porting heads...

[TGP37]

http://www.instructables.com/id/Drem...-Power-CNC-Ro/

^ something like that, except set up for five axis.

One issue is 2 ports are 30 degrees offset from the other. Atleast it is 15 degrees either way for the 3100 aluminum heads exhaust port. And you would need to reverse the movement from the primary. And the pockets are placed where the exhaust valve is outside on both ends. Making linear replication near impossible.


I think a caliper, shop vac and LOTS of light will do much more. I know you can bring each port to a closer spec by hand.

I sculpted many "little" statues and did all sorts of artistic work over the years. Your hands can form precision, it just takes patience and practice.

If you smoke or not, a good cigar hanging in the air helps calm the nerves and steadies the hand.

[ericjon262]

http://www.instructables.com/id/Dremel-CarverDuplicator-like-a-Human-Power-CNC-Ro/

^ something like that, except set up for five axis.

[TGP37]

If it works, good.

I can't see myself using something like that to port heads. Each pocket is different regarding the flaws and the short side radius is hard to reach.

Unless it was used to carve the combustion chamber side like deshrouding valves.

The geometry is already there, it just needs cleaned up. The flaws from factory casting will create a greater level of difference between pockets then a steady hand will.

[ericjon262]

I was talking about making a pantograph type device, so the work could be duplicated on each port.

similar, to this, but a little different.

http://www.badassbassplayers.com/forum/viewtopic.php?f=95&t=15083

[TGP37]

Not sure what you mean. Many say not to gasket match the heads, no real gains. The most improvement can be made just behind the valve seat. The valve seat itself acts as a guide. And when the factory cuts the valve seat, the back side of the cut has a bad edge on the floor of the pocket. Making the valve seat port flush and blend back will be the ticket. After that, a good texture on the intake pocket. Do not want it too smooth so no mirror polish for intake pocket. But you can and would want to mirror shine the exhaust pocket.

Think, if you had to pump a thick syrup through these heads. My heads, the seams were ugly. I didn't realize how slack the factory casts are.

[ericjon262]

I'm thinking about making a copy rig so I only have to do one port, and then run a stylus over that port to "copy" it.

[TGP37]

I even went as far as mentally noting how much time I applied the bit per port and tried to keep a consistent pressure. Also faced each port at the same angle, since 2 of 3 face one way I had to reposition my self for the 3rd off set port.

But all that was just background principle. What really made the job for me was running my hands through the area over and over. Knowing each and every little bumb or oddity. Seems our fingers are better at feeling a smooth bend then are eyes are.

Never try to reshape any geometry, only tighten what is already there. Get to know the shape of the ports and fix the rough edges.

Most of your gains will be right behind the valve seat. As that is the smallest spot along the way. Velocity through this area is key and it doesn't take much removal of head material. Since the valve seats are machined to a very nice spec, they can act as reference points. I gently removed the lip and made the port flush with the seat itself. Making sure they are flat to each other as well, no angle. Then gently blend the back side of the grind into the pocket.


This is what I did. I am not a professional like Ben nor did I have a flow bench. But with that in mind, I still was impressed with the results.

[ericjon262]

When I ported my heads I learned a trick for consistency. Don't complete each cylinder at a time. Pick a smaller goal like clean valve seat area and do all 6 before moving forward. This helps make it easy to repeat the process for more consistent results.

Also, carbides and sanding rolls wear down. Starting with a fresh tool on cyl1 and end with a dull tool on cyl 6 will create inconsistencies. I used sanding rolls for porting and dedicated 2 rolls per cylinder.

I tried to think across all 6 instead of 1 at a time. When ever I did something, I did it to all 6 whether it was valve seat area or casting flaws. And it is always a great idea to place duct tape over the valve seats themselves. 1 hit and it's over, the seat is flawed.

Me and my buddy mark thought of that while porting a set of iron 351 heads he had sitting around. I'm going to get some practice in on some old 305 and 2.8 heads I've got here before I go full bore on a set of 3500 heads...

[TGP37]

When I ported my heads I learned a trick for consistency. Don't complete each cylinder at a time. Pick a smaller goal like clean valve seat area and do all 6 before moving forward. This helps make it easy to repeat the process for more consistent results.

Also, carbides and sanding rolls wear down. Starting with a fresh tool on cyl1 and end with a dull tool on cyl 6 will create inconsistencies. I used sanding rolls for porting and dedicated 2 rolls per cylinder.

I tried to think across all 6 instead of 1 at a time. When ever I did something, I did it to all 6 whether it was valve seat area or casting flaws. And it is always a great idea to place duct tape over the valve seats themselves. 1 hit and it's over, the seat is flawed.

[ericjon262]

Have you tried McMasterCarr.com or MSC tools They supply a lot of metal working tools to various shops... prices aren't always the best but they usually have it in stock.

http://www.mcmaster.com/#rotary-deburring-tools/=gd918e

http://www1.mscdirect.com/eCommerce/NavigationServlet/Abrasives/Points-Burrs/Burrs/Burrs/_/N-77ch5?Ns=p_ListPrice_MSC%7C0&searchandizedOk=N

Thanks, didn't think about McMaster, they have everything!

[NateD4]

What kind of flow numbers are you trying for?

Also I've heard dipping the burs in automatic transmission fluid helps keep the aluminum from sticking to them.

Perhaps you can find some of them with the new DLC coatings on them. Might help with sticking.

[NateD4]

Have you tried McMasterCarr.com or MSC tools They supply a lot of metal working tools to various shops... prices aren't always the best but they usually have it in stock.

[ericjon262]

the real trickhas been finding one with an extended shank most of the ones I have found are short. now there are a few through northern tool and eastwood as superdave pointed out but all of those are for ferrous metals. the only place I have found long reach aluminum cut carbides is here

http://www.bestcarbide.com/index.php/products/carbide-burs/

but I'll have to email them for pricing.

[neophile_17]

As a price reference here's a guy on Amazon selling them. No experience with him or the product. May try to get one though.

http://www.amazon.com/s/ref=bl_sr_hi?_encoding=UTF8&node=228013&field-brandtextbin=Carbide%20Burrs%20-%20AlumaCut

~sam

[ericjon262]

@ Dave, I saw both of those already too, I was looking for the aluminum specific burrs, I'm gonna email that site and see about getting some pricing.