is head porting really that hard?

[birdman]

i just got done reading a whole walkthrough on head porting and i cant say it looked easy but it didnt look that hard to do a basic port and polish job. the walkthrough was on some 305sbc heads, would the LQ1 heads be totally different or roughly the same idea? and is it possible to really screw up these heads or as long as you dont go crazy is it fairly safe? any info appreciated. thanks.

[Superdave]

It's easy to screw them up but that's no different than any other heads...

i spent a good 20 hours on my 3400 heads to make damn sure everything was right.

[birdman]

ok well i guess part of my question is besides grinding into some other passage or messing up the valve seal, what else could i screw up? does the polish job have to be really good and is it easy to screw up around the valve guides and inner radius? thanks.

[ryan.hess]

you could have different ports different sizes, which will really throw off tuning.

[birdman]

hmm. would having the ports very slightly different be worse than stock or would it just not be as good as it could have been? thanks.

[RebelGT]

theres no way to determine if things are slighly different or way off with out the right tools. Just send them to ben, and he'll get you setup right.

[birdman]

ben dosnt do them right now. he's finishing up the pushrod heads and then hes got to test the dohc heads before he starts doing them.

[ryan.hess]

I don't know how the stock ports are, but I would assume they're fairly close from the factory. However, once you start eyeballing things, and grinding them with your rotary tool, all bets are off. They should be flow matched.

[Superdave]

My eyeballs are pretty accurate


I basically ground everything smooth and to the general shape i wanted on one port.. made a few templates out of plastic for the various places in the ports and used them as guides to make everything even.. worked out pretty well... the only thing i brown-eye'd was around the valveguides.. but all i did was smooth those out and get rid of the casting flaws.


Judging by my BLM's of 148 they're ported pretty well too

[birdman]

thats about what i planned on doing but im still not sure. if the ports didnt match what would happen? less than stock performance? or better but not real good?

[fieromadman]

http://www.fiero.nl/forum/Forum2/HTML/068893.html

You can see what Im doing/did there. I havnet finished them, But plan on doing so. I might actually sell them because I got a free set of brand new heads that I would like to port instead. Hopefully if I ever get time I will have on or the other on this summer yet.

[butchville]

easy port tool

something i use for porting is a 1/4" steel rod to fit air grinder cut a slot in it 1" deep use 1" sanding cloth rolls cut an doubled slide it in the slot cut in rod grit out. i've used bolts with the head cut off an you can make them as long as you need to get clearence with grinder. also you can flip the sandind cloth to use other side or slide a little cloth in the slot an wrap the cloth to any size you like to make your own rolls. you might want to invest in a carbide burr 22.00$ for roughing use atf fluid to keep from clogging the burr have ported cast iron an a alumium heads for multible engines with same burr. seems to hold up very well. the best tools are the ones i made. good luck.