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Thread: Sleeved port chamfer
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04-04-2003, 10:12 AM #1
Sleeved port chamfer
I know what I have to do already, but is there anything special about the chamfer put on the ports in the sleeve??
I thought I had enough chamfer in the ports, but when I put the piston in and gave the crank a turn, I could feel a very slight "catch" as the rings went past the port.
I can feel a slightly sharp spot in the port, I guess I didn't get it clean enough.
Any special instructions about port chamfering?JOHN MASON
'83/VECTOR/MERC 200-- SOLD
'98 Quartershot T-3/ MERC 200
"If your not living on the edge, your taking up to much space"
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04-04-2003, 01:21 PM #2
ttt
JOHN MASON
'83/VECTOR/MERC 200-- SOLD
'98 Quartershot T-3/ MERC 200
"If your not living on the edge, your taking up to much space"
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04-04-2003, 02:10 PM #3
I figured by now somebody would've chimed in with a good answer or a picture or somethin'. There ain't any real science to it, they just need to be rounded enough to remove any sharp edge, all the way out to the corners, buit more so in the middle. Too much and too deep can bleed off compression like raising port timing will and not enough and you hang a ring. Bottom of the ports are important too. I tore down an old 2 liter V6 years ago that somebody had bored and chamfered the tops of the ports only and the mess was ugly.
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04-04-2003, 02:21 PM #4
Thanks Raceman,
You would think that the factory would have chamfered them, or the machine shop would have done it BEFORE it was installed in the block.
I guess that the sides need to be done as well?
Thanks,
JohnJOHN MASON
'83/VECTOR/MERC 200-- SOLD
'98 Quartershot T-3/ MERC 200
"If your not living on the edge, your taking up to much space"
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04-04-2003, 03:08 PM #5
When ever I get a block back from the machine shop I use a brush hone in laft hand and right hand directions to clean up the ports. Never had a ring get caught and it always works.
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04-04-2003, 07:52 PM #6Screaming And Flying!
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Not rocket science...
Juss knock off the sharp edge...the wider tha port, that more chamfer...Make sure that the chamfer iz what your feeling, if your port width iz more than 72% of the bore, U iz feel'in the ring opening in the port, and U iz headed for premature ring failure, if not more!!...REX
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04-04-2003, 08:51 PM #7
I cleaned up the chamfers more, and as I put each piston in, I turn the crank, and FEEL.
Much better now.
I still worry.JOHN MASON
'83/VECTOR/MERC 200-- SOLD
'98 Quartershot T-3/ MERC 200
"If your not living on the edge, your taking up to much space"
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04-04-2003, 10:47 PM #8Supporting Vendor
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Chamfers
John .
I cut the port where I like it and leave about .005" of extra meat, then I have a chamfering tool ( looks like a fine bladed rotory file and is VERY small and very steep pitched) I go across the lip of the port several time just to break the edge,then I use a cartridge roll to smooth somewhat then last I cut a piece of abrasive roll 1"X 3' long and go in threw the bore and out the exhaust chest. I rapidly move the abrasive across the port chamfer with a shoe shining motion pulling up with an even pressure moving across the whole port opening and be sure to get from one extreem edge to the other. When you do this motion about ten pulls and you have done it evenly across the entire port you will have demished the material by about .005" and you chamfer is perfectly round and slick with no chance of hanging...........Jay @ JSRE
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04-05-2003, 01:10 AM #9
I have read about this in one of Gorden Jennings' books. From what he says, the angle and size of the champher can affectively change the port timing. This not only includes the champher but blending into the port as well. When I get back home (and can find the time) I will scan it and post it.
Any opinions on this?
Sounds like you have it going your way!
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04-05-2003, 12:46 PM #10
Jay sounds good, what about the finger ports and the sides and bottoms of the other ports?
JOHN MASON
'83/VECTOR/MERC 200-- SOLD
'98 Quartershot T-3/ MERC 200
"If your not living on the edge, your taking up to much space"
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04-05-2003, 05:39 PM #11Supporting Vendor
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Ports
On those I use a modified 90 degree die grinder with a VERY stubby fine textured diamond cut rotery file then finish off with cartridge roll the when completely finished as Jeff_G said a fine grit ball hone going to the left then the right with up and down strokes to cross hatch it !
Jay @ JSRE
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04-06-2003, 07:29 AM #125000 RPM
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Good idea Forkin...
By all means, scan and post that in here.
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04-06-2003, 10:13 AM #13
Heres from Gordon Jennings book
90 Comp V-King (original owner), Blueprinted Hull
Nicom 2.4 oval port, Ruck Lake cut, 140# comp.
Custom Laser EFI, Brucato ACU, TDR Reeds 1"
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04-06-2003, 10:14 AM #14
2
90 Comp V-King (original owner), Blueprinted Hull
Nicom 2.4 oval port, Ruck Lake cut, 140# comp.
Custom Laser EFI, Brucato ACU, TDR Reeds 1"
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04-06-2003, 10:15 AM #15
3
90 Comp V-King (original owner), Blueprinted Hull
Nicom 2.4 oval port, Ruck Lake cut, 140# comp.
Custom Laser EFI, Brucato ACU, TDR Reeds 1"