Port and Polish Job on a Clone Engine

Status
Not open for further replies.
A

AMMFAB

New member
Messages
57
Reaction score
0
Location
Phoenix, AZ
ok i never intro'ed myself but my name is mike and i do race car fabrication, engine building/ fabrication and head porting as a side gig. i did a quick search on head porting on here and didnt find anything that is a good representation for u guys on what a professionally ported head looks like. so im making this the thread for that reason. heres the scoop for the head pictured below...... my machinist had a guy that came in and wanted his clone head ported about 2 weeks ago. he got ahold of me and after a bit of talking i got an idea of what he wanted (not that theres alot to them). so i went ahead and got to it.... got about 3 hours in this thing and i was very happy with the final product. unfortunately i did not do a valve job on it as the customer said he was going to do it himself.... i can only assume he was going to use stones cause i know he doesnt have a serdi or sunnen or anyhting like that. this is for a 15 hp 200cc clone thats goes on roundy round dirt track kart. lmk what u guys think and if u have any questions just ask...


before intake port...




after intake ports....














before exhaust port...




after exhaust ports....















mike
 
A

AMMFAB

New member
Messages
57
Reaction score
0
Location
Phoenix, AZ
The first two images are before and after of the combo chamber.....

like i said the guy wanted to do the valve job himself... sad cause it would have looked similar to the last image....

mike
 

Attachments

  • IMAG2023_zpscd75fef0.jpg
    IMAG2023_zpscd75fef0.jpg
    63.1 KB · Views: 82
  • IMAG1994_zpse707c0c1.jpg
    IMAG1994_zpse707c0c1.jpg
    65.7 KB · Views: 89
  • IMAG1945.jpg
    IMAG1945.jpg
    260.1 KB · Views: 88
Last edited by a moderator:
G

gvfc2

wishing i was living
Messages
943
Reaction score
1
Location
Tacoma,wa
cool. nice and shiny too. how much does it cost to have it professionally done? for like say a 212cc clone
 
fowler

fowler

New member
Messages
5,463
Reaction score
0
Location
Bullsbrook West Aus
To make the path of the engine gasses easier

So the OP polished the exhaust and intake ports to make them "slippery" if u will

In the factory they cast the head and mill only the minimal amount, so the gasket surfaces and valve areas

They leave the lumpy texture on the rest as the cost to polish everyone of them in factory isn't worth the advantages u get
Sometimes u can get in there with a burr bit and enlarge the openings and trim off the corners of passages

If u don't know what u are doing u can stuff it up pretty good

U can do the same proccess to any engine
 
souperman000

souperman000

New member
Messages
2,466
Reaction score
1
Location
Westlake Village, CA
fowler said:
To make the path of the engine gasses easier

So the OP polished the exhaust and intake ports to make them "slippery" if u will

In the factory they cast the head and mill only the minimal amount, do the gasket surfaces and valve areas

They leave the lumpy texture on the rest as the cost to polish everyone of them in factory isn't worth the advantages u get
Sometimes u can get in there with a burr bit and enlarge the openings and trim off the corners of passages

If u don't know what u are doing u can stuff it up pretty good

U can do the same proccess to any engine
Click to expand...

That makes sense. Thanks for telling me. :D
 
A

AMMFAB

New member
Messages
57
Reaction score
0
Location
Phoenix, AZ
gvfc2 said:
cool. nice and shiny too. how much does it cost to have it professionally done? for like say a 212cc clone
Click to expand...

first off ide like to say what the term "port and polish" actually means...... "porting" is the material removal of the port walls in certain or key areas to allow air to flow more freely into and out of the engine. whether it be to hog them out to gain lots of air flow for good top end power and sacrifice some power and tq down low or to hit certain ares with minimal overall material removal for a good over all increase over the whole power band. the "polish" is just the cleaning up of the rough u could say "choppy" surface texture of the port walls that the porting tools (carbide burrs) leave. it does not mean to actually polish the ports to a mirror smooth finish. ill get into that later.

gvfc2......ive looked at some of the companies on line and they charge up to 300.00+ for ported heads with larger valves and stiffer springs. for the time i put into this into this head i dont see charging more then 150.00 with the porting, machine work and assembly with stock valve train parts. i havent looked to much in the aftermarket valvetrain parts just yet but i may soon here. even if after market springs and valves were installed i still dont see charging more then 200.00.

as for porting..... as fowler mentioned, basically its to enhance the air flow going into and out of the engine. the more air u add in the cylinder (with the correct amount of fuel of course) the bigger "bang" u get and there for a more powerful power stroke. that in turn it turns the crankshaft faster and with more "umph" on it giving u better throttle responce, power and tq. couple a ported head with a bigger cam, free flowing exhaust, a rejetted or bigger carb and governor removal and i would imagine u could double the output of a 5 or 6 horse pretty easily.

what u dont want in a ported head especially on theses little carburated engines is a mirror smooth finish. which alot of people think is what u want and they are wrong. if u notice i have a bit of a texture on the ports walls and thats on purpose. it helps the fuel to stay atomized as it enters the engine instead of "falling out of vortex and pooling" some people say. now techincally u could make the exhaust mirror smooth as there is no fuel to keep atomized in there but it wont help power any and is a waste of time IMO. the only thing that doing a mirror finish on combo chambers or exhaust would help to do is the slowing of carbon build up over time. which i dont think these things go for long enough to ever build up enough carbon to start to effect air flow.... but i could be wrong. anyways theres my quick lesson in head porting. if u have any more questions just ask and ill answer to the best of my ability.


mike
 
FatCat

FatCat

2 stroke Addict!
Messages
459
Reaction score
0
Location
Ottawa, IL
He is spot on with the polishing. Good info to share as many don't know this. I think the "ported and polished" bs is what puts that assumption in peoples head. Your sharing real engine builder info now.:thumbsup: better quit or they'll start keeping up.:) Very nice work by the way.
 
A

AMMFAB

New member
Messages
57
Reaction score
0
Location
Phoenix, AZ
FatCat said:
He is spot on with the polishing. Good info to share as many don't know this. I think the "ported and polished" bs is what puts that assumption in peoples head. Your sharing real engine builder info now.:thumbsup: better quit or they'll start keeping up.:) Very nice work by the way.
Click to expand...

its taken me years to get to the level I'm at now...... If they're gonna catch up it will be a little while lol, And thanks for the likes guys.


Mike
 
G

gvfc2

wishing i was living
Messages
943
Reaction score
1
Location
Tacoma,wa
i vote sticky too. so people can see what a pro doing it looks like. so they can compare theres to this and see how it looks
 
landuse

landuse

Moderator
Staff member
Messages
18,626
Reaction score
224
Location
Pietermaritzburg, South Africa
OK. I have stickied the thread. If the other moderators are in agreement with me it will stay stickied. I have also tried to find some info on the forum regarding porting and polishing, and it is hard to come by
 
Status
Not open for further replies.
Top