Polishing the Runners, What works Best

[RacingJake]

What work best to polished the runner inside the head. A friend of mine uses a tennis ball that is cut down and says it works great. Does anybody else have any better idea's.

Jake

[SqDancerLynn1]

Check this site:

http://www.eastwoodco.com/Department.asp?SKW=TBU7&Dep_Key1=mfb&Cat=Surface+Conditioning&SubCat=Abrasive+Rolls+%26+Tapers

or kit

http://www.eastwoodco.com/itemdy01.asp?T1=13149&Dep_Key1=mfb

[RacingJake]

Thanks for the link, that's just what I needed. I ordered a engine port kit, some more tapers and grinder's grease for around $30.

Looking at the exhaust ports where the exhaust gasket goes there is alot of metal with a flat area that needs to be removed. I say about 1/4 inch around the exhaust gasket area needs to be remove for a smooth flow.

Jake
1100E

[Anonymous]

If you can afford it, the new thing is "extrude honing". Basically they put a play-doh kind of stuff that contains abrasives in the intake and squeeze it through repeatedly. It cuts all the lumps, bumps, casting fins, and such right out, without changing the shape, area, or radius of the runner.

Don't polish your intake to a mirror finish unless you are running multiport fuel injection. A mirror finish will thicken the boundary layer and cause your mixture to separate on the walls of the runner. You want it smooth, but not slick. The extrude hone leaves parallel longitudinal scratches that keep the boundary layer stirred up to prevent this.

[Anonymous]

If you can afford it, the new thing is "extrude honing". Basically they put a play-doh kind of stuff that contains abrasives in the intake and squeeze it through repeatedly. It cuts all the lumps, bumps, casting fins, and such right out, without changing the shape, area, or radius of the runner.

LOL! I saw extrude honing being advertised back in the mid 80's as a "new" porting technique, at that time...It was probably older than that, too. After that initial bit of publicity, it seemed to drop out of sight for a while. I guess it's back; what goes around, comes around.

I'm not knocking the idea at all, by all accounts it works very well. Just find it amusing that it is the "new" thing once again.


Mark

[Anonymous]

I guess new is relative. Extrude-honing is a lot newer technology than a die grinder and flapwheels. It has been around for high dollar racing applications for years, but apparently has now come down to where the average street rodder can afford it.

[Dink]

Jake when porting a 16 valve GS(X) head you need to trying to extend and refine the port divider, not removing a lot of material. Alot of tuners made this mistake early on, now a lot of them are actually building up the port flood to flatten it and straighten the shot through the port.
I suggest a visit to www.bertaut.com/gsengine.html he in particular has a photo of an extremely well ported 16 valve head, he also explains how a later model GSXR head can be adapted onto a GS(X) motor.
Dink

[RacingJake]

OK, I'll just remove any rough castings and work on the divider. Should I make it alittle narrow or reduce the thickness of the divider and have a razor edge to the incoming air??

Jake