Hey guys , my b18a1 burnt a exhaust valve so i took the head off, cleaned up the valve seats and purchased the valves it needed/lapped them in, it goes in on monday for a resurface/cleaning. Anyway, i was thinking of useing a dremel to polish out the casting burs/seams in the intake and exhaust ports to pick up a little more flow/power? would this be a good idea or a bad idea? would it change the dynamics of the head for the stock cams/intake manifold etc? would it do anything? would it be worth it? I love doing that kind of stuff but i also dont want to mess up my head. Any advice would be awesome , thanks for your time.

 

If your just goin in with a dremel you shouldn't hurt anything SMOOTHING out things just don't get crazy trying to port. There are a few high sides that can be polsihed down, on the intake inlet side where the gasket meets there is a lip that can be smoothed. Look near the seat in the bowl for any casting that may hurt flow, after your done I recommend having the machine shop recut the seats on your valves and seats

 

Refaceing the valves and Seats would be nice but its $225 and im kinda on a budget

But thanks for the info, so polishing out some burs/casting seems in the runner and bowl is ok?

 

on the intake and exhaust?

 

Your probably going to need the valves resurfaced. 225 for that alone is a lot shop around.

 

I only pay $90 to have a 3 angle cut onto the seats, have the used valves cut and a 30 degree angle backcut added, resurface and jet wash the head. You need to shop around and find a better shop.
Don't bother with polishing, that won't do much. Just port match the gaskets, and remove the casting imperfections.

 

my advice is to not get crazy and do any actual "porting" unless you know exactly what youre doing.
Minor blending and gasket matching should be ok. Just use good judgement and keep in mind, its expensive to fix a bad port job.
If your not going to get a valvejob, be very careful to not hit the seats. You really should get a VJ though. Since everythings all apart. Kinda like rebuilding an engine with the same rings...
Id have a shop check the guides too. Worn guides will ruin a valvejob quick.

 

well i live up in canada and everything is retarted expensive here , maybe when he said 225 he ment to have new seats installed, but it does seem high, i would like to get it done but after i lapped all the valves in the seats really dont look that bad, they are making good contact with the valve. when they reface old valves dont they take alot of the margin off the valve? that cant be good.

 

Lapping old valves in ruins any decent valve job, very minimal amount is cut from the valve when they are cut is not bad in any way when done proper.

 

Well whats the point of lapping valves if it ruins the job?

 

A valve job performed on a sunnen or newen doesn't require lapping. They are highly precise pieces of machinery.

 

if your not paying to get a good valve job, don't waste your time polishing or smoothing. It won't give you anything. If you had a good valve job then you could pick up more flow then the polishing would give you. And you would have to do anything else but bolt it on the car when your done. On a budget, I would lap the valve in, and run that thing. Your not ruining anything because you don't have anything extravagant to begin with.