KNOT-RIGHT

Counter rotation engine.
Is the oil pump the same in a standard rotation engine?

Please respond
Gerry

Gary Anderson

In counterrotating engines, only the crank turns backwards. Gear driven rather than chain driven cam. So the oil pumps and distributor turn the same direction in both applications.
Gary

KNOT-RIGHT

Thanks for the response.
In this perticular application. The 139741 cam is custom
ground to spin "opposite" Compared to normal rot) with the crank. A timing chain is used so it actualy does spin with the crank.

The more I think about it the more confused I get.


The distributer gear is ground different to keep the distributer and oil pump spinning the same way.
The firing order on this custom grind is opposite of chevy. 12756348

From my understanding there were two ways of counter
rotation. Custom Ground cam as above.
or a gear drive two spin the Camshaft the original way.


Thanks again.
Gerry

Crazyhorse

All reverse rotation engines have that firing order, and you are correct in saying that with a belt drive, timing chain, or three-gear(idler) the cam has to be ground specifically for that application so that the cam and crank both turn clockwise (as viewed from behind the engine). In this case the cam gear and distributor gear are ground to turn the distributor and oil pump in the standard direction.
You are also correct in saying that the two-gear timing setup used in stock Merc counter-rotating engines spins the cam in the standard rotation while the crank spins in the opposite direction, allowing a standard distributor gear to be used.
Now that we've really got you confused,,,,,,,,
You just need to remember if you told the cam grinder which setup you intend to use; the belt/timing chain/three-gear setup, or the two-gear setup. have fun.