Nick Green

JR, I meant to refer to Rob's post before the one before Steve's, where he said the forces were N, not Nm. Therefore not torque... Thanks for the lever info! I shall see what I can come up with over the weekend. Cheers!

Steve, we've already stopped talking about torque. Check out Rob's post before your's. You mention 50-80 Newtons. How do you propose to measure it ?

So do you think my method of measuring the spring loading is viable ? Any idea if any "multiplier" needs to taken into account at all ? To be honest, it doesn't look like it to me...

In the interests of adding a few more facts and figures to this issue, I would like to attempt to measure the force the current clutch spring applies to the CRB. No one seems to be trying to do that yet. RobB quoted figures of 80-120Nm or 59-88 lbft. As others have pointed out, these are torque figures, which imply a turning or leverage force (don't they ?). If I re-fit the clutch spring to my car (5000 so far trouble-free un-preloaded miles BTW), and use a spring balance to pull back the clutch fork until it starts to move, then read off the figure, in lbs, on the scale, do I then multiply it by the length of the clutch fork from the bearing to the cable ? Or is it not as simple as that ? Assuming that lack of enough preload is the problem, then isn't the easiest solution just to fit a stronger spring ? How would one measure the force being applied by a rod, or something, pressing on the back of the clutch fork ?

Rob, There is no "inner and outer plastic casing"... There is a metal bearing, mounted on a plastic backplate which clips into the clutch fork. The plastic backplate has a sleeve which fits snugly over the nose of the gearbox. The metal bearing is in a number of parts: The casing that is attached to the plastic backplate, the race itself, and the...other bit that spins on the race and actually makes contact with the pressure plate fingers. I'm pretty sure I have some analog (ie not digital) photos from when I did the bearing swap last year. I can try scanning these and sending them to you if you like, but I would need an email address. Dave J has/had my old bearing off me, to further his own investigations I am still unclear on why the bearing *has* to be in constant contact. I would be surprised if my foot pressure on the pedal does not cause the necessary preloads to be attained pretty darn swiftly when doing a gearchange. The preloads you state for the bearing are (from a "doing up a bolt" point of view) very high! I don't see the spring Caterham fit on the clutch pedal being able to generate that sort of force... And the bearing can't wear anyway, if it isn't making contact. I'll have a go at scanning these pics and getting them to you. Cheers, Nick.

I've been thinking about this a little more... Perhaps the pre-load requirements are necessary for where constant contact *does* take place, to ensure that, for instance, drag inherent in the bearing is overcome, so that the correct part of the bearing mechanism is doing the spinning. Does it mean that constant contact *must* take place though ?

Hi Rob. Well done, on getting further down the information trail than I did when I tried! I can certainly claim no special expertise in the field of bearings, but in the absence of concrete information to guide me, I have been applying what I felt to be "common sense". I've had a couple of reads of your post, and I have a couple of things I'd like to clarify though. 1) You say if pressure is too little, then I'm afraid I don't see why the plastic should wear at all in this case. The back part of the bearing, that fits in to the plastic holder, that clips into the clutch fork barely moves when the bearing is new, but the bearing that came out of my car last year, moved freely on its plastic back plate. (Incidentally, this is why I've drawn no attention to needing to centre the bearing. IME, after a while the bearing seems perfectly capable of doing this for itself.) If anything is going to wear, given the above scenario, I would say the front face of the bearing which contacts the pressure plate fingers, is more likely to suffer. 2) The next bit: I also don't understand, as the pressure plate fingers don't touch any plastic. Perhaps it's me, but I don't understand why a bearing which is not moving should wear faster than a bearing rotating at engine speed. Cheers, Nick. PS I think I've got quotes sorted now... Edited by - nick green on 13 Dec 2002 12:07:13 Edited by - nick green on 13 Dec 2002 12:09:43 Edited by - nick green on 13 Dec 2002 12:16:00

Rob, I think Steve means a breather to the head, not to the catch tank from the bell-tank housing, which he should already have. I run a breather from the head to the catch tank. I have a piece of foam in the hole in the top of the catch tank, rather than the cap with holes in it. The fumes which make it to the catch tank mean that the foam is effectively "self-oiled", thus providing some filtration of air entering the head. I believe PC runs a natty little K&N type filter on his engine's head.

Steve, I can certainly take some pics, but it might take a day or two to get them to you or on the web.

My car's CRB started making noises last year, after about 2 years and 9k miles. I changed it before it fell to bits properly. My 6-speed box already has the steel sleeve fitted to it. I rang up the suppliers of the bearings to Caterham and asked them about alternatives. I was told the bearing supplied to Caterham goes in Cortinas, Sierras, Granadas, TVRs... I asked about bearings with metal back plates and was told they hadn't seen any for years. This has been confirmed by other people in the trade I talk to. Given the cars the bearings are normally fitted to, I don't see why they should fail in 7s. However, Caterham do like to fit a spring to pull the clutch pedal down. Or rather, I think its purpose is to keep the clutch cable under tension, to prevent it dislodging from the clutch fork or from the hole in the front of the pedal box. My theory (and I must stress it is only a theory; I haven't done enough miles to confirm it yet and it doesn't explain why some CRBs last <1k miles) is that this spring is the cause of the problem. It gives a similar effect to driving along with your foot resting on the clutch pedal ie "riding the clutch". The bearing is not designed to turn every revolution the crankshaft does over a long period of time. While there are clutches out there known as "zero clearance" clutches, which are designed so that the CRB is in constant contact with the finger things, I am led to believe these bearings are rather more substantial than the type Caterham use. The "fix" I have put in, may only work on the Caterham dry sump setup. I have removed the spring, and arranged the nuts at the pedal box end of the cable sleeve, so that they are either side of the bulkhead. This stops the sleeve from coming out of its hole. At the fork end, this is already tight enough on my car, so that the nipple on that end of the clutch cable doesn't slip out. With the split pin above, and a cable tie cunningly arranged to stop the nipple dropping down should it pop out anyway, I've done a year like that. When my foot is not on the clutch pedal, the CRB is now free to drop away from the clutch fingers. I can also put my foot under the pedal and lift it slightly, to be really sure. Haven't got up to 10k miles yet though... If the bearing in there now starts rumbling before then, it's back to the drawing board. Thinking about it some more, of course what I've done isn't so different from adding a spring to oppose the one Caterham fit. And someone has already tried this... Whatever, it has to be better than constant contact. Edited by - Nick green on 10 Dec 2002 11:28:15

No. You don't need to disconnect anything with a conditioner though. It only charges at half an amp or so. One of the advantages is that all the car security gear can continue to work. I've been using an Airflow one for 4 years now.

Demon Tweeks not got any stock ?

Just been checking with a mate of mine. One of his build helpers did the heater fitting, but he does recall packing washers being involved...

Martin, if you are talking of clear cycle wing repeaters, then I don't know. Haven't seen them, I'm afraid. Miraz and I are talking of oval clear repeaters that fit to the side bodywork.

Ah right. Perhaps its changed again then. Beginnnig to think I might be leading you up the garden path. I'll take the pics over the weekend, and zap them to you anyway. If they are of assistance, great, otherwise, I dunno. Have you spoken to Caterham at all ?

Colin, Does your heater have an actual "7" embossed in the front, or does it have the current Caterham triangle in a sort of circle logo ?

Dave, you are talking about the front indicator lenses, which are the LR parts. I have the side repeaters, to which Miraz is referring, fitted to my car.

Colin, You may possibly have to redrill the hole in the surround of the heater to make it match up with the rivnuts. It might just be a matter of squashing the foam a bit to make it line up. The operating knob thingy runs across the car and should fit through a hole in the bulkhead, such that the knob can be found in front of your right knee, or thereabouts. The 7 logo does face forwards. I can take a digi-pic or two for you, if you like ? Edited by - nick green on 15 Nov 2002 13:43:11

Fordy, if you have the plastic TB on your car, and assuming the filter is held on with a large jubilee clip, moving the clip round 90 degrees and re-tightening, might help you to reshape the TB. And don't be afraid to tighten! The TB on my car was a bit sticky initially. I tried this out and it worked for me. It seems to have worked permanently too, in that I can remove the filter altogether and the throttle butterfly moves freely now.

Colin, side repeaters have been required on cars for yonks. Officially. Many people (me included) don't like the side repeaters that Caterham supply. Bit clunky looking. When my car went for its SVA 3 years ago, I used adapted Caterham-supplied repeaters fixed to the side of the car, just below the bonnet line. The wires were sandwiched between the bonnet and the side of the car, and the indicators held on with double-sided sticky pads. It worked at the time, but a mate of mine tried the trick last year, and the tester wasn't having it at all... When I got back from the SVA test, I removed them. I have since fitted "universal" side repeaters (available from Halfords or Demon Tweeks) to the side bodywork of my car, in order to avoid just the sort of hassle you've had. Count, and others, on this list, use small repeaters fitted to the headlamp bowls. Both solutions look tidier than the Caterham-supplied jobbies. To be fair to Caterham though, they supply the same repeater for flared wing cars too, and for them, they are appropriate, as they are surface mount and so are better protected from road muck. The flared wings also obscure the side views of the bodywork and headlights more than cycle wings do. So to sum up, either find a "friendlier" MOT tester, or fit either of the types I've mentioned above. Hope that helps

Are there not left and right handed versions ?

There is a hose going from the rear-ish of the sump pan, up to the scavenge pump. You will need to remove this hose at the sump pan end. A good 1/5th of the oil will still be in the sump.

Neil, If the release bearing is going, it is more of a squeal, and it only occurs when you are putting pressure on the clutch pedal. As Mark succinctly says, what you are hearing is the normal first motion shaft idling rattle. Wait till your hear the diff noises! Edited by - nick green on 22 Oct 2002 17:19:10

JonP, My purple pump system came without the swirl tower. I have the swirl tower now (a small story), but it worked fine without. Dave J's works fine without and he's clearing 200bhp and lots of track use. Despite R500s having Apollos as well as the full DS system, I can't see it being necessary for you, given your stated usage.

AFAIK, the only real difference is the pumping capacity. The gold pump came in to address the perceived problem on SLR race cars a few years ago, that the oil wasn't being returned to the oil tank fast enough after a corner. Or something like that. It was (it would seem) then necessary to fit a much more sturdy tube from the sump to the pump, as the original job would collapse due to the degree of vacuum generated by the pump, and a swirl tower became necessary due to the amount of aeration in the oil. One bodge leads to another ? It would seem that Caterham have since decided to offer just the one pump.