Thread: A little head porting............

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I had a customer that wanted his head ported and polished while we had it off for an o-ringing. This is a head off a 5.9 24 valve Cummins Diesel. I don't know exactly how much power gains we get from these, but it has to help flow more air. Here are some pics of the head and the work I've done to it.

Stock



Starting



Stock Exhaust side



Starting Porting Exhaust Ports

Got to help some, just smoothing things out so the air can flow in and out of the cylinders with less restriction and turbulence has got to make a difference.... Is this head going on the K30 or a different project?

Looks good, Ryan.

Take this with a grain of salt since I haven't personally run tests and comparisons, but my impression about porting and polishing is that in most cases it seems to be positive, but there are cases where it can make things worse; ie, reduce power. The fluid velocity at certain points in the head can be adversely effected by porting since larger flow area and same inlet flow results in lower fluid velocity. Scavenging is also effected by fluid velocity. I'll shut up now since I don't know much more than that.

Originally Posted by Dave Severson

Got to help some, just smoothing things out so the air can flow in and out of the cylinders with less restriction and turbulence has got to make a difference.... Is this head going on the K30 or a different project?

Dave, this head is on a 02 Dodge. It is a work truck with topper and ladder rack. We just installed an after market cam, valve springs, head studs, and billet flex plate. It has a bigger turbo, injectors, and an edge comp, and a blue chip VP44. It probably is a 425hp daily driver. The same guy has a truck set up similar except with compound turbos, ladder rack and topper but short bed 6 speed, and it is 665hp. Wouldn't you be mad if you got beat by a truck with a ladder rack and a topper?

Originally Posted by Hot Rod Nick

Looks good, Ryan.

Take this with a grain of salt since I haven't personally run tests and comparisons, but my impression about porting and polishing is that in most cases it seems to be positive, but there are cases where it can make things worse; ie, reduce power. The fluid velocity at certain points in the head can be adversely effected by porting since larger flow area and same inlet flow results in lower fluid velocity. Scavenging is also effected by fluid velocity. I'll shut up now since I don't know much more than that.

Nick, I hear what you're saying. I've been worried about unshrouding the valves before. So, I just remove material around the valve guide to improve swirl, and I smooth out the casting under the valve seats if there any. I grind enough off the walls to get rid of the casting marks, and blend it all back together and try to leave the original shape of the ports. It's hard to see in the pics. I'm thinking if I do it this way, I won't alter the port flow. (I hope) On the exhaust side I open them up to the size of the gasket and blend it back to the throat of the ports. I really wish this truck could have been dyno'd before we took it apart. Then swapped cams, dyno it again, and then swap heads, and dyno it again. That way you have an idea of what each mod is actually doing. Now, we don't know.

I know it looks excellent and from your description it's obvious you have it well thought out. It's always nice to have before and after, with as few variables as possible, but in real life that seems like a rare treat.

Yeah it is. I also would like to do one and put it on the street and be able to pull it off and expect for cracking at different periods. But that's pricey and time consuming.