Fan position inside shroud

[balljoint]

I recently had my engine rebuilt and upgraded to doghouse style cooler,shroud and fan bought from scat. Now with the engine running I can hear a random knocking or like a low toned vibration sound coming from the area of the fan shroud...it's not constant but comes and goes. The noise is not there when the belt is removed and alt/fan is not spinning and also no signs of rubbing inside the shroud when the fan is removed.
On further investigation I noticed the fan not totally out enough and maybe not in the correct path to allow it to channel air properly to the cooler and I believe the mechanic said he used back some of the old mounting hardware to mount the new fan and I have the spacer pictured left over from the fan mounting kit I also purchased from scat.
Can you guys confirm if is this is where the fan supposed to sit in relation to the outside of the shroud and what the noise could possibly be?

And also the alt has not been in use for about 5yrs so I'm not sure if it's bearings but it spins more or less smooth.

[busdaddy]

That's one hell of a big gap, sure that isn't a 28mm fan? Or was the old fan hub for a 38A bus generator?, what does the plate between the generator and shroud look like?

You can usually confirm a fan rub issue by grabbing the shroud as it's idling and flexing it fore and aft, any noises?
_________________
Rust NEVER sleeps and stock never goes out of style.

Please don't PM technical questions, ask your problem in public so everyone can play along. If you think it's too stupid post it here
Stop dead photo links! Post your photos to The Samba Gallery!

Слава Україні!

[VeeDubWolf]

Yeah, looks like when the shroud was upgraded the fan wasn't swapped for the correct thicker fan, that won't cool properly.
_________________
Two Bugs-
'70 rust-bucket sunroof sedan
'69 PO hack-job special
-Plus a wide assortment of various parts'n'junk

[balljoint]

Fan is the wider one suitable for doghouse application.

Plate between alternator and shroud looks fine and will start it up again and check for rubbing, but the noise it makes doesnt sound like rubbing and as i said before there were no signs of rubbing when the alternator/fan was removed and inspected

[vwoldbug]

Can you measure the fan I think it should be 35 mm .

[busman78]

I have a new CB fan, blades measure 37mm, actually a little over that and there is a gap, correct spacing at the generator backing plate.

[balljoint]

I believe mine is 36mm and definitely wider than what I took off.

Apparently there are lots of hub sizes available and the one supplied with the kit had the fan touching the outer part of the shroud as it was too big so my original one was reused.

I will use a few shims to bring it out a bit as all I've seen looks a few mm further out as I'm using the amt of thread visible on the nut as a guide too.

Just to figure out the noise now....I've read here that having the belt too tight can give some sort of noise??

[busdaddy]

Shitty aftermarket pulleys sometimes make noise as they slowly self destruct, how about some pics of the back side of your engine?

As for the fan hub I suspect you have a bus only hub in there, maybe a 38amp inner plate as well (since the fan didn't lock up against the bug plate) when you shimmed for that gap specified in your Bentley manual.
The bus 38amp one is on the right, the chewed up one on the left is 30 amp or alternator.

(Desertbusman photo)
_________________
Rust NEVER sleeps and stock never goes out of style.

Please don't PM technical questions, ask your problem in public so everyone can play along. If you think it's too stupid post it here
Stop dead photo links! Post your photos to The Samba Gallery!

Слава Україні!

[balljoint]

I don't know what hub etc is in there right now because the mechanic mounted it and did the initial troubleshooting to figure out the noise.
The fan and the pulley does however have a wobble to it but he says they never really run straight and again it's not touching anywhere.
I have since put the engine in the car to check to see how the gearbox works but I will take it back out soon to scrap and investigate further.

[Lingwendil]

The fan should not wobble! If it does its defective, installed incorrectly, or the alternator shaft isn't true.
_________________
73 super beetle thread http://www.thesamba.com/vw/forum/viewtopic.php?t=649622 Back on the Road!

Modify your Kadrons for SVDA http://www.thesamba.com/vw/forum/viewtopic.php?p=8115884#8115884

Cast iron VJU4BR8 SVDA reference thread- https://www.thesamba.com/vw/forum/viewtopic.php?t=...mp;start=0

Need replacement filters for original Kadron aircleaners? WIX #42087 is a perfect fit, as is Napa Gold #2087!

[busman78]

There should be no wobble, since both fan and pulley are wobbling the alternator shaft is probably bent .

Course my curiosity to all of this is the fan gap to forward fan shroud, your gap is large and maybe it is the picture angle but does not appear to be an equal spacing around the perimeter, that points to a bent something.

If your mechanic says "but he says they never really run straight" is BS, without the belt attached you should be able to spin the assembly and it run true.

[balljoint]

Oh boy...well it doesn't look good.

https://youtu.be/9TQnai2n6Xg

https://youtu.be/lpYKJ1ugJME

[busman78]

Pull it, take the pulley and fan off, spin the alternator, if it spins true then your fan and pulley have been in an accident, suspect the alternator is trashed too. I would also take a serious look at the fan housing and backing plate while you have them off.

[balljoint]

Well I pulled everything out and it seems like a bus hub was used but when I put on the new hub that came with the fan it hits the intake size of the shroud as it's too long and there is about 8mm between the fan and the backing plate.

There is also a 5mm spacer that goes on the shaft which is exactly how much I have to reduce the hub length by to get a decent fit but I cannot remove it because the diameter of the new hub is too big to fit down in the hole around the alternator shaft.

Are these the correct backing plates that should be used?

[busdaddy]

From here it looks like you have a bus inner plate (against fan) and maybe even a bus outer plate (against generator), although that one looks oddly bulged, I wonder how thick the spacer is between them?
Here's what they should look like for an alternator:

https://www.thesamba.com/vw/classifieds/detail.php?id=2018446

Your inner plate looks puffed out like a bus one and the the outer has the depression close to the generator (although the rest is not flat like it should be).

Once you get the correct plates you'll have to play with shims until the fan is spaced correctly, or put the bus hub back in and shim out a little.
_________________
Rust NEVER sleeps and stock never goes out of style.

Please don't PM technical questions, ask your problem in public so everyone can play along. If you think it's too stupid post it here
Stop dead photo links! Post your photos to The Samba Gallery!

Слава Україні!

[balljoint]

After some researching it definitely looks like I have the wrong plates. The inner one is bulged out and the outer one is sinked in closer to the alternator but the rest of it is flat if you watch some of the earlier pics I posted.

This looks to be what I have along with others I've seen here strangely advertised as type1 plates

www.thesamba.com/vw/classifieds/detail.php?id=2216852

So my question is now...Is the 3pc plate kit that everyone sells for about $15 ok to get or should I get an original set?

[DurocShark]

I was able to compare the two sizes last weekend. Pretty significant difference. If anybody wants to see the difference...

_________________
No boom today. Boom tomorrow. There's always a boom tomorrow.

[busdaddy]