ive got a set of carbide cutting bits and a high speed air drill and ive been thinking about doing my own pnp job. im just wondreing if anyone else has done this or has any suggestions. if its a total pain in the arse i dont wanna do it

It is a pain, but rewarding.

Goto a junkyard and pick up any 4 valve aluminum head to practice on. Seriously.
Another thing. Pick up a standard abrasives kit, and that carbide bit will ruin your heads fast, it takes off quite a bit of material!

My first set of heads I've done were a set of V6 heads. 2 Valvers.

They came out great! Buut... It turns out they were turned into race heads, because I thought the idea was to allow more volume of air to come in, and that the velocity would catch up as long as I kept everything clear and open.

NOPE!

Turns out, you have to go very easy on the valve throat, and try not to take out too much material on the short side radius. Short side radius is the curve that transitions the roof of the port into the valve throat or bowl area. You can increase a LOT of port volume that way, but you will very much drop velocity.

As for the exhaust side, I went a little bit easier on that one, and it turned out it flowed better than any port Ive seen for the head. But it showed my intake side flower poorer than what others have benched at ( I did not do flow testing for my heads when they were stock so, I dont have a real comparison ) The reason for this, again was, the heads are only gonna work in a race application, they were ported to move a ton of air.


The best way to port as a novice is, gasket match the intake, and then gradually taper it into the valve bowl + short side radius. Do not try to hog it out to make the dimensions similar to the port entrance, you will kill velocity and it will only work at very high rpm, possibly out of the vehicles operating range.

It'll take you about 40 hours, before your proficent enough to make a positive impact on the heads. And then you're gonna want to flow bench it to see if you've junked the head or not before you put it on.

Or I can save you the trouble and port the head for you. ~$500 if the head is bare with a spare set of valves. A little more if you want me to before and after flow bench.

But I'll be honest with you, the exhaust side is most important on the LD9, as the intake flows pretty well already, although there is room for improvment.

You're biggest gain is gonna be going with a REAL set of cams, (not the not-so-secret) cam swap, thats barley a luke warm upgrade. You're gonna need some real lift and duration. You will gain much more power from doing that than porting.

If you can get past the e-dick swinging there is some good advice here:

http://www.j-body.org/forums/read.php?f=24&i=70457&t=70374#70457

I agree with 99% of what Beau said however I would like to add this:

If you were to talk to someone at Standard Abrasives, I highly recommend thier porting kit # 26001, they are going to tell you that you do not need to be a pro to P&P your head. Nor do you need to flow bench it. Now let me qualify that statement: If you are not going to flow bench the head, dont go in there thinking that you are going to remove a massive amount of material and re-engineer the shape of the ports. THAT you need a flow bench for. It is possible to pull 10 hp out of the LD9 or Eco head (all things considered, although the cam is going to have some say in it) by simply gasket matching, polishing and blending on the exhaust side, polishing the combustion chambers, and lightly porting the intake side. This is not rocket science BUT as Beau said, what it will cost you is alot of time. 40 hours is no exageration if this is your first head.

Good luck.



Edited 1 time(s). Last edited Thursday, October 25, 2007 12:40 PM



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thanx guys and big thanks to beau for saving my spare by telling me that carbide bits will riun em.
i was about @!#$ up. who makes cams for 2.4s other than rsm. they're the only ones i could find.

But I'll tell you what, it is rewarding. The exercise alone gives you a lot of intimate knowledge on how fluid dynamics works, if your thinking about whats happening when your porting. But whatever you do, as he said, do NOT try to reshape anything, if you think your eyes and the feel of it are going to improve the flow you'll be wrong. I still get confused as to why something decreased flow and not increased it.

I do recommend the flow bench though. While you can FEEL a difference after a port ( no other changes ) its best to know what you've improved. I say this because, anyone whos driven their car in cold weather versus hot, and can feel the difference will be able to notice a ported head over stock, but you can also fake yourself out, because hurting flow in some spots and improving it in others can cause the power band to move around, and you may not actually make more power, you might just change the where your peak VE falls ( even if it is lower ) and since you can feel a change you've diluded yourself into thinking you've made an improvment.

P.S. The stock LD9 head flows better than race versions of the 3.8 SII and SIII heads. But the exhaust side doesn't flow well at all.
Do NOT gasket match the exhaust side. If you want more volume thinking you'll get more flow, take no more than 1/8th of an inch on each side, and keep the port congruent, unlike the intake side, where you taper it towords the valve throat.

Standard abrasives is your best bet, and read up on their free literature. You CAN use the carbide to remove material around the intake, to gasket match if you wish.

Some other things taken from that thread. ( its best to stay out of it maybe )

DO NOT, knife edge the intake port where it splits. This contrary to the rhetoric in there, isn't because a piece might break off, go in your cyilinder and wreck your turbo blades.. ( rolls eyes ). its because it honestly flows better with a blunt edge on the intake side. ( exhaust side, knife edge it, nice and evenly. ) I was surprised at this myself, thinking a knife edge would be able to split the air and keep velocity up, from power numbers, and fluid dynamic models it actually causes too much turbulence to knife edge the intake port divider, so leave it blunt.

Another misnomer in that thread. About the "lip" on the injector bung. Leave it. When you gasket match you will have to bring it down a bit, but DON'T smooth the transition from the injector bung into the bottom of the intake port. You'll see what they mean ( at least what I think they are yappin about ) where he started to put an edge on it to make it hav esome kind of a transition, this will again cause unwanted tubulence if you do this. The reason being is this, giving the air a smooth exit from a place where air should be flowing over in the first place, will cause the air to fill this area, the air wasn't meant to flow downwared into this injector bung real far. Same thing as a truck bed. If your going down the highway, people think that leaving the gate down will increase their gas mileage and reduce drag. It doesnt. When you leave the truck gate up, it traps air in the bed, and the air coming over the windsheild over the roof, falls back onto the cushion of stable static air, and rolls off the truck. With the gate down the air falls hits the bed of the truck, and flows poorly off the truck but not before creating excessive drag. Its the same idea.

Another thing they rip him apart on is the fact you still see black where it wasn't ground up. Some of the best flowing port jobs Ive seen looked ugly. Because they knew what to touch and what wasn't nessecary.

Go start scouring the net. Get some practice in on a spare head. If you have specific questions ask, there is too much to go over. G/L!

Quote:

who makes cams for 2.4s other than rsm. they're the only ones i could find.

LZM makes them. or you can have someone in your area regrind your stock ones



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