Question:

I was wondering if port and polishing is really that beneficial. It seems that over time, the head is gonna get carbon caked anyways, so why pay $5-600 for a port/polish job for an extra 10-15whp that will go away in a matter of a few months....

am I missing something, or am I right in saying that its all a hype and not worth the money?

 

Check this out: go buy the book (slightly outdated but good nonetheless) "Honda Builder's Handbook" Volume 1 & 2 by Joe Pettitt. It should be in your local Barnes & Noble...that is where I got mine...It is a very well written, informative book that digs heavily into the technical side of things. It will give you the answer. I don't have the books with me as I am at work...
EDIT: I think that the P&P would make things smoother and prevent excess buildup in the head and combustion area and the head would flow better. Besides, If it is tuned properly you shouldn't have to worry about excess buildup I would think..........just my .02.


[Modified by GTlvr82, 5:41 AM 3/2/2003]

 

hmm...anyone else?

 

There will be some carbon build-up yes, particularly on the exhaust side. This will occur whether the head is ported or not. Porting it will clean out what's built up and enlarge the ports so whatever build-up returns is less restrictive. Plus once it's ported you can always take the head off every year or two and clean it up again. It's not like the ports are going to close up or anything. An engine is a big air pump so anything that helps it breathe better is beneficial.

 

sorry to hijack thread, but what kind of gains can you expect to see out of a port and polish on an otherwise stock sohc?

 

That will depend entirely on the skill of the man w/ the porting tool. Joe Alaniz suggested I'd see gains of 8-10% w/ a competition head ported by him for my GSR. Given his reputation and experience I'm prepared to take him at face value.

 

Good Tech

 

I don't know where you plan on getting your head port and polished. I payed less than 300 for a 3 angle valve job, port, polish, and mill.

 

Replika Maschinen inc. Home Page

you get what u pay for gains on P&P depends on mods you have done to ur engine.




[Modified by DC2Slow, 5:07 PM 3/4/2003]

 

Well Porting the head, or what it shoudl be called "reshapeing the airflow of the engine" is bennificial. When a 16yo with his EX port matches the head, it does nothing. But an artist with a flowbench and practice reshapes the ports and can weld up or grind the ports to be more paralell with the valve. Removeing or adding can greatly increase the airflow of an engine. Its all about changeing the "port angle" to be at a smaller angel to the valve. But on the other hand, if youre engine flows 200cfm and youre headder flows 25 cfm you are gonna get backpressure in the motor. and that is gay. So makeing the whole system flow is the other half of performance mechanics.

2 things needed Artist/Porter and a flowbench.

 

One of the biggest places to improve is the bowl to seat transition. Basically
since this is already done on the ITR, not much more work would probably be
beneficial for you unless you wanted to squeeze every last ounce out of it.
I might get oversize valves and machine the head to match, but otherwise i
do not think your head needs much more work if any.