Crank Pulley / damper bolt torque

RogerD · Post by **RogerD** » Wed Jun 03, 2015 8:41 am

I've removed my harmonic damper to attach a trigger wheel and then put it back on and tightened it up by hand. I wondered if there is any movement past the obvious so to speak?

When I slid it back on it (it was easy to remove and slide back on) it clearly hit metal on metal when it reached as far as it would go. There was no doubt it was full home. I tightened the bolt by hand.

I did notice it that either it was sticking too far forward by 4mm, OR, as I assumed, my water pump pulley was not far enough out and it explained why I'd always had terrible belt squeal (I have a custome made pulley set). I had a spacer made to pull the water pump pulley out 4.2mm to solve this. It all looks perfect.

I'm asking because now, between about 2k and 3k, the engine has a rythmic resonance, quite noticable. It does this in neautral, not just under load (in fact you'd be hard pushed to notice under load as there is so much else going on!).

I'm now starting to wonder if I put it back on tight enough - though when sliding it home it certainly felt like it had firmly reached it's stop point.

DEVONMAN · Post by **DEVONMAN** » Wed Jun 03, 2015 11:58 am

The pulley should be torqued up to about 150 lbf ft.

If the pulley is fully home then the end of the crank nose will be just below the surface where the thick washer sits in the pulley. This assumes you are NOT using a 4.6 crank as the nose is longer and an sd1 pulley will not bolt up without a 20mm thick washer.

I believe you have recently changed the belt drive pulley to a larger diameter item. Could it be that this bolted on item is jammed against the rim of the harmonic damper and making it effectively a solid item and ineffective.

The other factor regarding balance is that the trigger wheel has a missing tooth and unless the wheel has had a equivalent hole drilled opposite the missing tooth then there is theoretically an imbalance. This would be of minor concern unless you have paid loads to have the engine balanced to 0.5 gms

The other possibility is that as you have just set up megajolt, it is giving you too much advance at certain revs.

Regards Denis

RogerD · Post by **RogerD** » Wed Jun 03, 2015 2:47 pm

Thanks Dennis, I'll take a look at all that.

My new pulley fits exactly the same as the old one. They both were "over" the rubber damper, but the metal lip on the harmonic damper stops the pulley from squashing it.

I'm also playing with the MJ as we speak!

DEVONMAN · Post by **DEVONMAN** » Wed Jun 03, 2015 6:14 pm

RogerD wrote:Thanks Dennis, I'll take a look at all that.

My new pulley fits exactly the same as the old one. They both were "over" the rubber damper, but the metal lip on the harmonic damper stops the pulley from squashing it.

I'm also playing with the MJ as we speak!

I'm not sure what you mean by metal lip. It's the outer ring part of the pulley assembly that does the damping and this should not be in contact with anything or it won't act as a damper

RogerD · Post by **RogerD** » Wed Jun 03, 2015 10:33 pm

Hmmm. I think I need to look at an exploded diagram. I'll search for one.

Without seeing how they are made up, would running bolts from one side to the other negate the damping?

Edit: This is my Damper:

See how the metal part where the holes are is proud of the rest of the damper - so you can't "squash" the rubber part no matter how you try. That's what I meant by the "lip".

Looking at it, I am assuming the mass of the "outer" part of the damper acts as the damper - even though it's not connected to anything directly, it acts as a damping flywheel of sorts? Or is the outer part thie bit that is connected to the shaft, and the inner bit is connected via the rubber to the outer part? That would make more sense.

Before:

After:

SuperV8 · Post by **SuperV8** » Tue Jun 09, 2015 10:40 am

How does your trigger wheel attach to the back of the pulley? Is there a gap between it and the metal ring/mass damper?
The iron ring (I think they're iron) of the mass damper should only be coupled/bonded to the pulley hub by the rubber section.
You're rubber does look rather cracked, are you sure there is no play between it and the hub as that could cause noise?
Also noticed from your photo that the shaft looks rather rusty, hopefully the rust doesn't continue under the seal because that will never seal and leak.

Tom.

RogerD · Post by **RogerD** » Wed Jun 10, 2015 8:21 am

Hi. I'll remove it and take a look today. The vibes started the moment I messed with the damper ... I.e bolted on the timing gear.

The rust stops immediately as it enters the engine .

DEVONMAN · Post by **DEVONMAN** » Wed Jun 10, 2015 8:42 am

RogerD wrote:Hi. I'll remove it and take a look today. The vibes started the moment I messed with the damper ... I.e bolted on the timing gear.

The rust stops immediately as it enters the engine .

The outer ring of the pulley assembly is mounted on rubber and MUST be free to flex and not touch any other bolt on item such as the front belt pulley or the trigger wheel. Usually there is a 5mm thick spacer ring between the trigger wheel and the centre boss of the assembly. The rubber section of your pulley assembly is badly perished and it may have got too hard to do an effective damping job. Have you checked that the outer ring is not loose on the rubber and does the ring run true when viewed with the engine running?

RogerD · Post by **RogerD** » Wed Jun 10, 2015 6:28 pm

It's a mystery! - Did loads of testing today.

1- The vibes show themself around 2k. They vanish around 3k onwards (too high frequ to notice I assume). They vibe is rythmic (regular pulsing and can be seen by looking at the steering wheel - it visibly judders (not when held).

2- I took off the belt and the vibes stop 100%.

3- I pulled the crank pulley and it's all in order. 5mm spacer on back, rubber not being touched. Same on pulley side. The rubber is free from contact - and there is no slop in the outer wheel - you can't move it by hand.

4 - Spun the water pump pulley using a drill and large polishing wheel. No vibes. Runs true. Same with alternator pulley.

5- put belt on super loose (to the point the belt is flapping about a bit) - vibes are back.

6 - put belt on tight. Vibes are back.

7 - take belt off - vibes gone (two different belts to eliminate belt).

So as I see it - there are no vibes with belts off, yet vibes are there with belt on. And the vibes are enought to feed back through steering wheel. They must be being passed through the crank pulley - which means perhaps my new pulley is making "just" enough contact with the outer rubber lip to pass the vibes on where as before, my smaller pulley was touching slightly less rubber? or... the outer ring of the damper has been moving a bit but it totally missed my smaller pulley but is now making contact with my larger pulley as it covers more surface area?

I just don't get it!

DEVONMAN · Post by **DEVONMAN** » Wed Jun 10, 2015 7:19 pm

The fact that the vibration goes away when the belt is off leads me to say it's a problem with the water pump or alternator. They are now running at probably twice the speed compared to when you had the smaller crank drive pulley. Maybe the vibration was there before but happening at 4000 revs where it was drowned out by other events.

Questions:-
Is the new aluminium multi v crank pulley running true?
Do you have fan blades on the water pump pulley?

RogerD · Post by **RogerD** » Wed Jun 10, 2015 7:51 pm

Ahh - didn't think about them running faster!

New ally pulley - runs true - very true.
Fan blades on the water pump pulley - no
Fan blades on the Alternator - yes.

When running the engine I put my hand on the alternator and felt nothing. I couldn't do the same with the water pump obviously but I used a socket with an extension on it and could not feel anything.

What confuses me more - is the judder/vibe, that you can feel as a driver, and see on the steering wheel and mirror, - can't be seen on the engine, other than I can see my vac hose resonate with the vibration. When driving the vibe almost feels strong enough to slow the engine down a bit (don't think it does).

I wanted to run a smaller belt I have straight to the alternator as a test but it fouls the water pump shaft neck so you can't.

Like I said, I ran the pump and the alt via my drill at really rather high speeds and they were butter smooth - though of course they had no load/bet pressure on them.

SuperV8 · Post by **SuperV8** » Thu Jun 11, 2015 8:34 am

Just thinking out loud!

How about testing the alternator without any electrical connections? so driven by the belt but with no wires connected - maybe something strange/uneven with the electrical side? Is the alternator out putting a decent voltage?

Can you clock all the pulleys to measure how true they run?
maybe individually they aren't too bad but when the two high points are opposite it could cause vibration?

Do you have a spring tensioner? does this bounce/vibrate around at the engine speed which creates the harmonics?

Tom.

RogerD · Post by **RogerD** » Thu Jun 11, 2015 10:28 am

I'll try the alternator disconnected - though I'm on Megajolt/Edis so I'd be suprised - still - a simple test - voltage output is fine btw.

Pulleys - I've gone to quite some effort to make sure they are true. I ran the belt super loose as an experiment so it would not have any real force to impart on the pulleys and it made no difference.

No tensioner - it's a simple straight three pulley system.

I'll take a look at the belt when it's virating .

I'll find it eventually!

DEVONMAN · Post by **DEVONMAN** » Fri Jun 12, 2015 7:43 am

Just out of interest, How many miles has you engine done and is it a stock SD1 3.5.

Grasping at straws now, but if it's a high mileage unit then I would check to see if you can feel any up and down play at the front of the crank.

RogerD · Post by **RogerD** » Fri Jun 12, 2015 9:26 pm

My Odo shows 5400 miles - but who knows with a Westfield tbh.

It's not a standard 3.5 SD1. It started life as one I guess. It's 4.3 and makes 250Bhp and revs to 6200.

I'll check for play when I'm next under it early next week.

It was previosuly owned by someone quite festidious and it looks very well looked after - I've looked through the oil fill holes and it's very clean inside.

It was all fine until I started changing things. I'm also going to treble check the new crank pulley runs true. I've been watching the pulleys and belts when the engine is running but I can't remember paying special attention to the crank pulley. I'm even considering putting back the original pulley, just to eliminate that as an issue.