Fan Belt Woes?

Post by **Multiphonikks** » Sun Oct 24, 2004 10:34 pm

After replacing the fanbelt last week we were driving back from Norwich to Reading and somewhere on the M25 we heard a big screech, followed by a strong smell of rubber.

"Ahhhh!" thinks I. "The fanbelt has gone".

Lifts the hood (err bonnet) and check the fanbelt. (It's still there. It's still tight, and it's still intact.)

Start up Hebe - and she makes some screeching noises before settling down. - We decide to carry on as although I have the spare belt in the boot it didn't look like it was the belt. Clutch is fine, and the rest of the car.

Anyway - eventually happen accross an AA patrolman. Play the dumb female (bats her eylids) and convinces him to have a quick look. He thinks that it's not the fanbelt, but that there seems to be some sparks coming from the dynamo when the engine is revved. I get back in Hebe, and away we go - this time sticking under 65mph.

We got home without incident, and the fanbelt intact. There was a slight "squeak" on turning Hebe off and another one when I turned her back on. Does anyone have any ideas? is it the dynamo (given the problem I had last week with charging???) If the dynamo is on it's way out and got jammed, then the fanbelt would have slipped right and caused problems?

So yes... Ideas? (it seems Hebe just requires more attention...)

Nikki

Post by **grainger** » Mon Oct 25, 2004 1:53 am

hi

sorry, you may have already said ... do you oil your dynamo ? in the little hole in the back ?

cheers
grainger

Post by **d_harris** » Mon Oct 25, 2004 5:47 am

you're not having much luck with hebe at the moment are you nikki?

Post by **Multiphonikks** » Mon Oct 25, 2004 8:17 am

grainger wrote:hi

sorry, you may have already said ... do you oil your dynamo ? in the little hole in the back ?

cheers
grainger

Hi grainger.

No, not recently anyway...would that be causing sparks and the dynamo to stick???

Post by **Alec** » Mon Oct 25, 2004 9:12 am

Hello MP,
it doesn't sound too good, I would slacken off the fan belt and see how smoothly the dynamo pulley will turn.
I have a vague recollection that the drive end bearing is a ball race and it could be on the way out. The non drive end is a plain bush (hence the oil hole) and unlikely to seize. The sparks are also worrying, so a careful check is in order.

Alec

Post by **57traveller** » Mon Oct 25, 2004 9:13 am

I would suspect the sparking is from the carbon brushes/commutator. May be just dirty or the brushes and/or the commutator badly worn.
Sounds like it could be a problem with one or both of the dynamo's bearings. Is your fan belt too tight? If so this might have damaged the pulley end bearing and could eventually cause trouble with the water pump bearing as well. It might be just worth lubricating the back end bearing bush first though.
It could also be worth taking off the fan belt to check how freely the dynamo spins by hand and listen for any ominous noises from within.

Post by **doobry** » Mon Oct 25, 2004 10:28 am

If you do high miles and have never oiled the rear bush on the dynamo I suspect it has run dry and may now be may be badly worn. This can cause a nasty screeching and also the brushes will spark more as the shaft is rattling around.....
It may be the roller bearing at the pulley end (as already suggested) but in my limited experience the plain bush is likely to give up first (especially if it wasn't regularly oiled). You can just replace the bush if that is the reason, but a complete recon Dynamo is not expensive (about £25?)

Re the rear bearing running dry - I saw one where it screeched like a very loud fanbelt at start up and the owner had to rev the engine up to a few thousand RPM to stop it screeching. The whole thing was chattering around in the bush, but with some oil that kept going for another 6 months, then it was replaced with a recon unit.

Post by **polo2k** » Mon Oct 25, 2004 10:36 am

Play the dumb female (bats her eylids)

RIIIGHT we beleve you!!!
my guess is the oil seal on the timing chain cover because mine was doing it when i had her running the other week

Post by **Multiphonikks** » Mon Oct 25, 2004 12:15 pm

polo2k wrote:
Play the dumb female (bats her eylids)

RIIIGHT we beleve you!!!
my guess is the oil seal on the timing chain cover because mine was doing it when i had her running the other week

Nah- it's certainly the dynamo - I started her up this morning when putting her in the garage (blowed if I'm going to work outside in this wind... Blowed??? Geddit???

)

Anyway - I'm going to go and get an alternator from the scrapyard. I've decided that it's in my best interests anyway to do an Alternator conversion since a lot of my winter driving seems to be stop/start and I also want to convert to Hallogens for the states.

Now, I've got 40 quid in my pocket, and am planning on heading to the scrappy... Question is, how much will he sell me a decent Alternator for... (assuming I can get a mini one)

Post by **Multiphonikks** » Mon Oct 25, 2004 12:19 pm

Dan_Harris wrote:you're not having much luck with hebe at the moment are you nikki?

Dan, I think it's the case that she is becomming more and more reliable.

Initially, it was a case of "visit the hard shoulder" every time we went on a trip.

Now it's "I may decide to break if there's something you haven't thought of checking"...

Post by **Alec** » Mon Oct 25, 2004 12:29 pm

Hello MP,
I would have guessed at £10 - £15, replacement alternators of that size (Lucas) are less than £30 but of course you will need an old one.
Cut off as much of the wiring to the alternator as you can, you need the plug so you might as well have as much cable as possible. You need to reach up to where you regulator is mounted.

Alec

Post by **Welung666** » Mon Oct 25, 2004 12:34 pm

Hi MP

I got a pair of Halogens I've taken off Doris if you want them, lenses and mirror backs are both fine in them. I'm putting Sealed units back in, when I get to putting her all back together, as I'm getting her to concours class anyway. Send me a PM if you need a pic or any other info.

Lee

Post by **Cam** » Mon Oct 25, 2004 1:11 pm

As Alec says, cut as much of the brown wiring as you can, but it's only the small ignition light lead that needs to go up as far as the regulator. The two thick brown wires are joined together and fitted into an eyelet and bolted to the starter solenoid on the bulkhead crossmember.

Of course you need to disable the dynamo voltage regulator as well. I disabled mine internally and used it as a junction box.

Post by **Kevin** » Mon Oct 25, 2004 1:38 pm

Dont forget the engine brackets as well.

Post by **Multiphonikks** » Mon Oct 25, 2004 7:25 pm

Hi folks

Took the wuss option and have ordered a kit. Decided that I'd rather have a new alternator than a second-hand one

(Aren't I bad???)