theshow72

Hi,
What is the belt size needed if you have removed your smog pump but still need to power the radiator fan? I have an 82 with the 4.5 liter engine. I think I remember reading it was a 21" belt that was needed, but I can't remember for sure. I am hoping this is something I can get at a local auto parts store.

Thanks,
Joe

devilinblack

Yes, 21" works. The closest I was able to get at NAPA or the other places was 21.5" and that does not work. I ended up going to Granger for it and it fit fine.

On a side note and possibly unrelated, the rear bearing on my fan ate itself about a month (300 miles?) after doing this modification and I ended up going with an electric fan and thermostat after all.

If you go with the 21" belt you might want to put a couple washers between the fan mount and the engine on the top two bolts to decrease the tension on the belt and the bearing. If you want to convert to an electric fan let me know and I'll post the part numbers for what I used. I got it done for about $165 shipped from Summit Racing including a 2,500 cfm S blade fan and adjustable thermostat.

Edit: I just noticed you have a Weissach and will probably want to stay as stock as possible so the electric fan is probably out. My suggestion would be to use the short belt (with the washers or something else to shim the top bolts) for a short time if you can source it locally, but put the smog pump back on when you can get one.

Edit 2: I saw in an older thread where you asked about the engine size in my car. Yes, I have the 4.5L 16v engine also. They should be pretty close to the same engines from what I've read.

Lizard928

Gates 6821

If you search there are alot of topics on this, I know as I just had to do this.

SharkSkin

Instead of removing the air pump (Assuming you have good reason not to need it anymore) why not just gut it -- remove the vanes, put fresh bearings, and use it as an idler. It won't cost a measurable amount of power, and a single 0-100 WOT run would probably burn enough fuel to offset the weight.

shawscove928s

Has anyone else had fan bearing failures using the 21 inch belt mod?

Rod Underwood

Could you post the fan part number(s), I'd like to do this to the 82 sometime in the future and it's best to get the info when it's still hot. ;-)

Thanks
Rod

devilinblack

The fan is a Flex-a-lite 398 16" S-Blade Electric fan, part number FLX-398, $122.95 at Summit.
The controller is a Flex-a-lite Adjustable Electric Fan Controller 31147, part number FLX-31147, $28.95 at Summit.

A controller that has a sensor that mounts in the radiator hose would probably be better in the long run than this one that uses a probe stuck in the radiator, but this seems to be working just fine right now. It just took me a bit of playing with the adjustment to get it to turn on when needed, but to not stay on too long after the car was shut off. Using a relay and wiring it to an ignition controlled source of power would make this a bit easier.

123quattro

The belt I'm running on mine is a 15420. I spaced the fan forward about 3/4" and put it on the same loop as the power steering pump. It's been working just fine like that for several thousand miles. The only other change is longer bolts for the fan since the originals were too short after I moved it out.

devilinblack

That would seem to be the better way to do it since you still have a way of adjusting belt tension.

tailpipe

i have had the 21" belt on mine since 99 i just replaced the belt about a month ago cause i had worn it out no bearing failures for me although my air conditioning compresor bearing did go about 2 months back burned the belt right off the motor that was scarey though the car was on fire


paul with 4 79 928s and one 77 924

Rod Underwood

Thanks, I almost missed this.

Rod