[MK 72 240]

I also posted this in Banter and Chat......(Just so you don't have to let me know I repeated...hehehe)

okay in the how to modify..... book it says that when porting you need to get all the ports the same size...Now i should be able to get them very close but does it really have to be exact when the stock version has so much varience?? Like the average difference is around .020 or more...

Also in the valve area on the head the combustion chambers are all different to...some have ridges and some dont they just don't look uniform...now should I go ahead and smooth these areas out and go for more of a well rounded dome? and should I enlarge it to the area that matches up with the opening of the head gasket? ( I have a carbon ring on the flat part of the head larger than the combustion chamber of the head...ya know what I mean??)

I am pretty confident from what I have done so far that I can get some pretty precise ports and all but what will happen if I don't get them exact? Is it safe too assume that is is safe since original was not perfect?

If anyone else has done their own heads and you have any picts. or pointers please let me know...

Thanks all....more to come probably!!!


Z ya later
Mike K

 

[Andrei]

the reason for getting the ports all within range is so they folw the same ammount. they don't have to be the same size. all they have to do is let the same ammount of air/fuel through at a certain air speed. porting without a flowbench is not advised if you are planning on getting the most out of the head. the ports could even be .05 different, as long as the flow the same ( unlikely that the casting job is so poor) Good luck with this, and remember, if you make all of them the same size, you might end up with one or 2 cyl. running a lot leaner then the rest, causing premature wear on the parts.