Bore limit?

[Tylor]

Does anyone know if you need new piston heads for .030 and up? or is there a limit to how much you can take off before you need knew piston? Needing to know on a later 440

 

[happyjackdaddy54]

Does anyone know if you need new piston heads for .030 and up? or is there a limit to how much you can take off before you need knew piston? Needing to know on a later 440

dont understand your question

 

[Tylor]

dont understand your question

Like if I needed to bore a 440, is there a certain bores size that I would need to get new piston

 

[BB BELLA]

when the machine shop cleans up the cylinders to get them round and clean they'll measure the diameter and then bore them to the appropriate dia. for the next oversized piston available! shop should do final fit/hone when they have the pistons in hand and the manufactures piston to wall clearance spec.

 

[BeepBeepRR]

If you start at a standard bore size and you have it bored 30 over you will need to get new pistons. If you bore it 40 over you will need to get new pistons. You will also need to get new rings as well. Going from standard bore to 40 over would have way too much piston to cylinder wall gap the piston would rock in there and sound terrible. Update your pistons and rings to the new bore size.

 

[BB BELLA]

or maybe your question was how big a bore can a stock piston still be used if you were just honing to rering!I wouldn't go more than 50% over the original piston to wall clearance!
if the original was .003 I'd take a chance at .0055 but it's usually only done with power adders where the engine is going to see extreme heat/load!

 

[Tylor]

Ok sweet lol you guys knew what I was talking about. Yeah I was wondering how big the bore could be and still run stock piston. I guess I nees to take it to the machine shop and see what their opinion is on what it needs to be bored to and the figure out where to source my piston. Connecting rods should still be the same right?

 

[sam dupont]

Cylinders take on a Taper from wear, becoming a cone shape. Boring returns them to a cylinder shape. Depending on how much taper it has, it may or may not need to be bored. Less is better, as when the bore taken to the block's limits, issues like cracks or overheating can occur. Boring the least possible amount might allow another rebuild of the bores in the future.

Some say with 9 thousandths taper or less, a block is still within tolerances (at least for high nickel blocks).

 

[Red63440]

Yes, rods will be the same but you could have them checked while you are at it.

 

[Nate S]

Yes, connecting rods can stay the same. Pistons needs to match bores closely, pretty much anything beyond a hone and you need new piston and rings.

 

[Tylor]

The walls have some rust issues and I'm wanting to make it a strip engine and justbhave fun and twist the ears off of it. I hope it doesnt have to be bored to much

 

[Nate S]

The walls have some rust issues and I'm wanting to make it a strip engine and justbhave fun and twist the ears off of it. I hope it doesnt have to be bored to much

If it’s just light rust a hone might do. Big thing to look for is the ridge about 1/2” down the bore. Can you stop your fingernails on it? That’s an indicator for how out of round the cyls are.

 

[toolmanmike]

Just below the ridge is taper not out of round. THere is a lot of ring movement at the top of the bore when the combustion is the most violent and the piston is changing directions. There is always more wear at the top than at the bottom. To the op, send your block to the machine shop and have them decide what it needs. @Tylor

 

[BB BELLA]

too bad your so far away! i have a filled 440 block already clearanced for a stroker ready to run and I'll never use it!

 

[toolmanmike]

too bad your so far away! i have a filled 440 block already clearanced for a stroker ready to run and I'll never use it!

Good thing you are too far away. Unless he is building a 440 for a dragster or truck puller on alcohol or turbocharged, he probably doesn't need or could use a filled block. It sounds like he may be a newbie and even posted his question in the wrong forum.

 

[Runner 68]

 

[BB BELLA]

Good thing you are too far away. Unless he is building a 440 for a dragster or truck puller on alcohol or turbocharged, he probably doesn't need or could use a filled block. It sounds like he may be a newbie and even posted his question in the wrong forum.

well he did say he wanted a strip engine to tear the ears off it!I bought this one for the internals/heads

,now residing in Bella's block in the pic.

 

[66Satellite47]

Tylor, take the block to the machine shop, hopefully experienced in high performance builds. They will measure the cylinders and determine how much overbore is required. Go with the smallest overbore you can. New pistons are required. Piston selection can be complicated depending on piston material & size. If you want a drag motor, you want clean round cylinder bores.

 

[gkent]

Personally, I think the OP is in way over his head the moment he opens the hood. Just my opinion of course !!

 

[biomedtechguy]

twist the ears off of it.

Upgrade the hardware that holds it all together, like all the nuts, bolts, and/or studs, with ARP or the like. Weak point of stock setup.
If you twist too far, you will run slower by missing the torque curve, and possibly damage the engine.