The Ford Barn

The Ford Barn (https://www.fordbarn.com/forum/index.php)
-   Model A (1928-31) (https://www.fordbarn.com/forum/forumdisplay.php?f=3)
-   -   Piston orientation (https://www.fordbarn.com/forum/showthread.php?t=285362)

Brendan1959 08-10-2020 01:47 AM

Piston orientation
 

1 Attachment(s)
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.

dave in australia 08-10-2020 02:00 AM

Re: Piston orientation
 

Some, but not all, pistons are marked on the top which way is forward.

Richard in Anaheim CA 08-10-2020 02:24 AM

Re: Piston orientation
 

1. Flat part up

2. Split toward cam

Brendan1959 08-10-2020 04:15 AM

Re: Piston orientation
 

Thanks
No stamps on the top
split to cam will hep
Brendan

katy 08-10-2020 10:15 AM

Re: Piston orientation
 

The split goes opposite to the thrust side.

Bob C 08-10-2020 11:06 AM

Re: Piston orientation
 

I've seen that before where they run three rings on four groove pistons.

Brendan1959 08-10-2020 06:29 PM

Re: Piston orientation
 

I count 11 piston rings

Brendan1959 08-10-2020 08:40 PM

Re: Piston orientation
 

1 Attachment(s)
If the pistons are supposed to have the split to the cam then they must have been in the wrong way round!

1930-Pickup 08-10-2020 11:54 PM

Re: Piston orientation
 

Quote:

Originally Posted by Brendan1959 (Post 1918870)
If the pistons are supposed to have the split to the cam then they must have been in the wrong way round!

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.

Dodge 08-11-2020 01:33 AM

Re: Piston orientation
 

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.

Brendan1959 08-11-2020 01:57 AM

Re: Piston orientation
 

Quote:

Originally Posted by Dodge (Post 1918933)
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.

They will not be going around the block again, I wonder how well it ran with only one compression ring.
Brendan

Kurt in NJ 08-12-2020 08:18 AM

Re: Piston orientation
 

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,

rotorwrench 08-12-2020 09:01 AM

Re: Piston orientation
 

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.

abachman3 08-12-2020 10:45 AM

Re: Piston orientation
 

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!

Kurt in NJ 08-12-2020 02:37 PM

Re: Piston orientation
 

For my smiths compresser I switched #2,3 because the thrust is on the upstroke for the 2 air compressing pistons


All times are GMT -5. The time now is 06:59 AM.

Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2024, vBulletin Solutions Inc.