Colin Mill

Hi XFlow I have also heard that the extra weight is in the chassis but frankly there is little sign of extra structure in the DD car. And 25kg would account for over 100ft 15mm square-drawn tube or 7 sq m of 1.5mm ali sheet which would take a fair bit of hiding in a car of this size.

Well I'm confused - If the brake parts only account for a 1.5kg difference where does the oft quoted 25-30kg weight difference between the DD and LA cars come from?

One thing to consider - what is the effect on the unsprung weight. From some of the figures being quoted in a recent thread it was difficult not to draw the conclusion that the disks+calipers on the DeDion car were a lot heavier than the brake components on the LA car. I found the tread concerned - see:- Live axle / De dion : Pro's and cons Edited by - Colin Mill on 14 Oct 2004 17:52:51

You will need to slack off the clamp between the upper and lower column to allow the lower column to slide

Hi Bare Like I said cars had constantly engaged dynostarters in the 30's (If you want to research it I'm fairly sure the Talbot-Lago of 1937 had one) I think the main reason why this has not been considered much before (and probably won't be in the future!) is the difficulty of servicing should it fail. Conventional starter and alternator replacement is a fairly low labour activity. Having it inside the bell-housing and hidden behind the flywheel won't be helpful

Thanks, I understand that Ok now - to do what Jerry wants he would have to extend the pedal upwards to have a cable attachment point further away from the pivot. I just had a look inside the pedal box and there is a bit of headroom to do this.

Hi Peter Can I check that I understand what you did. Are you saying you extended the pedal upwards so that the cable attached further away from the pivot point?

Hi Oliver I finally found a source for the Curie points of some of the rare earth magnets. The Curie points for common magnet types are (Fahrenheit in parentheses): Neodymium Iron Boron, Curie point: 310 (590), Max Op Temp: 150 (302) Samarium Cobalt, Curie point: 750 (1382), Max Op Temp: 300 (572) Alnico, Curie point: 860 (1580), Max Op Temp: 540 (1004) Ceramic, Curie point: 460 (860), Max Op Temp: 300 (572) The max operating temperature is where the magnetism begins to degrade, but not permanently. I reckon 150C is probably OK after all the release bearing carrier melts at about 190C! At 42v of course it would only need to deliver about 35A which would make it quite straightforward. Edited by - Colin Mill on 11 Oct 2004 18:30:18

Sad to say I think much of the pedal travel before disengagement is caused by the 'give' in the release fingers of the clutch and there is not a lot you can do about reducing that. Putting a clutch pre-load spring on the release arm in the bell-housing would allow you to have some free play at the pedal end. With a spring pulling the pedal up and a stop for the pedal you could have as much free play at the top of the pedal as you like. You would need to make sure the cable can't drop down in the 'key hole' in the end of the release lever when its unloaded.

How much pre-load have you got in the cable. It could be that with little or no preload springing (which acts to press the pedal down) that you are using some of the initial pedal travel just to take up slack in the cable. John Vine is the expert on this bit!

From the temperatures some of the model electric flight motors get to I think the temperature could be OK. I guess the idea is that they use stator windings and then embed permanent magnets in the flywheel (or you would need slip-rings to feed a rotating field coil). Like a large 'outrunner' electric flight motor. The brushless DC motor technology is well established so that's not much of a challenge. The alternator side is a bit different to the norm as conventionally we regulate them by controlling the field current. With permags the charging side is going to have to cope with something like a 9:1 range of output voltages from the coils over the engine speed range so its going to need some switch-mode technology to match that up to the battery. It certainly would be easier at 42v than 12v simply because the power switching would be easier at the reduced currents you would have at 42v. Some electric flight motors produce 5kW so that's in the parish of a starter motor anyway.

Sounds a bit like the old permanently engaged dynostarters of the 1930's!

Sorry, I was not trying to be disparaging of the K series especially but like almost any modern engine you can look down on it and play 'spot the metal bit' without much success.

Sorry when you mentioned the cr@ppy plastic Rover bit I thought you had to be talking about a k series! 😬

I think it would be uncharitable for me to wish HGF on you just so you can investigate that as well

Hi Bob I think there is a float valve in the manifold where the small bore pipe going to the expansion tank connects. If you removed the float from this valve I think it would circulate water through the expansion tank. A somewhat bigger expansion tank mounted just in front of the heater (i.e so that it really was the highest point of the system) would be good I think

Hi John By current production I'm only going off how things are on my Classic kit which was delivered in June - I guess they may have revised things by now. However my conversations with the factory suggested that they were not going to rush into any changes. Thanks by the way for the article in LF. If cures for CRB and head gasket failures were found I think we would all be much happier with the cars. Regards Colin

Hi franky The clutch release lever gives a 2.55:1 mechanical advantage beteen the cable and the bearing so to get 100N of bearing preload you need 39N of tension in the cable (thats almost exactly 4kgf) After modifying my spring set-up I checked the tension by disconnecting the clutch cable and pulling it right out of the pedal box to make way for a wire attached to a spring balance. By pulling on the balance till the pedal was in the normal resting position I got the cable tension reading on the balance. regards Colin

Hi Stu Just a thought - it might be worth disconnecting the battery till you have had a chance to double check that the ECU really is fully dried out. I'm fairly sure that there is at least one unswitched feed to the ECU so you could get a bit of electrolysis going on in there if its still wet even with the ignition off. Your experience has prompted me to do something about waterproofing the ECU and MFU before I have a similar problem. Some careful use of tropicalising varnish or conformal coating on the circuit boards would not go amiss.

Hi Stu Is the tacho still dead? From the circuit diagrams it looks as if the rpm signal from the ECU exits via pin 55 of ECU plug 2 (the small one) on a white/black wire. This goes via pin 2 of the grey engine loom plug to the chassis loom. Amazingly staying white/black all the way to the tacho. If it stays dead after its all dried out I can take a look at mine to see what sort of voltages etc you should see on this wire.

Hi John Its also interesting that the current production arrangements give a preload of 27.5N which is still short of this lower range. Colin

batteredoldsupersport Take another look at stugrip's description "next to this on the bulkhead is an object that has a couple of wires and appears to be a sort of plug or switch what is it?..." Only a couple of wires - what he is looking at is the inertia switch

I think the thing you describe that looks like a switch mounted above the ECU on the bulkhead is the inertia switch. It cuts off the feed to the fuel pump in the even of a crash. It can be reset by pressing down on the rubber boot at the top.

I heard this thing about the bearing not liking spinning up fast but if it were a frequently encountered problem you would expect it to appear in bearing specs. I've never seen a max dOmega/dt quoted in any bearing catalogue and I chatted to one of our bearing factors who has never seen anything about it either. The whole bearing only weighs 167g and the speed of the bearing face at 6000rpm is about 30m/s which is not that fast. The info I got from CC also makes me question this. When I spoke to the factory about this problem the person I spoke to told me that they used to run this bearing without any preload and that they changed to using a preload on advice from the bearing manufacturer. Apparently both the non-preloaded scheme and the later pre-loaded scheme gave no problems. So the problems don't coincide with a change in the way the bearing is being used. I wonder if it has something to do with a materials change from which the self-centering carrier is made - it does not inspire much confidence especially when you see how easy it is to soften the stuff with a soldering iron.

Hi Ozzy I agree that the constant contact looks like a bad idea from a life viewpoint. Personally I would rather a bearing that only engaged when you pressed the clutch. I even contemplated gluing up the self centreing carrier and setting it up with a retraction spring in the bell housing but since its new and covered by Caterham I thought I'd go with what they wanted. If the bearing is designed right I guess it should do the time. An alternator front bearing is running quite a bit faster with a fairly heavy side load and they generally cope fine for years. Sorry I was trying to make a joke of the bearing life - I think I read of one doing only 500 miles before dying so perhaps its not a joke. I can't believe they can't get this right - a CRB is not exactly an automotive novelty item and my tin top has done near on 120K on the original clutch and CRB.