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914World.com _ 914World Garage _ 911 9146 engine fan housings

Posted by: bcheney Dec 12 2010, 09:03 AM

My conversion is using an original 9146 case. I am using a 911 fan housing and 55amp Bosch Alternator. I have assembled and I'm not sure if I have a problem. See pics. Belt doesnt seem to align properly. I have 5 shims under and 1 shim on the outside. I'm wondering if the housing that I'm using may be a problem as it is from a later model car. Housing number is 930106102OR and you can see it on the second pic.


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Posted by: jt914-6 Dec 12 2010, 09:20 AM

I'm using my orignal six fan housing # 901 106 101 5R. I upgraded to a larger amp alt. and my alt. stuck out too far. The opposite of your problem. I checked another six fan housing and it was deeper in the mounting area than mine. To make the new alt. work, I had my housing machined down to match the other fan housing and that made it right. It is being used on a 3.0 built on a 930/68 case (3.3 turbo). You may have to find the right fan housing or another alt. to line up the belt correctly..... a pic of my housing after it was turned down....

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Posted by: sixnotfour Dec 12 2010, 09:27 AM

The fan and housing are a mate, It is the alternator that is not.
You can add a spacer behind the alternator to make work as this fan assy is the 78/79 small diameter.
Or upgrade the alternator.
If you want an Origonal fan setup I will trade for the one you have.

Posted by: MDG Dec 12 2010, 09:58 AM

QUOTE(bcheney @ Dec 12 2010, 10:03 AM) *

Housing number is 930106102OR and you can see it on the second pic.


If I remember correctly the later housings are too deep; you can machine some off the back. Search the bird board - lots of discussions on this topic.

For my 3.2 I am using the old housing off my 2.2 (with the 901 . . . part number)and a new alternator I got from Dave Aase (Aase brothers).

m.

Posted by: sixnotfour Dec 12 2010, 10:48 AM

QUOTE
If I remember correctly the later housings are too deep; you can machine some off the back.

Yes too deep , therfore you need a spacer or correct alternator.
its the early (901) that you need to machine deeper for a late alternator.

here is a thread right here;
http://www.914world.com/bbs2/index.php?s=&showtopic=50841&view=findpost&p=669398

Posted by: bcheney Dec 12 2010, 11:35 AM

Do you know what could be used as a spacer if I decide to utilize the 930 numbered housing with the 55 amp alt? What would the exact height of the spacer be? Thanks for the help.

Posted by: rfuerst911sc Dec 12 2010, 03:44 PM

Brian I believe the proper count of shims is seven. You might want to put 7 under the pulley to see what it looks like. In regards to how thick of a spacer just put a straight edge on the face of the crank pulley and measure the distance to the alternator pulley.

Posted by: tomeric914 Dec 12 2010, 04:05 PM

Fan housings changed depth as the alternator amp output increased.

http://forums.pelicanparts.com/porsche-911-technical-forum/428673-engine-cooling-fan.html

Posted by: Cap'n Krusty Dec 12 2010, 09:52 PM

The alternator sits too far back. All the pulley shims in the world aren't gonna fix that. The new housing has to be machined to allow the alternator to sit in the same position as the old housing did. The only thing the shims do is adjust the space between the pulley halves to compensate for differences in belt length. They have nothing to do with the fore-and-aft location of the vertical c/l of the pulley.

The Cap'n

Posted by: Mark Henry Dec 12 2010, 11:40 PM

I'm seeing I'll have a similar issue...or not...

I have two of everything, fan housing and alternator. The fans "look" exactly the same, the housings have the same numbers, but one is definitely a 1/2 inch (approx) deeper than the other. Same with the alternators the Bosch being the shorter one, the other I can't find any part/make numbers, but again about a half inch diferance.
The Bosch also has a smaller pulley nut

I thought I had kept them marked as to which came out which housing but the short alt in the deep housing would have the exact same issue you are having. So I must have swapped them?

Which would be the higher output alternator?
My deep housing ring is fuched.

Posted by: sixnotfour Dec 13 2010, 02:57 AM

QUOTE
What would the exact height of the spacer be? Thanks for the help.

9.5mm for your setup - bosch alt/ 930.0R ring

You can use 6 spacers I suppose as the alternator will still be centered in the recess, keeping the fan centered.

Posted by: sixnotfour Dec 13 2010, 03:34 AM

Shim count


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Posted by: bcheney Dec 13 2010, 06:52 AM

As usual...thanks for all the replies everyone. You guys are the best. I am going to search a stash of mine to see if I have a 901 housing...that would solve the problem. Otherwise I will look into producing some 9.5 mm spacers to compensate.

Posted by: Mark Henry Dec 13 2010, 08:07 AM

QUOTE(bcheney @ Dec 13 2010, 07:52 AM) *

As usual...thanks for all the replies everyone. You guys are the best. I am going to search a stash of mine to see if I have a 901 housing...that would solve the problem. Otherwise I will look into producing some 9.5 mm spacers to compensate.


On the housing measure the depth of where the alternator seats in the inner ring. I was wrong about the half inch, it's closer to .400 deeper on the one ring I have.
This is about the same as your 9.5mm figure so you have the wrong alternator or housing, you have to swap one of them out.

Just adding a 1cm spacer to the pulley end is a bad idea, the pulley nut will nothing left to grab onto. Last thing I'd want is to have only a couple of threads holding my pulley and fan on. Putting shims under the alternator might be sketchy as well.

BTW both of the the housings I have are the same 901 part number even though the alt mount depths are different.

Posted by: Mark Henry Dec 13 2010, 11:01 AM

Here's what I'm talking about, both housing have the same 901 part#'s
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Posted by: sixnotfour Dec 14 2010, 04:57 AM

Mark , you have an early one (bosch) and a later 74?-77 to accomadate the larger alternator as tomeric914 wrote.

Posted by: Mark Henry Dec 14 2010, 07:25 AM

So how many amps on the smaller Bosch alternator?
It will be the one I'm going with, the deep housing I have is junk.

Posted by: bcheney Dec 14 2010, 07:40 AM

55 amp Bosch alt. uses the shallow housing...5mm mount depth. Your fan and outer pulley should have 8 holes in it (just like the one in post #12 twelve above).

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