If you want to delete that old, noisy air pump, lose some weight and reduce the parasitic drag, the only issue is finding the right belt to go directly from the crank pulley to the radiator fan pulley. (For the OB's)

I found it!

ACE Hardware. MBL Three Stars, General Utility V-Belt, 4L210. It is EXACTLY the right length. No adjustments/shimming necessary. Just remove the Power steering belt and the old air pump belt, remove the fan bracket and slip on the the new belt. Replace the PS belt and you're done.

The hardest part is removing the air pump itself, but you really don't have to do that if you don't want to.

 

Any 1/2" x 21" V-belt should work although some people have found that 20" works better on their engines.

 

couldn't you remove the fan and go efan and remove even more parasitic drag and weight?

 

btw, what does the air pump ACTUALLY do?

 

I believe the air pump is to supply the catalytic converter oxygen so it can do it's job.

 

LOL, i guess i don't need that thing then!

 

4L200 (20inch) for my 86.5, the 21 inch was too long.

 

I just had my mechanic remove my air pump when he was doing the TB/WP & the 4L200 or 20" worked best. I bought both the 20" & 21" belts from NAPA($5.77 each), & told him to use which ever one fit best. There was the thought of the smaller belt if too tight putting strain on the fan pulley & causing eventual bearing failure or the larger one stretching at some point & slipping. I still have the 21" one to return to NAPA.

 

OK, my first post here .. and keeping an old thread alive.

I recently bought a 79 Euro 928 "drive it across the country, car need nothing",.. yeah right

On the first real test trip the water pump almost disintegrated. Parked the car and it leaked out most of the cooling fluid.

Car came without any service records so I have started doing the timing belt while in there (of course).
The water pump had 2-3 mm sideways play so it must have been that close to havoc. Air pump rattles, the car has a borla SS system so I figured out that air pumps time has come to an end.

I understand people use the 20 or 21" belts and I am getting one belt in each dimension to try out.

Based on the threads about air pump delete I assume the new setup (no air pump) basically will be non adjustable, it is the only way I can figure out the setup. Right?

So basically the belt must be fit before the fan is tightened?

I did not see any clear answers on whether it is ok to remove the viscous fan so I suppose everyone is keeping them, anyone?

 

20 or 21 depends on the pulley you have at the crank.
On my 84, it is 21".

 

The pulley on the crank is dependent on whether or not you have rear air IIRC. If you have rear air the fan is supposed to spin faster at idle, so you would need the shorter belt (smaller diameter crank pulley section for the fan/air pump, for higher rpms).

You're right that there is no adjustment and I was nervous about this too, but I found that it's easy to put in and the belt will drive the fan just fine when you install it with the short belt and eliminate the air pump (I'm actually running without the aux electric fan I'm so confident).

The technique I used was to remove the upper fan console bolts, put the short belt on the pulley, then put the upper left one in finger tight. Then put the upper right bolt in and pull up on the console so the holes line up and put that one in finger tight. Torque them down and you should be good (I forget if there are any more bolts, but once the two top corners are in, it's not going anywhere so you can put them in after if there are any).

I can see my belt flex a bit when I rev it, but the fan has a clutch in it for when it's revved past a certain RPMs anyway, so it just has to do it's job at the lowest RPMs and mine appears to be doing so just fine.

Sorry for your other issues, good luck and if you need a hand, maybe start another thread on those issues.

Keep us posted.

 

I found that a 16" electric fan from Summit (along with an inexpensive relay) works even better than my 21" NAPA belt.

 

Yep I have a 20" on my '85 and w/ the Air on it never over heats, even in Hell ...!

 

My 78 has the 21" X 1/2" belt and it works great. Also, removing the air pump, and the little air filter in the front of the engine bay, and the corresponding hoses is very easy.

 

It's the fan pulley which is smaller for M319 (higher fan speed). It probably always comes with M570 (rear air), but it was installed on cars delivered to hot climates w/o rear air, too.

20" = 86mm pulley (M319)
21" = 106mm pulley

On the cars I've worked on with a small pulley, I've swapped to the larger pulley for less noise, and drain on the engine, but it's cooler where I live.

Installation wise, I did the same as Mike, slipped on the belt, then installed the upper, driver's side bolt, but since the belt was new, I used a prybar to align the other two bolt holes.