help with fan pulley assembly?

rockreid · 07-25-2013, 08:16 AM

1973 1/2 911 Targa stock 2.4T engine

I am at the stage of mounting the Marchal alternator/fan assembly onto the engine but need advice on what I am looking at in this picture. At Pelican this shows up as "Marchal Alternator Pulley Cover".

Pelican Parts - Product Information: 901-603-428-00-OEM

I am experiencing some scraping of the inside of the fan fan against the alternator so I can picture this being a spacer in back of the fan but no such part shows up in any diagram or tutorial I've found. Anyone know exactly what order this part should be assembled? (pulled form my cardboard boxes that slowly are forming an engine).

Flat6pac · 07-25-2013, 08:41 AM

That is the last cover before the nut
You need an alternator shim behind the keyway to thrust out the fan..not shown in the PET but in my picture, there is 2 styles.
There should be 6 fan shims for between the pulley halve and under the cap in the picture

Bruce
If you want one, paypal works

rockreid · 07-25-2013, 09:13 AM

wow, all those parts diagrams really f-ed me up. I have the lower shim part listed as "Tensioning Cap" on some parts diagrams.. obviously wrong. Bummer, now I am having a difficult time removing the fan off of the alternator. It is really on there tight. None of my pullers seem to be the right size... is there a method to use the little holes around the bub of the fan to pull it off?

fred cook · fred cook's Garage

Quote:

Originally Posted by rockreid

1973 1/2 911 Targa stock 2.4T engine

I am at the stage of mounting the Marchal alternator/fan assembly onto the engine but need advice on what I am looking at in this picture. At Pelican this shows up as "Marchal Alternator Pulley Cover".

Pelican Parts - Product Information: 901-603-428-00-OEM

I am experiencing some scraping of the inside of the fan fan against the alternator so I can picture this being a spacer in back of the fan but no such part shows up in any diagram or tutorial I've found. Anyone know exactly what order this part should be assembled? (pulled form my cardboard boxes that slowly are forming an engine).

The part in the photograph is a cupped washer that goes over the pulley spacers that are not used between the fan and front pulley half. The sequence will be fan, some number of metal shims, usually 3-4, then the outer pulley half, the remaining shims and then the cupped washer. The 24mm nut holds it all together. The number of shims used between the pulley halves controls the belt tension. Too loose and it will slip and squeal, too tight and you risk damaging the front bearing on the alt. shaft. Hope this helps.

rockreid · 07-25-2013, 10:27 AM

You forgot the thrust washer that is on the threaded portion of Flat6pac's alternator in his picture.

I do have this very part and on various parts diagrams I looked up prior to install it was listed in the wrong position (being outside the fan) and totally useless. So my fan was scraping the alternator as a result.

In your assembly instructions you too forgot this item which goes to show how easy this mistake is for those of us with '73 1/2 models to get screwed up by these incorrect parts diagrams.

So, at least for those of us with 73 1/2's, the order should be... Thrust Washer, then fan, adjustment shims, outer pulley half, remaining shims, metal cover, then nut. Thanks for everyone's help.

Flat6pac · 07-25-2013, 12:52 PM

The nut for this application is 22mm, the Verlo with the onboard regulator is 24mm
Bruce

Flat6pac · 07-25-2013, 12:55 PM

put the nut on the threads and tap the nut while holding the fan. spin the housing in your hand
Becareful of the threads because the nut is most unobtainable

Bruce

Walt Fricke · 07-25-2013, 06:07 PM

I've used the vibration from a chatter gun (air chisel) using a pointed tool end in the center of the shaft to loosen the fan up. Doesn't seem to mess up the alternator bearings. If you have a blunt end tool for your chatter gun, that should work also, but you'll need a helper to do the pulling on the fan while you chatter (or vice versa).

Or tap - plastic hammer? Brass hammer? I like the air tool, and the small divot in the end of the shaft hasn't caused any trouble.

That cup washer and the shims are very important. Put the outer pulley half on with no shims, and look at where the threads on the end of the shaft end. You will see that even with the cup washer being effectively like a much thicker washer sort of, it won't actually tighten the pulley half, which will be very loose. It takes those six shims for the cup washer to actually tighten everything up. If there is any looseness here, even though the nut may not work its way off, the outer pulley half will machine the slot in the shaft to the point where it is no longer a slot, but a circle. So the outer half will just rotate with the belt and the alternator will be pretty much junk without a somewhat expensive fix involving welding and remachining or something.

Also, without the proper number of shims you can bend the cup washer inward. This isn't going to help its holding power.