Fuel Pump Eccentric Counterweight


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By peeeot - 11 Years Ago
I am tearing down a 1956 292 that was supposedly rebuilt (and looks like it was at least to some degree) and I have spotted a couple of items under the timing cover I have never seen before nor heard reference to.

The main item is a counterweight in between the fuel pump eccentric and the camshaft sprocket. It is keyed into the cam and obviously intended to cancel the vibration of the eccentric itself.

The other item looks a lot like a timing pointer, screwed into the block with flathead screws and located in between the cam and crank gears. It looks like stamped steel and has a finger that extends out a little over the crank gear inside the timing chain toward the right side as viewed from the front of the block. I'm not sure what the function of this piece is.

Are these simply obsolete early production pieces, or are they needed? I'm just curious.

I'm also curious as to whether the oil plates that go between the rocker shaft bases and the cylinder heads are necessary. This 292 has them but seeing them reminded me that my '57 312 does not.
By lyonroad - 11 Years Ago
Peeot, I just rebuilt my '55 292 and it has the counter balance. I seem to recall that there has been some discussion as to whether it is needed or not. I believe the other item you are referring to is an oil drip trough to direct oil onto the crank sprocket. Finally some members of the forum theorize that the presence or absence of the oil baffel plates account for the two different push rod lengths.
By The Master Cylinder - 11 Years Ago
Peeot, In regard to the counterweight, don't just remove it. It is needed as a spacer. If removed you will need a spacer from a later engine.

The other item you refer to is an oil trough to route oil to the timing chain. I believe in '57 they were removed.
By peeeot - 11 Years Ago
Thanks guys! I'm guessing that the counterweight is not needed for balance purposes as none of the later engines I've been in have had them and can't imagine why people would just throw them away. The other piece being an oil drip trough makes total sense.

I didn't realize there were two different lengths of pushrods! Was there a specific year or displacement of engine that stopped using the baffle plates? I don't believe my '57 312 had ever been rebuilt before I got inside it, though the rocker shafts had been modified with external oiler lines. Again, those plates don't seem like an item that someone would have removed and discarded.
By Ted - 11 Years Ago

The offset counter balance located behind fuel pump concentric, the timing chain oil trough, and the rocker arm baffles were phased out during the 1956 model year. This looks to have been a cost cutting measure. During the same time period,the crankshaft rod journal holes were relocated to simplify the machining operations but the crankshaft did get an oil slinger at the back to help minimize oil leakage at the rear main seal.

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These past threads also touch upon the subject.

http://forums.y-blocksforever.com/FindPost24561.aspx

http://forums.y-blocksforever.com/FindPost52460.aspx

http://forums.y-blocksforever.com/FindPost74571.aspx