Is my cooling fan fouling my fan shroud?
- Johnny Graham
- 356 Fan
- Posts: 79
- Joined: Tue Mar 25, 2008 5:42 pm
- Location: Fife, Scotland.
Is my cooling fan fouling my fan shroud?
Hi foks. Well, there's always something.
Removed my generator to be repaired - but they tested it and it was fine, so I dont think the fan was even removed. Back to the voltmeter..
So - I replaced the generator in the car with new gaskets, and after tightening my belt I was just turning the engine over manually - and for a moment on each turn I get a quiet 'skffff' noise from the fan shroud.
I'm sure it is a brief brush of the fan against the shroud, and I cant remember if it used to do it.
I am tempted to leave it, but I bet you have other ideas..
Removed my generator to be repaired - but they tested it and it was fine, so I dont think the fan was even removed. Back to the voltmeter..
So - I replaced the generator in the car with new gaskets, and after tightening my belt I was just turning the engine over manually - and for a moment on each turn I get a quiet 'skffff' noise from the fan shroud.
I'm sure it is a brief brush of the fan against the shroud, and I cant remember if it used to do it.
I am tempted to leave it, but I bet you have other ideas..
Cheers!
Johnny
1965 356C Bahama yellow outlaw driver #222499
1989 911C4 daily driver
1984 M-B 280E W123 Morrocan taxi
1985 Citroen 2CV
Johnny
1965 356C Bahama yellow outlaw driver #222499
1989 911C4 daily driver
1984 M-B 280E W123 Morrocan taxi
1985 Citroen 2CV
- Ron LaDow
- 356 Fan
- Posts: 8092
- Joined: Wed Mar 26, 2008 11:45 am
- Location: San Francisco
Is my cooling fan fouling my fan shroud?
Johnny,
"So - I replaced the generator in the car with new gaskets, and
after tightening my belt I was just turning the engine over
manually - and for a moment on each turn I get a quiet 'skffff'
noise from the fan shroud."
I gotta assume you left the fan on while 'they' had the generator? Intermittent noise means the fan is not 'true'. It's still a judgement call, but I'll pull it back out for a look. The fan spins at ~1.8X crank speed, so if 'they' dinged it a bit, it should be fixed. Failure can be pretty 'exciting'.
Thanks,
Ron LaDow
Post generated using Mail2Forum via email.
"So - I replaced the generator in the car with new gaskets, and
after tightening my belt I was just turning the engine over
manually - and for a moment on each turn I get a quiet 'skffff'
noise from the fan shroud."
I gotta assume you left the fan on while 'they' had the generator? Intermittent noise means the fan is not 'true'. It's still a judgement call, but I'll pull it back out for a look. The fan spins at ~1.8X crank speed, so if 'they' dinged it a bit, it should be fixed. Failure can be pretty 'exciting'.
Thanks,
Ron LaDow
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Ron LaDow
www.precisionmatters.biz
www.precisionmatters.biz
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- 356 Fan
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- Joined: Thu Mar 27, 2008 9:14 am
- Tag: Official curmudgeon
- Location: Ft Collins CO
Is my cooling fan fouling my fan shroud?
Johnny,
Loosen the oil filter through bolt a bit and that might cure it. If too tight it distorts the housing.
Norm
Loosen the oil filter through bolt a bit and that might cure it. If too tight it distorts the housing.
Norm
Post generated using Mail2Forum via email.----- Original Message -----
From: Johnny Graham (jgraham3@nhs.net)
To: 356talk@356registry.com (356talk@356registry.com)
Sent: Wednesday, April 30, 2008 4:05 PM
Subject: [356Talk] Is my cooling fan fouling my fan shroud?
Hi foks. Well, there's always something.
Removed my generator to be repaired - but they tested it and it was fine, so I dont think the fan was even removed. Back to the voltmeter..
So - I replaced the generator in the car with new gaskets, and after tightening my belt I was just turning the engine over manually - and for a moment on each turn I get a quiet 'skffff' noise from the fan shroud.
I'm sure it is a brief brush of the fan against the shroud, and I cant remember if it used to do it.
I am tempted to leave it, but I bet you have other ideas..
Cheers!
Johnny
Registry#19478
1965 356C Bahama yellow #222499
1989 911C4 Daily driver
- Al Zim
- 356 Fan
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FAN RUBBING THE HOUSING
Loosen the clamp on the generator. Start the engine. Push or pull on the top of the fan shroud till the noise goes away. Tighten the generator clamp. All done! al zim
www.allzim.com
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- Johnny Graham
- 356 Fan
- Posts: 79
- Joined: Tue Mar 25, 2008 5:42 pm
- Location: Fife, Scotland.
Gentlemen, thanks - I will do all 3 things. The fan looked OK before i stuck her in, but I'll have another look. Had bad dreams last night about fans disintegrating at 9000 rpm...
Cheers!
Johnny
1965 356C Bahama yellow outlaw driver #222499
1989 911C4 daily driver
1984 M-B 280E W123 Morrocan taxi
1985 Citroen 2CV
Johnny
1965 356C Bahama yellow outlaw driver #222499
1989 911C4 daily driver
1984 M-B 280E W123 Morrocan taxi
1985 Citroen 2CV
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- 356 Fan
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- Joined: Fri Mar 14, 2008 6:47 pm
Johnny,
On installing the generator/fan a simple test should be performed.
Leave the belt off.
Jumper DF on the gen to D- on the gen.
Now jumper from B+ on the regulator to D+ on the generator.
The generator will motor in a CW direction.
Now you can listen for any noise/touching of the fan..
While the belt is off, see if there is any motion when lifting the pulley.
Any movement would suggest bearings or endbell problems.
There should be about 1/8 of a inch between the fan and the sheet metal.
You would want to check that.
Joe
On installing the generator/fan a simple test should be performed.
Leave the belt off.
Jumper DF on the gen to D- on the gen.
Now jumper from B+ on the regulator to D+ on the generator.
The generator will motor in a CW direction.
Now you can listen for any noise/touching of the fan..
While the belt is off, see if there is any motion when lifting the pulley.
Any movement would suggest bearings or endbell problems.
There should be about 1/8 of a inch between the fan and the sheet metal.
You would want to check that.
Joe
Joseph A. Leoni
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- 356 Fan
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Is my cooling fan fouling my fan shroud?
Fine Joe, but, if leroy & Bubba been there and over torqued the oil filter bolt through the housing you will be very unhappy 'cause you have checked everything you mentioned and it's OK and now you "button it up" and the fan rubs! So before you pull the d.... thing out again try loosening the above mentioned bolt. It could save a lot of time.
Norm Grumpy old curmogeon
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Norm Grumpy old curmogeon
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- Albert Tiedemann
- 356 Fan
- Posts: 1229
- Joined: Thu Apr 03, 2008 2:46 pm
I have not seen on any of the replies whether or not the large thick washer is installed on the farside of the housing beneath the nut and locking element used. The thick washer is very important as it guards against the over tightened nut that Norm mentions. Without it you will get "point" loading at the nut interface. Treating the back panel of the housing as a membrane, the deflection can appoach 4 times that that would be experienced with the washer under the same tightening torque. This would lend credence to the comment made by Norm.
And besides, it is such an easy place to check by the Concours Police for its absence.
And besides, it is such an easy place to check by the Concours Police for its absence.
Albert Tiedemann, C356C
"The Hermit"
"The Hermit"
- Johnny Graham
- 356 Fan
- Posts: 79
- Joined: Tue Mar 25, 2008 5:42 pm
- Location: Fife, Scotland.
If I had the concours police round, I suspect I would be apprehended and thrown in the back of the Mariah for multiple counts of bitsa-ism and crimes against good gaps.
But I do have the thick washer! And I did check it wasnt overtight - its actually pretty hard to torque up at all as its a pain to trap the bolt head on the filter can side.
I checked Joe's trick of moving the fan housing - and discovered a whole new rubbing sound, which isnt the one I have, so I dont think its rubbing. I think its loose.
Motoring the generator, (or even spinning it by hand - it should do that, right?) I now get no skff noise at all. Belt on, and low revs I get a bad noise from the housing - like a rumble - that goes away with some engine speed.
The fan looks true and undinged, with just a little wow and flutter on the clearance between it and the tinware as I spin it and eyeball it. I am now suspecting it was removed by Leroy and Bubba (more likely Jamsey and Shuggie over here) and most likely not put back As Dr Porsche Intended.
I (still) dont have an impact driver - but I can at least tighten it with a torque wrench? Or not?..I'll check the wsm for the torque. 72 ft-lb wasnt it?
But I do have the thick washer! And I did check it wasnt overtight - its actually pretty hard to torque up at all as its a pain to trap the bolt head on the filter can side.
I checked Joe's trick of moving the fan housing - and discovered a whole new rubbing sound, which isnt the one I have, so I dont think its rubbing. I think its loose.
Motoring the generator, (or even spinning it by hand - it should do that, right?) I now get no skff noise at all. Belt on, and low revs I get a bad noise from the housing - like a rumble - that goes away with some engine speed.
The fan looks true and undinged, with just a little wow and flutter on the clearance between it and the tinware as I spin it and eyeball it. I am now suspecting it was removed by Leroy and Bubba (more likely Jamsey and Shuggie over here) and most likely not put back As Dr Porsche Intended.
I (still) dont have an impact driver - but I can at least tighten it with a torque wrench? Or not?..I'll check the wsm for the torque. 72 ft-lb wasnt it?
Cheers!
Johnny
1965 356C Bahama yellow outlaw driver #222499
1989 911C4 daily driver
1984 M-B 280E W123 Morrocan taxi
1985 Citroen 2CV
Johnny
1965 356C Bahama yellow outlaw driver #222499
1989 911C4 daily driver
1984 M-B 280E W123 Morrocan taxi
1985 Citroen 2CV
- Johnny Graham
- 356 Fan
- Posts: 79
- Joined: Tue Mar 25, 2008 5:42 pm
- Location: Fife, Scotland.
OK, to wrap this up, I'm now all sorted:
Lesson, dont assume that when an electrics specialist dismantles your generator/fan assembly, that they will try in any way to re-mantle in the correct manner, despite their assurances to the contrary..
I now know that they removed all the spacer washers and stuck them on the pulley side, and then tightened the impellor to 'fanny adams' torque. No wonder the thing made a noise when I stuck it back in. 2 spacers and 72.5 ft pounds and the noise has gone.
I now know all about fans and spacers, and have had a refresher course in the 'assumption is the mother of all disasters' school of thought. Check everything, trust no-one.
Lesson, dont assume that when an electrics specialist dismantles your generator/fan assembly, that they will try in any way to re-mantle in the correct manner, despite their assurances to the contrary..
I now know that they removed all the spacer washers and stuck them on the pulley side, and then tightened the impellor to 'fanny adams' torque. No wonder the thing made a noise when I stuck it back in. 2 spacers and 72.5 ft pounds and the noise has gone.
I now know all about fans and spacers, and have had a refresher course in the 'assumption is the mother of all disasters' school of thought. Check everything, trust no-one.
Cheers!
Johnny
1965 356C Bahama yellow outlaw driver #222499
1989 911C4 daily driver
1984 M-B 280E W123 Morrocan taxi
1985 Citroen 2CV
Johnny
1965 356C Bahama yellow outlaw driver #222499
1989 911C4 daily driver
1984 M-B 280E W123 Morrocan taxi
1985 Citroen 2CV