Andrew Smith Posted October 2, 2016 Report Share Posted October 2, 2016 Hi Folks, I fitted a 4-synchro box to the Turk this afternoon and whilst I know the bell housing flange is 3mm thicker requiring longer studs and bolts, but I understood the overall length was the same. Problem: the bolt holes on the rear rubber mounting block do not line up with holes on the cross member plate, it’s probably a good 10mm out. Apart from the holes not lining up, the rear of the overdrive housing fouls on the rubber block too – see photos. I thought it would be a simple fix of drilling two new holes further back on the cross member plate, but the rubber mounting block will not drop down flush because of the 90 degree lateral strengthening piece. It would seem the simple solution would be to cut the cross member and welding in a plate, then drilling out new holes cross member plate, but the cross member is tapered and probably won't take an extra 10mm let-in. Has anyone fitted the 4-synchro box in their sidescreen TR, and if so how did you overcome this problem - does one of the suppliers offer a modified cross member plate? Any advice much appreciated. Cheers Andrew Quote Link to post Share on other sites
david ferry Posted October 2, 2016 Report Share Posted October 2, 2016 Andrew, What you need is the cross member plate from a TR4. This will be a direct replacement for your sidescreen plate. The mounting and gearbox will bolt to this without problem. This item is not available new but you should be able to get one from the usual sources. If you get stuck, let me know and I'll ask a couple of people for you. David Quote Link to post Share on other sites
Lebro Posted October 2, 2016 Report Share Posted October 2, 2016 Andrew. I did this, I actually used a Triumph 2000 box + 'A' type overdrive. I had the same issue, but I was fitting it to a bare chassis, so that made things a bit easier. I had to elongate the mounting holes in both the engine mounts, & the gearbox mounts to get it to fit. The engine ended up about ¼" further forward than normal. I was not aware that the TR4 gearbox mount was differnt to the 3 one, that would have helped. Bob. Quote Link to post Share on other sites
Andrew Smith Posted October 2, 2016 Author Report Share Posted October 2, 2016 Andrew, What you need is the cross member plate from a TR4. This will be a direct replacement for your sidescreen plate. The mounting and gearbox will bolt to this without problem. This item is not available new but you should be able to get one from the usual sources. If you get stuck, let me know and I'll ask a couple of people for you. David Many thanks David, The plate is now available from Moss (128055), so I'll call them in the morning and order one. Cheers Andrew Quote Link to post Share on other sites
Don H. Posted October 3, 2016 Report Share Posted October 3, 2016 FWIW, Andrew, here are a few shots under my car. TR3Bs (all of 'em, as far as I know) had full-synchro gearboxes from the factory. My 'box is stamped with a TSF-serial number. I've not measured bell housing flange thickness, but maybe the pix will give some idea to those who have compared them. This one bolts into to my car like it was made for it (which it was, of course!) Quote Link to post Share on other sites
david ferry Posted October 3, 2016 Report Share Posted October 3, 2016 Andrew, I did not know that Moss were selling them new. However, they list the same part for TR4 and sidescreen cars with notes about elongating holes if needs be. It may be worth taking yours in there to compare with their offering. David Quote Link to post Share on other sites
Andrew Smith Posted October 3, 2016 Author Report Share Posted October 3, 2016 Thanks for the heads-up David, I'll give Jeff Marks a call at Moss. Cheers Andrew Quote Link to post Share on other sites
BlueTR3A-5EKT Posted October 3, 2016 Report Share Posted October 3, 2016 (edited) I slotted the holes in the removable chassis mounting plate on my car to move the mounting point for the two mounting studs rearward by the thickness of the extra synchro. ...Which is all the TR4 gearbox mount plate offers but with once round holes. Peter W Edited October 3, 2016 by BlueTR3A-5EKT Quote Link to post Share on other sites
Lebro Posted October 3, 2016 Report Share Posted October 3, 2016 +1 Yep I did that, but found that I also needed to do the same on the engine mounts. net result was engine moved forward around ¼", and rear of box moved rearwards by around the same. I had by this stage gone narrow belt, & no mech fan, so moving forward was not a problem. Maybe the saloon box is a tad longer than TR4 ? Bob. Quote Link to post Share on other sites
BlueTR3A-5EKT Posted October 3, 2016 Report Share Posted October 3, 2016 Here's one I made earlier..... Quote Link to post Share on other sites
Lebro Posted October 3, 2016 Report Share Posted October 3, 2016 While you are at it Andrew, suggest you change the exhaust mounting system at rear of gearbox to the TR4 type, much better location, & easier to fit. Bob. Quote Link to post Share on other sites
foster461 Posted October 3, 2016 Report Share Posted October 3, 2016 While you are at it Andrew, suggest you change the exhaust mounting system at rear of gearbox to the TR4 type, much better location, & easier to fit. Bob. I was surprised to see that Don's TR3B is still using the old TR3 style bracket. Quote Link to post Share on other sites
Graham Harris Posted October 3, 2016 Report Share Posted October 3, 2016 (edited) I slotted the holes and trimmed most of the rear turned up angle so the upper part of the gearbox mount would clear the bracket, i also added a piece of 1/8 th packing under the mount so the OD would clear the forward part of the mounting plate. I probably should have done what Bob did and slotted the front mounts as well. I have used the later exhaust mount. Graham Edited October 3, 2016 by Graham Harris Quote Link to post Share on other sites
Ian Vincent Posted October 3, 2016 Report Share Posted October 3, 2016 (edited) I had the same problem and seem to remember turning the cross member up the other way and elongating the holes but it was a while ago and memory fades. I do recall it being a bit of a faff. I didn't have to buy any new bits. Rgds Ian Edited October 3, 2016 by Ian Vincent Quote Link to post Share on other sites
Andrew Smith Posted October 3, 2016 Author Report Share Posted October 3, 2016 Thanks all for the tips and advice - I like the idea of slotting the cross member plate and inverting the plate to avoid the rear OD casing fouling the top plate of rubber mounting block and to stop it fouling on the horizontal strengthening plate, see respective photos below. This would be a last resort if I couldn't locate a TR4 cross member plate - hopefully help is at hand. Cheers Andrew Quote Link to post Share on other sites
BlueTR3A-5EKT Posted October 3, 2016 Report Share Posted October 3, 2016 You've marked on the tape where you need to file to.....I think I might argue that a 8" or 10" bastard cut rat tail file and 10 minutes filing is cheaper than a replacement mounting plate - but there again I could be wrong. Peter W Quote Link to post Share on other sites
Andrew Smith Posted October 3, 2016 Author Report Share Posted October 3, 2016 You've marked on the tape where you need to file to.....I think I might argue that a 8" or 10" bastard cut rat tail file and 10 minutes filing is cheaper than a replacement mounting plate - but there again I could be wrong. Peter W Probably Peter, but look again at the photo and the rear of the rubber mounting is fouling on the vertical strengthening piece - this will need to be inverted and cut if it fouls on the exhaust. If the TR4 plate negates all this then that's what I would sooner use, particularly if the original plate is left weaker because of liberating amounts of metal. Cheers Andrew Quote Link to post Share on other sites
BlueTR3A-5EKT Posted October 4, 2016 Report Share Posted October 4, 2016 Probably Peter, but look again at the photo and the rear of the rubber mounting is fouling on the vertical strengthening piece - this will need to be inverted and cut if it fouls on the exhaust. If the TR4 plate negates all this then that's what I would sooner use, particularly if the original plate is left weaker because of liberating amounts of metal. Cheers Andrew I understand your concerns, but think about the TR4 item. It must be cut away to clear the exhaust of the TR4 - same chassis cruciform and exhaust as TR2-3... then that is all you need to do on your existing one. Peter W Quote Link to post Share on other sites
Graham Harris Posted October 4, 2016 Report Share Posted October 4, 2016 Trimming the rear of the mounting plate doesn't seem to have had any adverse effect on the strength of it. Graham Quote Link to post Share on other sites
Andrew Smith Posted October 4, 2016 Author Report Share Posted October 4, 2016 Thanks for all the useful input folks, I think I may now be sorted. Cheers Andrew Quote Link to post Share on other sites
Guest ntc Posted October 4, 2016 Report Share Posted October 4, 2016 Thanks for all the useful input folks, I think I may now be sorted. Cheers Andrew Andrew Please report as I did as the rest and worked fine Quote Link to post Share on other sites
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