Harry Flatters Posted January 5, 2001 Share Posted January 5, 2001 My 6 speed Caterham box performs brilliantly most of the time except when changing down from 4th to 3rd at medium to high revs it does graunch a bit. Is the synchro going and if so how big a job is it and can the box be dropped without taking the engine out. The car is a 95 VXL Inj. Link to comment Share on other sites More sharing options...
Mike Bees Posted January 5, 2001 Share Posted January 5, 2001 Changing the synchro means dismantling & rebuilding the box. You do need to take the engine out. Learn to double-de-clutch wink.gif Mike Link to comment Share on other sites More sharing options...
Harry Flatters Posted January 5, 2001 Author Share Posted January 5, 2001 Thanks for the advice, I can D-D-C but I was hoping to avoid it. Would you say the rebuild is a skilled job and if so can you recommend anyone who might undertake such a task. I live in surrey about 20 miles south of London. Steve Link to comment Share on other sites More sharing options...
TimNeill Posted January 5, 2001 Share Posted January 5, 2001 Steve Perks is THE man to go to, at SPC: Lighthouse Works, Feckenham Road, Astwood Bank, Redditch B96 6DS Tel:+44 (0) 1527 894232 He rebuilt my 6 speed and converted the diff to LSD, great service, reliable work, good value, really nice bloke. Tim Neill Link to comment Share on other sites More sharing options...
Harry Flatters Posted January 5, 2001 Author Share Posted January 5, 2001 Tim, Thanks for the info, I'll give the man a ring on Monday. Regards Steve (PTM 88) Link to comment Share on other sites More sharing options...
Rob Walker Posted January 5, 2001 Share Posted January 5, 2001 Phil Stuart of Road and race transmissions is on your door step, Corsham. Road and race rebuild all Caterahams boxes and many of the race boxes. I would ask Phils advice hes a nice helpfull chap. Typical rebuild costs for a six speed are around £100 plus parts. Tel 01959 525105 Link to comment Share on other sites More sharing options...
EFA Posted January 5, 2001 Share Posted January 5, 2001 To add to Robs comments.... Phil Stewart does the R & D on the six speed box for Caterham. Nobody knows the 6 spd better than Phil. He is very reasonably priced too. AW Arnie Webb Organiser- L7C Le Mans Trip Link to comment Share on other sites More sharing options...
Mike Bees Posted January 8, 2001 Share Posted January 8, 2001 Concur with Arnie & Rob. Because Phil looks after all the boxes for the Caterham race cars he knows exactly what to look for. There are other good gearbox folks around (SPC & BGH for example) but Road & Race are the place to go in this case. Mike Link to comment Share on other sites More sharing options...
Anthony Micallef Posted January 8, 2001 Share Posted January 8, 2001 Just as a matter of interest i've always wondered what is meant by double de clutching.Can someone please explain? Link to comment Share on other sites More sharing options...
JDoc Posted January 8, 2001 Share Posted January 8, 2001 This is interesting - mine is doing exactly the same thing. I wonder if there might be an inherant weaknes in the 6-speeds. How many miles have been put through the box? Mine's had around 9,500 miles in it's short life, and it's already showing signs of wear as you described. I mean, come on, it's only a car, right? Link to comment Share on other sites More sharing options...
Dave H Posted January 8, 2001 Share Posted January 8, 2001 Anthony, Double decluching...First the techie bit. There are 3 parts to the drive. Engine, gearbox layshaft & prop shaft/axle/wheels. When you depres the clutch you disconnect the engine from the layshaft. put it in neutral and you disconnect the layshaft for the prop shaft etc. To double declutch you first clutch down/neutral clutch up, match engine revs to road speed for the gear you are about to go into (this brings both engine and layshaft up to match the prop shaft/axle etc) then clutch down into gear clutch up...all nice and smooth - and it cuts down wear and tear on clutches, syncros etc. John Lyons (HPC) double declutches - he had a TR8 - took it into the main dealer to get the cluch changed as it had 150,000 miles on it - they said there was no point - it had amost no wear on it... Dave Link to comment Share on other sites More sharing options...
Anthony Micallef Posted January 8, 2001 Share Posted January 8, 2001 Thanks Dave for the explanation.Another mystery solved, i will have to give it a go next time im in my Citroen ZX! Link to comment Share on other sites More sharing options...
Anthony Micallef Posted January 8, 2001 Share Posted January 8, 2001 Thanks Dave for the explanation.Another mystery solved, i will have to give it a go next time im in my Citroen ZX!I suppose this would have to be done fairly quickly to avoid coasting along in neutral for too long. Link to comment Share on other sites More sharing options...
Harry Flatters Posted January 8, 2001 Author Share Posted January 8, 2001 For JDoc, My HPC with 6 speed has done just on 12,000 and I've been having these problems for about 2,000. I'll post results of my further investigation when complete. Steve (PTM 88) Link to comment Share on other sites More sharing options...
Harry Flatters Posted January 8, 2001 Author Share Posted January 8, 2001 Having spoken to Phil Stuart(what a nice man) it would appear that this is not an uncommon problem. Apparently, ratio wise, the drop from 4th to 3rd is the largest one in the box and can put strain on either the selectors or the synchro gear. Phil also said that if the box was an older type (as mine is 1995) it would be worth replacing the 5th gear (part cost: £125) with a modified one as it has been known for these to lunch themselves on high output (180bhp+) engines. Lastly, if you have a 6 speed that leaks a bit of oil from between the box and bell housing, this is also very common. Link to comment Share on other sites More sharing options...
Andrew Dent Posted January 8, 2001 Share Posted January 8, 2001 So that would explain the small patches of oil in my garage. Andrew Link to comment Share on other sites More sharing options...
simonwelton Posted January 9, 2001 Share Posted January 9, 2001 They all do that sir it's a caterham!, my old one did that from new and I found the secret was forget it and don't be gentle, more force less graunch was the answer (and blip the throttle) Link to comment Share on other sites More sharing options...
Geoff Johnson Posted January 9, 2001 Share Posted January 9, 2001 On that note, I am starting to have a slightly alarmed thought as I have had my car for two years & never topped up the gearbox oil. Mine is a 5 speed vx carb, there is oil around the bell houseing (but none on the garage floor), I assume this is from the gearbox. Where is the filler & what oil is best? Link to comment Share on other sites More sharing options...
Geoff Johnson Posted January 9, 2001 Share Posted January 9, 2001 On that note, I am starting to have a slightly alarmed thought as I have had my car for two years & never topped up the gearbox oil. Mine is a 5 speed vx carb, there is oil around the bell houseing (but none on the garage floor), I assume this is from the gearbox. Where is the filler & what oil is best? Geoff Link to comment Share on other sites More sharing options...
FH Posted January 9, 2001 Share Posted January 9, 2001 Shame on you Si, there's (nearly) nothing as satisfying as stringing together a series of beautifully executed double-de clutches. AND as mentioned earlier, it saves on wear and tear. If you need someone to show you the technique, come up and see me sometime wink.gif Edited by - fullharness on 9 Jan 2001 14:03:40 Link to comment Share on other sites More sharing options...
Petrolhead Posted January 9, 2001 Share Posted January 9, 2001 After reading the above threads I find myseld feeling a little dismayed. I am not sure how much a 6 spd box is, £2000-3000? I would have thought, when you are spending this kind of money, you expect a high quality product. Not a gearbox that leaks oil and is wareing out only after 8000 miles. What about other 6 speed boxes. Are they better? Link to comment Share on other sites More sharing options...
Hurdsey Posted January 9, 2001 Share Posted January 9, 2001 Anthony Citroen zx!!!! i bet my 1.9 TD is faster than yours! and my W E S T F I L D faster than your c******m Q63 GBA smile.gif Link to comment Share on other sites More sharing options...
murph7355 Posted January 9, 2001 Share Posted January 9, 2001 Don't forget you're only hearing from ones with problems in this thread... My car's had a 6spd box on it for about 25k miles and has neither leaked nor caused me any grief (and I don't think Mike Bees had any hassle with it previous to my ownership) aside from a couple of speedo cable angle drives breaking. And that will, of course be the kiss of death and mine will fail when I'm next out. But at least I know where I can get it fixed if it does :) Occasionally it's tricky to get into reverse (but there seems to be a knack to it as I'm usually OK) and I've buggered up a few changes recently but I think that's the new clutch/me rushing it. C7 AJM Link to comment Share on other sites More sharing options...
Peter Carmichael Posted January 10, 2001 Share Posted January 10, 2001 Come, come cms239. The production volumes for the six-speed box mean that it was going to come with a hefty price tag. The story that I have heard is that Caterham were sensitive about the development costs and they curtailed Brian Hill's work, essentially going to production with a prototype spec. A small number of post-production modifications have surfaced which are mostly retrofittable and cure most of the problems. The selector forks in particular have been beefed up and the fifth gear upgrade is merely a matter of a resited oil drilling which now doesn't cut through the roots of two of the gear teeth. A total cost rebuild to cure these two issues is less than 500UKP with Phil Stewart. With 27000 miles on my box he said there was no appreciable wear on the synchros, but then I double declutch fanatically. An often overlooked plus side of the six-speeder is that it is very light at ~29kg IIRC. The 10kg penalty of going to a Quaife sequential box will probably be enough to dissuade me - the ultralight flywheel/clutch that I have specced with my new engine had such an upgrade in mind, but makes the changes with the h-pattern box much better anyway. In short, the six-speeder is reliable, race-proven and light, with ratios that really suit the car. Looking for an alternative six speeder seems to me to be an exercise of pursuing problems for their own sake. Link to comment Share on other sites More sharing options...
Petrolhead Posted January 10, 2001 Share Posted January 10, 2001 Hi Peter I understand your viewpoint and accept that we have to put up with these anomolies. Take Microsoft, for instance, how many bugs do they ship with their products! But I feel that if we are not heard, then nothing is done to fix these problems. You had to pay another £500 to get the box right. I relise you had no choice but is this right or fair? Peter E Link to comment Share on other sites More sharing options...
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