Well where has the time gone? I can't believe I am responding to my own post from 14.5 years ago. That must be a record!
As mentioned in the orginal post, my plan was to pull the motor out, investigate etc... Since the post I have hardly driven the old girl (once a year if I am lucky). It has finally got to me and this weekend - out with the motor. Before doing so I was able to isolate what cylinder (or I thought so) it was. I took her for a drive and the knock was still there particularly under load. Coasting was ok. I then disconnected number 6 spark lead ie: to take the trust load off that cylinder and low and behold no noise what so ever. Out with the motor and before I had started to dismantle the motor, once the gearbox was removed, the problem was quite evident.
The flywheen bolts had clear evidence that somethings was making contact with them on the outer edge. On close examination on the back of the clutch (or is it the front) plate there was clear wear with the springs which were making contact with bolts. One of the springs had no wear but there was no tension in this spring as well.
I have read up on the newer clutch assemblies and the contact that they can make with the bell housing. This assembly is the old type. Bugger, I think the clutch plate was installed back to front. Interestingly when the knock was first evident almost 30 years ago, I pulled the gearbox out and checked for loose flywheel bolts as this can be a cause of the noise. Not that my memory serves me well, but I can't remember seeing any evidence of contact.
Still suspecting a gudgeon pin may still be in play, I was eager to check No.6 out. Not knowing exactly what I was looking for there seemed to be no wear in the pin and small end bush (the gudgeons were done on the last repair and there has been very few miles travelled). I did compare to others and there seemed to be no difference. I am glad I have pulled her down as there were many broken rings.
I measured up the bores and pistons to confirm what I thought was a 3 inch bore only to find that it is a 3.0625 bore. I always thought it was 3 inch. While it is 30 years since we rebuilt the motor I was sure we purchased 3 inch rings - maybe, maybe not. I measured one of the good rings in the bore and there was a significant gap between the ends - 60th plus so my thoughts may be confirmed. The motor is a replacement motor at some point as it has a Vic Police Engine Number. The second one I have, with the other being in my ute.
I was astounded by the condition of the Main and Big End Bearings. They were / are in unbelievable condition and could be reused again I am sure - Not that I am going to do so.
The final thing I did find was that there is a little movement in the harmonic balancer which I mentioned in the original post. I will replace that with a good original that I have. Is there anyone out there that refurbishes original balancers by popping the revitts and replacing the rubber???. I far sooner invest in this rather than the others that are out there.
I am excited as I work to put the old girl back together. Thirty years of wondering may be coming to an end.
Cheers
Rod
