Re: Too much oil in exhaust water 1984 chrysler 115hp
Late Chrysler and Force engines did have the ring locating pinns staggered 180 degrees apart. Wiseco aftermarket pistons are the same. Performancewise there really isn't much difference if the rings are gapped to specifications. However, the newer Force pistons with semi-keystone top rings do tend to break the top ring more often. There were two different types: One semi-keystone with a top land and one without a top land. The top of the ring was flush with the top of the piston on the one without a land. There is just not enough support for that ring. (The theory is that combustion pressure gets behind the ring, pushing it against the cylinder wall, sealing better)
If you look WAY back into the 1960s, Chrysler engines had three ring pistons with, at first, all three rings twice as thick as your current rings, Then they went to three rings the thickness of your current ones, and finally they went to a two ring piston. Getting rid of the third ring increased performance. The reduced drag more than offset any blowby that two rings might have.
The reason the connecting rods are so short and the wrist pin holes are so far down in the piston is because originally, pistons were designed with three rings AND caged needle bearings for the wrist pin in the piston itself. This took up a lot of room at the top of the piston. Given the state of American manufacturers in general, as ring and bearing design improved, they simply did not want to spend money to change tooling so rods and wrist pin placement remained the same. American auto makers did the same: They had a gullible consumer base that would buy anything they made, so why change--even if for the better? One thing we can thank the Japanese for is waking up American manufacturers to produce better quality goods.
NOTE that on late model Force engines Mercury DID change wrist pin placement and lengthened connecting rods BUT they also increased crankpin diameter so these pistons and rods can not be retrofit into early engines unless you can find oversized big end rollers.
No doubt that longer rods are better: They produce less side thrust on the piston and because of the various running angles of the rod the piston spends less time at top dead center. Timing advance can be reduced slightly and more horsepower is made.
