Rattling Generator

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hambone
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Rattling Generator

Post by hambone » Tue Feb 02, 2016 11:49 am

Hi, from time to time and especially when hot our 68 Beetle generator is getting rattly, sounds almost like someone lightly shaking acorns in a shoebox. It has been going on like this a couple years. It is sort of subtle, but not really.
I have to remove it to replace the oil cooler seals, should I replace the damned thing? Or will it go on years like that?
Brushes are wearing normally.

(Colin, is it possible to remove the fan shroud with engine installed if there is thermostat linkage??? I will take off the decklid)

Thank you trying to save money. Also have to again replace wiper linkage, and a new fuel sender.
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tristessa
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Re: Rattling Generator

Post by tristessa » Tue Feb 02, 2016 12:05 pm

hambone wrote:is it possible to remove the fan shroud with engine installed if there is thermostat linkage??? I will take off the decklid
You'll also have to take off the curved brackets the decklid hinges bolt to, three bolts on each one. Mark them before removal so you can get them back where they belong, the ones on my '65 seemed to be side-specific but it's been years and years since I had that car.

Might be worth swapping to an alternator if you can find a real Bosch one not a Chinese knockoff...
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asiab3
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Re: Rattling Generator

Post by asiab3 » Tue Feb 02, 2016 12:13 pm

hambone wrote:...our 68 Beetle generator is getting rattly, sounds almost like someone lightly shaking acorns in a shoebox. It has been going on like this a couple years. It is sort of subtle, but not really.
I have to remove it to replace the oil cooler seals, should I replace the damned thing? Or will it go on years like that?
Brushes are wearing normally.
I removed my alternator to replace the "rattly" bearings once, and it turned out I had a cracked fan. Do your rattles show up at idle, acceleration, and deceleration?

F.A.G. generator bearings are available from autohausaz.com (maybe elsewhere too) for about $6. If you have time, it might be nice to check to see if your generator bearing housings are wallowed out from a bad bearings; that might mean generator replacement. (I have a core 30a generator you can have for the cost of shipping.)
(Colin, is it possible to remove the fan shroud with engine installed if there is thermostat linkage??? I will take off the decklid)
I took Mom's '69 engine down to the long block in car last week. It did not have a thermostat linkage, but it's easy enough to deal with.

Upright (non-doghouse) oil cooler engine:

- Disconnect battery ground. Disconnect generator wires.
- Remove deck lid, then remove deck lid mounting brackets
- Remove carb, belt, thermostat, and generator strap. (Loosen the strap and push it towards the front of the car. It doesn't need to come off.)
- Remove two M6 fasteners on sides of fan shroud.
- Lift fan shroud (with generator attached) straight up, careful not to skew thermostat rod in cylinder head.
- Have informed helper disconnect thermostat rod from right side flap. Flap must be at a certain angle for rod to slide out. Eat your Wheaties beforehand.

At this point, the four M6 fasteners on the generator backing plate can be removed, and the generator comes out towards the back of the car with the fan still attached. Now the fan shroud will be significantly lighter, and you can weasel it straight up and tilt it to the right and over the oil cooler.

I am thinking over this in my head for a doghouse cooler setup. If yours is, let me know, and I will think about it on here in another post. :bom:

I have no problems with the original generators. Their components seem to be more easily replaceable for the budget-minded.
Robbie
1969 bus, "Buddy."
145k miles with me.
322k miles on Earth.

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hambone
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Re: Rattling Generator

Post by hambone » Tue Feb 02, 2016 1:38 pm

It seems to rattle only at idle. Will the bearings seize some day, or will it just rattle forever?
Have never removed the entire fan shroud with engine installed but have replaced a million generators. How big a deal to replace bearings? Of course the armature etc. has a lot of miles on it too. This generator looks ancient but still puts out the juice. Maybe I should just let it fail in it's own time, just seems a shame to pull it again in a year. (I should have replaced the oil cooler seals 2 years ago when I had the engine out....)
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asiab3
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Re: Rattling Generator

Post by asiab3 » Tue Feb 02, 2016 2:56 pm

Is the belt so loose that it "slaps" around at idle?

It's a shame to do the oil cooler seals and not at least inspect the generator bearings. BUT if the sound cleans up above idle, perhaps there is another cause. I put a 19mm socket in a drill and spin the generator up with the belt off to listen carefully. With a careful slow application of the trigger, and a quick pull back of the drill once up to full speed, you can speed up the generator and test the bearings and electrical output without running the engine. Listen for howls, grinds, groans, and irritations.

From my readings and parts books, both generator bearings are the same, and the insides are not too complex. I think Colin did it in a field in New Mexico once. A seized bearing could destroy the shaft necessitating a new generator. IF the bearings are bad, replacing them now could save a more costly repair later. IF the bearings are bad. IF.

Image


I don't know if there is any technical merit here, but here are some pictures of disassembly. You can do better ;)

http://61vdub.blogspot.com/2012/01/vw-g ... art-1.html


Robbie
1969 bus, "Buddy."
145k miles with me.
322k miles on Earth.

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Amskeptic
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Re: Rattling Generator

Post by Amskeptic » Fri Feb 05, 2016 10:28 am

hambone wrote:It seems to rattle only at idle.
Next time you hear the rattle, reach around to the front of the fan housing and apply tension to the flaps cross bar, towards drivers' side then back right. Does the rattle go away?
Chloe had a bunch of engine rattles:
thermostat cross bar (all I had to do was make the fail safe spring a little more taut)
right side fan housing 10mm head bolt at upper cylinder cover
left deflector tin
then the stupid throttle cable guide tube went all buzzy, now clamped with a section of fuel hose at front of engine pressing lightly against the front tin.
Colin
BobD - 78 Bus . . . 112,730 miles
Chloe - 70 bus . . . 217,593 miles
Naranja - 77 Westy . . . 142,970 miles
Pluck - 1973 Squareback . . . . . . 55,600 miles
Alexus - 91 Lexus LS400 . . . 96,675 miles

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hambone
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Re: Rattling Generator

Post by hambone » Fri Feb 05, 2016 12:46 pm

Cross bar! Man I never thought of that.
How long can these old Bosch generators run before they fail? That's really my concern, since I'll have it out already.
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http://pdxvolksfolks.blogspot.com
it balances on your head just like a mattress balances on a bottle of wine
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Amskeptic
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Re: Rattling Generator

Post by Amskeptic » Fri Feb 05, 2016 6:36 pm

hambone wrote:Cross bar! Man I never thought of that.
How long can these old Bosch generators run before they fail? That's really my concern, since I'll have it out already.
You know that is unanswerable. One stupid tight belt adjustment changes everything. One long distance push through a red generator warning light (instead of immediately addressing it) can pit the commutator, etc.
Colin
(a happy generator should last indefinitely, bearings and brushes changed in a timely fashion))
BobD - 78 Bus . . . 112,730 miles
Chloe - 70 bus . . . 217,593 miles
Naranja - 77 Westy . . . 142,970 miles
Pluck - 1973 Squareback . . . . . . 55,600 miles
Alexus - 91 Lexus LS400 . . . 96,675 miles

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hambone
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Re: Rattling Generator

Post by hambone » Sat Feb 06, 2016 12:14 pm

A fair answer. What causes a commutator to get out of round? That happened to me a couple years ago.
It may be amusing to replace the bearings, I've never had a generator apart.
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http://pdxvolksfolks.blogspot.com
it balances on your head just like a mattress balances on a bottle of wine
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asiab3
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Re: Rattling Generator

Post by asiab3 » Sat Feb 06, 2016 2:59 pm

hambone wrote:A fair answer. What causes a commutator to get out of round? That happened to me a couple years ago.
It may be amusing to replace the bearings, I've never had a generator apart.
Out-of-roundness in the axial dimension is not uncommon, the brushes gradually wear the commutator. If brush compounds are not 100% uniform, one side of the brush can wear the commutator or brush side faster. Uneven spring pressure can also cause this; same with commutator manufacturing defects. We can clean it with sandpaper in a field or true it on a lathe for like-new conductivity. I've done this (both work environments!) to starters and generators, and I've never seen one anywhere NEAR their respective wear limits.

I've never heard of an commutator going out of round radially. Is this even possibly?

If you had a generator apart, it would be hard to test the bearings for their required 6,000+ RPM cruising speed, but it would be easy to feel for grit or slop. At that point, replacement would be wise IF the replacement parts are trustworthy........

Robbie
1969 bus, "Buddy."
145k miles with me.
322k miles on Earth.

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hambone
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Re: Rattling Generator

Post by hambone » Mon Feb 08, 2016 7:18 pm

It did. Bouncing brushes that wore out quickly.
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http://pdxvolksfolks.blogspot.com
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asiab3
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Re: Rattling Generator

Post by asiab3 » Mon Feb 08, 2016 8:54 pm

Wow, I would love to see that.

On second thought, I'd rather NOT see it. Even if it COULD be cured on a lathe.

Robbie
1969 bus, "Buddy."
145k miles with me.
322k miles on Earth.

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Amskeptic
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Re: Rattling Generator

Post by Amskeptic » Tue Feb 09, 2016 9:49 am

hambone wrote:It did. Bouncing brushes that wore out quickly.
Yep. I have seen a groove worn into the sides of the brushes where they chafed against the holder.

a) most typically, wallowed bearing holders and worn bearings allow the generator shaft enough radial play/vibration to push the brushes back and forth .001" + and they just wear away in clouds of black dust
d) some generature armatures get bent from reefing on a stuck fan nut or prying a recalcitrant generator pulley off with a crowbar as you wedge the generator under a rear tire . . jus sayin'
BobD - 78 Bus . . . 112,730 miles
Chloe - 70 bus . . . 217,593 miles
Naranja - 77 Westy . . . 142,970 miles
Pluck - 1973 Squareback . . . . . . 55,600 miles
Alexus - 91 Lexus LS400 . . . 96,675 miles

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hambone
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Re: Rattling Generator

Post by hambone » Tue Feb 09, 2016 1:27 pm

We broke a rare cast pulley once, I remember...
http://greencascadia.blogspot.com
http://pdxvolksfolks.blogspot.com
it balances on your head just like a mattress balances on a bottle of wine
your brand new leopard skin pillbox hat

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Amskeptic
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Re: Rattling Generator

Post by Amskeptic » Wed Feb 10, 2016 7:08 pm

hambone wrote:We broke a rare cast pulley once, I remember...
No we di-INT, I'M TELLING, you're a TATTLE TALE!

Mike had a horrid beetle pulley that newish cad plated two blades style.

We, you and I, bought a cast iron pulley as I tracked down vibration. Who was that guy with parts and shop in Portland there? He charged me $60.00 for this current cast iron pulley, the same guy who sold me this generator with the crinkle shim holding the rear bearing in the wallowed-out end plate that makes my brushes wear down quickly.
Colin
BobD - 78 Bus . . . 112,730 miles
Chloe - 70 bus . . . 217,593 miles
Naranja - 77 Westy . . . 142,970 miles
Pluck - 1973 Squareback . . . . . . 55,600 miles
Alexus - 91 Lexus LS400 . . . 96,675 miles

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