My interest lies in the H-226 series and M-254 engines, and redeveloping them including state-of-the-art concepts; just sent my valve train parts to Ferrea Racing Components; finally getting into the buildup; utilizing the '51 226 first, and holding on the 254 for later.
"RING GAP POSITIONING: Piston thrust. This is the direction the piston head is
being thrust or “pushed” during combustion. Ring gaps should not be positioned
on the thrust side of the piston because the thrust side of a piston head
receives a lot more pressure and heat during combustion. Should a ring gap be
located on the pressure side, the increased heat and pressure (sharp corners at
the ends of the rings heat quicker and hotter) will cause the ring gap to vary
and affect the amount of ring tension against the cylinder wall. Piston thrust
can easily be determined if we think of it as being the leading edge on the top
of the piston head during the cylinder’s combustion cycle.
Example: A flathead V8 engine crankshaft rotates clockwise when viewed from the
front of the engine. Then the thrust side on all 4 piston heads on the drivers
side of the engine will be the side of the piston head furthest from the block’s
intake manifold surface. The thrust side on all 4 piston heads on the passengers
side of the engine will be the side of the piston head closest to the block’s
intake manifold surface.
Having determined the piston thrust, the ring gaps are positioned as
follows. Starting with the bottom ring........
(1) Oil ring expanders: This goes on first and the ends of the expanders are
not critical in location. Position as you will.
(2) Oil ring:
On 3 ring pistons, the gap is to be located at the center of the
opposite side of the piston thrust.
On 4 ring pistons, position the gap of the two oil rings 45 degrees
fore and aft of the center of the opposite side of the piston thrust.
(3) Oil ring segments (2 per oil ring):
On 3 ring pistons, the gaps are to be located ½" from the oil ring
gap. One fore and one aft.
On 4 ring pistons, the gaps are to be located ½" from the their oil
expander ring gap. Each oil ring will have it’s two segment rings located fore
and aft of it’s gap. Also see the following section SEGMENTED OIL RINGS.
(4) Bottom compression ring: Gap to be located directly over the wrist pin
towards the front of the engine.
(5) Top compression ring: Gap to be located directly over the wrist pin
towards the rear of the engine."
---------------------------------------------
I copied the above quote over from http://www.flatheadv8.org/rumblest/engine.pdf
I'll be using 3 ring pistons; my guess is that the thrust side of all 6 pistons is located passenger side, any disagreements?
(1) Oil ring expanders: This goes on first and the ends of the expanders are
not critical in location. Position as you will.
(2) Oil ring:
On 3 ring pistons, the gap is to be located at the center of the
opposite side of the piston thrust.
(3) Oil ring segments (2 per oil ring):
On 3 ring pistons, the gaps are to be located ½" from the oil ring
gap. One fore and one aft.
(4) Bottom compression ring: gap to be located over the wrist pin and to the rear.
(5) Top compression ring: gap to be located over the wrist pin and to the front of the engine.
Do these guidelines make sense?
"RING GAP POSITIONING: Piston thrust. This is the direction the piston head is
being thrust or “pushed” during combustion. Ring gaps should not be positioned
on the thrust side of the piston because the thrust side of a piston head
receives a lot more pressure and heat during combustion. Should a ring gap be
located on the pressure side, the increased heat and pressure (sharp corners at
the ends of the rings heat quicker and hotter) will cause the ring gap to vary
and affect the amount of ring tension against the cylinder wall. Piston thrust
can easily be determined if we think of it as being the leading edge on the top
of the piston head during the cylinder’s combustion cycle.
Example: A flathead V8 engine crankshaft rotates clockwise when viewed from the
front of the engine. Then the thrust side on all 4 piston heads on the drivers
side of the engine will be the side of the piston head furthest from the block’s
intake manifold surface. The thrust side on all 4 piston heads on the passengers
side of the engine will be the side of the piston head closest to the block’s
intake manifold surface.
Having determined the piston thrust, the ring gaps are positioned as
follows. Starting with the bottom ring........
(1) Oil ring expanders: This goes on first and the ends of the expanders are
not critical in location. Position as you will.
(2) Oil ring:
On 3 ring pistons, the gap is to be located at the center of the
opposite side of the piston thrust.
On 4 ring pistons, position the gap of the two oil rings 45 degrees
fore and aft of the center of the opposite side of the piston thrust.
(3) Oil ring segments (2 per oil ring):
On 3 ring pistons, the gaps are to be located ½" from the oil ring
gap. One fore and one aft.
On 4 ring pistons, the gaps are to be located ½" from the their oil
expander ring gap. Each oil ring will have it’s two segment rings located fore
and aft of it’s gap. Also see the following section SEGMENTED OIL RINGS.
(4) Bottom compression ring: Gap to be located directly over the wrist pin
towards the front of the engine.
(5) Top compression ring: Gap to be located directly over the wrist pin
towards the rear of the engine."
---------------------------------------------
I copied the above quote over from http://www.flatheadv8.org/rumblest/engine.pdf
I'll be using 3 ring pistons; my guess is that the thrust side of all 6 pistons is located passenger side, any disagreements?
(1) Oil ring expanders: This goes on first and the ends of the expanders are
not critical in location. Position as you will.
(2) Oil ring:
On 3 ring pistons, the gap is to be located at the center of the
opposite side of the piston thrust.
(3) Oil ring segments (2 per oil ring):
On 3 ring pistons, the gaps are to be located ½" from the oil ring
gap. One fore and one aft.
(4) Bottom compression ring: gap to be located over the wrist pin and to the rear.
(5) Top compression ring: gap to be located over the wrist pin and to the front of the engine.
Do these guidelines make sense?