I could use some of the high-powered expertise from fellow members on the board to help diagnose a problem that led to my engine failing this weekend at a high performance driver's event at Sebring.
The engine is a Keith Craft 427w with an all-aluminum block and TWM fuel injection with FAST FXI software. It has less than 2,000 miles on it, 98% of which have been street miles.
Leading up to the failure, I had been experiencing what seemed like the rev limiter kicking in at strange times, usually in 1st and 3rd gears at around 4000 rpm. At other times, this symptom disappeared. This had been going on for a couple of weeks. The engine had been dynoed only four weeks earlier without any apparent problems.
On Saturday, as I was pulling through a relatively low-speed chicane, I experienced several loud backfires (and a driver behind me said he saw bursts of flames exit my exhaust) and a loss of power. I coasted to the side of the track and the engine sputtered and died. The motor will turn over with the starter depressed, but it won't start. Instead it issues forth with explosive backfire.
Interestingly, when this car was being test driven for Car & Driver magazine, a similar problem occurred. On that occasion the culprit was a gear in the distributor that broke into pieces. Upon inspection it turns out the gear was made of some non-metallic substance. Dennis Olthoff replaced it with a metal gear and we figured all was well. This means that on the only two occasions where the engine has had a load put on it, there has been a failure leading to the engine shutting down.
The car is at my brother's house, and we haven't yet started tearing into it. Some questions: Does this sound like the distributor again? Could a faulty gear, perhaps with a tooth broken off, have been responsible for the sensation that the rev limiter was kicking in (under certain torque loads, for example)? If it is the distributor, what with this having happened twice, could it be that the shaft within the distributor is overheating and causing the gear to seize and break? Or could the source of the problem be a faulty cam shaft?
In a couple of days we'll have the distributor out and check if the shaft turns, In the meantime, any thoughts in advance of trying to sort this out would be greatly appreciated. I'd be especially interested if anyone else has had a similar problem. I'm facing having to transport the car several hundred miles to Olthoff Racing unless there might be some easier-to-fix remedy.
Thanks guys!
Kim
The engine is a Keith Craft 427w with an all-aluminum block and TWM fuel injection with FAST FXI software. It has less than 2,000 miles on it, 98% of which have been street miles.
Leading up to the failure, I had been experiencing what seemed like the rev limiter kicking in at strange times, usually in 1st and 3rd gears at around 4000 rpm. At other times, this symptom disappeared. This had been going on for a couple of weeks. The engine had been dynoed only four weeks earlier without any apparent problems.
On Saturday, as I was pulling through a relatively low-speed chicane, I experienced several loud backfires (and a driver behind me said he saw bursts of flames exit my exhaust) and a loss of power. I coasted to the side of the track and the engine sputtered and died. The motor will turn over with the starter depressed, but it won't start. Instead it issues forth with explosive backfire.
Interestingly, when this car was being test driven for Car & Driver magazine, a similar problem occurred. On that occasion the culprit was a gear in the distributor that broke into pieces. Upon inspection it turns out the gear was made of some non-metallic substance. Dennis Olthoff replaced it with a metal gear and we figured all was well. This means that on the only two occasions where the engine has had a load put on it, there has been a failure leading to the engine shutting down.
The car is at my brother's house, and we haven't yet started tearing into it. Some questions: Does this sound like the distributor again? Could a faulty gear, perhaps with a tooth broken off, have been responsible for the sensation that the rev limiter was kicking in (under certain torque loads, for example)? If it is the distributor, what with this having happened twice, could it be that the shaft within the distributor is overheating and causing the gear to seize and break? Or could the source of the problem be a faulty cam shaft?
In a couple of days we'll have the distributor out and check if the shaft turns, In the meantime, any thoughts in advance of trying to sort this out would be greatly appreciated. I'd be especially interested if anyone else has had a similar problem. I'm facing having to transport the car several hundred miles to Olthoff Racing unless there might be some easier-to-fix remedy.
Thanks guys!
Kim
Last edited: