[ba] port and polish cylinder head?
thequattroking at yahoo.com
Fri Jul 26 03:50:04 EDT 2002
I am no pro, but I have ported and polished 5 or so heads. It is VERY
tedious work. The last head I did was on a 4kq. It took me 15 to 20 hours
of actual work time to get it done. I was still not happy with it when
finished. That however has more to do with my inability to do any better
(read little experience).
I have a friend who owns a machine shop. He told me an average P&P job on
an American small or big block takes him 7-10 days for both heads (not
working straight of course). He said it is simply cost prohibitive for most
people to have it done.
As for the performance gains, don't expect 10 extra HP. Infact, I would say
expect 1 hp if not none. The difference I noticed is in throttle response
and smoothness of the motor. It just seemed to run "cleaner". It did rev a
bit quicker up top too.
I would personally not recommend doing this with a drill. They are to slow
and lack the ability to control easily. I use a cheap 20$ mini air grinder.
It is useless for anything but this job. I love it because I can go for 2
hours straight and not tire my hands.
If this is your first bout with P&P and flow matching, I would highly
recommend checking out a book or two on techniques and learn them as well as
what wheels are used for what stages of the grinding applications.
Remember it is very easy to take metal off. Impossible to put it back. It
is also all to easy to bore into a water port and screw up the the head.
Before I ever ported anything of importance, I got a junk head to practice
on. Then, I moved to something simple to see how it affected performance.
My choice was a string trimmer. THAT TRIMMER TRIMS!!!!! Then motorcycles,
Jet Skis, and so on. That was before I ever touched a car head.
Enough Audis to give plenty of headaches.
Parting: 1972 Mercedes Benz 280 SE 4.5
> From: "Johnny ." <thesonofdeath at hotmail.com>
> Date: Fri, 26 Jul 2002 00:16:40 +0000
> To: ba-group at audifans.com
> Subject: [ba] port and polish cylinder head?
> Im thinking about porting and polishing my cylinder hea don my 86 4kCS Q and
> im wondering what type of gain i should expect to get out of this? And also
> wondering where i could get the drill kit to do the job myself? Or if it's
> worth it to trade in my stock cylinder head to have it done for me?
> 86 4kCS Q
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