KA24DE-T Head Porting Suggestions? Please give input!

[eazye2000]

So after reading a post on here, I got a hankerin' to mess with my head since it's apart. My original plans were to gasket match the intake mani to the head, and just smooth out some of the casting marks...along with getting rid of those annoying lumps at the bottom of the upper intake mani left over from where the butterflies seated up against. On the head I wanted to just smooth out the casting marks and blend-in at the valve seats.I know not to polish the intake side, but I thought about polishing up the exhaust side and possibly gasket matching the exhaust side as well.

If anyone has any suggestions, please feel free to let me know. I'm open to just about anything. Just none of that bi-curious stuff..
Modified by eazye2000 at 11:57 AM 1/22/2007

[KATwo40]

So after reading a post on here, I got a hankerin' to mess with my head since it's apart. My original plans were to gasket match the intake mani to the head, and just smooth out some of the casting marks...along with getting rid of those annoying lumps at the bottom of the upper intake mani left over from where the butterflies seated up against. On the head I wanted to just smooth out the casting marks and blend-in at the valve seats.

I wouldn't do any more than that. The port flow on the DOHC head is pretty incredible in stock form. If you start digging out the ports, you'll likely created pockets that negatively effect the flow.

I know not to polish the intake side

I could argue this all day long with anyone on this forum, or any other for that matter. The reason you're not supposed to polish the intake side is because you loose turbulence/swirl and the fuel falls out of suspension, puddling in the intake tract, instead of reaching the cylinder, particularly at low velocity.

However, stop and think about this for a minute. Take a long hard look at where the injectors are placed in reference to the intake port on the head, considering the angle of entry. You can't convince me that the fuel is going to fall out of suspension there. The injector nearly squirts directly into the combustion chamber.

Old carbureted engines that carry fuel through the intake manifold are the setups where the intake port polishing is an issue.

Just none of that bi-curious stuff..

[WDRacing]

For the record, I agree with the fuel puddling issue.

[nissanfanatic]

The idea behind not polishing the intake side is the same as the theory behind the dimples on a golf ball. The only reason the exhaust side is different is because of carbon deposits..

http://www.sciam.com/askexpert...F0000
Modified by nissanfanatic at 7:07 PM 1/21/2007

[KATwo40]

For the record, I agree with the fuel puddling issue.

Which part? That it'll puddle in the KA head if you polish it?

[eazye2000]

Yeah, not thinking about anything.......It's not a wet-flowing head. So I suppose I could polish it if I want to speed up the air in the manifold before it hits the injector/head. This is my first import/fuel injected engine that I've actually 'got into' like this.

2x 4bbls sitting on an 8-71 FTW

[WDRacing]

That it won't make the fuel puddle...

[KATwo40]

^^^ Right on!

[eazye2000]

Ok, here's a few pics of what I have so far. Probably typical stuff, but I would like u guys to look at the pics and tell me what you think I should do/shouldn't do, or shouldn't have done.. lol But here they are....and not necessarily in order.

[eazye2000]

And here is what I have at the end of the night. Just a bit of rough work, but I'll smooth it all out later. It's going on 6am and my wife is about to get up for work, lol. Let me know what you guys think.

Ok, you guys can say it....

[KATwo40]

Well done!

[WDRacing]

Before



After



The key I've found in a diy port is the getting an exact gasket match. This is your best bet for improved flow. But this has to match both the intake and the head, or exhaust and the head.

Obviously you can't measure the port volume to be exact. But by not removing alot of material, you'll be able to keep the ports "close". Also, the partition that seperates the port into seperate runners should also be looked at closely. Just make sure an equal amount of material was removed from each one.

If you wanted to get technical, a cheap DIY method for measuring the volume is by plugging the valve holes and filling the port/runner with fine sand. Then weigh the sand after...obviously the closer the number the better you are. These can very even from the factory do to casting defects and cast ridges.

For the intake manifold itself. Try getting a flex hone for redoing brake calipes and whatnot. They are usually used for cylinder cleaning, but a small one will fit right into the runner of the intake mani. Get one that barely fits and ream out the runners. Do an equal amount of thrusts per runner and you're golden. Just another idea for you to think about.

They look good so far. I always went over mine with sand paper by hand after.

WD

[eazye2000]

......They look good so far. I always went over mine with sand paper by hand after.

WD

Yeah, those aren't 'totally' done yet. I've found what works good is that sander-wheel-flapper-thingy you can get for a 1/8" shank (dremel tool size) and chase the runners with that. It will even any rough spots up without taking too much material away. Here's what I used so far. Dunno if I'm gonna polish anything yet or not. We'll see.

[Edub1]

Seems like it would help to make that septum part in the middle come together as sharp as possible so as to reduce the amount of flat surface that the air can run into. Obviously air flows around a knife blade better than it flows around a stick.

Remember, angle of incidence = angle of reflection.

[eazye2000]

Seems like it would help to make that septum part in the middle come together as sharp as possible so as to reduce the amount of flat surface that the air can run into. Obviously air flows around a knife blade better than it flows around a stick.

Remember, angle of incidence = angle of reflection.

That is what I've been debating with myself for 2 days now. I've been working on the exhaust side and put the intake side on hold. Should I sharpen the divider like Edub1 says? Or should I round it just a bit to aid in the 'turbulence' because the injector is right there shooting at it? It's obviously thinner, so I can't really put that back, lol But I've been thinking about it as well about whether or not to sharpen that up, or leave it rounded. I've never dealt with a split-runner like this before.Let me know what you guys think. Lets throw some theories around. Or maybe let me know what the outcome is/was from personal experience.

[WDRacing]

You don't need to "add" turbulance. I'll get a pick of a very well done porting job, I just have to find it.

WD

[nissanfanatic]

Make sure each port has the same volume when you are done. Its definatly not the only factor in a good port job, but it at least gets some level of consistency...

And another thing.. I wouldn't focus too much on the intake side. It flows ~240cfm.. The exhaust side is probably the largest restriction on the head. It only flows 180cfm.. I'd work on that side more than the intake..

[eazye2000]

And another thing.. I wouldn't focus too much on the intake side. It flows ~240cfm.. The exhaust side is probably the largest restriction on the head. It only flows 180cfm.. I'd work on that side more than the intake..

What a coincidence. I've been out there grinding my *** off! I can see why the exhaust side flows so little. My hand is about numb from all that ****! I couldn't get very good pictures of it, but if you've ever looked at a KA head on the exhaust side, you'll see why. Plus if you ever hold an exhaust gasket up to the head, you can cut like 1/8" off from all the way around the exhaust port! I'll post pics up in a little but. I'm in here relaxing because I'm about beat...

= all the input!

[WDRacing]

I found those pics, here's an excellent head port. Stock compared to Ported. Very nice job...

[WDRacing]

This is what I use for doing alot of my porting. They insure you maintain the same size runners etc. Flex Hones

[nzmoman]

was the porting on those pics done by hand(do it yourselfer) or was it a shop? I am getting more and more tempted everytime I read stuff in the forum...

Is polishing going to really help that much from a good port job?

[eazye2000]

Aww, here we go. Mo***r F****r showing off making my DIY port job look like S**T !!!! The pics I've been posting are all my own work. (not that great, I know)WD's pics, I assume, are of a professional port job. Or at least someone with all the right tools. You can tell from the pic that the valve guides were removed while they were ported. That's the number one b**ch I have when doing it yourself and you're trying to save a buck. Although not 'all' that important, it does make it easier when those suckers aren't in the way. I got around mine pretty good, but it's still not one hundred percent. You can even grind those little casting humps out of there and cut the valve guide down if you wanted. I don't know for sure about that on a KA head, but I've done it on small blocks before.I'm fixing to post up some pics, so anyone who's surfing the forums will have something in about 5 minutes.

[eazye2000]

And another slew of pictures from tonights adventure.

The next two you can see where I only lapped one of the two intake valves. Shown Side by Side for comparison. The lapped valve is on the left. The greyish color is the new seat that was formed.





This picture shows three of the four intake ports finished. The one all the way to the right still has the gasket ring around it.



^This is after I got done with gasket matching.\/ This is before(sorry they're backwards)









These last two show you just how much was in there before. Excuse the mess but the d**k wads that 'cleaned' my head didn't so such a hot job. They didn't even clean the valves....






Modified by eazye2000 at 1:30 AM 1/24/2007

[WDRacing]

The pics I posted were done by hand, but by a pro. You can see the occasional defect at the gasket area.

Easy, your ports will look alot better once you're done and have polished everything up.

WD

[Swedish Mike]

About the valve guides, I normally grind down the part sticking out. Only a few mm´s in most engines and wont effect the valve stability.Port the exhaust ports to chrome finish, will help you keep the ports clean and nice many miles.

A lot of opinions on the intake side but I always keep them scratched for better air/fuel mixture.The more you can blend air and fuel the better. Less fuel going to waste and out the exhaust.

Looks good, impressive to see people porting at home, most guys can´t handle the time and work effort.

[WDRacing]

It took me two weeks to port my RB20's head. It just never seemed to get finshed. When I started the project, I figured 3 days or so max. Yeah, I was dreaming. Admittedly I went back over stuff alot to keep things as perfect as I could. But attention to detail is a large part of head porting.

Easy, are you having the valves done. A nice 3 angle will compliment the head port.

WD

[KaNasTy]

WD do you have any advise or maybe even pix on SOHC port work. im put'na t66 on it thanx

[WDRacing]

Basically the same thing as DOHC port. Clean up the combustion chamber, and port out the runners as equally as possible.

Use the pics in this thread as an example.

WD

[eazye2000]

Easy, are you having the valves done. A nice 3 angle will compliment the head port.

WD

I just lapped them in is all. I figured I'll let it go for now. I'm gonna save up and get valves, and cams and have everything done all at once later on. I wanna get everything together right now. So yeah, basically I'm skimpin'..

[babowc]

is this on an air die grinder?maybe i should take my spare head off and do this..couldnt you achieve the same thing with an electric dremel? lmk! i'll go take the head off.