porting

[DTanklage]

dont know if it will last forever but this should flow

i'm tired

[seeker1056]

You can make huge gains in flow if you remove that huge lump around the valve stem, taper it to look like a tree

[DTanklage]

not really lookin for huge gains

just thought i would help the low lift numbers

quicky pocket port job before grinding seats

thanks for tip

open to ALL suggestions

you got any idea how narrow the seats can be and still be reliable???

thanks, don

[seeker1056]

I have no idea in a deisel how narrow you can make a valve seat.
Is it for strictly racin or will it have to live on the street?
For the street I say leave it wide for heat dissipation.
For racin we always used one of those multi seat cutters (multiple angle seats and valve faces)and the widths are preset
Most of your flow gains on a street head are just behind the seat where it transitions around the corner into the port, and around the actual valve stem as i already suggested.
Without a flow bench all of the rest is just conjecture as to how much and where is good

[DTanklage]

I have no idea in a deisel how narrow you can make a valve seat.
Is it for strictly racin or will it have to live on the street?
For the street I say leave it wide for heat dissipation.
For racin we always used one of those multi seat cutters (multiple angle seats and valve faces)and the widths are preset
Most of your flow gains on a street head are just behind the seat where it transitions around the corner into the port, and around the actual valve stem as i already suggested.

yes, this head is for my ve motor. prolly end up in my 2nd gen. 400 hp range and have to go a lot of miles. pockets are opened up to i.d. of seat, basically, then blended by hand after seats are ground. i agree, that is the most important area, for any application imo. dont know how much diff it will make on this motor, but it should be noticable.

i am leaving the seats really wide, prolly wider than they need be (080 int, .100 ex). at least i know it will hold a valve adjustment like that. and transfer the heat as you had mentioned. if it were race only i would have put a really narrow seat right on the edge of the valves, and opened the pockets up that much more. start doing that tho and not much left for support, these things crack already, i dont want it to fall apart when i am in the middle of no where

is the tool you were referring to called a serti?

i have used them

dont like them

lol

[BC847]

not really lookin for huge gains

just thought i would help the low lift numbers

quicky pocket port job before grinding seats


open to ALL suggestions

Don't forget to unshroud the valves. Do it so as to promote/take advantage of swirl in the cylinder . . .

[DTanklage]

wow

super nice unshroud job!

looks like a machine did it!

i planned on doin mine, and then taking it back for surfacing, but the guy that tanked it cut it before i picked it up?

he was all worried about the valves being too shallow in the head (because of the cut)

whoopie - he took 10 off and i am using a 020 gskt

not to mention both the valves and seats get cut

why worry about valve to piston clearance?

i was ticked - surface should always be the last thing you do

[GLHS]

BC; Those are the flow numbers for you head? If so is that at .400 or .500?
I looked at PDR's website and the website numbers are a lot lower.
Just wondering.
Is that a PDR head?

[BC847]

BC; Those are the flow numbers for you head? If so is that at .400 or .500?
I looked at PDR's website and the website numbers are a lot lower.
Just wondering.
Is that a PDR head?

Those numbers are at .400" lift.

Those numbers on the website are indeed lower.

That is a PDR head.

. . . . . .. . with a little extra sumpthin .. .

[DTanklage]

400 tho and how many inches of mercury?

how often is there vacuum in your intake tract?

how often is there not 10 psi or better of back pressure in your ex tract?

what kind of air speed do you think there is when there is 60 psi of back pressure in it and you are only at 3000 rpm?

see where i am goin with this?

don

[BC847]

400 tho and how many inches of mercury?

how often is there vacuum in your intake tract?

how often is there not 10 psi or better of back pressure in your ex tract?

what kind of air speed do you think there is when there is 60 psi of back pressure in it and you are only at 3000 rpm?

see where i am goin with this?

don

Don,
As you may well know, changing any of the variables you mention, changes the outcome. It's all a compromise of one degree or another.

I'm assuming those enhanced numbers are provided by the standard test procedure using a flow bench.

It's further assumed the base numbers were derived by the same machine using the same procedure.

Sorta kinda.

[DTanklage]

Don,
As you may well know, changing any of the variables you mention, changes the outcome. It's all a compromise of one degree or another.

not really...

that is what i am getting at

it is most likely a complete waste of time to do all this work

lol

because once there is boost i dont think any of it will be noticable

what i am hoping for is that it is more efficient when it is making little or no boost

[BC847]

not really...

that is what i am getting at

it is most likely a complete waste of time to do all this work

lol

because once there is boost i dont think any of it will be noticable

what i am hoping for is that it is more efficient when it is making little or no boost

With that train of thought, clean-up the bowl of the intake maintaining the cork-screw type layout ~





Open the exhaust bowl ~





And continue that on out ~





And again, unshroud the valves ~





Speaking of valves, be sure to keep the swirl on the backside if you whittle there ~

[DTanklage]

nice lookin head

what size are your pockets?

are you going to run those valves like that or have them back cut before you put it together?

[DTanklage]

ps - just noticed that in that shot of the ex bowl, it sure looks like they took a ton off of the short side radius and floor

wonder if it is just the angle that the pic was taken at?

thanks for the pix

don