Head Porting- Milling (CNC)

[mynameisowen]

Yes it is a good post, love nearling new things...

One thing to note though, we are talking about small displacement engines here, like bikes and small car engines. On a small displacement engine the stroke and bore arent very big. So the depression created as the piston moves down isnt that large. So this "charging" using the momentum off the fluid to continue filling the cylinder is important.

But on a large displacement engine you get a larger depression and sice its still the same fluid in use you can take advantage of the greater depression with high flowing heads to get more mixture in. A big depression but a small port will greatly slow down the fluid. Compared to a medium depression and small ports.

You could also take advantage of valve timing and close the intake valves earlier, when mixture is beggining to get pushed back out of the cylinder.

My thoughts upon reading...

[hondaNickx]

You are right on that Owen , that's why i think you should test this on a flowbench with some clay first.The CFM needs to be same while adding clay.This way you could get a port that still flows the same amount of Cfm and has lot's more velocity.The D14 engine could gain from this mod and a proper cam design is a big key in this indeed.
I think my Bisimoto cam has this allready calculated in the cam design .

[Law_]

My thoughts upon reading...

Great thoughts BTW x)

[pardizzle21]

hey, was wondering if anyone has any major do's and dont's regarding head porting on a d14z2? and any info on spark plug contact with head etc?
want to find out if its worth doing! thanx, pardizzle21

[mynameisowen]

In the absence of proper flow testing I think its best not to do too much, maybe 1mm off everywhere. If you go overboard you can damage the flow rate.

[Dodo Bizar]

Very very very immature, but in the future I might actually start a flowbench project...

[hondamake]

Excellent info, a great deal to digest. My head will be rattling for days trying to compute all the permutations.

[mynameisowen]

Very very very immature, but in the future I might actually start a flowbench project...

Immmature.... or awesome?

[Dodo Bizar]

Ow darn, I see my lines can be completely misinterpreted. Let's set it straight. With the word "immature" I actually refer to the status of my plans...

But a side thought on flow benching, I am completely absorbing Motoman's stuff right now... He really got interesting ideas about flow benching. Contradictive ideas to some, but I think he got it right. Gonna try myself hopefully in the future. Let's put it this way, can't wait for Nick's results in the future.

Actually Nick, if you read this, we all saw some graphs with increase of CFM of your head was it? One, is my observation correct? Two, are you applying any of Motoman's ideas somehow then?

[hondaNickx]

My head was worked over by Endyn.They used a cnc machine to port the head but they didn't enlarged the ports much as far as i can tell.They didn't applied Motoman's technique ,but i know a guy who has done it on his D15 head.And that worked out great gave him a gain of about 8cfm and lots of velocity. Throttle response was very aggressive he said.