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JFairman JFairman is offline
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Join Date: Jul 2006
Location: S. Florida
Posts: 7,289
Nice work!
I've done some cylinder head ports too. Mostly old 4 and 6 cylinder BMW's.
When I use carbide burs in a die grinder dry they load up with aluminum quickly and a machinist scribe is needed to dig the aluminum out of the flutes. A wire brush gets the last of it.
To keep that from happening you can stop and dip the bur in a little cup of WD40 lubricant or something similar every couple minutes and then aluminum doesn't load up in the flutes of the bur. A plastic cap from a spray can works good to hold a little lubricant.
I opened up my 930 heads and flat intake manifold holes to 40mm, port matching them to 40mm aluminum injector blocks. I like to leave a little more aluminum around the valve guide then you did to help transfer a little more heat out of the valve guides and valve stems into the heads.
I cut little pieces of vacuum hose and pushed them on to the valve guides to protect them while doing the work.

These heads have been on my motor for a couple years and it all works real good. The porting only makes more power up top if more fuel is injected with the additional air that can flow into the combustion chambers.
Bigger intake ports slows down intake air velocity so you may have to richen up the AFR a little bit in the midrange to avoid having flat spots or surging during around town part throttle acceleration speeds.


Old 11-24-2016, 06:03 PM
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