tkjoe
L3 The Proven Snowmobile that never lets you down
Posts: 117
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Post by tkjoe on Apr 7, 2013 9:37:13 GMT -5
Do the Rockwell motors from like 1975 have the same issues as the later Cuyuna motors? (run hot, crank case leaks, ect. ?)
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Post by scorp11 on Apr 7, 2013 18:19:16 GMT -5
6 Bolt style was all the same from 75 on up. Change to center plug heads was really the only significant change to the motors.
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Post by pararailer on Apr 8, 2013 22:12:51 GMT -5
The early ones had bad center seals. Then was redesigned. Is that correct?
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Post by scorp11 on Apr 9, 2013 0:28:18 GMT -5
The early ones had bad center seals. Then was redesigned. Is that correct? From those I trust, that really wasn't the case. The pre 75 motors had a single center bearing with a labyrinth (no contact) type center seal. I suspect the single center bearing may not take as much power for a long time Like I said, those who I know who have done a lot with the older jlo's don't seem to agree the center seals were an issue. I know your dad has stated he does. I don't really know how a labyrinth type seal could ever wear out unless a bearing went out allowing contact with the crank |
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tkjoe
L3 The Proven Snowmobile that never lets you down
Posts: 117
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Post by tkjoe on Apr 9, 2013 19:24:28 GMT -5
What about PTO side getting too hot like the cuyuna's?
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Post by scorp11 on Apr 9, 2013 20:35:52 GMT -5
What about PTO side getting too hot like the cuyuna's? Yes to a degree. The older motors weren't tweeked power wise quite as much as the newer motors so they built a little less heat overall, but the basic design is the same. The 73's had all kinds of under hood temp issues when they sealed them up under the hood. I suspect if you took an older 4 bolt head 440, stuck it in a newer sled with the same pipe, you'd see pretty equal heat issues. |
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Post by scorpionlilwhip on Apr 9, 2013 22:31:10 GMT -5
i noticed with the 6 bolt heads the newer the engine the more sloppy the castings are, earlier versions looked a lot cleaner
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Post by obj1 on Apr 9, 2013 22:48:03 GMT -5
German craftsmanship and quality control vs made in mn. ??
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Post by scorpionlilwhip on Apr 10, 2013 11:42:08 GMT -5
the quality was good in the earlier Cuyuna's and seemed to dip after they were bought out, this assumption of course is based on partial observation of examples we have, and it is possible that it is just a coincidence that our later engines castings look rather sloppy on the later engines
not sure what the castings look like on the later post scorpion Cuyuna/2si engines, but i do know they removed half the fins in the heads and cylinders on the starter side of the engines
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