Ade-TR4 Posted February 4, 2012 Report Share Posted February 4, 2012 Having removed the gearbox from the TR4 I've found that the oil leak that I thought was most likely coming from the crank is actually coming from the input shaft of the gearbox. Unbelievably, the rear main is bone dry! OK, so while the gb is out, it's having a new OD with uprated clutch, is it worth swapping the clutch for 4a and if so, is a lighter flywheel worth a go? I have already lightened the original and was running a normal TR4 clutch, which was slipping due to being covered in oil. I don't want to to take the gb out again, so any input from you intelligent types (creep creep) who but useful. Basically, is a standard TR4 clutch NOT covered in oil, able to cope with an uprated engine output? Engine is running DCOE40s, 4-2-1 exhaust, road cam, 87mm cyls, balanced etc etc. Not a TrTony engine, but not a pootler either (reckon on 140bhp) Cheers all! Adey Quote Link to post Share on other sites
TR 2100 Posted February 5, 2012 Report Share Posted February 5, 2012 Adey, Depends partly on how much you have lightened your own flywheel and how confident you are with its strength. TR 2100 is not too far away from your spec (89mm cylinders, 42DCOEs) and I DID fit a lighter ("finger") flywheel and TR6 clutch. The very light flywheel makes the engine very sensitive but it really doesn't take long to get used to it. Not regrets on my mods. Remember, the TR6 clutch setup is designed for the much higher power that you and I have. That's not to say the standard TR4 clutch won't take the extra power, but it must be nearer to its limit that a TR6 clutch. AlanR Quote Link to post Share on other sites
Bob Smith Posted February 5, 2012 Report Share Posted February 5, 2012 Adey, Another option is to use a Stag clutch cover with you existing drive plate if in acceptable condition. The Stag engines in standard form gave 135? BHP so should be suitable for your uprated engine. The Stag is lighter than the standard TR4 cover but as it is a diaphragm you also need to change the clutch release bearing to the later type. Quote Link to post Share on other sites
Ade-TR4 Posted February 5, 2012 Author Report Share Posted February 5, 2012 Hi Alan, It's lightened to about 21lbs: TR-bitz had it done for me to their recommended spec, so I guess it's as light as is safe. Like your idea Bob, I supose the flywheel has to be drilled to take the diaphragm clutch a la TR4a fitting? I'll keep you posted on progress, I'm just glad I've found that there IS a problem (big oil leak) that hopefully when fixed should improve the drive and the the underside of the car! Adey Quote Link to post Share on other sites
Ade-TR4 Posted February 6, 2012 Author Report Share Posted February 6, 2012 OK, So going to go TR5/6 clutch route and get my flywheel converted to suit. How many extra dowels are required over the original ones for the spring-type TR4 clutch? Other than that, I guess I need: Clutch kit (Cover/ plate/ bearing) Bearing carrier (TR4a/5/6 type) Anything else? (probably forgotten something... ) Cheers Adey Quote Link to post Share on other sites
Dean Posted February 6, 2012 Report Share Posted February 6, 2012 The 4A and later gearbox's had a shorter nose piece. this holds the front seal and the throw out bearing carrier slides on it. It is shorter to clear the fingers of the 4A pressure plate. If you have a later gearbox it may already have the shorter nose piece. Dean Warwick GT TR6 TR4 TR3 Quote Link to post Share on other sites
Ade-TR4 Posted February 6, 2012 Author Report Share Posted February 6, 2012 Cheers Dean, I'm fairly sure it's got the shorter nose already, but I'll be double and triple checking before refitting! Adey Quote Link to post Share on other sites
Bob Smith Posted February 6, 2012 Report Share Posted February 6, 2012 Adey, If you have a TR4 flywheel which is designed to take a 9" clutch and driven plate then changing for a TR6 type which is 8 1/2" will require you to change the flywheel to a later 4A type or to drill 3 additional holes at the smaller P.C.D. A Stag clutch cover has 3 dowel holes spaced equally at 120 degrees the TR4 cover has only 2 dowel holes spaced at 180 dgrees; it is possible to fit a Stag cover on to a TR4 (9" flywheel) without modification as one uses one of the studs to position the cover - the other stud on the flywheel "misses" the Stag clutch cover. If you are in a position to bore dowel holes ACCURATELY then the Stag route is more cost effective as you don't need a new flywheel or driven plate only a clutch cover and a gearbox release bearing. Quote Link to post Share on other sites
stuart Posted February 6, 2012 Report Share Posted February 6, 2012 Differences in nose piece for reference. Stuart. Quote Link to post Share on other sites
Ade-TR4 Posted February 7, 2012 Author Report Share Posted February 7, 2012 Thanks Bob: Is it the same friction plate? It does sound a more sensible route. I do have a very good local engine machine shop that can do the alterations and balance the whole shebang too. Stuart; awesome. Thanks! Can't beat decent photos when checking stuff like this. Cheers! Adey Quote Link to post Share on other sites
Bob Smith Posted February 7, 2012 Report Share Posted February 7, 2012 Adey, Effectively so as both are 9" it all boils down I guess as to cost either a Stag Driven(friction) plate or a TR2/3/4 (9") will fit your TR gearbox shaft the splined dimensions in the centre are the same. If the cost is not critical then I would use the Stag one as it was designed to transmit 135? BHP in its original application. As I have said previously you only need 2 extra holes for the dowels at 120 and 240 degrees the tapped holes for the fixing of the cover are in the right place already. If you need further reassurance why not take the flywheel and offer up a Stag cover before you start. Hope that helps Quote Link to post Share on other sites
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