about the, clutch in while idle, question
I use to work at a speed shop where we dealt with a Japanese car that had a bad reputation for a case called "crank walk". I am not familiar with any other automobiles that suffer of this case. The best way to describe the problem is:
The crankshaft's "THRUST BEARING", not to be confused with the "THROW-OUT BEARING", wears out on the side facing the clutch. The purpose of the "THRUST BEARING" is to maintain proper tolerance on the endplay of the crank. When the "THRUST BEARING" wears out on the side facing the clutch, it makes the crank move back and forth about .0625"--which I think is the average thickness of the sides of a thrust bearing. What this causes is the crank to move those .0625 inches back and fourth. When the crank moves this much it puts an excessive side load on the pistons side facing the timing belt. The metal shavings from the aluminum of the pistons, the iron of the crank, the iron of the cylinder walls, and the bearing material, all flows through the entire motor carried by the oil system. The shavings get into your oil pump they scrape the main journals and the rod journals, all the camshafts journals ect. ect. Everything that receives oiling (basically your motor is no longer any good).
There are many rumors about why this problem happens to this Japanese car. Some say it’s the materials that the crankshaft is made of. Others blame it on poor "thrust bearing" lubrication designs.
But the most popular one, and the one I believe is the most solid reason, is that the motor does have a poor lubrication design and that there might have been a poor batch of alloys in the castings of these crankshafts. All of the owners of these cars have one habit in common when they post on the Internet. They always leave the clutch in at stop lights, idle, and ect. ect.
Why would this be the major cause for Crank Walk?
The answer is because when the clutch is disengaged, meaning over 2,600 psi (pounds per square inches) of side load on the crank shaft, you are multiplying the risks of getting crank walk because there isn’t enough oil pressure to maintain the "THRUST BEARING" against crank properly lubricated. With 2,600 psi pushing on the "THRUST BEARING" against the crank I don’t believe it would have any oil at all in between these two parts, at least not with the oil pressure available at 500-1,500 rpm which is about 90 psi. Another fact that would support my opinion is the design of this particular thrust bearing it is a flat surface on the side with only two slits on it, and the part of the crank that touches this side is also flat with no slits or perforations. The perforations within the design of other "THRUST BEARINGS" would help maintain proper lubrication under 2,600 psi of side loads, during the low oil pressure at idle.
In conclusion I just want to advise "don’t put the clutch in while you are idling the car”. And I would also advise to disconnect the plug for the clutch sensor, so that you don’t have to start the car with 2,600 psi of side load on a motor that has very little oil pressure.
( ( ( ( (((WARNING))) ) ) ) )
I DO NOT SUGGEST THAT YOU UNPLUG THE CLUTCH DISINGAGEMENT SENSOR FOR STARTING THE CAR IF YOU CANNOT UNDERSTAND THE FACT THAT YOUR CAR HAS TO BE IN NEUTRAL WHILE CRANKING.
<NOT RESPONSIBLE FOR ANY BLOWN OUT FERRARI STARTERS>
NOTHING WILL HAPPEN TO YOUR STARTER IF YOU START THE CAR IN NEUTRAL.