DIY port and polish?

[Obin Robinson]

anyone done a basic port and polish on a 924 head before? i've called EVERY place in my phone book and NOBODY around here wants to take on this task. the next closest place i can find to do it is so far away i'd have to ship the head to them and wait a few weeks.

if i follow the advice in this article, can i get some basic performance improvements?

http://www.sa-motorsports.com/diyport.htm

at the VERY least, what about just polishing the exhaust ports? i'd rather get this done before the new engine comes in.

thanks!

obin

[pst]

You can get very good results yourself. If you follow those guidelines you will feel a remarkable difference. The 924 n/a head suffers from very poor port design and casting. This can be improved dramatically with a little clean up.

[Obin Robinson]

awesome!!!! thanks! i am going to do this on my spare cylinder head. that way if i screw something up, then it's no huge loss.

i also found this:

http://www.eastwoodco.com/cgi-bin/sgin0101.exe


thanks!

obin

[Obin Robinson]

Originally posted by mideastmafia:
can you port and polish a 944 head?


SHAUN

yes you can, the improvements are good too!

http://www.huntleyracing.com/heads.htm

944 N/A, 928 2V (X2)
$500 core charge applies

Stage I - Basic re-build with new valve guides, valve stem seals, proper shimming, seat work, fully assembled. Price $500

Stage II - Same as stage one plus flow benched hand porting and aggressive valve seat work (like dyno tuning, flow bench testing is the only way to port and polish). This is not your basic P&P job! We also add .3 to .5 compression points during the surface job. Price $875


obin

[Dave951M]

It can be done DIY but for best results, a flow bench is a must. You can make significant gains with just polishing and matching the runner sizes, we used to use a gasket for the template, you just have to be careful with the grinder, and be sure to thoroughly flush the grinder dust off when finished.

Dave951M

[Obin Robinson]

Originally posted by Dave951M:
It can be done DIY but for best results, a flow bench is a must. You can make significant gains with just polishing and matching the runner sizes, we used to use a gasket for the template, Dave951M

hmm, so the most important thing is matching the intake manifold to the cylinder head intake port... and the exhaust manifold to the exhaust ports?

intersting!

thanks!

obin

[Dave951M]

Yep- they don't do it from the factory on any stock production engine I've every worked on.

One way to check it is to take the gasket for the intake and exhaust, and check the clearance on each part on either side of the gasket. I think you'll find that they aren't the same. This is a really old trick, we used to use it building domestic V8 engines. It does make quite a bit of difference and is cheap to do. The only caution is to not go crazy with the grinder and take off too much metal. One other caveat, don't use a grinding wheel on aluminum, it will only load up the wheel. With it's expansion rate, it is very possible to shatter the wheel or burr. For aluminum, you can use a high speed steel bit.

Good Luck-
Dave951M