OzVMX Forum

Clubroom => Tech Talk => Topic started by: mainline on September 13, 2009, 10:20:20 am

Title: should I be cleaning these ports up a bit?
Post by: mainline on September 13, 2009, 10:20:20 am
I've got the barrel off to clean up the top so the head stops leaking, and the ports look a bit rough and ready. The mob who've rebored it cleaned up some of them, but further in they're still fairly rough.

Should I be polishing these up a bit with the dremel while it's apart?

the other question is whether this is an acceptable finish from the company that did the job? should I just be taking it back?

(http://i300.photobucket.com/albums/nn38/mainline_bucket/ports.jpg)
Title: Re: should I be cleaning these ports up a bit?
Post by: vandy010 on September 13, 2009, 12:04:32 pm
gotta wonder what they were doing in your ports when you asked for a rebore.
unless you asked them to give it a clean up of course.
i'd be wanting to take a few measurements to determine the "blow down" time in degrees. ;D before i got gun happy with the dremel.
Title: Re: should I be cleaning these ports up a bit?
Post by: mainline on September 13, 2009, 12:20:27 pm
the port edges had a couple of small chips, so they were going to clean them up while they had the barrel.

Is "blow down" time something to do with Popeye?  Can I buy a measuring device on ebay?
Title: Re: should I be cleaning these ports up a bit?
Post by: Lozza on September 13, 2009, 01:48:04 pm
The port windows should be chamfered that's a must a pic would help. The 'work' seems to consist of running the tool along the duct wall and knife edging the transfer divider( ::) ) will account for 3/5ths of SFA of performance.Blowdown refers to the duration is degrees from exhaust port open to transfer open, measured with verniers.
Title: Re: should I be cleaning these ports up a bit?
Post by: mainline on September 13, 2009, 01:52:24 pm
after having a think about it, there's a good chance that the port job in question was already there and just looks fresh after everything was blasted clean.

The port windows have definately been chamfered.

I think I'll just put it back together, there doesn't seem to be anything too drastically wrong in there, and the Dremel doesn't fit ;D

Cheers guys