Piston orientation

Brendan1959

Brendan1959

Member
Can anyone tell me which way the split in the piston faces, I marked the cap but not the rod (fool).
They must have had an issue finding piston rings at the last rebuild, Have a close look.
 

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If the pistons are supposed to have the split to the cam then they must have been in the wrong way round!
 

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Brendan1959 said:
If the pistons are supposed to have the split to the cam then they must have been in the wrong way round!
Click to expand...

A few years back I had a 1925 Dodge Brothers roadster. Someone in the past had put all the piston split skirts in the wrong direction.

I was driving to work one day and...KER-BLAM-tinkity-tink-tinkle! One piston disintegrated and it rained small crumbly bits as gravity sucked them into the bowels of the engine.

Too fun.
 
They probably cut the ring grooves and added spacers to save the pistons.
In any case those pistons have been more than once around the block.
 
Dodge said:
They probably cut the ring grooves and added spacers to save the pistons.
In any case those pistons have been more than once around the block.
Click to expand...

They will not be going around the block again, I wonder how well it ran with only one compression ring.
Brendan
 
According to the service bulletins the split goes to the left side(left/right determined from drivers seat)
This makes the camshaft side the thrust side that has the solid skirt,
 
The direction of rotation sets the thrust side. When a connecting rod is going down on the power stroke in a clockwise rotating engine (as viewed from the front), the piston thrusts the opposite direction. In the case of the model A, the thrust side is toward the valve chamber. Split skirts are for piston expansion as they heat up but that spit is a weak point on the skirt so you don't want the split on the thrust side.
 
I recently took apart a motor at the museum and it had two pistons facing each way... guess they were doubling down that at least they would be half right!
 
For my smiths compresser I switched #2,3 because the thrust is on the upstroke for the 2 air compressing pistons
 
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