Porting suggestions/pics for 3x00 heads

[SappySE107]

http://www.geocities.com/trentomatic/flowbench.html

[SappySE107]

No design. Just make a box and position the source so its not biasing the swirl in the cylinder. I used a metal house vent in the bottom of the box to make a nice wide opening in the bottom so that it wouldn't be directed to 1 cylinder.

My next box will have the standard superflow top for mounting adapters for cylinder bores. My box now only does 2.8-3.5 60V6. I can flow briggs motors and big block heads with my next bench. The vacuum box I have schematics for. There is a site/forum for flowbench owners who have made their own setup but I forget the name. You can google it and the flowbench design to find everything.

[ForcedFirebird]

Again, did you get the design from somewhere, or just base it off commercial ones? I'm now interested in making one.

[SappySE107]

I built a box with 3 cylinders in it to mimic the block sleeves. Currently using 2 vacuum motors but I already have 6 vacuum motors for my new box. I just need an $800 box that adjusts the depression automatically to make that all work well. The thing with the flowquik, is that it compensates depression automatically, and yes, it works great. I have used 1 and 2 motors and my numbers are nearly the same (1%). The only reason I want more is because nascar teams test past 90 inches of water! I figure that will be useful to know, and work better once I get the wetflowbench setup going as well. Sucks not being rich:P

[ForcedFirebird]

Speaking of fancy equipment, I was looking around a benches/accy's after you mentioned it. There is a valve-spring opening tool that can mounted to your bench to mimick these "real life" scenarios. Thought that was interesting, and wondered if you could "program" cam timing into them to help further the understanding of flow in real-world applications.


Did you build your bench from a design/plans? I found the flow quik components you mentioned, but couldn't find any kind of dimensions/drawings to use to build one. There was diagrams of some commercial units, though. I also saw where people are using two vacuums with a "y" fitting to up the cfm capabilities.

[SappySE107]

Yes, it will matter but you are looking at different pressure with boost just like NA. You can make testing as complicated as you want really:P Its all still depression in cylinder and it still flows both directions based on rpm and cam timing. You would just change the depression on the flowbench but to know what depression to really test at for closer to real world would take some fancy equipment indeed.

3500 top end will still produce a lot more power than most ported 3400 heads so no worries there on your decision

[ForcedFirebird]

The 3500 has a lot of advantages but I am not sure the ultimate 3400 or 3500 based boost build will use 3500 heads.

Yes, I know. We have discussed this earlier. You said because of the lack of aftermarket parts on the 3500, the 3400 boost-ported heads could be better. The deal I got for the 3500 top end was hard to pass up, along with the advantage of using the 3.4 Camaro pistons during the N/A tuning and testing with the larger chambers was enticing.

Is there a difference when flowing on the bench to simulate boost vs N/A? I was pondering today, and thought "Is there a difference where the static pressure is?".

Or, if the valve is seeing vacuum on one side during an N/A test, does it make a difference if it sees boost on the other side during the test with all other variables equal, or is flow just flow?

With the machines I now have available to me, perhaps I'm getting way too anal?

[SappySE107]

Oh it never ends really. I want to setup a wet flowbench later (because fuel injection doesn't mean the mixture is moot... far from it). That would be the best way to go, but even then you are looking at a lot of time to test with different pressures, to make it even more valid. Since engines don't flow at a steady depression, you would have to do a lot of tests based on RPM and simulation data.

The 3500 has a lot of advantages but I am not sure the ultimate 3400 or 3500 based boost build will use 3500 heads.

[ForcedFirebird]

All I can do is give advice. I have done more than flowbench work to determine how I port these heads. If you do the same with 3400 heads and 3500 heads, I promise you will have fucked your 3500 heads up. Ill put money on it.

Not mine! I will listen to someone who has worn the path before me.

My only problem, Ben, is you keep showing/telling me all this cool stuff that I can have at the shop for this and future projects. Things that I probably shouldn't be buying, like flow bench parts/burette (buret).

No more red-necking here .

[SappySE107]

All I can do is give advice. I have done more than flowbench work to determine how I port these heads. If you do the same with 3400 heads and 3500 heads, I promise you will have fucked your 3500 heads up. Ill put money on it.

[ForcedFirebird]

I don't know about anyone else, but I've never been able to "over port" a head, unless you hit water, of course.

Not to sway your judgement but I went friggin' nuts on my 3400 heads.

I cut the exhaust port all the way to the gasket edge, smoothed the bowl, straightened the dog leg a bit, cut the chamber wall out to the fire ring to deshroud the valves, ground down the guide bosses, and killed the hump in the intake port and the chamber near the plug boss. The port and chamber looks beautiful, and should flow well. More power will be gained by increasing port flow and stabilizing combustion by deburring then by the CR increase from the small amount of metal you remove. Less detonation = more timing.

Do I have a flow bench? No. Have I ported a stock engine to 1st place in a few circle track races? Yes. Air likes a straight shot and long radiuses.

Being it's port injected, the fuel is shot at the intake valve, so fuel suspension is moot. Finish isn't really relevant to bulk flow, so I'm content with carbide dimples and a sand roll finish.

Will I never be able to utilize the flow I created? Maybe. But the ground work for a large cam and/or boost has been laid.

Just my .002 ppm

Pics?

That is the thinking I followed on the SBC iron heads. This is the first port job on both aluminum and v6 heads, never modded a 60* until I got this car.

I can tell you that what I am strting with is a lot better than we had sometimes ended up with after porting.

I plan on taking full advantage of the flow on theses heads. I'm going all out on this build, and will be boosting to the limits of the stock 3.4 bottom.

[Monzsta]

Got my gaskets finally, and will start porting this weekend. I was fitting the gaskets on and noticed two surfaces of the heads lined up with the gaskets.

I'm planning on a gasket match, but was unsure on a couple of things.

1. Are you guys removing material from the port floor/wall? It looks like a little can be removed to make a more direct shot to the valve.

2. Has anybody ported to the carbon stains around the exhaust ports? I've seen pics of some of your portings, and nobody has gone that far.

3. How large should I go? I'm planning on using Camaro 3.4 pistons and 3500 heads to get up and running again, but then switching to 3400 pistons to re-boost the car, which leads to my next questions:

1. When modifying the chambers, I see the valves could be slightly less shrouded as there is a little material, almost like a lip, up against the valve. OK to remove?

2. The large area around the sparkplug, should I just smooth the edges here?

3. The sharp edges on the heart-shape, OK to remove?

I don't know about anyone else, but I've never been able to "over port" a head, unless you hit water, of course.

Not to sway your judgement but I went friggin' nuts on my 3400 heads.

I cut the exhaust port all the way to the gasket edge, smoothed the bowl, straightened the dog leg a bit, cut the chamber wall out to the fire ring to deshroud the valves, ground down the guide bosses, and killed the hump in the intake port and the chamber near the plug boss. The port and chamber looks beautiful, and should flow well. More power will be gained by increasing port flow and stabilizing combustion by deburring then by the CR increase from the small amount of metal you remove. Less detonation = more timing.

Do I have a flow bench? No. Have I ported a stock engine to 1st place in a few circle track races? Yes. Air likes a straight shot and long radiuses.

Being it's port injected, the fuel is shot at the intake valve, so fuel suspension is moot. Finish isn't really relevant to bulk flow, so I'm content with carbide dimples and a sand roll finish.

Will I never be able to utilize the flow I created? Maybe. But the ground work for a large cam and/or boost has been laid.

Just my .002 ppm

[ForcedFirebird]

Chambers down to 80 grit is my plan, I will also be removing a little material to get the compression down just a tad.

[MY91GT(Z)]

what do u polish the bowls with and how far do u recommend goin on the bowls and what r the advantages other than the hot spots

[IsaacHayes]

Jon, it may not be perfectly smooth but the casting texture now has smooth edges instead of rough sharp pointy ones. I would think that would help with hotspots too.