Internal balanced

[Duster2022!]

I have a 1978 440 big block. I would like to convert this into an internally balanced motor. I have a forged steel crankshaft. What other components do I have a 1978 440 big block. I would like to convert this into a internally balanced motor. I have a forged steel crankshaft. What other components do I need to do this conversion? Any help?

 

[Plymouth 65]

Crankshaft and internally balanced damper. 65

 

[Lefty71]

Crankshaft and internally balanced damper. 65

And a neutral balance converter or flywheel.

 

[PROSTOCKTOM]

I have a 1978 440 big block. I would like to convert this into an internally balanced motor. I have a forged steel crankshaft. What other components do I have a 1978 440 big block. I would like to convert this into a internally balanced motor. I have a forged steel crankshaft. What other components do I need to do this conversion? Any help?

You can't just toss a crankshaft in and add a neutral balancer and call it good.

The whole assembly should be rebalanced if you're mixing and matching parts.

There are far to many variables to assume it will be correctly balanced.

Tom

 

[Lefty71]

@Tom....i never would have guessed he meant "bolt in mod" but good point lol.

 

[Duster2022!]

You can't just toss a crankshaft in and add a neutral balancer and call it good.

The whole assembly should be rebalanced if you're mixing and matching parts.

There are far to many variables to assume it will be correctly balanced.

Tom

You can't just toss a crankshaft in and add a neutral balancer and call it good.

The whole assembly should be rebalanced if you're mixing and matching parts.

There are far to many variables to assume it will be correctly balanced.

Tom

Was not thinking off just throwing in a forged crankshaft. I have done a little research and I know that everything needs to be balanced. I have also read that there may need to be some modification to the block to fit the forged crankshaft in it. I am only wanting to do this conversion because the specs on my engine build are 540 horse. Not sure that the cast crank will hold up to that I see many different thoughts on that idea.

 

[PROSTOCKTOM]

Was not thinking off just throwing in a forged crankshaft. I have done a little research and I know that everything needs to be balanced. I have also read that there may need to be some modification to the block to fit the forged crankshaft in it. I am only wanting to do this conversion because the specs on my engine build are 540 horse. Not sure that the cast crank will hold up to that I see many different thoughts on that idea.

There is no block modification required to put a forged crank in place of a cast crankshaft.

Your cast, external crankshaft will hold up fine at 540 HP.

Tom

 

[Duster2022!]

There is no block modification required to put a forged crank in place of a cast crankshaft.

Your cast, external crankshaft will hold up fine at 540 HP.

Tom

Ok thanks then no need to spend the extra money to convert

 

[PROSTOCKTOM]

You also have to be careful with the later Truck/ Some RV engines that came with the heavy 440 6-Pack style rods, as those cranks are balanced different than the normal LY rod

crankshaft engines were.

Tom

 

[PROSTOCKTOM]

Ok thanks then no need to spend the extra money to convert

No need, there are thousands of hopped up, well running engines floating around using cast, external balanced crankshafts.

Tom

 

[Duster2022!]

You also have to be careful with the later Truck/ Some RV engines that came with the heavy 440 6-Pack style rods, as those cranks are balanced different than the normal LY rod

crankshaft engines were.

Tom

I did read that, but if I’m gonna stick with the original 78 440 crankshaft that is externally balanced I guess I should probably just keep with the original rods that are with the crank and just change out the studs and bolts with a heavier and strong stronger
But if I then decided to go ahead with the forged steel crank, I have read that I want the LY rods for that set up

 

[GTX JOHN]

Tom is right on all counts.

All the late cast crank engines I have torn down
have the 6 pack rods (908 number I think).

Nothing wrong with a Cast Crank and either of the rod
designs in a street/strip kind of car.

However, for the couple hundred bucks they cost, I run
the steel cranks.

 

[PROSTOCKTOM]

I did read that, but if I’m gonna stick with the original 78 440 crankshaft that is externally balanced I guess I should probably just keep with the original rods that are with the crank and just change out the studs and bolts with a heavier and strong stronger
But if I then decided to go ahead with the forged steel crank, I have read that I want the LY rods for that set up

Unless you plan to put a big cam it that short block and spin it 6500 rpms all day you'll have no need for the studs or rod bolts.

The rod beams will break long before you'll ever have any issues with the bolts. If you really want to spend some money buy yourself a new crankshaft damper.

In my opinion you want LY rods in any engine over the big heavy 440 6- pack style rods. The LY rods will allow the engine to accelerate a lot faster (rpms per second).

Tom

 

[GTX JOHN]

If he has the stock pistons, they are about .150 down in
the hole and 8:1 compression.

Plenty of piston to valve clearance though!

 

[RustyRatRod]

Was not thinking off just throwing in a forged crankshaft. I have done a little research and I know that everything needs to be balanced. I have also read that there may need to be some modification to the block to fit the forged crankshaft in it. I am only wanting to do this conversion because the specs on my engine build are 540 horse. Not sure that the cast crank will hold up to that I see many different thoughts on that idea.

Cast crank will hold up just fine at that power level.

 

[PROSTOCKTOM]

If he has the stock pistons, they are about .150 down in
the hole and 8:1 compression.

Plenty of piston to valve clearance though!

The last one I had was in the hole .156"

If you just want to have some cheap fun deck the block .100" and buy some new pushrods. We built dozens of them like that and beat the daylights out of them.

Tom

 

[MOPARMAGA]

Tom is right on all counts.

All the late cast crank engines I have torn down
have the 6 pack rods (908 number I think).

Nothing wrong with a Cast Crank and either of the rod
designs in a street/strip kind of car.

However, for the couple hundred bucks they cost, I run
the steel cranks.

I couldn't get lucky like that all 3 of my late 440s are ly rods

 

[GTX JOHN]

We prefer the LY rods in any application that
we run stock rods.

I have never had an issue myself
with them in anything 6500RPM or less and less
than 500HP.

Back in the 60s/70s we ran them a lot in our Max
Wedge 426 Stock and Superstock cars without a failure.

 

[67Dart273]

The simple answer is, if you take ANY OEM engine that is claimed "internally balanced," and, for example, overhaul it by boring it, adding different weight replacement pistons, JUST LIKE THAT it is no longer balanced, internally or otherwise.

Whether the weight difference will result in problems with a 5-6K shifted street engine is up for grabs, depending.

This applies to ANY engine, internal or external. You start mixing parts, and they are not the same weight or "weighted for balance," then the thing simply is not...............balanced.

 

[oldkimmer]

There is no block modification required to put a forged crank in place of a cast crankshaft.

Your cast, external crankshaft will hold up fine at 540 HP.

Tom

U just need to use the older thrust bearing to match the forged crank. Kim