Hi folks
since i have my engine apart right now and a new wiseco piston is standing in the shelf i was wondering about vertical pistonporting, which i wanted to try for ages anyways.
Im about to dril 12 0.040 holes from the deck into the first groove in order to be able to use just one total seal ring( with which i made great experiences). I figured i´ll mark the holes and then very very carefully drill through with a titan nitr. bit on highest speed. Well that wouldnt be the problem i assume also not getting into the bottom of the groove since i´ll lay an old thin oilkeeper there, to avoid touching it. But what can i do about burrs from the bit coming out of the bore??? any ideas besides using ultrahigh speed and really good bits?? I figured perhaps lapping compound on an donorring, but wouldnt that make the grooves kinda roundish?? Besides the top groove is 0.040 high so no way to get with tools in there.
Any ideas will be verya appreciated
regards
christian
Piston porting
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bill jones
- Guru
- Posts: 2651
- Joined: Sun Sep 05, 2004 6:38 pm
- Location: salt lake city, ut
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-I'd practice on a junk piston first until you get your procedure figured out and learn how easy it is to break the little bitty drill bits.
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-It's not too bad doing flattop pistons but domed pistons need serious attention to getting started down thru the angle of the domes.
-I use a little center drill to get all of the holes started.
-To drill the holes I use a 1/8" air die grinder clamped out the side of my mill quill and I have a digital (or a dial indicator will work) readout so I can watch how deep I peck the drill.
-The 1/8" die grinder requires special 1/8" shank circuit board drills that you can buy at Harbor freight in small odd quantities for about $5 to $8.
-These are usually solid carbide which I personally like better than HSS material.
-You should be able to find an assortment that has close to the size you want.
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-The 1/8" grinder supposedly spins 80,000rpm but mine I've strobe lighted at about 30,000 and air tool oil makes huge difference.
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-The exit of the hole should only show in about the upper 1/3" of the .040" ring groove.
-This means you have to just barely break thru into the ring groove and you are basically done.
-The dial indication of your drill depth is very important when you are starting to break thru because you are drilling the hole directly above the inner wall of the ring land so the drill is having to drill half a hole diameter in that wall for .015" of depth.
-This makes the drill want to catch and break as it breaks thru into the ring land.
-I use a dropper of WD40 for lube.
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-I've never had any issues with burrs left inside the ring land so I wouldn't worry about that at all.
-The top rings are usually chamfered back there in that area anyway so the ring isn't likely to interfere at all with the drill exit edges.
-----------------------------
-I use 8 holes on small bores under 3-3/4", 8 to 10 holes on 4" bore, 10 holes on 4.600" bores, and I use .030" to .032" drills and the center drill leaves a very slight chamfer at the top of the hole on flat tops and much more chamfer on the slanted edges of the domes.
-------------------------------
-It's not too bad doing flattop pistons but domed pistons need serious attention to getting started down thru the angle of the domes.
-I use a little center drill to get all of the holes started.
-To drill the holes I use a 1/8" air die grinder clamped out the side of my mill quill and I have a digital (or a dial indicator will work) readout so I can watch how deep I peck the drill.
-The 1/8" die grinder requires special 1/8" shank circuit board drills that you can buy at Harbor freight in small odd quantities for about $5 to $8.
-These are usually solid carbide which I personally like better than HSS material.
-You should be able to find an assortment that has close to the size you want.
----------------------------------
-The 1/8" grinder supposedly spins 80,000rpm but mine I've strobe lighted at about 30,000 and air tool oil makes huge difference.
--------------------------------------
-The exit of the hole should only show in about the upper 1/3" of the .040" ring groove.
-This means you have to just barely break thru into the ring groove and you are basically done.
-The dial indication of your drill depth is very important when you are starting to break thru because you are drilling the hole directly above the inner wall of the ring land so the drill is having to drill half a hole diameter in that wall for .015" of depth.
-This makes the drill want to catch and break as it breaks thru into the ring land.
-I use a dropper of WD40 for lube.
-----------------------------
-I've never had any issues with burrs left inside the ring land so I wouldn't worry about that at all.
-The top rings are usually chamfered back there in that area anyway so the ring isn't likely to interfere at all with the drill exit edges.
-----------------------------
-I use 8 holes on small bores under 3-3/4", 8 to 10 holes on 4" bore, 10 holes on 4.600" bores, and I use .030" to .032" drills and the center drill leaves a very slight chamfer at the top of the hole on flat tops and much more chamfer on the slanted edges of the domes.