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Message |
    
chancekea
New member
Username: chancekea
Post Number: 1
Registered: 07-2004
| | Posted on Tuesday, July 20, 2004 - 07:33 am: | 
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Hi guys, I have a p60 in my Allied chance 30, and since replacing the original alternator with a delco unit, have found an overheating problem. The waterpump is not spinning, although the distributer etc are fine. Upon looking further, I discovered that the actual shaft is shifting back and forth by close to half an inch. Short of completely removing the shaft, I cant see anything wrong. The problem is that while being driven by the engine, the shaft moves far enough to dissengage the waterpump drive. Any ideas? I'm thinking that extending the length of the alternator drive shaft to limit the forward movement would work but I'm hesitant to do something that drastic. Please note that this engine has been seriously neglected by previous owners, and will probably be retired at the end of this season (I bought the boat earlier this year). I would appreciate any input as I don't have a schematic of what holds the shaft in proper position. Thanks.....Paul |
richardday
Senior Member
Username: richardday
Post Number: 267
Registered: 11-2003
| | Posted on Tuesday, July 20, 2004 - 06:45 pm: |
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I wonder if you have looked at the accesory drive shaft for the alternator drive pulley. There are two angular contact ball bearings back to back in the housing. Removing the two cap screws that hold the alternator drive pulley housing to the distributor drive housing would let you remove the unit without disturbing the engine distributor timing. Just work the alternator drive housing off carfully so as not to pull the rest of the gearing out. See if a previous owner took out one bearing and the belt on the previous alternator was holding the drive shaft more or less engaged. I think it curious that the move is about 1/2" which is probably the width of one of the bearings. Come back to me with comments after you have examined the shaft out of the engine. |
richardday
Senior Member
Username: richardday
Post Number: 268
Registered: 11-2003
| | Posted on Thursday, July 22, 2004 - 09:13 am: |
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I took apart a junk alternator drive assembly to try and figure out for sure what was going on. The housing for the bearings and the bearings on the shaft are a press fit. The bearings are two New Departure type H. The distance from the outer end of the inner race of one to the the outer end of the inner race of the other is approx 1-21/32". The pulley end of the shaft projects approximately 1-1/2" from the face of the bearing housing. There is a roll pin in the drive shaft that mates with a slot on the gear unit that drives the waterpump. Between the roll pin and the bearing housing of the alternator drive housing is a fiber washer that acts as an oil slinger.
In the unit I disassembled it is obvious that one of the bearings is in serious trouble. Probably cage collapse but being sealed bearings I didn't bother to tear into it to find out. The point being that I now suspect that what is happening in your case is both outer races of the Type H bearings have been turning in the housing of the alternator drive wearing it to the point the entire shaft is moving back and forth in the housing. The location of the pulley could possibly be moved to line up with the new alternator which would allow the belt to more or less hold the roll pin end engaged with the drive gear but that would not be a particularly prudent move. If my suspicions are correct you need to replace the housing and the bearings. Then move the pulley to line up with the alternator pulley if you can. A longer drive shaft would be easy to make as it is a straight shaft with only the hole for the roll pin in one end and a keyway in the other. No fancy lathe work required. I would be interested to know if my diagnosis is correct. |
chancekea
New member
Username: chancekea
Post Number: 2
Registered: 07-2004
| | Posted on Thursday, July 22, 2004 - 09:59 pm: |
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Hi Richard, the bearings in my shaft appear to be ok, and the shaft has not shifted as evidenced by the original paint on it. The problem appears to be with the main accesory shaft with the driven gear on it. I'll have a closer look tomorrow, but I think with a 1/2 inch extension on the alt shaft it should be ok. I have the shaft out, and with me but I wont be down to the boat till Monday. I'll keep you posted. Paul |
richardday
Senior Member
Username: richardday
Post Number: 272
Registered: 11-2003
| | Posted on Sunday, July 25, 2004 - 07:56 am: |
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I will be interested to see how the main driven gear could be moving in the housing enough to permit the water pump tang disengauging. I took the main driven gear out and it appears to be a press fit on the shaft with the tach drive gear pressed on and a snap ring retaining it. There is about 1/32" lateral movement in the main driven gear. At this point I begin to wonder what is really going on. Be interested to hear you diagnosis. |
chancekea
New member
Username: chancekea
Post Number: 3
Registered: 07-2004
| | Posted on Thursday, July 29, 2004 - 07:25 am: |
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I got the extended alt shaft back in yesterday, and started the engine. It appears to be working fine. I checked end play before reinstalling the water pump, and it's about a 16th of an inch. Having not taken the distributer housing off, I couldn't see if the retainer clip had failed, but truthfully, I didn't see anything else it could be. Hopefully I'll be taking the boat out for a sail today. Thanks for the help........Paul |
richardday
Senior Member
Username: richardday
Post Number: 273
Registered: 11-2003
| | Posted on Thursday, July 29, 2004 - 10:03 am: |
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I wonder if you have solved the problem or simply put off the problem. Hope its the first. The tang on the water pump should show wear and the width of the wear should give an indication of how much movement in the drive to the pump you have to play with. Good luck. |
chancekea
Member
Username: chancekea
Post Number: 4
Registered: 07-2004
| | Posted on Tuesday, August 10, 2004 - 07:28 am: |
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Sorry for the delay in update. The engine seems to be working for now, after reinstalling the lengthened alternator shaft. I realize it's not the proper way to "repair" the problem, as I still don't really know what the original issue was. I think the circlip that positioned the accesory shaft must have failed, but I have not confirmed this. As the engine sees only limited use in and out of harbour, and will be removed in the winter, it should be OK for the remainder of the season. Thanks for the input. Paul |
richardday
Senior Member
Username: richardday
Post Number: 285
Registered: 11-2003
| | Posted on Tuesday, August 10, 2004 - 08:28 am: |
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Good to hear you are back in business. Keep in mind that if you take the engine out fill the water jackets with straight anti freeze to keep oxygen away from the salt in the iron. If you let them dry out the salt will expand and crack the iron just like freezing. You could use old motor oil like the old timers did but it makes a big mess if it leaks. The going rate for a useable exhaust manifold is at leat $500 so you may be able to make a little on your old engine. The only engine part that is worth saving is the crankshaft. The marine trim may have some market value with people looking for reverse gear, carburetor, pump, starter, distributor etc. parts. There are a lot of P-60s still in service so people seem to be looking for parts to get one more years service out of their engines. |
