INTERFERENCE ENGINE BEING OBSTRUCTED BY SOMETHING. WE RE-TIMED IT AND IT'S STILL NOT SPINNING FREELY
1997 Ford Probe
August, 25, 2011 AT 8:35 PM
97 Ford probe 4 cylinder. This car sat for a couple weeks before we tried to drive it again. Me and my wife are ex mechanics ourselves, but this one has us stumped. We know that an interference engine won't crank all the way over if the timing is off. My wife tried to start the car the other day, and she said it was cranking and just before it started, it felt really different like it lost all compression so she immediately stopped cranking. We thought the timing belt loosened up or the tensioner broke as these have a bulletin on bad tensioners that are supposed to be fixed under recall. We called the dealership and they said it had already been done on this car, so we re-timed it, and tried to hand crank it with a ratchet on the crank pulley, and it still only freely moves until a certain spot on number 3 and 4 pistons when they are TDC and it won't budge after that unless you go backwards to the previous piston in which it gets stuck again. So that's where we are now and we are stumped. We are trying to borrow a bore scope from somewhere so we can look at the valves, but haven't had any luck with that yet either. We really don't wanna take the head off if we don't have to, so any info or knowledge would be greatly appreciated! Thanks! -Ozzy
An Interfernece engine actually will keep running if timing belt/chain/tensioer fails and will cause engine damage. Non-Inteference motors are set up to shut down to avoid damage usually by the distributor and crank position snesor beign out of phase.
You have an actual mechanical contac when turning by hand that will be worse if oyu try to run it and the vsvle stretes.
There must be some damage from the first timiing chaing and tensioner failure.
I am guessing the valves are bent and need replacement.
Lucky you have a bore-scope you can use, they are very helpful.
Let me know how things go.
August, 25, 2011 AT 10:58 PM
I'VE BEEN THINKING ABOUT THIS ONE TOO
I HAD THE THOUGHT OF MAYBE PULLING THE PLUGS AND CHECKING FOR WATER IN A CYLINDER POSSIBLY HYDRAULICALLY LOCKING IT UP. POSSIBLE HEAD GASKET LEAK? WE SORTA EXPERIENCED THAT, WHEN WE GOT A BIT TOO FAR OUT IN A POND.
JUST A THOUGHT
June, 14, 2012 AT 11:01 AM
Would like just to clarify that non interference engine doesn't use the cranckshaft sensor, but they are mechanically designed as the valves dont comme all the way down till hit pistons when they are on TDC (may be 1mm of space), impossible to stop the crankshaft movement at less than 1/10 of second, it's phisics laws.