Andy Clayson Posted May 3, 2003 Share Posted May 3, 2003 My gearbox has died ☹️. It was being service by C and during a test run it stuck in fourth and did not come out. Taking the top off the gearbox revealed a random distribution of joints, springs, etc. It's knackered. My 7 is a 1.6k SS with a standard 5-speed box. I need to decide what to do and I'd welcome any advice or thoughts from you all. I guess my options are: - refurbish/rebuild the existing one - replace with a new 5-speed - replace with a standard Caterham 6-speed - replace with something else C advised me that if I go to a 6-speed, I might want to swap the rear diff as well. I've seen the recent discussion on final ratios and that seems to suggest that if I want a decent top speed for track days I should do this, but C want circa £1k for the privilege of doing this... Of course, sunny days are on us, and I'd like to get this done quickly. I also live somewhere close to the arctic circle (Middlesbrough ) so if any actiosn involve using someone other than C I'd like them to be in the northern half of the country if possible. So, does anyone have any opinions on swapping to the C 6-speed or should I go with a Quaife/etc. What would you look at? Also, should I change the rear diff ratio? If yes, does it have to be done now or can it wait a bit? Thanks in advance. Link to comment Share on other sites More sharing options...
Tight fart Posted May 3, 2003 Share Posted May 3, 2003 What diff do you have? SLR for sale T.F@O.F. www.griptv.com Link to comment Share on other sites More sharing options...
John Howe Posted May 3, 2003 Share Posted May 3, 2003 If you can spare the cash, go for the six speed box, its a joy to use and you soon just slip into the rhythm of endlessly changing - increases second hand value of the car . Word of warning... I have been known to attempt to select reverse in other vehicles, for want of a sixth gear. JH Deliveries by Saffron, the yellow 222bhp Sausage delivery machine Link to comment Share on other sites More sharing options...
KenEvans Posted May 3, 2003 Share Posted May 3, 2003 I stayed with the standard diff (3.9??) when I changed to a 6 speed box. I don't have any issues with top speed at all though I've only done a couple of track days at Oulton Park. Ken Link to comment Share on other sites More sharing options...
Andy Clayson Posted May 3, 2003 Author Share Posted May 3, 2003 When I bought the car I never asked and I'm a bit of a mechanicophobe 😳. It's the standard diff for 5-speed boxes - 3.9 I presume... Link to comment Share on other sites More sharing options...
Bare Posted May 3, 2003 Share Posted May 3, 2003 If it were my problem I would FIRST get a Price quote for: 1) a rebuild 2) a replacement 5spd 3) a price quote for the 6 spd The price of the 6 speeder is rather steep in my opinion. Link to comment Share on other sites More sharing options...
Andy Clayson Posted May 3, 2003 Author Share Posted May 3, 2003 Caterham quotes are: rebuild = £350 plus labour new 5 speed = £1k plus labour new 6 speed = £2300 all inclusive alternative = £??? Not sure what else I could replace it with nor who to ask, hence the original post! Link to comment Share on other sites More sharing options...
KenEvans Posted May 3, 2003 Share Posted May 3, 2003 Shop around for a 6 speed box - see what some of the dealers might be prepared to offer........ Link to comment Share on other sites More sharing options...
Tight fart Posted May 3, 2003 Share Posted May 3, 2003 Could we start a bulk buy for 6 speed box's ANTHONY !!!! SLR for sale T.F@O.F. www.griptv.com Link to comment Share on other sites More sharing options...
timbo Posted May 3, 2003 Share Posted May 3, 2003 alternative: @ £1K for a new caterham 5 speed you'd be mad. - for the same money speak to Steve Perks - SPC - semi helical close ratio 5 speed. This is the second box i've had off him (in 2 caterhams). Ratios are c. 2.34, 1.54, 1.21, 1, .89/.92 i think. Obviously its not a 6 speed but for a fraction of the price it is as good as 5 speeds come. Straight swop - in & out with the old box. Plus if your running a 3.62 - get a price for an exchange 3.9/4.1 diff. Sub £1500 should buy you a lot more oooommppphhhh. I am running a 4.1 - very little penalty for long road use - except for a wildy inaccurate speedo reading. JLZ7447 1.6K this week Link to comment Share on other sites More sharing options...
Leadership Team SLR No.77 Posted May 4, 2003 Leadership Team Share Posted May 4, 2003 Andy, Are you interested in a 5 speed straight out of a 1600K Caterham? Andy Best has just swapped to 6 speed, and the "old" 5 (circa 10,000 miles I think) is sat nice and clean awaiting a new owner. I know he will not want a fortune for it - would get you running quickly - he's Manchester area. Stu. Link to comment Share on other sites More sharing options...
stevefoster Posted May 4, 2003 Share Posted May 4, 2003 Road and race transmissions are highly recommended. I had a diff done there. They are near Sevenoaks in Kent. Give them a call if you are near. A 5sp CR box is sweet enough in a 7. Quaife / SPC do a semi heli version that's not too bonkers noisy. Alt. BGH. Search the atchives there's loads of praise about him. My racing pics, 7 DIY, race prep. Updated often here Photo's of the year here Hants (North) and Berkshire Area club site here Edited by - stevefoster on 4 May 2003 10:14:00 Edited by - stevefoster on 4 May 2003 18:16:27 Link to comment Share on other sites More sharing options...
Chris W Posted May 5, 2003 Share Posted May 5, 2003 Andy I have tabulated some figures below giving the top speed in each gear for a standard Caterham 5 speed using the 3.92 final drive ratio normally fitted, and for the 3.62 final drive ratio normally fitted to the 6 speed box. I don't know the max permitted revs of your engine so have calculated these figures at 6750 rpm max for my 1.8K. The numbers scale linearly so you can move the rev limit up or down accordingly very easily. I have also tabulated the normal CC 6 speed box as supplied with its normal 3.62 final drive for comparison. (and with a 3.92 fitted) Not knowing your tyre/wheel combination, I have used my own size of 205/45/16 which gives a circumference of 73.1". You can scale again for your own tyre size or I would be happy to re-run the numbers if you let me know your actual tyre/wheel size and max rev limit. You can see that the final drive ratio choice available doesn't really affect the speeds much on a 5 speed box. Your speedo will misread of course with the 3.62 final drive fitted if no change of speedo drive is made and it also goes without saying that your ultimate top speed in the high gears is limited by air resistance (it's claimed to be 125mph or so for mine). CALCULATED TOP SPEEDS 5 sp with 3.92 final drive (normal as supplied by CC) 1_______35mph 2_______66mph 3_______95mph 4_______119mph 5_______145mph 5 sp with 3.62 final drive 1_______38mph 2_______71mph 3_______102mph 4_______129mph 5_______157mph 6 sp with 3.62 final drive (normal as supplied by CC) 1_______48mph 2_______64mph 3_______81mph 4_______98mph 5_______114mph 6_______129mph 6 sp with 3.92 final drive 1_______44mph 2_______59mph 3_______75mph 4_______90mph 5_______105mph 6_______119mph Note the limited (by gear ratio) top speed on the last combination. Hope this is of some help Chris 1.8K SV 140hp see it here Edited by - Chris W on 5 May 2003 12:22:42 Link to comment Share on other sites More sharing options...
Andy Clayson Posted May 5, 2003 Author Share Posted May 5, 2003 Thanks to all of you for this info. Lots to think about, though I probably won't want to stick with the original 5-speed box - this is an upgrade opportunity to good to miss... Link to comment Share on other sites More sharing options...
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