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CSR 260 engine trouble - Advice sought


DStew

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Hello to the Caterham community!

I suppose you could say I'm arriving with a bang...

 

 

I've owned a CSR 260 for 14 blissful months, realizing a lifetime dream with these remarkable sports cars.

 

 

I blatted every weekend and tracked the vehicle regularly on CR500s, terrorizing all but the quickest slick-shod, race-prepped cars at these events in California.

 

 

Then, on track day No 13, my oil temp spiked at Turn 10, Sonoma, last lap of the last session. I immediately came into pit lane as hot engine cut. My mechanical knowledge doesn't stretch beyond changing oil, spark plugs, pads if I'm honest so I sent it to a Caterham guy Rich, in Sonoma.

 

 

initial inspection of motor revealed:

 

 

The rod bearing on #2 cylinder had failed, after compression test showed it was 20% down. It exhibited signs of overheating severely. So much so that the bearing has melted and found it's way out of the connecting rod big end. See pictures I have attached.

 

 

Screwdriver tip pointing to the melted bearing material that has centrifuged out of the big end.

 

 

Additionally the bearing has spun, wiping away the locating tangs which secure it to the connecting rod and it allowed the bearing shell to spin inside the connecting rod.

 

 

The crankshaft journal is also damaged, heavily scored.

 

 

Because of the amount of damaged bearing material and the damage to the crankshaft, I'm guessing a complete strip down and replacing all worn and damaged parts is one of few options, because unless I engine swap, I'd want all metal that has been run through the motor to be removed.

 

 

I've discussed replacing:

 

 

-Crankshaft

-Connecting rod

- Oil Pump

-Piston ring set

-Bearings

-Modine oil cooler

-Gaskets and seals

 

 

also removal the bell-tank oil reservoir from the gearbox, strip it and throughly clean it and reassemble it.

 

 

My flywheel shows signs of big overheating and the clutch disc friction material is loose and disintegrating - I don't want to damage the bell housing so looking to replace, given regular future track days.

 

 

I'm guessing I could opt for having the cylinder head rebuilt along with the bottom end to clean all the oil passageways, and a fresh valve job.

 

 

Alternatively, I could bite the bullet, trade the short motor and go on the search for a recon:new engine in the US or from some UK engine builders. Does anybody have knowledge or advice to impart on this?

 

 

I have no intention of gently blatting down country lanes after this trauma, I want to keep going down the Open Passing Group/Time trial route so any upgrade or preventative advice from experienced track-day attendees would be very welcome.

 

 

I'm in a bad spot, but I want to emerge from it stronger.

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Welcome to the forum DStew! I wish you could have joined under better circumstances.

 

I have the same Cosworth sourced motor with a slightly uprated power. The damage your engine shows would look to be caused by running low oil or the wrong oil for the temp range from your usage (should be 5W50). The Cosworth engine used by Caterham runs at very high oil temps on track. Mine tends to sit around 120 degrees on my gauge at the end of a track session with the red zone kicking in at 130. Thats ok so long as you have the right oil weight and plenty of it. There is a modine hanging off the block which works to cool the oil or at least stabilize it with the cooling system temps but there is no dedicated oil cooler although for your rebuild you may want to add one. On really hot days it will sometimes start to head beyond the 120 marker and thats when I bring it in to cool. I watch the oil temp gauge and the oil pressure gauges very carefully as that is where I can avoid a problem

 

How did you check oil levels? Did you use the dipstick or the "overfill and let the engine find its happy level by sending excess to the catch tank"? The latter is the best way as the dipstick approach can be inaccurate since the oil can pool in several locations around the engine preventing an accurate reading from the dry sump tower. Thats why you always have to measure the oil coming out of a CSR260 engine when you do an oil change so you know exactly how much to put back in. If my car is not puking oil into the catch tank then I always add more until it does. Then I know I am not under-oiling.

 

For options to fix, I have thought through my what ifs for this event, and mine are:

1) You can always give it back to Cosworth to fix. They know them and are located local to you in CA. The downside is this is not cheap.

2) Give Bruce Beachman a call (he is on this forum). He is a Caterham specialist who knows CSRs well and he has an engine upgrade package that bumps up the hp. Since the boat anchor engine has to come out and be stripped down its an ideal time to add a few more ponies at a reasonable cost point (since the engine is apart for the rebuild) and surprise your track friends when you next show up.

 

My preferred is option 2). I have not thought about swapping out the engine as quite frankly I like mine too much. It really is a superb engine. It is also a Cosworth so that counts for something.

 

Good luck with the fix.

 

mike

Edited by Croc
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One other thing. Maybe post your message to the CSR Forum.

http://csr.informe.com

 

There is not a big membership as it is only of interest to CSR owners but I think 2 guys have had to rebuild their engines and all know their cars very well. There will be a better perspective on options for rebuild as there are not many CSR owners on this forum.

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woah; great job shutting down and pulling in; another few seconds and it was going to put the rod through the block, destroying the block and probably destroying the head and everything else too. definitely want to replace that rod; crank, all bearings, rings, gasket kit, etc, at minimum. might have scored the camshaft journals too if it starved for oil. complete teardown and rebuild is in order. sorry for your troubles, but glad it wasn't a total 'kablammo!'.

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