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Post by slingy1052 on Feb 23, 2015 1:30:50 GMT
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Post by slingy1052 on Feb 23, 2015 2:14:36 GMT
So, i got to thinking, seems a shame to buy a pump and through half of it away. So i bought another pump (only $15) to see if their was a more resourcefull way to make a scavange pump. So here it is: Start with one of these  Cut the excess parts off to just the triangle shape pump body. Drill out the threaded holes to 5mm and discard the old steel cover. make a thick alloy cover with holes that line up with the pump body holes tapped to an M5 thread. Also, in the pump body there is a larger 6.5mm hole which i think would of been for a locating dowel. This will now be our oil gallery for the intake side to get to the intake port on the pump. So the cover also needs a hole through it with a hose barb fitting to line up with this gallery. Lastley, a slot needs milling/drilling/filing between this gallery and the intake port. I bought a 3 flute 3mm end mill and used this in my pillar drill on the highest speed. Worked quite well. So, apart from the Tap's, just hacksaws, files and a drill are needed to make the body. Next, the cover. Well i made a jig from my old cases to mark the crank centre on the inside of the cover, only to find that if you treat the main part of the cover as round , and strike arc's from multiple points, this will find the centre just as well. Then drill a centre hole to fit the nose of the pump body through. Next sit the pump body on the cover in its hole, and scribe around it so you know how big a flat to create for the pump body to clamp up to. Once done use your 3mm end mill in the pillar drill to slowly machine flat to suit. Sit the body back on the cover, drill the through the 3mm holes to drill through the cover for mounting, then mark the exit port hole on the cover. Use the 3mm end mill again to make your exit port hole. Counter sink the 3 5mm holes on the inside of the cover for mounting. you should now have a kit of parts that looks like so:  Hopefully in the picture below you can just see the slot between the gallery hole and the inlet port at the bottom of picture  The mounting bolts will sandwich everything together between the ignition cover and the pump cover, but to get a good oil tight seal and help hold it together i used JB weld between the pump body and the cover   So, the only tricky part of the whole thing is the drive shaft. No option here but to lathe it i am afraid.   And the finished article, slot more compact than my first one and works really well. It could be even more compact with a steel cover. 3mm steel with a hose barb or nut welded on for banjo fitting would work well i think too.    Anyway, havnt tried it on the engine yet, but with drill testing, this pumps works better than my first one. Even turning by hand it will draw oil up the 8mm line. Anyway, hope this gives others an idea of what could be achieved with minimal tooling. And everyone knows someone who knows someone with a lathe to do the little shaft lol |
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Post by greasemonkey on Feb 23, 2015 11:24:19 GMT
That 's a nice solution you found there.
I wonder if there's a problem with vacuum if it sucks that hard.
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Post by slingy1052 on Feb 23, 2015 12:21:33 GMT
I have heard this mentioned a bit, but I don't think so. The seals on the exhaust side of a turbo are hardly a seal at all, merely a piston ring seal to stop any remnants of oil that hasn't been centrifically flung off the shaft from creeping out the exhaust. So basically the entire bearing centre runs at exhaust housing pressure so not a problem with ever pulling a vacuum.
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Post by CHR15 on Feb 24, 2015 21:26:03 GMT
simple engineering is the best! this is one going on my drag bike;  ![]()  |
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Post by greasemonkey on Feb 24, 2015 21:37:16 GMT
that looks very, very good.
how much does it protrude the back? it looks almost to compact.
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Post by CHR15 on Feb 24, 2015 22:50:36 GMT
the entire unit is 43mm thick.
the machined body sticks out 17mm from the casing.
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Post by slingy1052 on Feb 24, 2015 23:52:04 GMT
Very nice, makes my efforts look very turd like lol.
Any shots from the other side or is that classified information?
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Post by captain chaos on Feb 25, 2015 8:03:45 GMT
Very nice, makes my efforts look very turd like lol. could be but you made your own. Anyone can build a cheque-book special. (Not saying that CHR15 is building one, far from that.) |
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Post by slingy1052 on Feb 25, 2015 9:34:46 GMT
Very nice, makes my efforts look very turd like lol. could be but you made your own. Anyone can build a cheque-book special. (Not saying that CHR15 is building one, far from that.)Love Chris's build. Real cool mix of home grown ideas but with access to cool toys to make it happen. Definitely not a cheque-book build like you say. I'm just jealous lol |
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