No amount of grinding with a carbide bit would ever be able to get the passages to the size of a factory housing. You would grind through the wall long before it was larger enough.

You guys seem to believe that water flows like toothpaste out of a tube. It doesn't. It's a liquid, not a semi-liquid. The pump gives energy to the water, and the energy can be in the form of pressure or velocity (or temperature for that matter). This energy changes from pressure to velocity when the flow encounters a smaller cross-section, and changes from velocity to pressure when the cross-section increases.

But there's no free lunch. The restriction costs some energy, and a lot of that loss is from the sudden change in cross-section, both entrance and exit. So the best way to use those housings with the restrictions is to make the restrictions as large as you safely can, then make gradual transitions to the larger sizes both upstream and downstream of the restriction itself. Think venturi-like shapes.

On to heat load: If you're not using the extra horsepower your stroker is capable of, the power being generated is the same. The amount of heat rejected into the coolant COULD increase by the proportional increase in cylinder wall area, except that most of the heat comes from the head. The extra surface uncovered by the piston is at the bottom of the water jacket, and that's where temperatures are lowest. Also there's the extra friction caused by the longer stroke, meaning both longer piston travel and faster piston speeds.

It is my educated guess that the extra heat load from your stroker is no more than proportional to the displacement increase, and probably less. If you increased the compression ratio and increased thermal efficiency it may be quite a bit lower than directly proportional.

What this means is that a stroker doesn't necessarily reject a lot more heat into the coolant than the engine from which it was derived.

R.

Not true, the exterior dimensions are virtually identical therefore you could potentially grind the passages to the factory size. BUT, having done this, I can tell you that you're better off buying a housing with large passages in the first place. Its extremely difficult to get into the angles of the passages and you'd end up spending more on a selection of bits that you will on the proper housing.

I'll have to take pics and post them showing the differences.

You guys seem to believe that water flows like toothpaste out of a tube. It doesn't. It's a liquid, not a semi-liquid. The pump gives energy to the water, and the energy can be in the form of pressure or velocity (or temperature for that matter). This energy changes from pressure to velocity when the flow encounters a smaller cross-section, and changes from velocity to pressure when the cross-section increases.

But there's no free lunch. The restriction costs some energy, and a lot of that loss is from the sudden change in cross-section, both entrance and exit. So the best way to use those housings with the restrictions is to make the restrictions as large as you safely can, then make gradual transitions to the larger sizes both upstream and downstream of the restriction itself. Think venturi-like shapes.

On to heat load: If you're not using the extra horsepower your stroker is capable of, the power being generated is the same. The amount of heat rejected into the coolant COULD increase by the proportional increase in cylinder wall area, except that most of the heat comes from the head. The extra surface uncovered by the piston is at the bottom of the water jacket, and that's where temperatures are lowest. Also there's the extra friction caused by the longer stroke, meaning both longer piston travel and faster piston speeds.

It is my educated guess that the extra heat load from your stroker is no more than proportional to the displacement increase, and probably less. If you increased the compression ratio and increased thermal efficiency it may be quite a bit lower than directly proportional.

What this means is that a stroker doesn't necessarily reject a lot more heat into the coolant than the engine from which it was derived.

R.

If there wasn't a problem, why did 440 Source retool a new version with larger passages?

I'm glad you don't want me to convince you, I give up. You choose to ignore fluid dynamics, that's your loss, not mine. And don't bother to snark back, I really couldn't care less what you think.

Why did they retool? To make a better product. Simple.

Just because I said it could be made to work doesn't mean I think there isn't some optimization that should be done. And to 440Source's credit, they did.

R.

Yes, you better do that.

On the 440Source casting I had (about 5 years ago) I hogged it out enough to easily get my thumb in and never came close to breaking through the walls. The toughest part to grind is the slotted opening to the impeller and that's virtually impossible but the rest was no problem with a selection of cutters.