in the process of porting out my head... was wondering what to do for more power and efficiency... is it better to leave the swirl style ports as is or can i shave off the lip and make it a more direct airflow passage??like the 20r head? will removing all that material in turn drop my motors efficiency too much??
Match porting the intake to head reduces distortion and is positive. Never polish because it causes fuel to collect and stream, so a ruff but not very ruff port is good.
Gasket match is the first thing you should do. Its easy and doesnt hurt anything. What intake do you have? The carb'd 22R intake blows.
gasket match port and polish the exhaust side. don't polish intake side, you need the turbulence for the air/fuel mixture.
yeah i figured match porting would be the first thing i do when i get the gasket for now i have an EFI intake and a carb intake..also have a cannon sidedraft intake bt no sides interesting... i figured polishing intake side would give better flow?? but your reasoning for the cons makes alot of sense too! really got me thinking soo what about removing the excess material in the intake side of the head to eliminate the swirl induction style that the 22r head has? i know torque would drop bt how would it do for topend?
Would I remove the "swirl" if I was to do it to my truck. I mean come on, my hybrid motor has huge intake and exhaust ports, is mildly cammed and still has decent low rpm torque. The stroke is soo long that it helps it a ton. But where you really see gains (In almost every motor) is in the bowl area right above the valve. If you could imagine it, I cut mine out bigger than the valve seat. By quite a bit too. This was factory valves on a ported 20R head. Ran really well. And here is with big valvework done (seats put in, but not matched to old porting. and re-matched (and ported some more) This is how it is now.
Deburring the whole intake manifold and match porting the intake with emery cloth is the way to go, deburr the combustion chamber, be careful not to remove to much material, if you remove to much you will lower your compression . Check to CC's when you're done, deburr the exhaust port, and match port the exaust gasket. Polishing the exhaust doesn't do anything because after a couple hundered miles you will have built up enough carbon it wont matter. If you dont remove a bunch of material during porting you will not loose any bottom end. The greatest compliment to your work would be larger valves. What your hard work will get you is faster thottle response, the power gain will depend on the other mods you have done. And best of all if you dont change your driving style you will get better gas mileage. Starting in the late 70's people would brag about porting and polishing. But as technology got better we found that it didn't help but hurt the atomization of fuel. By polishing you create a surface for the vaporized liquid to accumulate like condensation on glass. Leaving a mildy ruff surface prevents this from happening. Deburring and smoothing prevents distortion, or tumbling.
awesome info guys just to be safe im going to rip off as much material as i can on my spare trashed head... just to see when enough is enough!
