Thread: Need our engine experts to help me out.

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Thanks all for the suggestions, they are all good ones. I just came home from tearing down the engine.......it is now a bare block again. I was expecting to find something very obvious when I pulled the heads or pistons, but everything looks really fine. A couple of the rod and main bearings have VERY minor scratches on them, obviously some piece of trash got under them, but nothing that would cause a knock.

Jerry, you mention the fuel pump eccentric. I had the same thought because I always have run an electric pump before, but this time decided to run a Carter mechanical pump. The outer ring of the eccentric seems sloppy and a little out of round, like it has been deformed by something. Not really badly, just a tad. But I could wiggle the outer ring on the inside one and it makes a little noise.

The biggest thing I noticed is that my cylinder walls have vertical lines going up and down them from top to bottom, but only in the very top of them and at the bottom. I envision that the stroker crank is pushing the pistons in those two planes as it rotates. The rest of all of the cylinders have the normal cross hatch pattern , but every cylinder has these scratches that cover an area about a half inch wide going from top to bottom (see my little drawing) It looks like the piston is scuffing the walls in that area. This seems extremely premature as the motor probably has 15 minutes on it tops.

Finally, I noticed that the very bottom of each cylinder is a little jagged, like there is a lip that needs smoothed there. You can run your finger around the very bottom edge of the bore and it is sharp. The skirts on the pistons go below this line, so they are passing over this sharp edge.

I am going to take my camera back to the shop now and take some pictures, hope they show the things I mention. In the mean time, thanks again guys for the help.

Here is my little drawing showing where the scuffing seems to be on each cylinder.

Don