DIY Cylinder Head Porting?

[5PointOh]

Anyone have any sitesfor DIY cylinder head porting websites or related threads?

 

[autronicDSM]

www.yahoo.com

 

[1fast97gsx]

no take it to a shop. This has to be very precise.

 

[DSMJim]

THere is no such thing as DIY head porting. DIY head porting ends up being DIY Head disasters. If you do anything to your head yourself you will do nothing but make it lose power.

 

[philipkrotch]

THere is no such thing as DIY head porting. DIY head porting ends up being DIY Head disasters. If you do anything to your head yourself you will do nothing but make it lose power.

hes not kidding.

 

[hostile]

If your going to do any non professional porting on you head it will have to be very basic stuff.

Gasket matching the intake and exhaust ports, polishing the exhaust side and knife edging the dividers shouldnt hurt performance.

Some people also polish the combustion chamber and remove any casting flaws.

I wouldnt actually try to hog out anything because it is pretty good size wise from the factory.

 

[5PointOh]

Very pricise on a forced motor? Umm...no? I've done other stuff, mainly Ford Windsor heads like 302s, 351W, 289s, etc. These heads are all anemic from the factory, very restrictive runners and smog humps in the exhaust sides. Now those you have to be precise on. On an NA head you have to consider port velocity, hogging out a runner won't work because the only drawing air is vacuum. The bigger the port, the slower the velocity. A properly contoured smaller port will flow well because the air can maintain a higher velocity and fill up the cylinder easier.

On forced heads that's not nearly important because you've got 20psi of air pressure forcing air into the cylinders. I was just curious what areas of the stock head could use touching up? The divider looks like a good place to me. Since it's a forced motor, we can probably knife edge the dividers(no airfoil here). Clean up the intake runners and do a little blending in the bowl area around the valve guide. On the exhaust side, there's some work to be done too... Mainly polishing the runners well and some bowl work too.

If I screw up, I've got two more heads under the bench

 

[philipkrotch]

Some people also polish the combustion chamber and remove any casting flaws.




DO NOT POLISH THE COMBUSTION CHAMBER. this surface needs to be sort of rough so the air/fuel mixture can stay suspended, it also helps the fuel atomize. im in wyotech biatch. chassis fab teaches u all the cool shit.

 

[5PointOh]

I've read different thoughts on cc polishing. I'm not sure how that would affect fuel atomization and distribution. Usually polishing is encouraged, it keep carbon from forming as well. And carbon can keep hot spots in the combustion chamber leading to detonation...

Usually it's the intake side that they encourage a rough feel to the ports/runners, because the rough texture causes the air to tumble as it goes in which is extremely important to fuel suspension. It shouldn't be that big of a deal in a fuel injected engine because the injectors are spraying into the back of the valves...

 

[1fast97gsx]

I've read different thoughts on cc polishing. I'm not sure how that would affect fuel atomization and distribution. Usually polishing is encouraged, it keep carbon from forming as well. And carbon can keep hot spots in the combustion chamber leading to detonation...

Usually it's the intake side that they encourage a rough feel to the ports/runners, because the rough texture causes the air to tumble as it goes in which is extremely important to fuel suspension. It shouldn't be that big of a deal in a fuel injected engine because the injectors are spraying into the back of the valves...

if you know what to do, then why are you asking?

 

[5PointOh]

I know the basic stuff and ideas from porting v-8 heads, however, when it comes to DOHC stuff I'm kinda clueless because these ports are so much superior than anything I've seen in a Windsor Ford it's scary. Fuel atomization is pretty basic, but my question was more along the lines of specifics for these heads as far as removing material from one spot, etc.

 

[philipkrotch]

I've read different thoughts on cc polishing. I'm not sure how that would affect fuel atomization and distribution. Usually polishing is encouraged, it keep carbon from forming as well. And carbon can keep hot spots in the combustion chamber leading to detonation...

Usually it's the intake side that they encourage a rough feel to the ports/runners, because the rough texture causes the air to tumble as it goes in which is extremely important to fuel suspension. It shouldn't be that big of a deal in a fuel injected engine because the injectors are spraying into the back of the valves...

when i meant u dont want to polish it, i really mean polishing it. you can port the shit outta it and clean it up with a polishing bit, but u dont want it smooth. and carbon will build up regardless because of EGR valves and all that emissions bull shit. your not gunna want it to look like the exhaust ports is what im trying to say. keep it a little rough. we were taught this..it helps keep the air/fuel mixture suspended.

 

[Nautica985]

Could a incorrect port job cause bad gas mileage? The guy I bought my car from said he ported the head and put in 1mm oversized valves in it. I have done just about everything to correct my gas mileage. fuel filter, plugs/wires, o2 sensor ect. I only get about 13 mpg.

 

[hellotbone]

Cylinder Head porting without a flow bench = Pointless

 

[NDgsx]

If I screw up, I've got two more heads under the bench

Go for it, there's no point in paying $1k for a head if you have some skill with a die grinder.
I just spent some time porting my head for my new motor. I didn't alter the port shape on either side, just got rid of the casting lumps on the intake side. I spent most of my time smoothing out the bowls as the factory leaves a lot to be desired . The short side radius is a little rough too, but not nearly as bad as what you're used to on those windsor heads.
On the intake side I did my porting with 40 grit cartridge rolls and then bead blasted the ports. I also took a punch to the area of fuel spray in the top of the port.
I unshrouded the valves (larger bore, 2.4l) and left the combustion chamber alone. I knife edged the exhaust port collector, and polished the ports.
Pretty basic stuff.

 

[NOSNUSE]

Cylinder Head porting without a flow bench = Pointless

BINGO!!!

 

[hostile]

Cylinder Head porting without a flow bench = Pointless

That is bullshit, that is like saying porting out your turbo is worthless if you don't have flow ratings before and after.

Common since stuff like taking out casting flaws is not going to need a flow bench to back up the work.

 

[NOSNUSE]

Common since stuff like taking out casting flaws is not going to need a flow bench to back up the work.

True, but if you really want the porting to be beneficial then you need a flow bench, for the simple fact that if you take out to much you will hinder your performance, also helps to know how the flow numbers to help match up your cams ,intake and turbo.

 

[hellotbone]

Taking out casting marks isn't porting if he had said taking out casting marks I would not have said that porting without a flow bench = pointless. Removing casting marks is just cleaning things up nothing more. Porting is removing material and changing port dimensions hence the name porting.

 

[gsxstac]

try putting sand in a bag and zip-tying it to a throttle body and strating the motor so it sucks it in. then your head will be ported automatically. then take off the break booster line and fill the intake manifold with about a quart of polish so then it will be polished. sand from the beach is always good

 

[gsxstac]

That Was A Joke By The Way, For Anyone Who Is Gonna Cry About Me Setting A Bad Example For A Newbie

 

[NDgsx]

Flow benches are steady state devices, they don't stimulate resonance from the intake valves opening and closing. There is also nothing showing the effect of the low pressure area created by the downward moving piston when the intake valves open, or the high pressure chamber when the exhaust valves are open and the piston is traveling up. Flow bench numbers by themselves are useless as actual measurements of performance. A head can flow great on the bench and perform like crap in the real world. Flow benches are really useful for matching flow between cylinders, but they are by no means a end all for performance.

There is a huge difference between porting in the sense of old V8 motors and what is required on a mitsu head.