TNTUBA

iTrader: (1)

I'm just about to finish up my motor project for next season and wanted to share some pics of my head. It's a MSM Head that I have "mildly" ported and polished. I unshourded the intake and exhaust valves, "softened" all the sharp edged and mirror polished the combustion chambers, blended the bowls and tear dropped the guides on both the intake and exhaust ports, Raised the port roofs on both the intake and exhaust ports as high as the gaskets would allow and then mirror polished the exhaust ports. I'm dropping it off at the machine shop on Monday to be trued up and the valve job completed. Hope you enjoy the pics and I hope it makes at least 1/2 of 1 HP more than a stock head would.

Intake Port


Exhaust Port


Intake Bowls


Exhaust Bowls


Combustion Chambers


Full Head


All the best

jbrown7815

iTrader: (1)

Very nice work!

TNTUBA

iTrader: (1)

Thank you sir. I just hope it works 1/4 as well as it looks. With head porting its all about the shape...not the shine. I didn't do anything out of the box. just simple tried and true steps.

squeegee

iTrader: (1)

From Hakuna Miata's anecdotes, you'll notice changes in the butt dyno.
What am I seeing about halfway down the intake?

240_to_miata

iTrader: (2)

injector ports

NiklasFalk

iTrader: (1)

Do you mean the valve guides?

Rallas

iTrader: (9)

Looks real nice. I did almost the exact same stuff on my 96 head. It definitely added more power up top.
I would recommend that you CC each combustion chamber to ensure that the compression ratio is not greatly changed or is changed by the amount that you intended it to. I ended up dropping my compression a good bit with all the material I removed while deshrouding the valves. It will probably be beneficial once I go turbo, but running NA right now it makes the low end a little weak, but once it hits 4000rpm it pulls real strong.

fastivab6tg25mr

what bits did you use for the combustion chambers and polishing? i tried doing that to my head but i couldnt get the bits i have to get in the little nooks and crannies nor could i get the exhaust ports so smooth

Faeflora

iTrader: (2)

So.. how did you figure out that your compression ratio was drastically changed? Compression test numbers drop?

I have 9:1 pistons and a very ported FM head. Stock height head and block. From day one I have only had 145psi on compression test.

Rallas

iTrader: (9)

My compression on the rebuilt motor (stock rebuild) was less than what it was before I pulled the engine. This was with an overbore and a slight head shave to clean things up. It also feels like it has less power down low than before, but that's the butt dyno speeking. This might be accentuated by the very strong pull above 4k though.
The big thing is to check each chamber to make sure your combustion volumes are the same. After all you are increasing the chamber volume by hand, not by a controlled process like CNC or whatever FM uses.

18psi

iTrader: (76)

agreed on checking for consistency across all 4.
otherwise looks like real good work for a diy
good job

hustler

iTrader: (6)

Bauce

JasonC SBB

Did you knock down the sharp corners at the very edge of the combustion chambers?

Savington

iTrader: (31)

Have you ever tried a different gauge? I get ~160psi cold on my 8.6:1 motor, and the 10:1 block in the Rental tests in the 190+ range.

Rallas

iTrader: (9)

145psi does seem a little low. I read ~165ish with my calculated 8.6 CR ratio and cheepo HF gauges.

TNTUBA

iTrader: (1)

I used a mix of an air powered die grinder and a dremmel tool. To get the ports and the chambers that smooth you have to do it in stages. I did "mass metal" removal with a carbide cutter, the moved on to a fine stone, to coarse sand paper, fine sand paper, finishing wheel and polishing pads. I't very time consuming and tedious. You have to be aware that every stage is taking away metal. So you don't want your final port shape to be what you cut with the carbide cutter. You want your desired port shape when you are finished. You need to keep one thing in mind when you are doing head work....it's all about the shape....not the shine.


Good catch. I did cc both the chambers and the ports. The chambers are all within .5cc which is as accurate as my tools were. the ports are all within .5cc's as well. Thanks for the compliments.

Thank you sir.

Yes. All the "once sharp" edges are now smooth. This motor is going to have an actual static compression ratio of 10.13:1 with 16psi boost from a M62 blower on C16. So I needed to get rid of anything that could make a hot spot.

And before you all get your panties in a wad....C16!!! Not pump gas

Rods and pistons have arrived. Hope to have the short block assembled this week, in the car over the weekend and delivered to DIY autotune for a tuning session in early Feb.

mx594m

iTrader: (1)

those pistons are just lovely, just eff'ng lovely

Miater

Very nice work. Im hoping to get my hands on a spare head to port this summer. Are you goin to port the manifold runners to match? Also what intake manifold will you be running?

TNTUBA

iTrader: (1)

^^^ The Intake is still up in the Air. I spent about an hour and a half on the phone with Corky on Friday. If he doesn't build me something one off I'm going to use a squaretop. The price is right on the squaretops right now through Mazdamotorsports Development...and they have them in stock.

falcon

iTrader: (13)

Ok... so I don't know anything about head porting and it looks really nice, but I thought I read somewhere (while researching porting on my own which I decided not to do) is that a perfectly mirror finish is not actually what you want and it can actually hinder flow? Correct me if I'm wrong.