showing a discharge, but the warning light didn't come on at tickover. More work to do I think, starting with the fan belt, then re-check the control box. Pete Quote Link to post Share on other sites
stillp Posted August 20, 2016 Author Report Share Posted August 20, 2016 Phew! New fan belt and cleaned the grease off the pulleys, cleaned the cut-out points, and all seems well - fingers crossed! Where do I contact the PQI - old fanbelt had only been on for 26 years... Pete Quote Link to post Share on other sites
RogerH Posted August 20, 2016 Report Share Posted August 20, 2016 Hi Pete, have you still got the receipt. Roger Quote Link to post Share on other sites
stillp Posted August 20, 2016 Author Report Share Posted August 20, 2016 Probably! I saved them all during the restoration - came to just under £2100, including the car and a new electric drill. Don't know where the file is now though. Pete Quote Link to post Share on other sites
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.