Sophomore Rider
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Post by dude on Apr 28, 2013 23:04:15 GMT -5
I have 2 63cc eng. But the oil pump gears are a different ratio.
1st one has 22/47 the other 16/33.The oil pumps are different
also why? Not sure about the ratio of the oil pumps, but they
Are different. Is one better than the other?
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Post by alleyoop on Apr 28, 2013 23:10:15 GMT -5
One pumps faster than the other, so maybe one came from the factory as a 63cc and one was built up to a 63cc.
Alleyoop
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Post by triker on Apr 29, 2013 0:44:46 GMT -5
Who knows why? It is like the different valve lengths in the heads.  The pump that has 47/22 gears turns at a ratio of 2.1363 but has thicker gears in the housing.The thickness of the gears is 10mm. The pump that has 33/16 gears turns at a ratio of 2.0625 but has thinner gears The thickness of these gears are 8.75mm. The diameter of the gears in both pumps is the same and they have the same number of teeth. If both pumps are turning at the same rpm's(not engine rpm's but the pump shaft) the pump with the thicker gears will pump more oil. So even though the pump with a 47 tooth gear turns slower than the pump with a 33 tooth gear at the same engine rpm, it should move more oil. I haven't tested this yet though. Roy |
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Sophomore Rider
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Post by ej132 on Apr 29, 2013 11:18:10 GMT -5
So is it recommended to upgrade to a higher volume oil pump when installing bbks?
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Post by triker on Apr 29, 2013 11:43:36 GMT -5
Both of my engines have a pump with 47/22 gears. The hoca stroker crank that I have had a 16 tooth gear. so I ordered a pump and the 33 tooth gear. Gears are not interchangeable with pumps. The pumps have different dowel pin locations also, so I couldn't use the pump with the 33 tooth gear. The pump with a 47 tooth gear has two dowel pins, one in the top hole and one in the bottom left hole in the case. The pump with a 33 tooth gear has one dowel pin in the bottom right hole in the case. in the photo the pins in the bottom holes are reversed because the pump is turned around to see the back of the pump.  Roy |
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Post by triker on Apr 29, 2013 11:52:13 GMT -5
So is it recommended to upgrade to a higher volume oil pump when installing bbks? The difference in the volume is probably minimal, but I haven't tested the pumps for pressure and volume yet. Roy |
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Sophomore Rider
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Post by ej132 on Apr 29, 2013 16:33:52 GMT -5
Alright triker, well if you ever do test them let us know! Would be interesting.
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..BAD TO THE BONE..
