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Did all e21s come with an adjusting bar part#21 near the alternator for setting serpentine belt tension? My e21 does not seem to have one, but the manual I referenced doesn't actually mention one either. And the adjust bar (part #6) is flipped around. However my vin number on real oem shows it should have one. Is it fine to set tension without this 'toothed' bar? I just pushed on the alternator, tightened the adjusting bar (part #6), and flipped it so it matches the manual picture I referenced, where the affixed hole is on the alternator itself, and the slide is attached to the supporting bracket. It seemed to have helped with my annoying belt squeal. Just wanted others opinions.
alternatoradjustingbar.jpg
Last edited by YoungSensei; 05-21-2023 at 09:23 PM.
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No adjusting bar (part #21) on my E21, just the adjust bar #6.
Member
Same on my 06/1981 E21, no #21, only #6. Also it looks like mine is installed in a 3rd orientation, not RealOEM or the Factory Manual you shared.
IMG_20190901_002549.jpg
'81 E21 320i / '90 E30 325i / '̶9̶2̶ ̶E̶3̶4̶ ̶5̶2̶5̶i̶t (sold) / '15 Toyota XW30 / '̶̶8̶0̶ ̶E̶2̶1̶ ̶3̶2̶0̶i̶A̶ (sold)
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Thank you both for your replies
Yes, this is exactly how I have mine now. Thank you for sharing and putting my concerns at ease.Originally Posted by amarino
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Kind of interesting how the factory manual picture shows the point of the bracket bend facing down, instead of up how we mounted ours. I don't think it would actually fit how they pictured it, as it would clash with the alternator blades. Their bracket must be shaped differently, or an older part I guess.
Last edited by YoungSensei; 05-22-2023 at 12:12 AM.
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Where did you find the screenshot from the Factory Repair Manual? The crank pulley looks different and there is a sensor that I don't think our cars have.
'81 E21 320i / '90 E30 325i / '̶9̶2̶ ̶E̶3̶4̶ ̶5̶2̶5̶i̶t (sold) / '15 Toyota XW30 / '̶̶8̶0̶ ̶E̶2̶1̶ ̶3̶2̶0̶i̶A̶ (sold)
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I guess this is the 320-323i "blue binder". I'm looking for a bentley manual similar to the one I have for my e30 but havent managed to find a download link yet.
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I also don't have that extra bar (the straight piece) but I'm pretty sure my bracket is oriented the same way as in the picture.
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Do you think you could upload a photo if you get a chance? I'm curious.
Member
I've seen that toothed bar on other BMW models, not sure which, but I don't have one on mine.
Member
I've had another e21 before that did indeed come with one, it was also a 320i, but it was from the year 82. They must've revised the part later in the e21's life.
Member
The service manual photo is showing the M20 engine which matches my 323i. The M10 per my 320i uses part #6, with the long slotted hole at the alternator per the parts diagram.
Member
That is how mine was originally setup, but I found it difficult to apply proper tension while tightening both the nut and bolt at the alternator. Therefore I flip my bracket, matching @amarino's picture, so the long slotted hole is on the AFM support bracket, and the circle hole is at the alternator side. I found it easier to position the adjusting slot for proper tension this way, as the bolt at the AFM bracket has no nut, meaning I could push on the alternator with one hand, and tighten the bolt up with the other. Otherwise I honestly don't see how someone could set tension alone, I feel you'd need 2 people.
Member
Good point. Adjusting tension with the slot at the alternator is not easy, but doable.
Member
The toothed adjustment bar is aftermarket. I have one installed, it takes a few other items as well, I pieced together-new, still uses the slider adjustment bar. Its handy to adjust the fan belt tension, loosen the top nut on the alternator and with a ratchet and socket push down and the toothed Hex nut tightens the belt, worthwhile upgrade and did not cost very much.
IMG_20230522_144958_692.jpg IMG_20230522_145056_147.jpg IMG_20230522_145123_616.jpg
Randy
Last edited by 320iAman; 05-22-2023 at 06:22 PM.
Member
So do you still have to push on the alternator to set the tension, and then the teeth hold it until you retighten the nut? Or are you able to crank on the adjustment nut slowly until the belt is at desired tightness? To me, that "knob" looking adjustment nut, looks like it should be able to walk up the adjusting bar as you continue tighten it down. Not sure if that's how the part functions in practice though..
Last edited by YoungSensei; 05-22-2023 at 10:01 PM.
Member
The latter as the adjusting nut is turned the fan belt tightens or loosens, the adjusting nut and the bar are like geared together.
Randy
Member
Sweet, I might get those parts and install them aswell if I start having trouble with it squealing again. Thanks!
Member
Sure, the purpose of adding in these aftermarket parts is too make easier to adjust the fan belt tension , no more using a pry bar to get the belt tightened, time saver too, I'd put this on the list of items to install, like yesterday, last week, etc.
Randy
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