Ford PI 2v Heads, porting ?

[DavidHarsay]

Here's a cutaway:

http://forums.modulardepot.com/attachme ... tid=515839

Well, since I have acquired a set of PI heads that someone milled off the swirl dams, and also started some poor intake porting work on, I decided to cut them up.... To take a good look at the ports, and the wall thickness we have to work with.

One very interesting note on the PI heads... the swirl dam would be located on the RH side shrouding that side of the valve... these ports are obviously designed for swirl... most of the intake charge enters on the LH side of the valve (orientation as shown in the cutaway). Aside fron trimming the sharp edge on the SSR, are these ports pretty much a lost cause? The SSR will have bad airflow seperation at that sharp turn no matter what... smoothing it out may even make it worse, and destroy the swirl.

Any suggestions?

Thanks,

Dave

[DavidHarsay]

Wanted to add... I asked a few questions about these heads a few years ago from an infamous porting guru on the PI heads... here's what I got:

Answers.......
While I'm normally very secretive about stuff, I'll try to answer your questions here.

1. Does it pay to unshroud the valves just a little bit more on those heads?

Depends on the application. For most street style heads, no. If you step up to the oversize ModMax valves, yes.

2. What area is there the most gain on these heads?

Exhaust ports.

3. Is it beneficial to polish the exhaust... and the combustion chamber?

Exhaust yes, combustion chamber no.

4. Have you tried "dimpling" medium to sharp radiuses in the intakes? And was there a benefit?

I'd try voodoo and witchcraft if it would help further. Dimpling doesn't help at all. Can't seem to find out why but the flow and velocity numbers drop drastically.

5. Are there areas where it's beneficial to fill in the ports (raise the floor)?

Nope. Tried that and it didn't do a damned thing. I was shocked too.

6. Are there areas "not" to touch, or to be really careful of?

Naturally, be careful of the short side radius on the intake side. Don't take too much material away from the right side wall either.

Hope this helps.

[ADR]

Here are some pictures I found awhile back....http://www.modcamponents1.com/modifications.htm

Some interesting stuff there. Anyway maybe John Haskell will say a word or two about these heads...he has a lot of time in one of my projects from last year. Went from around 170 to over 240 on the intake and around 190 or so on the exhaust.
Dale

[ADR]

I forgot to mention that the so called swirl dam has also been called and emissions mask.....it might give you a different angle of looking at it. Most guys with blowers take it out but the more savvy guys use it to there advantage....as an extension of the port maybe ??
Dale

[cboggs]

Dave,

I can help you with those, .. I've done a TON of development
on those since we build mod motors for many of the "name" tuners.

I always try to " fix" the short turn by grinding strait down from the
bottom angle to make it "taller", then work with that material to
get rid of any seperation on the flow bench.

The long curved port wall acts more like a "short turn" would in
a normal wedge head. Meaning this is where I've fond some high
lift flow and can tune the flow curve like I would with a short
turn in a normal wedge head.

That damn in the chamber, .. I don't remove the entire thing but
lay it back from the valve. Remember an important part of the
flow path is the air coming out of the valve at the pressure recovery
area, .. so taking that damn out all the way will hurt it a little, ..
just lay it back.

The BIG part of this ( or any ) head is the valve job, ..

Curtis

[DavidHarsay]

Thanks guys, that's some good help. I do plan on keeping the swirl dams, as I think it helps the N/A motor... just cutting back like Curtis mentioned. Thanks again,
Dave