Anyone here done just gasket or match porting on an engine? Experience any gains? With today's engines I think it takes a very good pro to get improvements out of a port and polish job but gasket matching seems like a no-brainer way to pick up a little better breathing?
Biggest gains (usually) are by leaving that totally alone and porting just behind the valve seat and in/around the valve guide.
However, there are special cases where literally any (generic) advice you'll find is wrong.
Probably going to depend on the engine quite a bit. I was going to port match one of my 4AGE 20 valve motors. When I took it apart to look, it was perfect right from the factory. As in you couldn't match it any closer if you tried. Now, on a 1965 straight 6 Chevy, well, maybe you could do better.
Most late model castings are quite good, but there are exceptions. If the ports, and gasket match look good, then the gain will be minimal, if at all.
I'll generally place the gasket on the studs and appreciate how it follows the holes, then repeat on the intake or manifold. Adjustments are made with either an Ex-acto or a Dremel with a small sanding drum.
It can't hurt.
On old 2-stroke motorcycles port matching the barrels - cases - gaskets can make a significant difference. New cars not so much.
my advice.... only port the gasket if it is in the air stream!
I recently had to port match an over ported 4KE intake manifold to a stock head. The manifold had been enlarged so much that the gasket had to be ported to match
ported gasket on top
I've done it. Never been able to feel the difference.
Matching the gasket is a good idea and polishing the "roughness" off the castings can't hurt anything. Its when you bust out the die grinder that you need the flow bench.
I stop at matching the intake and exhaust, making it smooth, a little shiny and removing any obvious casting issues. Otherwise, I'm just as likely to have to trade it as scrap.
As stated, it matters whether the OEM port match is well done. Last one I did was a Neon 2.0 DOHC. The OEM head-to-manifld match was passable, but the manifold-to-throttle body match was sized and aligned pooply, I have no dyno figures to back me up, but I feel I got considerable gains from cleaning it up. Then I put an aftermarket manifold on the fitted head. The match was OK on the middle 2 cylinders, but way off on the end ports. Again, the throttle body-to-manifold hole presented a formidable ledge (thinkNASCAR restrictor plate) that once smoothed just had to give better flow.
NYG95GA wrote: a formidable ledge (thinkNASCAR restrictor plate) that once smoothed just *had* to give better flow.
I found Larry Widmer's site to be informative on "gasket matching" and porting.
http://www.theoldone.com/articles/b16a_head/
http://www.theoldone.com/articles/
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