Engine Piston Placement 440

[KL_Mopar_GTX]

Started the rebuild on my 440 20 years ago and circumstances didn't allow me to continue with it until recently. Looks like I put 3 of the pistons in the wrong cylinder holes. #7 is in the #8 hole. #8 is in the 5 hole. And 5 is in the 7 hole. The assembly rotates fine with a breaker bar, but I'm wondering if this will cause issues or not. Thanks

 

[Jerry Hall]

What kind of rebuild is it? Machine Shop work? If you took it apart and were going to just do an at home rebuild rings, inserts, and mains. I would make sure everything went back as it was, because it ran like that until a rebuild was deemed necessary. If it went to the machine shop and things were changed and balanced yes, definitely put the pistons in the correct holes. So I guess just sitting here and rambling with my statements, yes correct it. My opinion.

 

[R413]

Are these new pistons and a fresh bore? The pistons are not all the same size, by a few thousandths of an inch. The machine shop makes the bores the correct size for each piston so you will have the correct piston to cylinder wall clearance. To tight is a recipe for disaster.

Black Death, too much friction, scored skirts, Running hot, low power, etc,etc.

They should go in the correct hole.
Do it right, or it’s wrong.

 

[Dipstick]

The pistons are not all the same size, by a few thousandths of an inch.

Of course, you mean a few ten thousandths.

 

[33 IMP]

Kinda depends on where the valve reliefs are, or even if there are any. If you have an intake valve over an exhaust relief, it's time to change em.

 

[Kern Dog]

Equally important is the chamfer of the big ends of the rods. The beveled edges go toward the crank pin, the flat edges meet with another rod. It is the oil squirting out of the rods that oils the camshaft!

 

[KL_Mopar_GTX]

The engine is not a rebore. It is just being freshened up from setting. 7 and 8 are new pistons. About 20 years ago I honed the cylinders, put new rings in it, and put new bearings in it. Sounds like I will be moving those pistons to the correct location. Thanks for the help!

 

[69Bee]

Equally important is the chamfer of the big ends of the rods. The beveled edges go toward the crank pin, the flat edges meet with another rod. It is the oil squirting out of the rods that oils the camshaft!

Thank you, finally someone hits on the MOST important thing. Rod chamfer needs to be correct so it will not bind up. The only cavate to that is if it is an aftermarket crank and rods with narrow bearings, it will usually still work due to the generous clearances. The oil squirt hole is of no consequence anymore as you will be hard pressed to find replacement bearings with the "V" notches in them anyway. On stock rods, bearing tangs out, 1-3-5-7 on the DR side, and 2-4-6-8 on the pass side. Piston notch/dot/"F" should face front always.

 

[66Satellite47]

If they are factory pistons, they are different side to side, pins are offset.

 

[wyrmrider]

Take before and after pics if there are valve reliefs
If they are down the hole flat tops with no valve reliefs then does not matter much
but the rod orientation does

 

[451Mopar]

Thank you, finally someone hits on the MOST important thing. Rod chamfer needs to be correct so it will not bind up. The only cavate to that is if it is an aftermarket crank and rods with narrow bearings, it will usually still work due to the generous clearances. The oil squirt hole is of no consequence anymore as you will be hard pressed to find replacement bearings with the "V" notches in them anyway. On stock rods, bearing tangs out, 1-3-5-7 on the DR side, and 2-4-6-8 on the pass side. Piston notch/dot/"F" should face front always.

good points! a stock crank is undercut at the counter weights, so no chamfer to hang up on. Only thing that means, is the engine will spin without binding even though the piston and rod orentation is wrong.

 

[KL_Mopar_GTX]

Heard loud and clear...swapping the pistons to their original cylinders. Everything came out and went in just as they were ment to, engine rotates flawlessly thanks everyone for the great advice.

 

[BSB67]

....a stock crank is undercut at the counter weights, so no chamfer to hang up on. Only thing that means, is the engine will spin without binding even though the piston and rod orentation is wrong.

This. There is no radius so no binding.

Sounds like the OP made a mistake during assembly. Take 15 minutes and put them in the right holes.