Knock Knock is back, and then some.

[jd52cranbrook]

Thats kind of the sad part Norm, this will be the third time I've pulled this motor. I was really hoping to go to special occasion with it the 4th of July, but oh well. I go on vacation after that, hopefully it will be ready to drop in when I get back.

Plus this will give me time for a good detail job in the engine bay again.

[jd52cranbrook]

Well, my buddies talked me into going further instead of pulling the motor.

I put on the stock head, same noise.

I put in 100 octane to eliminate spark knock. Same noise.

Took a stethoscope to it, sound is defiantly out of cylinders one or two.

Their educated guess is either a wrist pin, or circumferential crack around a piston under a ring.

Either way I will pull the head, and pan once again this weekend, drop some pistons and take a good look.

They are right, it is easier then pulling the complete engine out. Time will tell if I end up having to do that anyway.

[Tim Frank]

Just to throw out one more of my oddball ideas, could you jerry rig a recording device with input from the stethoscope and a mic?

You could convert the analog recording readily to a digital format ~ wav, mp3 or whatever.

If the actual noise was available to the masses in here, you might get some even better feedback.

Rgds,

Tim

[jd52cranbrook]

Too late Tim, I have the pistons out. But I should have, the noise is quite loud upon revving the engine up to 1500 or so.

I did find a broken alternator bracket while dropping the oil pan. But I could not see where it could hit anywhere to cause the noise. Just the same it's dis concerning, as the bracket is right next to number one cylinder, where the noise seems to be from.

The rod bearings show too much wear to me for just being put in. They show copper, with some grooves in them. Something is going on for sure. I am taking the complete pistons to the builder tomorrow, and he will come out again to look at the crank this week.

If we don't find anything out of the ordinary, I may pull the front timing cover to peek inside. If nothing obvious then I guess I will pull the motor and have it gone through.

In the meantime I will make up another bracket for the alternator.

Man,,,,,,,,,,,,,,,,, I hope that was not the sound all along,,,,,,