bazyli56i Posted January 1, 2017 Report Share Posted January 1, 2017 (edited) Hi Guys, A happy new year to everyone, whilst working on my 1966 TR4A I came across this very heavy weight(see attached photo) which was clamped to the rear of the gearbox where the propshaft joins the gearbox, the small plate seen beside the weight in the photo was attached to the clamp but was not clamped to anything although there is a hole in stay that fits from the silent bloc mounting to the gearstick fixing. I cannot find anything about it in any of the manuals I have. I also asked about this weight whilst I was through at Chic Doig classic sportscars getting some parts and he had not come across this part. The car originally came from North Carolina in the USA. Does anyone know the reason it would be fitted? Cheers John Edited January 1, 2017 by bazyli56i Quote Link to post Share on other sites
bazyli56i Posted January 1, 2017 Author Report Share Posted January 1, 2017 sorry guys fie too big to upload , will try and get the picture posted another route Quote Link to post Share on other sites
RobH Posted January 1, 2017 Report Share Posted January 1, 2017 A factory addition to damp out transmission vibration. There has been discussion about it in earlier threads. Quote Link to post Share on other sites
RogerH Posted January 1, 2017 Report Share Posted January 1, 2017 Hi John, that lump was fitted to the 4A to stop a resonance from the engine at about 2700rpm. I have removed mine and there appears to be no after effects. Regarding your pic - go into 'MS paint' and resize it to apprx 100Kb. Roger Quote Link to post Share on other sites
Motorsport Mickey Posted January 1, 2017 Report Share Posted January 1, 2017 (edited) As Roger says this was a factory "fix" to a resonance ( a "buzz" or hum) that had been noticed with some engines and transmissions. The back of the gearbox or overdrive acts like the end of a tuning fork, if you do any work on the engine and have the component parts balanced (including the clutch cover and flywheel) the resonance normally disappears and you may be able to dispense with it as per Rogers example. I've searched for you (try it on anything use the box on the top right side), try this thread if you want more info on it. http://www.tr-register.co.uk/forums/index.php?app=core&module=search&do=search&fromMainBar=1 Mick Richards Edited January 1, 2017 by Motorsport Mickey Quote Link to post Share on other sites
bazyli56i Posted January 1, 2017 Author Report Share Posted January 1, 2017 thanks for the replies guys, roger cheers for the info to reduce the size of the photo, it's now on, I think I will leave it off for now and see if there is any difference when I get it rebuilt and back on the road. john Quote Link to post Share on other sites
BlueTR3A-5EKT Posted January 1, 2017 Report Share Posted January 1, 2017 It is a mass balance to reduce remove vibration - just the same principle as mass balance on an aileron. https://www.bing.com/images/search?q=image+mass+balance+on+aileron&view=detailv2&&id=F57A76AE378C0F248CBDA329BAED9A6EB4EE8EDE&selectedIndex=2&ccid=yLyztsoq&simid=608036412563066038&thid=OIP.Mc8bcb3b6ca2aa7d6295fdf17784da7c7o0&ajaxhist=0 Quote Link to post Share on other sites
TR 2100 Posted January 1, 2017 Report Share Posted January 1, 2017 See above to identify the item. the "blob". Most owners have thrown these away Which leads to a shortage And that leads to Some silly prices on eBay. AlanR Quote Link to post Share on other sites
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