Hi All

I have a 1985 7.4L 340HP right hand motor in my Bertram 35 (the port motor) which has a grinding noise akin to a stuffed bearing on an alternator. Upon removing the timing cover, I could see that the cam gear was grinding on the cover. This would indicate that the thrust plate is worn and there is too much end float. I am not surprised as the motor was designed for chain and sprocket which would not have any real thrust on this plate, whereas the helical gears will generate a constant forward thrust on the camshaft.

I don't want to have to strip the entire top of the engine down to remove the camshaft and I am concerned that I could damage the gear pressing it off the camshaft when the gears are no longer available.

What I am proposing to do is have a button made that will sit on the end of the camshaft to rub on the timing cover. The button will simply plug into the hole in the centre of the camshaft and have a mushroom head. The thrust won't be huge and the current thrust plate would never have lasted this long if it was. That combined with a speed that will never realistically exceed 2000rpm makes me think this will be a good, long lasting fix.

I am wondering if anyone has done this before? If so, what material did you use? I am thinking some hard plastic material similar to bakelite. Something that will not wear much in an oily environment. The motor is old now and runs sweet, but it is getting towards the end of its life (at least to a rebuild) with 1600 hours. This modification should last a few years and I believe it will be a better solution than the original thrust plate.

I hope someone out there has done this. I suspect most people just handover a could of $K to their mechanic and have the thrust plate replaced.

Regards

Mark Dutton.