I was at a PCA DE at Gingerman Raceway this past weekend, where one of participants with a 2007 CS with 90K miles on clock had a bit of an "interesting" experience. First issue, which I assume was minor, was he had the notorious cloud of white smoke upon start-up for the 2nd or 3rd session of the day. I explained to him about the AOS issues, that perhaps it was a 1-time event, but if it recurred he may have to replace the AOS. Thankfully the problem did not recur. But what did happen was this: near the end of his next session coming down the front straight he heard a strange grinding noise and the oil low pressure indicator came on, so he coasted off track and killed the ignition. He sat for 10 seconds or so, and then tried to restart the engine, and a huge ball of flame came out the tail pipe. To those of us watching from the paddock area it looked like a flame thrower - a good 2 feet of flame I would guess. Needless to say he didn't try starting it any more and, was towed in. Later as the car sat in the paddock he checked the oil level and it reported it to be OK. Any idea as to what may have happened? Could the earlier issue of the white puff of smoke somehow been a factor, or was that merely coincidence? It seems to me that such a huge ball of flame would most likely be unburned gas, not oil. Could an injector have failed and started squirting gas into the cylinder at the wrong time, like on the exhaust stroke?
Just a pure WAG. Intermediate shaft packed it in. Oil pump and cams are driven off the IMS IIRC. It fails and low oil pressure. Try and start and valves are miss timed so open on ignition. Hence fireballs.
I'd be curious to know what it really is if you ever find out.
I agree with Les. The "grinding noise and low oil pressure" are not good signs. Also if the intermediate shaft eats it and the valves get out of time, it's likely that the pistons have contacted (some of) the valves.
I'd say that engine is probably done.
The ims can't get loose enough for the cams to jump timing without loudly proclaiming the failure immediately after the ball cage fails. See the pic attached. The stub in the flange has .020" clearance to the inside of the shaft n will support it while it makes bloody awful noises. The one pictured was driven 8 miles gently after this failure!!! It had 145,000 miles.
