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SOHC Port match and polish (illustrated)

For those of you who are curious and don't really understand why head work can/is so expensive I pulled this write up so that anyone can kinda see what goes into just a mild port job.

Here we go. I dug these off another site from a head I did on my Hatch when it still had the SOHC motor in it. That was a monster of a N/A SOHC motor!

Ok, so here's where I'm starting at on one of my Single cam heads...

Got a fresh surface on it so I'll have to be extra careful of that.

The valve job and start of the ports. Nothing you haven't seen if you've been keeping up.

Unmollested exhaust port...

Unmollested Intake port...

All the rest of the goodies!

Close-up of the intake and it's ports. I'll be smoothing out the casting inside here for maximum efficiency.

The icing for this proverbial cake! Powdercoating...Mmmm...

Haha!!!! Yeah right!!!!  

Check this out! This is the home made port bench we have. It's quite nice actually! Smile

Ok, so remember how I said I was gonna have to protect the fresh surface? You'll laugh, but this is how we acomplish this task...

Duct Tape!

Get it up on the bench and trim it out so we know where we're working.

I'm goin to be 'Port Matching' this head and this is how we start that process. Put the desired gasket up there so we can map out where all we need to go...

Break out the Prussian blue...

And dye the head so we can get an acurate map...

Remove the gasket so that it doesn't get chewed up and you have a nice clean stencil.

Repeat the same for the intake side.

Our little metal muncher...

Here we go! No turning back now!!!

Get all the heavier cuts removed...

Then we move on to shaping and sanding...

Gotta get down in there and blend everything together making it as seamless as possible... That little line going up the port is the casting line. That is what we are ultimately lookin to eliminate in this venture.

After we get done with the manifold side we flip it and start to dig out the valve side. Since this head already had a valve job done on it, that makes it that much more difficult to maneuver around in there because you have to make sure not to hit it with the sanding roll.

Next we move on to the exhuast side...

It undergoes the same treatment. Dig out the big parts first then go back and sand and finish.

Little comparison...

...and done!!! 2.5 hrs later Razz

I'll be ceramic coating the exhaust ports next!

It's crazy because after we do this the ports look so slick that they look greasy. It's like almost Powdercoating them just with ceramic instead.

Got around to putting this bad boy together this morning! Well, got the valves in anyways.

Starts like this...

Put all the parts out on the bench, get em organized, assess inventory then assemble.

We put a little oil on the top of the guides before we shove the stem seals on. This keeps the stem seal from grabbin the guide and tearing. It also ensures that it seats on the guide all the way.

Slip the spring shim on first... These keep the bottom of the spring from eating a ring into the head from the constant pounding that they hand out and it also helps with what is called deflection which is where the spring will try to walk from side to side. If that were to happen you would, over time, experience premature wear on your springs, broken springs, or bent valves, or even all of the above.

Now for the stem seal. To put it on we use a stem seal installation tool that comes with a large variety of different cups and pilots for the wide variety of heads that we actually do have come though here.

Line it up with our guide and all it takes is a good firm push.


Repeat that 16 more times and we're ready to put the valves in.

Oil the tops of the valves so that as they pass through the stem seal that it doesn't tear that new stem seal. This also lubricates the guide as well so that the guide and valve don't rust together and stick open the first time you try and start it up. How tragic and frustrating would that be? Yeesh!

Springs are next. Let's take a moment and talk about springs... There is a certain way to install springs. Yes a right and wrong way for valve springs. Too many times have I seen someone bring a head in that the cams keep getting chewed up on. This is some times due to poor installation. All factory Honda valve springs are progressive. Means they get a tighter wind towards the bottom. This is where the spring does most of it's work. The progression also helps eliminate sympathetic waves from coursing through the spring which again could lead to spring failure. Dual springs act as the same purpose. So if you get a head re-done at a shop, make sure to give it a really thorough inspection before handing that person your hard earned cash!
Springs installed like this Will screw a cam up in a hurry!

Lay all the springs up there and get the keepers together and ready to go!

They're so TINY!!! Here's the installation tool for putting keepers on! Smile  Makes life SO much easier!!!

Basically the same operation as installing the stem seals. Line up good and push!


Everything is repeated for the exhaust side.

Yeah Yeah... I forgot  to put one of my exhaust valves back into the bag o' parts after I was showin some of the guys the back cut on the valves.

There it is!

Unfortunately I never got actual numbers from this head/motor combo but I have testimonies that a stock B16 in the same trim car couldn't catch it.

sticky this. great info.

Thanks alot for posting this great information I cant wait to use this for my DIY port job excellent work.

thanks for posting! gonna try that on my spare heads.

Looks nice, I see it says you never got any number from the motor I'm assuming you mean hp. Did you get any flow bench numbers to see what kind of gains you got over a stock head?

No.  Sad  Wasn't able to get those either. Sorry.

Do work.

Great post. Very helpful info here. Thanks!

89ef2 wrote:
Do work.

Used to. Trying to get back into it. Confused Forum Index -> Drivetrain
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