I am just curious how long they are actually effective. I know you can get some good gains from them but how long do those gains actually last for? if you look inside alot of intake manifolds they get covered in oil and blow by. Same goes with the intake and exhaust runners of the head. Once they are covered the port and polish is kind of useless unless everything is unassembled and recleaned.

some insight into this would be nice. Thanks you.

 

Correct me If Im wrong but a port and polish consists of making the IM bigger. ANd then its polished on top of it

 

I think it would be harder for build-up to stick to a polished surface than factory cast

Port matching would not be affected by build up

I think power loss(if any) would be spread out over such a long period it would not be noticeable. A dirty port&polish job would probly still make better numbers than factory IMO

 

Acidcrakker, what you are thinking of is called port matching. You ink the IM to the size of your head after a port and polish has been done to the head. You then file away the un inked areas to make a flawless transition between the head and IM.

H22luda720, that makes a bit of sense. I guess my question is more, how long does it take for blow by to happen in the IM and runners? the second you have blow by sticking to the head and IM the air is not really benefitting from the P&P because it is now travelling along uneven gunk instead of the polished metal.

 

There is to many variables across different engines, builds, and tunes to accurately predict how long it takes for build-up to occur.

I don't think the possibility of build up affecting flow is enough to outweigh the benefits of a good/proper Port & Polish.

 

hmmm ok. I was just curious so i thought i would post my question. Thanks for the reply. I'll just get a catch can to try and prolong the inevitable.

 

port and polish has to do with the head. There isn't a generic port and polish. You send the head to the machinist and they reshape the port runners to flow better and cut the valve seats at multiple angles so that the flow rate increases...or at least thats the idea behind it.

If you keep your engine maintained you wont have a problem with carbon build up.

 

Valve jobs do wear out over time. Ask any porter and they'll give you their own estimate on how long the valve job will "last".

You won't so much not run right as you will just start to lose some CFM as the cuts wear.

That is the only aspect of a head job I'd worry about wear and tear on.

 

Thanks guys.