diesel head porting question

[rebelrouser]

I got a guy who wants me to port the head on his Ford 5000 diesel tractor. he pulls it at the local fairs.
256 CID, the rules say he has to run governed RPM and they have a speed limit on the track as well. Specs say 67HP @ 2,100 rpm

My question is that it has a large step in the intake runner similar to a Chevy Vortec head. I am sure this is to swirl air past the injector in the combustion chamber. My question is this step covers at least 1/2 the port on the short side radius. I know I have to leave a lot of it top maintain the swirl and my bench does not have a swirl meter. Just stock it flows 204cfm @ .5 lift, valve lift looks like it is around .460 on the intake
exhaust flows 157 cfm on my bench stock now.
Any ideas on how to treat the step in the intake port? I do have a velocity probe on my bench.
It has 30 degree intake valves and 45 degree exhaust seats.

I think the main thing I can do for him is work on the intake manifold it kills 20 cfm when you bolt it on. It has a turbo and the exhaust loses no flow bolted on.

[mt-engines]

Do the basic work, and let the turbo eat

[Carnut1]

Similar design to Chevy tbi high helix port, Early vortec. Do not remove ramp, angle the end of the ramp that blocks ssr. Air speeds will dictate how much. Fix ramp shape and increase bowl area.
This design uses the full perifery of the valve so deshroud as evenly as you can. Do not open throat too much. This design uses less than 30 degrees spark advance. Thanks, Charlie

[mag2555]

I would first get that intake manifold to as closely as possible match the head cfm numbers.

[BLSTIC]

Not related to porting, but to general airflow...

I've seen some absolutely disgusting inlet manifolds on diesels. Simply increasing the plenum volume on some increases power, leans mixtures and evens out egt. Damn mitred joins on a manifold that has to fit under a bus but gets used in SUVs from manufacturing convenience.

Exhaust manifolds, too, often don't follow any flow principles I've heard of but on turbo ones at least they are compact and there's not much volume between the valve and turbine. If it's a single scroll manifold it almost certainly has 180 degree blowdown interference at that rpm, but if it's low overlap that might not be too much of a problem. EngMod4t or Lotus or similar can answer that question. Manifold design can mitigate that, twin scroll can eliminate it. And improved manifold design can also deliver more energy to the turbine, lowering backpressure and sharpening boost response at the same time.

What turbo is it running? There could be huge benefits there too if it's old tech or adapted from the wrong application

Got pics of the manifolds? I've gone and got myself curious now.

[rebelrouser]

I got the head with manifolds bolted on to 200cfm 28 inches .5 lift and exhaust to 177cfm at .5 lift.

The exhaust manifold he gave me was new and casting was pretty rough inside. With just a little cleanup the exhaust actually flows better with the exhaust manifold bolted on. The intake still kills 10 to 20 cfm depending on lift, but I think the main issues are first the small inlet to the manifold and the runners nowhere were close to the opening of the head. I opened up the runner some to get them close. The head bare flows 219 cfm on the intake. And opening the short side up by the ski ramp was the main thing that improved the head flow. Cleaning up the runners and port matching on the intake side did very little.

[BLSTIC]

Be careful you're not losing too much charge motion getting rid of the ski ramp. It would suck for combustion quality to take a step backwards, especially if this machine also earns its keep doing normal tractor things.

Edit: I see you were working by the ramps, not on the ramps themselves, so the "getting rid of the ski ramp" comment doesn't really apply.