DenisMc Posted July 20, 2020 Report Share Posted July 20, 2020 Hi All, I got my TR5 over a friend's pit this morning. This was the first time so I checked the gearbox and rear axle oil levels and had a good look at everything. I'm pleased to report that in general all was well, but I did notice that one of the sump screws was loose. When I came to tighten it it just turned so clearly the thread is stripped. As it is at the front of the engine I can get at it quite well. I am thinking of installing a 5/16" UNF Helicoil thread insert. I know that this involves drilling out the thread and tapping it a larger size to take the insert. I'm assuming that the tapped holes are blind holes so that oil doesn't leak out. Can anyone confirm this? Also is there sufficient metal around the tapped hole for it to be opened out slightly? Many thanks, Denis Quote Link to post Share on other sites
Steves_TR6 Posted July 20, 2020 Report Share Posted July 20, 2020 (edited) Hi Denis i don’t have the diagram to hand but iirc there is an alloy bridge piece that the front sump bolts bolt into, notorious for stripping threads. perhaps a new bridge piece, and iirc someone makes them in steel now, is the best solution? otherwise a helicoil should be fine steve Edited July 20, 2020 by Steves_TR6 Quote Link to post Share on other sites
RogerH Posted July 20, 2020 Report Share Posted July 20, 2020 Here it is in steel at Revington https://www.revingtontr.com/search.asp?for=151134&cartype=tr6cp Roger Quote Link to post Share on other sites
harlequin Posted July 20, 2020 Report Share Posted July 20, 2020 I fixed mine with a Helicoil, it's a little fiddly but quite doable with the engine in place George Quote Link to post Share on other sites
DenisMc Posted July 20, 2020 Author Report Share Posted July 20, 2020 Thank you all for your very helpful suggestions. As only the one thread seems to be faulty I'll try fitting a Helicoil first. Thanks again. Quote Link to post Share on other sites
elclem1 Posted July 23, 2020 Report Share Posted July 23, 2020 You will need a long drill bit to do in situe. But certainly doable as opposed to taking the front of the engine to pieces. Quote Link to post Share on other sites
DenisMc Posted August 10, 2020 Author Report Share Posted August 10, 2020 The Helicoil tapping drill is 8.3mm diameter. I have bought an 8mm drill with a hexagon drive and extension pieces so that I can get directly below. As the bridge piece is aluminium alloy I am hoping that I can tap a thread within the 8mm pilot hole. Anyone know if they are blind or through holes? Thanks Quote Link to post Share on other sites
boxofbits Posted August 10, 2020 Report Share Posted August 10, 2020 Worth making sure it has the correct length bolt in it? One of my sump threads (TR4a where the slave bracket mounts) did the same thing) albeit in cast iron . I measured the full depth of the hole, ran a tap in and and fitted a longer bolt. Made short work of a potentially long job, and it only pinches the gasket up anyway. Nothing to lose even if you have to eventually fit a helicoil. Kevin Quote Link to post Share on other sites
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