Engine: piston and rods

[Maxeffort]

Putting flat top (std) pistons on the rods for my 289.

My 1 3 5 7 pistons all look proper. Arrow facing forward, chamfer facing forward, stamped numbers facing down, clinch nut facing the drivers side and the oil squirter holes
( in the rod beam ) facing up toward the cam.
However
My 2 4 6 8 pistons all concern me. Arrow facing forward, chamfer facing rearward, stamped numbers facing down, clinch nut facing the drivers side
BUT the oil squirter holes are facing down toward the pan.

I thought all oil squirter holes were to face upward toward the cam.

Input?

[StudeRich]

I would be More concerned about "Flat Top" Pistons in a Standard 289 I assume, Non-R1 or R2 Engine?
This will result in 10.25 to 1 Compression with most ANY Standard Head except R2 or Truck and will not work with Regular 87 Oct. Fuel and barely with 92 Premium.

Stock 289 Pistons are "Deep" Dished, and Avanti Lower comp. aftermarket replacement Pistons, are Shallow Dished for about 9.0 to 9,5 to 1.

[studejohn]

Not that I can help. did these rods come with the motor or have you replaced them somewhere along the line. Sasco had a crate full of New rods, but they were all machine for one bank only. If this is the case, you’ll have to take the one side, flip them around and have them machine so the little hole in the rod is pointing the right direction Best of luck

[r1lark]

Putting flat top (std) pistons on the rods for my 289.

My 1 3 5 7 pistons all look proper. Arrow facing forward, chamfer facing forward, stamped numbers facing down, clinch nut facing the drivers side and the oil squirter holes
( in the rod beam ) facing up toward the cam.
However
My 2 4 6 8 pistons all concern me. Arrow facing forward, chamfer facing rearward, stamped numbers facing down, clinch nut facing the drivers side
BUT the oil squirter holes are facing down toward the pan.

I thought all oil squirter holes were to face upward toward the cam.

Input?

Are you positive that you have four (4) odd side rods, and four (4) even side rods? You can't go by the casting number because both the odd and even rods were machined from the same casting. If you are unsure, this picture (below) will help you verify:

[Maxeffort]

"Are you positive that you have four (4) odd side rods, and four (4) even side rods? You can't go by the casting number because both the odd and even rods were machined from the same casting. If you are unsure, this picture (below) will help you verify"

Yep, they look just like the picture.

What am I missing here?

All even ( like that #6 pictured ) then have the oil squirt hole facing down?

I know mine are inverted from the picture and the holes are on the other side, but same as picture above.

I thought all oil squirter holes were to face upward toward the cam.

Input?

[mbstude]

Putting flat top (std) pistons on the rods for my 289.

My 1 3 5 7 pistons all look proper. Arrow facing forward, chamfer facing forward, stamped numbers facing down, clinch nut facing the drivers side and the oil squirter holes
( in the rod beam ) facing up toward the cam.
However
My 2 4 6 8 pistons all concern me. Arrow facing forward, chamfer facing rearward, stamped numbers facing down, clinch nut facing the drivers side
BUT the oil squirter holes are facing down toward the pan.

I thought all oil squirter holes were to face upward toward the cam.

Input?

I think you're good to go.

We have two late 289 short blocks on stands stored in the shop with the oil pans removed. Both are low mileage engines that appear to have never been previously disassembled (standard piston bore, pal nuts on con rod bolts, etc).

They're both as you describe with your engine. Con rod ID numbers are all facing downward. Odd numbered rods have the oil hole facing up towards the camshaft, even numbered rods have the oil hole facing down towards the pan.


Number 7 rod, oil hole pointing up:




Number 8 rod, oil hole pointing down:

[Maxeffort]

Thanks mbstude. That post of yours is reassuring.

The following was a post here that added confusion to my re assembly.

This is a Quote from made by Joe Hall in a post started by Vetteson from: 12-17-2021

"Just study it a minute, and you'll figure it out. There are several ways to insure it's right. I insure the notch on each piston is facing forward, and the oil passage side of the rod big end is facing the cam, and the rod numbers are facing the bottom of the oil pan. But if you cannot figure it out, I'd say stop assembly until you do.

Also, when tightening the pinch bolt nut, if you tap on the nut, while still loose, you'll get a bit more of a rotation on the nut. The tapping helps seat the angled stud and align it with the matching pin surface. Be careful not to over tighten the nut also."

Last edited by JoeHall; 12-17-2021, 03:22 PM.

If the original post is not correct, it now serves as mis-information.

[Dwain G.]

Visualize the rods with the oil holes facing downward. Think of where those holes will be as the crankshaft turns and the piston and rod rise. They give a quick squirt of oil to the cylinder walls each revolution when the oil holes in the crank journal line up with the squirt holes.

[Maxeffort]

Visualize the rods with the oil holes facing downward. Think of where those holes will be as the crankshaft turns and the piston and rod rise. They give a quick squirt of oil to the cylinder walls each revolution when the oil holes in the crank journal line up with the squirt holes.

If that is to be the case then 4 holes (1 3 5 7 ) squirt up at the cam and not the cylinder walls.
And the 4 other holes ( 2 4 6 8 ) will provide lubrication only to cylinder walls on one side of the motor and not the cam.

So some lubed walls, some not?
Some lubed cam lobes some not?

[yeroldad]

Think about the rotation of the crank. The hole is facing down, but the crank is rotating into the 'squirt down hole'. The oil spray from the crank gets 'thrown' upwards, which is towards the cam and cylinder walls. Make sense? Put the motor together the way it came from the factory, and enjoy it.