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Ultimate High Output Bosch Alternator fits 1985-1995

 
Old 03-18-2018, 07:57 PM
  #166  
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So, I have one of these alternators in hand and the motor needs to be put back together. We also have a new front main harness from Greg that will 100% be part of the refresh.

I have two questions:

1.) 928s leak a lot of oil around the area of the alternator. However, this alternator does not have shielding like the stock alternator. It is true that the stock alternator will probably ingest quite a bit of oil despite the shielding that the fresh air hose is hooked up to. My car shouldn't leak any oil once re-assembled. BUT, is this a potential problem, if the motor is not completely sealed compared to the stock alternator?

2.) Getting back to heat, is there not some way to hook up the fresh air hose? I understand that the newer 911s supposedly have a hotter engine compartments. But, it also seems not correct to just leave it hanging there.

I am just trying to put all these observations into perspective. Can anyone comment?

Last edited by Red Flash; 03-19-2018 at 06:22 PM. Reason: I meant newer 911s have hotter engine compartments. Not 928s!
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Old 03-19-2018, 04:19 AM
  #167  
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Originally Posted by Red Flash View Post
So, I have one of these alternators in hand and the motor needs to be put back together. We also have a new front main harness from Greg that will 100% be part of the refresh.

I have two questions:

1.) 928s leak a lot of oil around the area of the alternator. However, this alternator does not have shielding like the stock alternator. It is true that the stock alternator will probably ingest quite a bit of oil despite the shielding that the fresh air hose is hooked up to. My car shouldn't leak any oil once re-assembled. BUT, is this a potential problem, if the motor is not completely sealed compared to the stock alternator?

2.) Getting back to heat, is there not some way to hook up the fresh air hose? I understand that the newer 928s supposedly have a hotter engine compartments. But, it also seems not correct to just leave it hanging there.

I am just trying to put all these observations into perspective. Can anyone comment?
This alt was originally from a newer 911 and those run much hotter than most 928s ever will so a cool air supply is not necessary in our application.

I also wouldn't worry about oil getting ingested. The shielding behind the alt is only there to direct the cool air supply from the back to the front of the alt and give optimal cooling to the diodes.
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Old 03-19-2018, 06:14 PM
  #168  
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I'd fix the oil leaks regardless. No alternator does well when sprayed with oil. Even the stock unit is sort of open in front around the pulley and fan. the new one from Greg has an axial outflow fan in the middle, so will be drawing in air from the front and rear. If there's oil loose in that area, it will get in and coat the windings.

In my limited experience, oil on the alternator comes from leaking cam cover gaskets, sometimes camshaft seals, but most often from power steering hose leaks at least on cars I've had my fingers in. Be sure to replace any tired PS and maybe the oil cooler hoses on your car.

Most cars have open-frame alternators. Somehow they survive. I know from personal experience that they don't do well with engine cleaning chems, so better to keep it clean than to let it get oily and try to wash it.
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Old 03-19-2018, 06:29 PM
  #169  
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Originally Posted by The Forgotten On View Post
This alt was originally from a newer 911 and those run much hotter than most 928s ever will so a cool air supply is not necessary in our application.
My bad. I meant to write "911s supposedly have hotter engine compartments." I edited above. I still wonder what one can do with the fresh air hose.

Originally Posted by dr bob View Post
I'd fix the oil leaks regardless. No alternator does well when sprayed with oil.

........

I know from personal experience that they don't do well with engine cleaning chems, so better to keep it clean than to let it get oily and try to wash it.
Bob, I am not the kind of guy to leave things leaking in an engine compartment. (Not that you could know that.) I will have ALL new hoses on this car including a complete set of Greg's fuel lines.

Nonetheless, given the oily messes I see in engine bays, we have to stay the stock 928 alternator does an excellent (or at least way above average?) job dealing with massive oil slicks...

The restriction on cleaning with cleaning chems might be a good thought with this alternator given the open design. In Northern EU countries, it is standard procedure to wash down engine compartments prior to inspections. I am going to talk to some people about how this handled with 928s.
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Old 03-19-2018, 11:28 PM
  #170  
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Originally Posted by Red Flash View Post
My bad. I meant to write "911s supposedly have hotter engine compartments." I edited above. I still wonder what one can do with the fresh air hose.



Bob, I am not the kind of guy to leave things leaking in an engine compartment. (Not that you could know that.) I will have ALL new hoses on this car including a complete set of Greg's fuel lines.

Nonetheless, given the oily messes I see in engine bays, we have to stay the stock 928 alternator does an excellent (or at least way above average?) job dealing with massive oil slicks...

The restriction on cleaning with cleaning chems might be a good thought with this alternator given the open design. In Northern EU countries, it is standard procedure to wash down engine compartments prior to inspections. I am going to talk to some people about how this handled with 928s.
I've had no reports of any issues from oil, on cars equipped with my alternator. Perhaps everyone who is installing one of these has engines that don't leak, but I'm seriously doubting this is the case. Certainly, the voltage regulator is encapsulated and doesn't care about oil. The "windings" are wire covered with that clear, super tough, winding insulation. I guess if there was a "flood" of oil that got to the alternator, the brushes could get oil between them and the armature....but I'd think centrifugal force would make pretty quick work of any oil there.

I've got to think that alternators are designed with a certain "tolerance" of oil, since they live in an engine compartment.

As far as the cooling duct is concerned, I simply leave it close to the front of the alternator, if it is in good condition. I've also thrown a couple of them away, if they are badly damaged. From my testing, I've found that this newer designed alternator (with the windings exposed and fans on both ends) do not suffer from the same heat soaking that the original alternators did. The cooling duct is essentially a "vermiform appendix" when using my alternator (as far as I'm concerned) and I place it near the front of the alternator simply to pull air through the hose for better function of the temperature sender for the HVAC system.
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Old 03-20-2018, 02:04 AM
  #171  
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Old 03-20-2018, 02:17 AM
  #172  
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My negative experience with cleaning alternators is rooted in using solvent-based chems and then water to clean them on the car. the bearings are good but still manage to suck that stuff in and start the failure routine. No doubt it's easy to clean an oil-fouled alternator. I've done it often enough. I've learned by experience not to try to do it on the car. Learn from my experience. It's cheaper and easier than learning stuff like this on your own.
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