I'm getting ready to port my internal wastegate and a few other things on the turbo upgrade I have as there is a fair amount of core shifting going on. How many have tried this and how much r&d did you put into the subject and your skills before tackling this?
I used to port stuff all the time in my DSM days. Was pretty easy, just get a nice die grinder (electric, or air powered if you have a big compressor that will do 12+CFM all day long) and have at it. I used chinese carbide burrs and for cylinder head finished them with the little sandpaper rolls.
I never CC'd a head, just did general removal of casting flash and whatnot. Mainly manifolds and turbos.
Dont expect miracles unless there is some super well documented fix that is dyno proven to add 500 horsepower. You do risk running into boost creep if you port your turbo too much and dont have a large enough wastegate to compensate. Ahh the good ol days of a 16G creeping up to 25 psi with nothing but an AFC and a set of 550s on a cool fall night.
Lots of intake manifolds and engines, and a couple exhaust manifolds.
Shape is a lot more important than size, and a big part of shape is keeping cross sectional area from changing a lot, like what you would get if you gasket matched a manifold and head, making the CSA get larger and smaller again. CSA changes mean the airspeed changes and airspeed change takes energy.
A few heads, intakes, throttle bodies, etc.
Generally just tried to clean up, but the head i did for the neon i went full tilt with oldschooltoys help and guidance.
I've done all the heads on my Datsun. I use a simple dremel.
The more you want to remove, the more you need to think about it.
Just making port sizes match and getting rid of casting flaws is hard to mess up.
Ported shock and fork pistons, on a dirt bike. There are a few specific models that can really benefit from improved port flow as you end up choking the flow at the high end of the shaft speed range. Shock ended up being unnecesary, but the fork pistons resolved my slapdown landing pressure spike issue that was killing my wrists. Dental bits can be good for the really small stuff like this. Didn't do any R&D besides the good old A-B comparison, but I have enough basic background in fluid mechanics to be able to visualize the more egregious problem spots.
A bit. Did fairly heavy porting on a set of stock 88mm vw heads for a turbo build. I unshrouded and did heavy exhaust porting on an old Briggs L head for a trike, coupled with a much improved exhaust. It sure felt faster, but hard to know for sure. And general smoothing and port marching on a cast sbc intake, but I never ran the engine before doing that so I don't know if it made any difference.
LS oil pump with an electric die grinder. Actually i started with the air grinder but I got tired of hearing the compressor cycle and thought "Isn't this why I bought an electric grinder to begin with?"
Getting ready to to the intake manifold on the 2GR-FE that's going in the MR2 as soon as the gaskets arrive. I think that one is going to be a job for the mini belt sander.
I've ported engine oil distribution systems.
Most oil pumps are fixed displacement, each revolution pumps the same volume of oil.
Bearing oil pressure is developed by forcing that volume of oil past the bearing clearances.
So flow distribution split is determined by the bearing clearances and the hydraulic flow pressure losses in the passages.
Obviously, passage branch sizes & lengths are different, but also losses due to intersections, and abrupt sharp edges.
Equalizing the pump to bearing hydraulic flow resistance from pump to bearing equalizes the flow volume to each one.
This also helps to eliminate or minimize the cavitation and aeration of the oil at high flow velocity, which plays havoc
with the load bearing capacity.
In reply to Gettingoldercarguy :
Clean up and smoothing things is going to give you the most return for effort. Making things bigger can really backfire on you. Cross sectional shape is critically important rather than bigger.
I opened up more than a few heads thinking I was really doing wonders. Then when things started to go on the dyno I found out how bad those big smooth ports were for power.
The really sharp guys understand so much more. Most of all they understand how much is too much and stop short of that. If you look and think to yourself. I can open that up and it will flow better and make more power. Put down the tools. Walk away.
I've only ported rotary powered stuff. That was easy to do, you just buy the template and get to work.
I will say that it's comforting to have some scrap pieces to practice on to get the feel of things. In my case, I had a couple of rotor housings that were trash that I ported out first.
On my Dart, I ported the cylinder head, matched the ports to the manifold, and ported a few water and oil passages as well. Used an electric rotary tool and cheap carbide burrs. It wasn't too difficult once I got the carbide burrs. The wrong tools will make you miserable.
I used some pictures from other slant six builds. The easy win in porting are to find when fluids must go around sharp corners, and smooth the corner. The inside radius is more critical than the outside.
In reply to clshore :
OmG yes, porting oil passages is crucial, on my engines of choice (Mazda rotary). The oil pump inlet is full of weird knobs and casting flash, the pump outlet has a cast passage feeding a sharp edged hole that then goes to three or four right angled drilling intersections, just on its way out of the engine to the oil cooler. It gets worse once it gets back in!
All I really pay attention to are the pump inlet, outlet, and the right angles that I can get to. My oil pressure comes up early, with the small oil pump, and keeps 80psi all the way out to 10k instead of dropping off due to cavitation.
The eccentric shaft's oil passages are also ported with lead-in and lead-out grooves where appropriate. An old racer measured oil pressure inside the shaft at a certain speed and found only 7psi, with 100psi system pressure. And that was with a dry sump system pumping "solid" oil, not oil foam. So I do what I can to make it easier for oil to get into the shaft, and out into the rotor bearings.
In reply to Gettingoldercarguy :
I plan on making molds of the wastegate ports, scanning them into Solidworks and then printing up a couple of trial pieces to practice porting as well as a calculated optimal flow for a non divided wastegate of similar diameter and length.
In reply to Pete. (l33t FS) :
This is a huge thing for the fa20 engines as well, especially since we don't have priority main oiling.
I've taken a die grinder to every engine I've built. Mostly light to moderate bowl cleanup, port matching, and knocking off impediments to quality airflow, but also plenty of oil pumps and block passages. Always worth my time. Even the flathead Onan generator was happier for it.
I can't overstress the importance of using the right burr--single cut for aluminum, crosscut for ferrous. I almost never use abrasives. Cheap burrs work almost as well as the expensive ones but don't last and aren't as well balanced & true.
I agree on the expensive burrs not necessarily being better.. but I've just got a set of burrs from Headgames and these things are night and day from the other ones I've used. https://headgamesmotorworks.com/product-category/burrs/ oddly the double cut 3/8 is really good for minor cleanup on alum heads.
Unless you have some info on the particular cylinder head your porting just a simple clean up is all I'd do on a head. The two that I know well are the Ford 2.0 OHC Pinto engine as I followed info in a book written by David Visard on building this engine. I also ported a head for the Ford Kent engine, again based on what Mr. Visard determined was required for this head.
There's plenty of info on the various versions of the Chevy SB and nearly as much on the Ford SB.
But unless I had some guide lines I'd keep it to a simple cleanup.
Good tip on the Head Games burrs Paul, those look nice. I'm always fighting galling with more than light cleanup passes using crosscut/double-cut on aluminum. It's easy to tell which castings are made of recycled Bud Light cans vs those made from metal by how much of it you have to pick out of the teeth.
I tried porting the heads on my Caddy 500. High nickel content casting + cheap die grinder = hell no. I took them to a proper shop.
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