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CSR 260 Clutch fail / Inside of a CSR dry sump bellhousing


Croc

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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.   

Resolution

With 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.

CIMG1199_edited-1.JPG.11d34ee95560641b778627d9a0541550.JPG

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:

IMG_5798.thumb.jpg.f40c50b258a2fb4266b0f968bd8b45cc.jpg

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:

IMG_5797.thumb.jpg.5aa724644cc178f0446cf0f738fd3c62.jpg

While I did not have to, I removed the blanking plate to see the oil tank interior:

IMG_5799.thumb.jpg.7044743e027a3ce922c69cafc2fadcef.jpg

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.

Cheers

mike

 

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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  

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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...

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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.       

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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/

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