Tonyloz Posted November 21, 2015 Report Share Posted November 21, 2015 Hi all, Just a quick question........ Can you fit a J type gearbox and overdrive to a TR3a ? Standard 3a engine and clutch and flywheel Thanks again Tony Quote Link to post Share on other sites
John Morrison Posted November 21, 2015 Report Share Posted November 21, 2015 Yes, if you want to, but better to try and find an A Type. John. Quote Link to post Share on other sites
Tonyloz Posted November 21, 2015 Author Report Share Posted November 21, 2015 Can't find an a type hence the question! Quote Link to post Share on other sites
Kiwifrog Posted November 21, 2015 Report Share Posted November 21, 2015 Yes I run a 2.5 J type in my 3A. Changed the clutch plate for a saloon plate, works a treat and I prefer the overdrive switch on the gear knob (cut down saloon gear lever) cheers Alan Quote Link to post Share on other sites
Tonyloz Posted November 21, 2015 Author Report Share Posted November 21, 2015 Hi Alan, So it's just the clutch plate to change? Is that the drive plate and the cover? Thanks T Quote Link to post Share on other sites
Alec Pringle Posted November 21, 2015 Report Share Posted November 21, 2015 Any saloon box (A or J) runs the smaller diameter input shaft, so the clutch assembly has to be changed to suit, and the flywheel drilled for diaphragm clutch. The TR A and J box run the larger input shaft - and if I was using a later gearbox I'd also have the flywheel re-drilled to take the diaphragm rather than the spring clutch. A and J overdrive gearboxes utilise different mountings, which requires adaptation one way or another . . . . . Cheers Alec Quote Link to post Share on other sites
John Morrison Posted November 22, 2015 Report Share Posted November 22, 2015 You can simply run the saloon driven plate with the TR Pressure plate. Saloon Driven plate is 8.5 inches, TR 9 inches, but it does work really well, can give you a guy who has run this set up for nearly 20 years. John. Quote Link to post Share on other sites
Kiwifrog Posted November 22, 2015 Report Share Posted November 22, 2015 (edited) You can simply run the saloon driven plate with the TR Pressure plate. Saloon Driven plate is 8.5 inches, TR 9 inches, but it does work really well, can give you a guy who has run this set up for nearly 20 years. John. That is what I have done it appears to work ok. Buy the CTM rear gearbox mount as well it just bolts in place of the TR rear mount and is superbly made http://www.ctmengineering.co.uk/CTM-homepage.html cheers Alan Edited November 22, 2015 by Kiwifrog Quote Link to post Share on other sites
Guest Posted November 22, 2015 Report Share Posted November 22, 2015 A TR6 J type works good as well. I have one in my car for years now without a problem. You need a special adapter for the mount at the back. But that is no problem. Menno Quote Link to post Share on other sites
Tonyloz Posted November 22, 2015 Author Report Share Posted November 22, 2015 Thanks everyone for the feedback Looks the way to go,just need to change the friction plate and the rear mounting by the sound of it Tony Quote Link to post Share on other sites
BlueTR3A-5EKT Posted November 22, 2015 Report Share Posted November 22, 2015 (edited) Nobody going to mention the drive flange bolt hole spacings then? The flange is drilled differently on the saloon compared to the TR. See Peter Cox's notes on how to do it in the Moss Europe TR5/6 printed catalogue - free - just order it from them. We took the Dolomite Sprint 'J' type out of brother's TR2 as he got fed up with it clouting the exhaust - another issue I fear. Peter W Edited November 22, 2015 by BlueTR3A-5EKT Quote Link to post Share on other sites
Lebro Posted November 22, 2015 Report Share Posted November 22, 2015 Nobody going to mention the speedo drive being a different ratio then? TR is 2.5:1 Saloon is 3.5:1 My fix was to use the insides of a Mk2 2.5PI speedo (840 turns per mile, & fit it inside my TR speedo housing. TR speedo is circa 1180 TPM (depends on exact model.) You would not notice the difference, & it is accurate. Bob. Quote Link to post Share on other sites
BlueTR3A-5EKT Posted November 22, 2015 Report Share Posted November 22, 2015 (edited) Nobody going to mention the speedo drive being a different ratio then? TR is 2.5:1 Saloon is 3.5:1 My fix was to use the insides of a Mk2 2.5PI speedo (840 turns per mile, & fit it inside my TR speedo housing. TR speedo is circa 1180 TPM (depends on exact model.) You would not notice the difference, & it is accurate. Bob. Keep 'em coming... The flange thickness at the top three studs is greater on the 4 synchro box. The 4 synchro box is a synchro longer than a 3 synchro (3/8" ish) Clutch release bearing arrangement is different but useable with the right type of clutch cover (diaphragm) Overdrive switch may be in the wrong place (on a plate attached to the gear lever bolt) Peter W Edited November 22, 2015 by BlueTR3A-5EKT Quote Link to post Share on other sites
Tonyloz Posted November 22, 2015 Author Report Share Posted November 22, 2015 So not a straight fit after all! Nothing that isn't fixable though,I think! Tony Quote Link to post Share on other sites
BlueTR3A-5EKT Posted November 22, 2015 Report Share Posted November 22, 2015 So not a straight fit after all! Nothing that isn't fixable though,I think! Tony Absolutely. Just be aware of the painful ones before you fit the thing. Peter W Quote Link to post Share on other sites
TRnorm Posted November 24, 2015 Report Share Posted November 24, 2015 I fitted a saloon MK2.5 G/B and J type O/D in my TR4 with all the mods mentioned and it is fine, other than the engagement being a little slow. I guess this has something to do with the hydraulic pressure but I've yet to look into that aspect in any detail. I checked my speedo drive ratio just a couple of days ago by measuring the distance travelled for 10T of the speedo cable and lo and behold, found it needed a 1.4:1 change to get the speedo accurate (Exactly the 2.5:1 versus 3.5:1 that Bob mentioned - so I'm now looking for a saloon speedo). Bob - can i ask if your saloon speedo is 120mph or 140 mph. I can only find the latter on eBay at the moment? And perhaps what the Smiths part number is? PS I see a fair priced G/B and J O/d on eBay right now (http://www.ebay.co.uk/itm/Triumph-gearbox-2-5-2500-2000-TR6-/321925172238?hash=item4af43c4c0e:g:ZPgAAOSw6dNWTfgB) Regards Norman Quote Link to post Share on other sites
Lebro Posted November 25, 2015 Report Share Posted November 25, 2015 Norman.It was 2½ years ago when I did this, but from memory it probably was 140MPH. This does not really matter because you will probably want to re-calibrate the speedo anyway - Not too difficult, you have to either tighten or loosen the hair spring which pulls the needle towards Zero. To fit the saloon innards to the TR casing requires a few tweaks: Make new "keyhole" in the rear of casing to accept the trip reset cable. Relieve some of the inside casting material to make room for parts of the new innards. lengthen the slot in the dial where the trip mileage shows through. Make sure your purchase has 840 turns per mile (written in small writing under the total mileage readout) Most saloons (T 2000, T2.5 Mk1) use 1000 TPI which is no good. I chose a 2.5PI Mk2 unit. Finally you will need a new speedo cable, as the fitting on the rear of the speedo is different. I converted my TR one, but somewhere like speedy cables would be able to make what you want, if the standard saloon one is not the correct length. Bob. Quote Link to post Share on other sites
TRnorm Posted November 25, 2015 Report Share Posted November 25, 2015 Thanks Bob, So a little fettling to be done then! Have seen quite a few 1000T/m speedos about but the 840 seems to be much rarer - but I keep looking. Appreciate you nailing down this approach for me. I now have a few options which is this one, using a miniature gearbox in the cable and I have just asked Speedy Cables if they can recalibrate my 1184T unit (answer awaited). Thanks again Norman Quote Link to post Share on other sites
Tonyloz Posted December 11, 2015 Author Report Share Posted December 11, 2015 Hi again Just to let you all know,I'm going ahead with the j type conversion I need to get the drive flange to prop sorted in 1 off a few ways Can the a type output drive flange be fitted to a j type Or I could change the Uj flange on the prop to match the j type Don't want drill the flange to make it match,could give vibration problems Thanks Tony Quote Link to post Share on other sites
Willie Felger Posted December 12, 2015 Report Share Posted December 12, 2015 Tony, Relax - it is straightforward and it is a super gearbox and OD. I have a 2.5 PI estate box in my TR3A and fitted a 2000 saloon box to my TR6 (since sold) and both work faultlessly. You need just the clutch friction plate for the J type box. The standard TR3A clutch cover is fine. I used the Moss rear bracket on both cars and it fits fine and used a new release thrust bearing (J type). The rear flange splines are different and you need to get the J type flange drilled by a friendly machine shop. I took the "old" flange off the original box along as a pattern. Neither of mine vibrated at all and the TR3A is smooth as you like up to max revs. You will need an angle drive for the gearbox outlet. I had my speedo recalibrated by JDO instruments and it agrees to 1 mph with my Garmin GPS at 70. For an even better job you can upgrade to a diaphragm clutch as Alec suggests as I did subsequently along with the TR4A flywheel and Hi-Torque starter, but it is not essential for a start. You don't say where you are located but I'm happy to give you a hand if you are near here. Good luck, Willie Quote Link to post Share on other sites
Lebro Posted December 12, 2015 Report Share Posted December 12, 2015 Funny, I thought I had posted a reply to your last question yesterday, but it seems to have gone ? Anyway, If you have a TR gearbox flange it will fit directly onto the saloon box. Clutch wise, the splines are different so you need a suitable friction plate, I used a GT6 one. If you retain the TR3 cover plate, then you will need to change the release bearing, & carrier to suit. I left the saloon system as it was, & fitted a GT6 cover plate which is a diaphragm type. Only snag is that the flywheel needs to be drilled & tapped to take the slightly smaller cover. Hope this post stays put ! Bob. Quote Link to post Share on other sites
Tonyloz Posted December 12, 2015 Author Report Share Posted December 12, 2015 Thanks for the reply I've got the old a type box,non overdrive,so I can take the drive flange off it and it will fit the j type? I've got a saloon box and a saloon friction clutch plate and was going to fit the existing clutch cover and a type thrust bearing I've got the angle drive for the speedo so almost sorted Tony Quote Link to post Share on other sites
Lebro Posted December 12, 2015 Report Share Posted December 12, 2015 Re flange - I think so. My TR flange fitted my T2000 "A" O/D gearbox OK, as far as I know the output flange should be the same for the "J" type, but I'm prepared to be corrected. I guess you will use the release bearing carrier from the old TR box with a new bearing ? The later box is a tad longer than original, but there is usually enough give in the mountings to accommodate, but I did have to elongate the mounting holes in my new engine mounts to allow enough movement. Trial & error I'm afraid on that one. Good luck Bob. Quote Link to post Share on other sites
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