MRC-Hirobo
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Location: Edison, NJ
My Posts This: Topic Forum | Dialing in Fan hub/Clutch shoeHere are some tips.
1) Make sure the clutch shoe fits easily into the fan hub. If not, when tightened down, the shoe will not sit flat on the fan hub and you will get an out of round condition. You may need to "relieve" the clutch shoe locating hole in the fan hub to get this easy fit. TMoores suggestion is dead on.
2) Now the clutch shoe is seating easily and removing easily, spin the clutch shoe while it is seated on the fan hub checking for easy spinning with no "bumps" while spinning it. If you feel bumps while spinning it on the fan hub, check for burrs on the fan hub and or clutch shoe bolt holes that may be causing the "bump" This bump will also cause the shaft to go out of round when the bolts are tightened down.
3) It is a good idea to check the run out of the fan hub to identify the high spot and verify that when the clutch is bolted to the fan hub that the high spot at the bottom of the clutch shaft is in the same place. This measurement will also tell you how much and what direction you will need to shift the shoe to get under or as close to .001 run out.
4) Now check the runout of the clutch shoe by measuring the bottom part of the clutch shaft. Mark its high side and compare to that of the fan hub just for info sake. Try turning the shoe and see if the runout changes for the better. If not, put it back in the other orientation.
Now make a mark on the fan hub opposite the high side of the clutch shoe/shaft and open the fan hub clutch shoe mounting hole using sand paper or an xacto knife using this mark as a reference for where to open the hole (be careful!) just so you can feel the shoe moving a little bit side to side, (high spot to opposite high spot). Try to open only half of the hole in the direction you need to move the clutch shoe. For reference, when you can feel it move side to side, this is usually about .002"
Now, install the clutch shoe mounting bolts and while pushing the clutch shoe in the opposite direction tighten them up and recheck your runout. Keep repeating this process until the shaft reads .001 or better. If need be you can also open the fan hub clutch mounting hole a little more at a time as well as the clutch shoe mounting bolts to get more area for movement.
When this is done, you will have a precisely mounted clutch assy that will be vibration free and virtually maintenance free. The more you do this, you will get faster at it and it will not be a "tedious" as it might be right now.
Hirobo is always looking to make improvements so they will do their best to make this part of the building process even easier. Note, there are no parts to wear out here, so once done it is done for the life of the engine or clutch shoe.
On a side note, the Eagle 3 fan hub is a more precise unit that virtually eliminates the need to do some of this extra work, but it does cost more and you still need to check the shafts run out.
If you have any other questions and/or would like me to get to do it for you. Just let me know.
Good luck and be sure to ask more questions if you need to.
Jeff |
