Port and polish Job on EA-82

[RallyKeith]

Anybody ever done a port and polish job on a set of EA-82 Heads? Anybody done it on ANYTHING that is willing to share what to do and what not to do? Advice for getting the best results?

 

Keith

[archemitis]

yes, the ea82 exhaust side can stand alot of work, as there are two areas, that have large buildup of slag, that acts like a bottle neck. and on the intake side, you can open them up a bit, and clean up the seam where the mold came together.

to be carefull, use sand wheels, instead of metal bits(wich take out alot of metal)

unless you want to sacrafice low end for high end power dont go crazy and hog them out, just clean them up and open them up a bit.

take a punch to the crack between the valves, to smooth it out, and eliminate it as a source for pre ignition.

gasket matching helps line up the intake manifold and the heads, so use old, or new gaskets as a guilde on how much to remove.

basically, if it looks good, its gotta flow better than stock.

just dont exagerate any bit dips, by removing metal from them, the less curvy, and rough a path the better.

have fun, maybe practice on a junk set first.

[calebz]

take a punch to the crack between the valves, to smooth it out, and eliminate it as a source for pre ignition.

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Elucidate please.

[RallyKeith]

From what I understand Polishing the cumbustion chamber and the top of the pistons will keep detination lower. Also, doing work on the exhaust side will only help since increasing the flow rate should decrease turbo spool time.

 

Keith

[oddcomp]

p and p on chambers reduces detonatioon by smoothing out sharp bits of metal

the samll sharp acsting bis that are thinner absorb heat faster and also get hotter and cause pre ignition

 

so yeah pretty much what archemitis said

and also sort aliek eh said unless you know what your doing and can flow test the heads as you do them don't go much beyond just smoothing out casting lines and gettind rid of sharp changes in port angles if you can

think in terms of asthma .. i guess.. the les restriction and smoother the path.. the better a person can breath . same with motors

[archemitis]

also, alot of people end up taking out alot of the hump, that is the right behind the valve seat, but that just makes a sharper angle for the air to turn, wich negates anything you gained by making the port bigger. instead make the space on the opposite side of the hump a little more open, and smooth the hump.

 

on the crack between valves, smack it with a punch, to get the sharp angles of the cracked aluminum mashed back down, not a huge thing, just worth it while your in there. dont fill it with jb weld =].

 

i did my first set on my harley, and messed up, by the end i had a 100cc combustion chamber, instead of the 90 i was goin for. but that was more involved with big valves, and massive amounts of metal being removed.

so just take a piece of sand paper to the combustion chamber, or you will be left with lower compression, wich is not cool =].

also sharpen the valve guides, so theres not a 90 degree angle right there, next to the valve shaft.

 

its all hard to describe with words, just think of water flowing through it. i always think of sticking a stick in a stream, it makes the little ripple in front, and turbulance behind it. so smooth, non abrupt angles is what your goin for.

[archemitis]

sorry, this is my favorite part about building a motor =]

 

you might hear talk about not making you intake too smooth becasue it will cause fuel to pool, and reduce the amount of fuel mixing with gas.

 

as far as i can tell this is bs, with efi or a carb. my harley is almost mirror smooth, and i have no problems.

[RallyKeith]

sorry, this is my favorite part about building a motor =]

 

 

 

Thanks for the input. I'm actually using heads that I bought from CCR for the final build, so I don't need to worry about the crak between the valves. I've got about three sets of heads with that crak though.

 

Keith