Crank Pulley / damper bolt torque

v8250 · Post by **v8250** » Sat Jun 13, 2015 7:49 am

Roger, just a note for you on your original crank pulley. I've compared your pic to my pulleys in the the garage, the outer crank weight ring looks to have moved inward thus causing a step between the crank pulley centre body and the ring. I think this is caused by the vulcanized rubber becoming hard and the ring shifting. If all other options fail it would be worth getting another pulley just in case.

RogerD · Post by **RogerD** » Tue Jun 16, 2015 1:50 pm

Did some more testing.

- Ran without alternator plugged in - no difference
- Took the alloy pulley off and put a spacer between it and the balancer to eliminate the possibility of it hitting the pulley - no change.
- checked again that it runs vibe free without the belt on - still does.
- Eyballed the outer balancing ring when running and I can see it's ever so slightly out of true - and i mean very slightly. I'd expect that for a rubber mounted iron ring?
- noticed in the V's of the crank pulley (and water pulley) several small pieces of belt material. Little chunks.

Now trying to source a replacement balancer, though I can't undestand

- how , with the belt off, I feel nothing, yet with it on, the vibes are there? Perhaps, if my balancer is knackered, it doesn't manage to transfer it's "wobbles" through the crank back into the engine but it does manage to transfer them via the belt?
- how come my balancer was fine until I removed the pulley to install a trigger wheel? perhaps I disturbed a very nearly knackered balancer?

I dunno - running round in circles really. I guess it HAS to be the balancer, water pump, or alternator. Though the latter two I can't believe can generate enough harmonic vibes to shake the steering wheel, and they run smooth when powered with drill and a large polishing wheel.

DaveEFI · Post by **DaveEFI** » Tue Jun 16, 2015 2:01 pm

If there are old bits of belt stuck to the pulleys, I'd remove them. Good pulleys in service have a smooth polished surface.

DEVONMAN · Post by **DEVONMAN** » Tue Jun 16, 2015 2:16 pm

DaveEFI wrote:If there are old bits of belt stuck to the pulleys, I'd remove them. Good pulleys in service have a smooth polished surface.

And do the Water pump and alternator pullies run true.

DaveEFI · Post by **DaveEFI** » Tue Jun 16, 2015 3:08 pm

I've got an non standard 100 amp alternator on my SD1 - still driven by a V belt. Best I could do with the available spacers on the alternator pulley etc was about 3mm out. So thought I'd just try it, until I got time to make some new spacers. About 3 years ago.

RogerD · Post by **RogerD** » Tue Jun 16, 2015 4:40 pm

Oh I cleaned them the moment I saw them

All the pulleys run true. Before I tinkered, the water pump pulley was 4.2mm out and it ran fine , albeit squealing a lot! I've sorted that now.

I've bought a used harmonic damper / crank pulley assembley off ebay so we'll see if that does the trick.... hoping that it's all a coincidence and that my damper have up whilst I was tinkering.

If it's not then at least it's "only" £30 to eliminate that part....

RogerD · Post by **RogerD** » Sun Jun 21, 2015 6:05 pm

Well the plot thickens. I've now tried a different harmonic damper - no difference at all. So that leaves

Water pump
Alternator

(Vibes go without a belt on)

Both spin happily with a drill, although I can't spin the alternator fast enough to energise it.

I'd love to be able to drive the water pump on it's own to eliminate it or the alternator but my belt is far too long. Is there any trick I can use?

RogerD · Post by **RogerD** » Sun Jun 21, 2015 6:05 pm

Well the plot thickens. I've now tried a different harmonic damper - no difference at all. So that leaves

Water pump
Alternator

(Vibes go without a belt on)

Both spin happily with a drill, although I can't spin the alternator fast enough to energise it.

I'd love to be able to drive the water pump on it's own to eliminate it or the alternator but my belt is far too long. Is there any trick I can use?

DEVONMAN · Post by **DEVONMAN** » Sun Jun 21, 2015 7:07 pm

My money is on the alternator as it will be spinning much faster than it did with your previous smaller crank pulley driving it.
At 2000 rpm crank speed the alternator will be at 6000 rpm. You could put your small crank pulley back on just to see if the problem disappears.

Regards Denis

RogerD · Post by **RogerD** » Mon Jun 22, 2015 6:34 pm

I ran a belt made from tights from the crank pulley to the water pump today (no alternator in the loop) and the vibes were there, albeing spaced out further, and lasting twice as long.. so a vibe for a good second, every other second, rather than the "normal" vibe for 1/2 a sec then nothing for 1/2 a sec.

Water pump pulley looks straight. Cant feel and bearing wobble etc. Water pump also doesn't create vibes if I "drill" spin it, but the speeds will be much higher with the engine running.

Very odd. I'll try the old pulley too.

DEVONMAN · Post by **DEVONMAN** » Mon Jun 22, 2015 7:39 pm

What diameter is the water pump pulley?

Stu E · Post by **Stu E** » Mon Jun 22, 2015 8:25 pm

If the water pump is running faster, could it be cavitation?

RogerD · Post by **RogerD** » Mon Jun 22, 2015 8:29 pm

Cavitation is a high rpm thing. This is all happening from 1500- to 2800 ish rpm. I did wonder about it too at 1st.

I'll check the measurements but the crank and water pump pulley are very close to 1:1 which is the recommended ratio I believe

ged · Post by **ged** » Thu Jul 23, 2015 7:19 pm

Just curious, but did you sort this out Roger?