I'm going to starting a porting job next week. Plans are to not get to intense with the porting, since its my first time. Mainly just clean things up, polish the combustion chambers, port matching. Is there any thing I need to do to a Poston intake other than gasket matching? I've printed off the porting instructions by Charlies Evans, But not any info. regarding work that can be done to an intake, if any. Any help would be appriciated.:grin:
One thing you want to watch out for. Make sure the intake manifold ports are the same size or a little smaller than the intake ports in the head!!:Smarty: Same goes for the exhaust side. Make sure the exh. ports on the head are smaller than the header. Gives a little bit of anti-reversion help that way.
Thanks Scott. I would not have thought of that. Stand to reason you would not want your air flow to run into an obsticle you created though. Thank again.:grin:
yeah so far i ported out one of my 70' heads and the poston's intake, but the first time around i screwed up one of my 70' head's so im looking for another, one thing make sure you see your port lines because when your diegriding you get to those lines real quick, good luck:TU:
One other thing....once you touch the carbide bit to the metal - KEEP MOVING!!:Brow: The bit has a nasty habit of 'burying itself' if you stop or slow down too much.:eek2:
Thanks for the warning Josh. Don' think I'm gonna get to radical with the porting. Just clean up the ports and polish the exhaust side. Polish combustion chambers. Someone mentioned to me that i ought to have the valve seats, I believe he used the term hogging them out. What is this process?
One more question. Do I need to cut the divider down on the intake? Read something about that a while back.
David - Take a look at this. Should give you a basic idea what a 'bowl hog' looks like. Basically, it's a quick way to remove the unwanted material that is below the 60* cut of a 3 way valve job. Alot safer than porting that close to the seat.:Brow:
Photos? David! This interests me as well; I think the only time you can gain from this is at high rpm:s, sacrificing the low rpm. Then again, thats just me! uzzled: And if proven wrong, then I learned something new (again) :error: BTW if you got a 350, is it possible to take some photos during the port work? This will be off big interest for me! And lot off others to Im sure! I am planning to do some port work my self next spring! :TU: Lars
gsxmen that file didn't work..............i just ported all the way to the seats and was very careful............i probably have 2.5 lbs of shavings or more out of the one head i have yet to to the header ports all other ports are done............i wouldn't mind seeing some of this literature on how to port
i guess i gotta have the pdf file format to view this cause it keeps coming up file unknown, i think that's a macintosh program???
I finally finished the port work on my heads. Didn't remove a lot of metal, just got rid of the casting flash. Smoothed and polished the exhaust runners. Left the intake side unpolished. Ground the valve seats down on both sides a little. Polished the CC's. Gonna do a gasket match on the intake in the morning. New valveguides and a 3 angle valve job next week. Had a valve job done a year ago. Turned out to be a patch job. Guess thats what i get for not tearing the heads down last yr. myself. The valveguides were probly wore out then. The guy didn't even replace all the valve seals. He did replace all but five of them though. What a prince. Needless to say, he will not be doing any more work for me. I'll take some pick before I put her back together. I appreciate all the advice from everyone.
Heads are at the machine shop now. 3 angle valve job,new bronze guides. I'll take some pics when I get them back. Hopefully tomorrow. I would like to get it back together and running by monday.
Lars there are some nice pics of some home porting in the "wenching secrets" section, if your interested.
