im in the process of porting and poishing my b16 pr-3 head and was wondering how far to go with the polishing? i have consentrated on one combustion chamber and have got it to a highly polished/mirror finish, going by pics on sites like endyn it would seem i have taken it too far as theirs are rougher than mine. i was just wondering what the best finish is to have and why?

any help much appreciated, thanks

 

Don't polish it to a mirror finish.

https://honda-tech.com/zerothread?id=2205908

 

Do several different heads with different finishes and let us know which dyno's better.

 

The best way is to do the same head and just sand the chambers to different grits for each test,that way it takes out the variation of the castings/porting.

 

Are you deshrouding the valves also?

 

im not sure what all the terms mean, deshrouding? pictures speak a 1000 words so i'll let them do the talking...









any opinions and critisism welcomed
thanks

 

you should have never touched that head if you dont know what those terms are, read and learn before you get yourself into trouble, or ruin things.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by sirdeus &raquo;</TD></TR><TR><TD CLASS="quote">

any opinions and critisism welcomed
thanks</TD></TR></TABLE>

oh lord heaven mercy!

 

got to start somewhere, even if the head is not used having a go is an experience.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by sirdeus &raquo;</TD></TR><TR><TD CLASS="quote">im not sure what all the terms mean, deshrouding? pictures speak a 1000 words so i'll let them do the talking...


any opinions and critisism welcomed
thanks</TD></TR></TABLE>

What are you trying to accomplish? Just trying to practice, do you plan on using this head? The polishing job looks good, but you really should do some research before you attempt to learn how to do ANYTHING correctly and efficiently, otherwise your just wasting your time, materials, and money.

 

to be honest i had this head in my shed and have got hold of some crower cams, springs, retainers and was going to build this up with new valves, guides and seals so when it came to installing valvetrain i could save time. i wanted to give p+p a go so i thought what the hell if all goes wrong i still have my old head. if this head turned out good id use it if not no loss. sometimes the best way to learn and gain knowlege is to get stuck in.

so what is wrong with what i have done? can it be fixed?

 

im sure it can be fix, maybe Mr. 80Grit can answer some questions.

 

80 grit paper? surely that is a bit extreme. i started with 180 then 400, 600, 800, 1200 then finished it off with AUTOSOL abrasive paste.

 

lol not one pic or description in endyn's site does it say to super mirror polish the chamber..

an 80grit isnt extreme.. its normal i use that myself..

it would be extreme if u wet sand ur paintjob with 80grit..


if the air fuel mix had eyes? theyd prolly love that chamber u did.. sadly they dont have eyes? lol

 

You did no real damage to the head,you just wasted alot of time thats all.I hate to tell you that you should go back and repolish w/180 or so but thats all the chamber needs.Cylinder haed flow isn't something you just "get stuck into" it takes lots of experience and knowledge to know what and where to remove material and maybe even add material to make ports flow better then stock.
I hope you had fun at least

 

Read up as much as you can on head porting, atomization, boundary layers, etc. As others have said, you didn't really do any damage, the fuel will most likely not ignite properly with that polished of a finish.

 

It would never work...but it sure looks good! I agree with ed, you didn't do any damage except to your lungs and your time..I say hit it with 120 grit though, get a valvejob done

 

so what can you polish on the head ? Basically it sounds like the exhaust port and deck and thats about it correct ?

 

Exhaust port is the only thing that gets polished. DO NOT TOUCH THE HEAD GASKET SURFACE/DECK WITH ANYTHING. Other than a proper head milling machine at your local engine shop.

 

pls dont polish the deck lol.. that is to be done by a surfacing/milling machine

 

so no harm done thats good news, thanks for all your imput, im off to do some more reading. the hardest bit was trying to smooth out the area's directly between the inlet and exhaust valve seats. do you guys use die grinder/dremel type tools or just sandpaper and elbow grease?

thanks again.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by GhostAccord &raquo;</TD></TR><TR><TD CLASS="quote">Exhaust port is the only thing that gets polished. DO NOT TOUCH THE HEAD GASKET SURFACE/DECK WITH ANYTHING. Other than a proper head milling machine at your local engine shop.</TD></TR></TABLE>

good info guys thanks.

 

Look at the differences between the two sides of the chamber. On one side, the left with the intake on top, the casting humps from the top cut sweep are nicely blended out, but on the right , they are still there, just mirror polished. It is fairly obvious in the 4th pic. Please have a VJ done as you have already damaged the seats.

 

Question...

Would any carbon build up help deflect/insulate heat away from the head?

 

I'm pretty sure carbon retains heat in the combustion chamber. It can also cause hot spots that could lead to pre-ignition/knock/Ping if it is a bad enough.

There shouldn't be all that much carbon build up in the CC itself. There maybe a small film of it but a quick blast with carb cleaner should clean it right off. It is usually found to be a bit thicker, and tougher to clean, in the exhaust side of things. IE exhaust valves and exhaust ports. That is why a high polish is desirable on the exhaust side. It helps keep the carbon build up to a minimum.