(BR)G-Machine

It is the latter than I am suggesting. The slightly rough surface traps a few of the air particles and uses them as a lubicant because there inter-molecular forces seperate them more than if it were just air on metal. The Colebrook-White formula, which is a negative logarithmi funtion on the roughness (k) side of the equation I am sure works greater than a certain k value then decreases as the k get smoother as alot of formulas do. But that is an interesting forumla, but the scrates in the metal I am suggesting would be like on the microscopic leave, just enought to trap a few air molecules. Although I think skin friction is so minor when we are talking about the moderately fast air molecules. But when you are breaking the sound barrier and the air molecules are traveling, relatively, the spead of sound then it would be a greater factor.

SlowMaro

ok uhm...so should the intake areas after i gasket match look like ) or like / ????

also ho wmuch should i be taking off the valve guides?

Riley's35089rs+

not sure about your symbols..But you should taper the openings 1/2" in....

Mark W. Winning

Well, if more air isnt good then less must be better...right? So, the newest trick mod should be running a cold air intake with a straw as the air tube??!!??


I agree that, as with everything else, to much of a good thing can be bad. If you do a heavy port job on your heads and do not change anything else, you will gain very little, if anything. You may even go backwards. Being a big friggin air pump, the more air you can feed a motor, the more power you will make, BUT the fuel, cam heads and everything else has to support the entire process.

Mark

SlowMaro

what im meaning is, should it be rounded inward from the intake entry wider on the outside then rounding inwards gradually decreasing the width of the opening, ... best way i can describe it is ...like ... ) lol

or is it supposed to be a straight line instead of rounded inwards...like \ /

i just fear eating through the wall of the intake....that and itll take anouther 4 hours to get them like \ / as opposed ito ) (

i seriously need to take a pic so yall can tell me if im doing it right ......ill get on that in a minute.... its about the only way you can tell if ive opened them enough or need more

dimented24x7

iTrader: (2)

as for the surface treatment of teh intake ports, as was said before you want it to be slightly rough. The reason for this is that, although the air is already quite turbulent in the intake port, with a smooth surface, slow moving boundry layers (caused by zero velocity at the surface of the port) will form near the walls of the port and some of the fuel can come out of suspention and cling to the port walls. With a slightly rough surface, small scale turbulence in the boundry layer will form near the surface that helps to keep the fuel droplets in suspention.

gmsmallblockguy

As a general rule of fluid dynamics you would rather avoid the / because angles tend to creat eddy currents. however ending the / with a small ( will reduce that effect.

SlowMaro

well then they stay rounded out like a concave .... like ) i was wondering if the peak of the concave would hurt air flow.

am i supposed to shave any of the top of the valve guide off, or just basicly cut as much off the backside of it as possible....and leave the height alone....

SlowMaro

ok see how i mean its rounded, concave ...like )

SlowMaro

and how much more of the valve guide shoud i take off??? bad pic i know....but you get the idea

SlowMaro

oops

SlowMaro

and another intake

SlowMaro

and just to prove *im not the village idiot....

rx7speed

your still the village idiot to me


as far as the valve guides
not sure

kinda working on a set of pontiac heads right now

I'm cutting away as much as I feel comfortable

but by no means does that mean I'm right

kevinc

Dude, I've read your other posts and even tried to help back when you couldn't figure out how to reinstall your distributor...

...you need work your way *up* to village idiot level.

SlowMaro

you fool, the oil pump shaft was turned 90 degrees and it WOULDNT go in right, and you as well as everyone but one person failed to mention this being a problem.

you go be happy now and think you are the man. im off to lap my valves.

dimented24x7

iTrader: (2)

hmmm... nice to see how many kind and caring individuals we have here

SlowMaro

its all good, im used to his failed attemptions to belittle other members of the board, ..too bad we all werent born with his know it all capacity. im sure ALL of us knew how to work on cars from the day we were born and never had a problem ever.....

hate people who down other people because they didnt know how to do something correctly ...all because no one told them crucial need to know info....

The_Raven

The problem I see with posts like this from man people on many different boards is the way this thread like many others played out, a person starts the thread with some "new found wisdom" from someone they may have chatted with, that may or may not have any merit and no matter what it is, in that conversation where the "new found wisdom" came from, not all nessisary info was explained, or not enough detail.
So then the incomplete info is posted as "end all be all" knowledge and is quickly explained to be other wise or that other info was needed, at which point the thread originator then asks for more info here, usually after a small discussion on "who is right or wrong". get the idea?

BTW this is one long thread.

kevinc

Lack of inherent mechanical knowledge is a problem we all share. The only knowledge I and others have that you (and some others) seem to lack is the ability to read and comprehend.

Here's the big crucial need-to-know info once again...invest in a Helms manual or other solid reference before you get into the engine. Follow what it says to the letter and you'll rarely, if ever, have the kind of problems you have had in the past, and you'll learn about your car along the way. It makes all the difference between frustration and long hours troubleshooting in the dark, versus a nice clean process where every session ends w/ the car runing better.

Posting on the Internet asking for procedures is risky business, because you're depending on people to hork it up from memory/experience. That distributor and oil pump driveshaft alignment thing is covered quite well in Chiltons, Haynes, and Helms books, and wouldn't have bitten you if you had read one.

And as far as my "attemptions" to belittle people...you guys do that yourself without any help from me. All I do is point it out.

SlowMaro

thats funny, this went from my lack of knowledge, to everyone lack of knowledge. make up your mind. so if we are all spposedly stupid in your eyesm why are you even a member of this board? why post? whats your soul purpose of being here? to make a mockery of yourself? if thats the case then youve outdone yourself.. congrats lets all give kevn a hand. better yet, lets just slack him, and give him the finger.

kevinc

OK...call me slow on the uptake here...just figured out I can't drop my IQ low enough to communicate w/ this guy...stopping now.

Riley's35089rs+

"Cant we all just try to get along"

88 350 tpi formula

iTrader: (9)

wow there goes my plans. thanks I guess I will tell my brother inlaw to through his ported heads away! man he almost mad a big mistake!

SlowMaro

thats funny, i was simply stating that its not all is cracked up to be,that in some cases, the wrong method of porting and polishing may very well hurt more than it helps. also the more material you take away from the head, the more you weaked the structural integrity of the head. i was just posting some very justifiable opinions.

MrDude_1

that only happens if you dont do it right.


btw, i would have told you to leave the valve guides alone.. heh, its pretty easy to screw that up... as you found out...

Nixon1

Man...if everyone replied back this way whenever I was in my less experienced days, I would've left this board loooong ago.
Give the guy a break....

MrDude_1

mmk.. wasnt trying to be harsh on him...

but, basicly, heres what i was trying to say..

clean up the ports, and you dont have to worry about any "structural integrity" issues.

also, i never said anything about going near the valve guides.. mostly because thats a really touchy area....

anyhoo... i really wish i saw the post on the previous page... the one right before the "oops" one.... heh...

lil late though.... as for the angle thingy, i have them going mostly straight with a slight curve near the ends of teh port...

88 350 tpi formula

iTrader: (9)

I agree that everyone gets that way on this board (me too now), I remember when this board was the old setup.(black and yellow I think?) it was a lot better back then no one jumped on everone like they do now. I had stopped comming to the board for a long time then when they had a newer setup and my user name did not work and I needed a password. I got around to registering and wow every one was acting like jerks. so I guess I started to as well

OMINOUS_87

I am a DIYer that ported and polished my own heads. Oh boy I sure I hope I didnt hurt the ability of the heads to deliver good performance, LOL!

SlowMaro

so should i have not trimmed the valve guides down?? ...dammit...no one told me not to! i saw them as being in the way lol.....i mean that have like 2-3 mm of material at the tip...i shaved them down lik e apencil, just not nearly as angled, ...its a real nice rounded flow....f they dont brea --prays-- it should actually help alot..... i dunno how much stress the ends of the valve guides get....i doubt they get alot, i mean its in a 4 inch long chamber, ...the very tip of it shouldnt matter...not like it can wobble.....even if it did crack a lil i think it would be all good.....doubt itd would mess up...i hope.....

so how bad did i mess them up heh..

AJ_92RS

Thank you OMINOUS. It's about time SOMEONE got back to the subject at hand. Too many soap boxes floating around.

Slowmaro,

The valve guides are fine. Just try and keep about an 1/8" around the valve stem. It looks like yours are fine. Don't worry.

If you want to play it safe, don't try to do a "spectacular" porting job for your first job. K.I.S.S. Concentrate on the ports, about one inch under the valve seats. Clean and de-burr the combustion chambers. De-burr the intake and exhaust runners.

Then if you feel confident enough, polish the exhaust ports/runners and the combustion chambers. Don't worry about the valve guides. They really aren't in the way as much as people think they are.

Again, KEEP IT SIMPLE S_ _ _ _ _!! (you fill in the rest ).

rx7speed

the biggest problem I would have seen

is you posted in a matter of fact tone

ie
porting should never be done at home

not under these chances might you not port on at up

or could this happen

but rathat if flat out shouldn't be done

that is where most of your problem came from with people bashing you