Croc Posted September 22, 2020 Share Posted September 22, 2020 Problem is diagnosed and solved but posting for the next CSR owner who has this problem.Symptoms I have clutch action when the engine is cool. As it gets hot during a track session, I lose the ability to select gears via the clutch - at the half hour mark I have lost either 4 or 5 gears out of my 6. I can still rev match and get all gears so its not the gear box. Let it all cool off and the clutch comes back and all works normally again. Clearly a heat soak related issue. ResolutionWith kind thanks to Malcolm (MadMalc), he suggested it might be the clutch pipe unions onto the bellhousing being loose and the system requiring a bleed. Sadly it was not but it is an excellent suggestion for potentially saving to have to pull the engine.So I pulled the engine. For those not used to the CSR, the original build photo below, shows the dry sump tower on top of the oil tank integrated within the bellhousing.Clutch fluid fittings are the yellow and red plastic caps on the upper side of the bellhousing.Pulling the gearbox apart from the bellhousing shows:The dry sump tower is the extension to right. The black blanking plate is the side of the integrated oil tank. The metal ring is a concentric release. Flywheel side looks like this:While I did not have to, I removed the blanking plate to see the oil tank interior:Oil pick up is left curved tube on the floor of the tank. Oil return is the longer curved pipe on right heading up to tower. Clutch pipes to concentric release can be seen. While apart, I check that clutch pipe unions are tight inside this tank.My failure was the little rubber seals that reside within the concentric release. As the oil heated up, the seals were failing plus some air was present in the system. Once it cooled off the seal restored itself. Ultimately, it would have failed completely no matter what temperature the oil tank was at. Flywheel is off to get a smoothing and then all back together. Hope this saves someone some time in the future.Cheersmike Link to comment Share on other sites More sharing options...
David Brown Posted September 22, 2020 Share Posted September 22, 2020 Thanks for the info, presume you're replacing the o rings on the pipe stubs between the engine and bellhousing. I've still to source them but believe they are 17mm bore x 2mm dia, have you a source. Link to comment Share on other sites More sharing options...
Leadership Team Shortshift Posted September 22, 2020 Leadership Team Share Posted September 22, 2020 Thanks Mike - that's a thread and images to print off and keep somewhere safe!James Link to comment Share on other sites More sharing options...
Croc Posted September 22, 2020 Author Share Posted September 22, 2020 Thanks for the info, presume you're replacing the o rings on the pipe stubs between the engine and bellhousing. I've still to source them but believe they are 17mm bore x 2mm dia, have you a source.Hi David - while they were not the source of my failure, I will replace the O rings on the oil pipes between bellhousing and engine. Your dimensions close to what came out of mine. Caterham and Redline do not have them in stock. I have access to an infinite supply of rubber O rings at a local US supplier so will next hunt around opportunistically in their catalog. Most unknown pieces are usually off a Ford Mustang Fox body for some reason. Once I find something I will post on this thread for you in case you are still looking. Cheers mike Link to comment Share on other sites More sharing options...
David Brown Posted September 22, 2020 Share Posted September 22, 2020 Thanks Mike, you may struggle to get metric :). Im sure I will find a local stockist without too much trouble. Link to comment Share on other sites More sharing options...
David aka Blue7 Posted September 22, 2020 Share Posted September 22, 2020 I think it was that O ring seal that was faulty on my first CSR and it had to go back to Cosworth via Caterham for replacement. So I assume Cosworth may carry a stock of the O rings but if it is any help, James Gibson of Caterham, referred to them as "Titan parts" Link to comment Share on other sites More sharing options...
Doctor Posted September 22, 2020 Share Posted September 22, 2020 The dry sump oil tank in the bell housing on CSR in known to cause the clutch to overheat on the track. Race CSR cars had the swirl tower and the oil tank blanked off and a separate oil tank present 620 style - instead of the passenger footwell. Link to comment Share on other sites More sharing options...
elie boone Posted September 23, 2020 Share Posted September 23, 2020 If the oil reservoir in the bell housing overheats the clutch wouldn't it be easily overcome by drilling a number of say 40mm holes and glue some mesh behind in the bell housing to let the hot air out ? Link to comment Share on other sites More sharing options...
ECR Posted September 23, 2020 Share Posted September 23, 2020 Constant failures with the annular clutch piston on my VX presumably due to heat. I ditched it in the end and went cable operated. The annular design is neat and no doubt suitable for road use but seems marginal in heavy track use. A nice write up and useful photos croc... Link to comment Share on other sites More sharing options...
Wrightpayne Posted September 23, 2020 Share Posted September 23, 2020 . Link to comment Share on other sites More sharing options...
Croc Posted September 23, 2020 Author Share Posted September 23, 2020 Constant failures with the annular clutch piston on my VX presumably due to heat. I ditched it in the end and went cable operated. The annular design is neat and no doubt suitable for road use but seems marginal in heavy track use. A nice write up and useful photos croc...Hi Roger - I assume this is a motorsports design where frequent pulling of the motor to replace a race clutch or make clutch adjustments is expected compared with the CSR as a road car? In a road environment, I would expect the heat issue would not be a factor like it is on track? All the race CSRs have gone for a separate dry sump tank plus added oil coolers and this concentric slave seal is less of a maintenance factor. The lesson I draw from all of this is the CSR is less suitable for regular/heavy track usage in its standard road guise than say a regular de Dion chassis car, unless the CSR is modified to address its extremely high oil temperatures which create various problems around the car in heavy track usage. Phenomenally competent car to drive on track though which is why I love it. Link to comment Share on other sites More sharing options...
Doctor Posted September 23, 2020 Share Posted September 23, 2020 Hi Croc, funny you should mension the oil temps - I tracked CSR regularly for four years and my oil temps have never been a problem. I had 2.0 Duratec engine from R500 Duratec Superlight mated to CSR 260 cooling and lubrication system with Caterham 6 speed box and Stack dash. the car had a massive CSR radiator tilted forward with the plastic lip funneling the air to the top nose cone cut out, no oil cooler and modine oil/coolant heat exchanger in oil filter housing. Despite full throttle at Silverstone or Brands the oil temp has very rarely gone over 100'C. Immediately down to about 94-95'C on the cool down lap. High oil temp has never been an issue. I've used 10W-60 oil viscosity.Changed to 620R SV now, my CSR is up for sale here:https://www.sevensandclassics.com/showroom/caterham-csr-superlight-500/ Link to comment Share on other sites More sharing options...
Ian B Posted September 23, 2020 Share Posted September 23, 2020 and that is a phenomenal car for sale Link to comment Share on other sites More sharing options...
Doctor Posted September 24, 2020 Share Posted September 24, 2020 I know about another one:https://www.lotus7.club/forum/market-place/csr-260-rather-nice-and-only-8700-miles-£37250I love the interior! Link to comment Share on other sites More sharing options...
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