Piston orientation

[DWinTX]

Hi folks,

I'm putting together a 318 poly stroker (349 c.i). It's the first time I've assembled a short block and I've got a couple of what are probably rookie questions.

The pistons are KB Silv-O-Lites. They are flat top with no valve reliefs. They have an arrow shaped notch on the top, and I'm wondering if that should point to the front of the engine. There's no word "Front" anywhere on the piston, and there is no mention of orientation on the instruction sheet. Since there are no valve reliefs or dome I'm not sure if it matters, but I don't know why that arrow would be there. If it does matter, do I have it oriented correctly in the first pic below?

I'm using this book:

http://www.amazon.com/How-Rebuild-Small-Block-Mopar-Engines/dp/0895861283/ref=sr_1_2?ie=UTF8&qid=1437259227&sr=8-2&keywords=how+to+rebuild+small+block+mopar

as a guide. It's for LA engines but most of the parts are the same or similar. On page 127 (if any of you have it) it has this warning:

"If the rod and piston have been correctly assembled, the oiling notch should point toward the opposite cylinder when the arrow or notch on the piston faces forward and the cap is installed in the same direction it was originally-with the numbers on the rod facing out. If you must reverse the cap to get the oiling notch in the correct direction, stop! The piston and rod assembly must be disassembled and turned around. Never reverse a cap on it's rod."

Is the "arrow or notch on the piston" he's referring to the notch I'm asking about above? I know not to reverse a cap, but I don't know what the oiling notch he's referring to is. Is it a notch that is supposed to allow oil between the sides of the rods and/or crank throws? I don't see any notches in either the new rods or the originals. Plus he's talking about the numbers on the rods facing "out". Well, there are numbers on both sides of the rods, and they both face out. Just in opposite directions. This whole statement confuses me. Can somebody translate it into newbie-speak?

 

[lewtot184]

the "notch" your seeing at the top of the piston goes toward the front of the engine.

 

[DWinTX]

So it doesn't "point" to the front, but should on the side closest to the front, right? That would be the opposite of how I have it in the pic.

 

[lewtot184]

So it doesn't "point" to the front, but should on the side closest to the front, right? That would be the opposite of how I have it in the pic.

the opposite of the top picture. the wrist pin on those pistons has an offset, not centered in the piston. correctly orientating the piston takes advantage of the offset. also look at the rod (are those chevy rods?) and see if one side has a larger chamfer. if so that goes to the outside of the bearing journal,

 

[DWinTX]

They may be Chevy rods, I can't remember. This a kit that was put together by Gary Pavlovich, who has done with some really cool stuff with polys. I'll have a look at the chamfer tomorrow. Thanks.

 

[68 HEMI GTS]

notch goes toward the front. on the rods, the locks "tangs" should be on the outside (oil pan rail), for the side of the motor they are on. if that makes sense.

 

[747mopar]

The side of the rod pictured in pic # 2 with the chamfer has to go facing away from the other rod where the radius in the crank is and the notches on the pistons go facing forward.

 

[DWinTX]

OK, I gotcha on the chamfer/crank radius. Thanks all for the help.