SpeedPete Posted May 13, 2019 Share Posted May 13, 2019 After an intense track day, I drove my Caterham another 45 Minutes home without noticing anything particular. When I started it 3 days later it sounded as if the muffler was filled with lots of stones rattling in it. 5 Minutes later it stalled and the crank was blocked. The mechanic in the workshop told me today that all the pistons have marks from hitting valves. On one cylinder the valves are bent, causing the blocked engine.I would understand happening this during track racing, but not after 3 days parking. Any ideas for a possible cause, I should check?And is there something you'd recommend to modify / upgrade to take advantage of the engine being disassembled anyway?The engine is standard 2010 factory spec. Link to comment Share on other sites More sharing options...
SM25T Posted May 13, 2019 Share Posted May 13, 2019 Has the belt jumped a tooth or two, or lost teeth? Link to comment Share on other sites More sharing options...
SpeedPete Posted May 13, 2019 Author Share Posted May 13, 2019 No, it didn't Link to comment Share on other sites More sharing options...
ChrisC Posted May 13, 2019 Share Posted May 13, 2019 The front pulley bolt holds the timing chain drive and oil pump / dry sump drive, all are friction fit. That bolt comes loose and valves will meet pistons. Link to comment Share on other sites More sharing options...
Jim 123 Posted May 13, 2019 Share Posted May 13, 2019 Valves sticking open or slow to reseat. Interesting that all valves appear to have been affected. Any clues when you were on track from water temp, oil pressure, or oil consumption. Link to comment Share on other sites More sharing options...
rj Posted May 13, 2019 Share Posted May 13, 2019 Sorry to hear about your misfortune.Sounds like a hydraulic lifter that has pumped itself up.I know this can happen to some Fords if you cold start them many times without letting them warm up. Link to comment Share on other sites More sharing options...
p.mole1 Posted May 13, 2019 Share Posted May 13, 2019 Oh dear that's not good. I think the crank and cam wheels are all a friction fit ie no woodruff keys. I think the there are friction washers incrusted in diamonds! that hold the pulley's in place. If any of these bolts loosen the cam timing can shift. Best speak to a ford expert. Link to comment Share on other sites More sharing options...
ChrisC Posted May 13, 2019 Share Posted May 13, 2019 No woodruff keys or hydraulic lifters on Duratec’s (or Sigmas). Friction fit for the cam pulleys as well as the crank drive. Have you had any work done recently? Link to comment Share on other sites More sharing options...
7 wonders of the world Posted May 13, 2019 Share Posted May 13, 2019 Diamond washers on the crank and cams are a proven Cosworth design which give no problem if fitted correctly, Duratec are solid lifter and shim - With long periods of non use the valves on many engine can stick with certain fuels but they stick just off the seat nd the Duratec clears the pistons on cranking SWMBO MX has done this on supermarket fuel On possible area is the timing chain tensioner that under lift off at high rpm can break the teeth of the ratchet meaning the tensioner goes back inside, this would be most noticeable on start up and the oil pressure would have fallen away thus meaning chain tension was lost.There is a simple mod to the tensioner to prevent this happening.Front cover off and look for signs of DIY dentistry .... Link to comment Share on other sites More sharing options...
SpeedPete Posted May 13, 2019 Author Share Posted May 13, 2019 The only thing touched shortly before was the TPS sensor and air bypass valve which aren't typical suspects. On the track, oil temperature and pressure has always been within usual ranges. I'm not so sure about oil level, though. I'm not yet much familiar with measuring the level in the dry sump system without having a dipstick. How would a loose front pully bolt look like? Maybe my mechanic missed this. I'll ask him to check that tomorrow. He suggested to high revs caused by changing to a gear to low. That would have led to a piston moving faster than the valve, as forces of inertia were higher than valve spring force. Link to comment Share on other sites More sharing options...
rj Posted May 13, 2019 Share Posted May 13, 2019 That wouldn't happen at start up. You will not be in doubt when you have contact and destroy the engine. Been there... Link to comment Share on other sites More sharing options...
SpeedPete Posted May 13, 2019 Author Share Posted May 13, 2019 I forgot to mention that just before stall/block, I'd noticed some smoke coming from where the starter is. After disassembly it seemed like it was the source of the smoke, but the starter motor and gears looked fine to me.7 wonders, I'm not sure if I understand correctly what you're saying regarding startup behavior. The engine was always running pretty rough, especially when cold or at low revs. Indeed, the last startup just before this catastrophe required a very long cranking. Link to comment Share on other sites More sharing options...
7 wonders of the world Posted May 13, 2019 Share Posted May 13, 2019 with the engine running the chain tension is maintianed by oil pressure fed to the tensioner, the internal ratchet within the tensioner is there to maintain chain tension when the engine is turned off, if the teeth have sheared the tension will not be maintained. therefore on initial start up the chain will not be tensioned.Did you check the cam timing prior to stripping..? Link to comment Share on other sites More sharing options...
7 wonders of the world Posted May 30, 2019 Share Posted May 30, 2019 Did you get to the bottom of your problems...... Link to comment Share on other sites More sharing options...
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