Fan housings

[bumble]

I have two fan housings:

901.106.101 5R and
930.106.101 0R

The later housing has much deeper ribs around its circumference and is obviously stronger, but are the earlier ones prone to problems? They appear to be interchangeable. Will be used on a 2L race motor.

TIA

[BURN-BROS]

Hi Bumble,

Verify that the 930 # is not for the 226mm fan. Those have tall ribs in order for the fan shroud to fit properly.

[Flat6pac]

The 901 part has 2 different depths or thicknesses where the alternator fits to and bolts up for the 245mm fan.
There is a real old housing that takes a 250 mm fan.
The 930 number for the 78/79 engines , the blades of the fan are smaller and as Aaron said the webs to the outside are thicker with deeper grooves to make up for the fan size.
By 1980 the coimpany was back to the 245mm fan and in 1984 the air cooling openings next to the belt were in place.
Bruce

[bumble]

Many thanks Aaron and Bruce.

Yes, the 930 part is 226mm and the 901 part is 245mm - I just measured them . I have the correct 11 blade fans for both of these so I guess there's no reason not to use the earlier fan?

[tom1394racing]

Here's the complete rundown on the production fan shroud rings:

1. Early 250 mm Al sand cast shroud ring (no coil studs) 1965-'67.5 - Casting # 901.106.101.03
2. Early 245 mm Al die cast shroud ring (no coil studs) 1967.5 - Casting # 901.106.101.0R
3. Later 245 mm Mag die cast shroud ring 1967.5-'77 - Casting # 901.106.101.5R
4. Early SC 225 mm Al die cast shroud ring 1978-'79 - Casting # 930.106.101.0R
5. Late SC 245 mm Al die cast shroud ring 1980-'83 - Casting # 930.106.102.0R
6. 3.2 Carrera 245 mm Al die cast shroud ring 1984-'89 - Casting # 930.106.102.4R
7. 3.3 Turbo 245mm Al die cast shroud ring casting # 930.106.667.4R

My experience is that the late Al die cast shroud rings are more prone to cracking that the early ones. I would recommend the earlier ring in your case.

[bumble]

Thanks Tom, that's good info

I haven't put the housings side by side but presumably the mag housing will be slightly lighter - which is good in a situation where every little bit helps.

[Flat6pac]

Tom,
How about the difference in the base thicknesses for the different alternator thicknesses on the 67 to77 magnesium. I know there is 2 different thicknesses
Great info on all the housings

[tom1394racing]

Bruce

As best I know, all the 245 mm mag housings have the same thickness for the alternator mount flange. There is a difference between the 3.2 Carrera and the SC mount thicknesses that accounts for the larger alternator for the 3.2 application.

I'll check my stock of housings when I get the chance to see if there are differences in the 245 mm mag housings.

[Walt Fricke]

I know there are differences in alternator lengths. Longer ones require the housing which was milled deeper in order to have the pulley line up with the crank pulley. Here is a comparison I scarfed from a post here at some point, but I ran into that when mixing and matching what I had to put together a race motor.




When the pulleys didn't line up I knew I had to use a different combination.

Whether these changes from a less to a more powerful alternator took place without a change in fan size or housing material I don't know, as it seems that the alternators all have their mounting bolts in the same position, and so on, so only the depth of the milling in the housing determines what alternator fits with what case.

[tom1394racing]

The difference is roughly 10 mm and is between the SC and the 3.2 alternators.

Here's a comparison I made for a customer showing a 3.2 alternator on the LHS and an SC alternator on the RHS. Note the SC alternator has a 10 mm spacer ring installed making it the same depth as the 3.2 alternator thus allowing it to be installed in a 3.2 fan ring. Usually people want to go the other way round and use the larger alternator in the early fan ring a thus requiring that 10 mm be machined off the early shroud mount face.

[Flat6pac]

Walt and Tom, youre both showing Paris-Rhone alternators but the era I m refering to is the era of the Bosch and the Motorola alternators. When I m in the shop this week I ll look at the difference in the housings and picture them.
Bruce

[kepperly]

Tom, I got the email but I'm probably over thinking this. When you shorten bye 10mm the back alternator plate that seats into the mounting flange, does,t this make the alternator too thin to accommodate the internal rotating stator? I just dropped off at my machinist the back cover and told him to take 10mm off the surface that goes against the external field laminations. Did I just screw up an alternator? Please tell me this will work. Do you have personal experience doing one of these?

Keith Epperly

[tom1394racing]

Originally Posted by tom1394racing

Usually people want to go the other way round and use the larger alternator in the early fan ring a thus requiring that 10 mm be machined off the early shroud mount face.

Keith...You have an email from me.

[pht9]

Originally Posted by tom1394racing

Here's the complete rundown on the production fan shroud rings:

1. Early 250 mm Al sand cast shroud ring (no coil studs) 1965-'67.5 - Casting # 901.106.101.03
2. Early 245 mm Al die cast shroud ring (no coil studs) 1967.5 - Casting # 901.106.101.0R
3. Later 245 mm Mag die cast shroud ring 1967.5-'77 - Casting # 901.106.101.5R
4. Early SC 225 mm Al die cast shroud ring 1978-'79 - Casting # 930.106.101.0R
5. Late SC 245 mm Al die cast shroud ring 1980-'83 - Casting # 930.106.102.0R
6. 3.2 Carrera 245 mm Al die cast shroud ring 1984-'89 - Casting # 930.106.102.4R
7. 3.3 Turbo 245mm Al die cast shroud ring casting # 930.106.667.4R

My experience is that the late Al die cast shroud rings are more prone to cracking that the early ones. I would recommend the earlier ring in your case.

can anyone advise the casting number for the fan housing on a 1976 3.0 930 engine type 930/50 or 930/52 ?

[tom1394racing]

This should help.

PM me with any questions

911 Fan/Shroud/Alternator Data

year # fan blades fan diam (mm) fan P/N shroud P/N shroud casting type shroud casting # shroud depth (1) (mm) Alterntor Current (amps) alternator length (2) (mm) comment crank pulley diam (mm) fan pulley diam (mm)
1965-66 11 250 901.106.101.03 901.106.101.03 sand cast Al 901.106.101.03 86 35 114 no coil studs 110 95
1965-66 11 250 901.106.101.03 901.106.101.04 sand cast Mg 901.106.101.0R 86 35 114 no coil studs 110 95
1967 11 245 901.106.010.03 901.106.011.00 sand cast Mg 901.106.101.0R 86 35 114 no coil studs 110 95
1967-68 11 245 901.106.010.03 901.106.011.00 die cast Mg 901.106.101.0R 86 55 114 no coil studs 110 95
1969-74 11 245 901.106.010.03 901.106.011.00 die cast Mg 901.106.101.5R 86 55 114 with coil studs 110 95
1975-77 3.0 Turbo 11 245 930.106.012.00 911.106.008.00 die cast Mg 901.106.101.5R 95 70 123 with coil studs 130 83
1975-77 5 245 901.106.011.00 911.106.008.00 die cast Mg 901.106.101.5R 95 70 123 with coil studs 130 83
1978-79 11 226 930-106.011.01 930.016.005.00 die cast Mg 930.106.101.0R 95 75 123 with coil studs 130 80
1980-83 11 245 930.106.012.00 930.105.006.00 die cast Mg 930.106.102.0R 95 75 123 with coil studs 120 83
1978-89 3.3 Turbo 11 245 930.106.012.00 930.105.006.00 die cast Mg 930.106.102.0R 95 75 123 with coil studs 120 83
1984-86 11 245 930.106.006.07 930.106.102.07 die cast Mg 930.106.102.3R 106 90 137 with coil stud hole 120 83
1987-89 11 245 930.106.006.07 930.106.006.07 die cast Mg 930.106.102.4R 106 90 137 with coil stud hole 120 83

(1) lip to alternator mount face
(2) hub nose to mount face

[tom1394racing]

Here's the Fan/Housing/Alternator data in a better format

[Luislang]

I need your help, please.
I'm trying to install a 90A alternator on a 3.3 turbo. Fan shroud 930.106.102.0R.
Alternator bolts are too short. How can I fix this?

[tom1394racing]

Originally Posted by Luislang

I need your help, please.
I'm trying to install a 90A alternator on a 3.3 turbo. Fan shroud 930.106.102.0R.
Alternator bolts are too short. How can I fix this?

You need to machine 10 mm off the alternator mount face on your 3.3 shroud. This will move the alternator deeper into the shroud, the studs will protrude further and the alternator pulley will line up with the crank pulley.

[ornas]

Originally Posted by tom1394racing

You need to machine 10 mm off the alternator mount face on your 3.3 shroud. This will move the alternator deeper into the shroud, the studs will protrude further and the alternator pulley will line up with the crank pulley.

If you machine alternator mount, back side of alternator with all conections pops out. How you fit that plastic air guide, that stands behind alternator?

[TwoBluPorsches]

Looks like this old thread has been resurrected and Ornas asks how to put the air guide on the housing if you machine the housing for a deeper alternator.

first, I would probably try to source the correct alternator for the housing instead of machining it.

second, if you have a 3.2 alternator and correct housing or if you have machined the housing so the alternator sticks further out the back you will discover that the air guide is a bit different.

In the interest of making it obvious, along with the previous pictures, I submit my own pictures that show the different air guide and how the housing is much thinner at the 6 alternator mounting bolts. Also a picture that shows how the air guide notch clears the regulator.