Alternator alignment .

[IanCC]

Hi,
I have a yanmar 3gm30f. The alternator, saddle mount, has 10mm holes. The bolt is 8mm. How does that work? As you tension, the alternator twists.
Also anyone know if the hole through the thermostat housing, for the bolt, is a snug 8mm or does it, too, have some wiggle.
Just trying to reduce the black dust.
Thanks in advance.

 

[Refueler]

So get 10 - 8mm sleeves to centre the bolts ... any alloy tube or similar will do the job ... cut to length. Even plastic tube as it only has to centre the bolt ..

Black dust ? That means belt failure soon ...

 

[vyv_cox]

Hi,
I have a yanmar 3gm30f. The alternator, saddle mount, has 10mm holes. The bolt is 8mm. How does that work? As you tension, the alternator twists.
Also anyone know if the hole through the thermostat housing, for the bolt, is a snug 8mm or does it, too, have some wiggle.
Just trying to reduce the black dust.
Thanks in advance.

I also have a Yanmar 3GM30F. Installed new in 2000, it has now run for 2800 hours. It has only ever had two pairs of drive belts, the second of which remains in place. There is a small amount of dust but I doubt this is a consequence of significant misalignment.

 

[IanCC]

I also have a Yanmar 3GM30F. Installed new in 2000, it has now run for 2800 hours. It has only ever had two pairs of drive belts, the second of which remains in place. There is a small amount of dust but I doubt this is a consequence of significant misalignment.

Thanks for response

I guess, then, you don't know the hole sizes on your alternator or thermostat housing. Mine goes through a belt a year.

 

[earlybird]

I had a 2GM that chewed through belts. The reason turned out to be that the flanks of one of the vee-pulleys were quite rough with corrosion This was not obvious unless closely inspected. Cleaning with emery cloth cured the problem. IIRC it was the crankshaft pulley, but it was some time ago.

 

[Refueler]

Thanks for response

I guess, then, you don't know the hole sizes on your alternator or thermostat housing. Mine goes through a belt a year.

Sorry to say it - but not surprised if the belt is providing dust ....

Get those mount bolts sleeved to centre .... then maybe you can have a belt last longer ...

 

[IanCC]

I had a 2GM that chewed through belts. The reason turned out to be that the flanks of one of the vee-pulleys were quite rough with corrosion This was not obvious unless closely inspected. Cleaning with emery cloth cured the problem. IIRC it was the crankshaft pulley, but it was some time ago.

Yes checked that thanks. The alternator is deffo skewed when tightened.

 

[IanCC]

Sorry to say it - but not surprised if the belt is providing dust ....

Get those mount bolts sleeved to centre .... then maybe you can have a belt last longer ...

Yes i think so. Not sure how much play there should be in the thermostat housing where the bolt goes through to hold the alternator. For 8mm bolt, i guess it should be 8.2mm. Might need to pull that and get it drilled and sleeved.

 

[Refueler]

Yes i think so. Not sure how much play there should be in the thermostat housing where the bolt goes through to hold the alternator. For 8mm bolt, i guess it should be 8.2mm. Might need to pull that and get it drilled and sleeved.

My Perkins has had the same belt for over 15yrs .......

Get it aligned .... and you can then enjoy belt long life !!

 

[vyv_cox]

Thanks for response

I guess, then, you don't know the hole sizes on your alternator or thermostat housing. Mine goes through a belt a year.

No, but variation through production seems unlikely. What year is yours?

 

[IanCC]

No, but variation through production seems unlikely. What year is yours?

'99

 

[IanCC]

No, but variation through production seems unlikely. What year is yours?

Do you mean 10mm hole size with 8mm bolt is ok?

 

[Refueler]

Do you mean 10mm hole size with 8mm bolt is ok?

Sorry to be blunt ... but do you have the correct Alternator on the engine ? in terms of mount etc. ???

But anyway - its easy to buy an alloy tube of 8mm ID / 10mm OD and cut sleeves to centre your bolts .....

 

[IanCC]

Sorry to be blunt ... but do you have the correct Alternator on the engine ? in terms of mount etc. ???

But anyway - its easy to buy an alloy tube of 8mm ID / 10mm OD and cut sleeves to centre your bolts .....

Ha ha, yes. Right part number and evryfin.

 

[Refueler]

Ha ha, yes. Right part number and evryfin.

Has it always been like this or something changed ??

Pal of mine had misaligned alternator on his Yanmar ... but that was his fault !! Its not easy to get out of align if correct gear ...

It really presses home to me - SLEEVE the 10mm holes ..... nothing to lose in trying.

Are you sure mounting is straight before bolting up ?? Maybe shims to correct any out of align ??

 

[IanCC]

Well I discovered it a couple of weeks ago. I don't know how long it had been like that. Bought a recon alternator and it's just same. Deep digging says this is the way they are, which suprises me because they are both the correct part number.

 

[colhel]

Rather than a spacer, wouldn't oversize washers be more useful. I'm thinking the slotted bracket isn't thick enough even with less clearance to alter the alignment.

 

[Refueler]

Well I discovered it a couple of weeks ago. I don't know how long it had been like that. Bought a recon alternator and it's just same. Deep digging says this is the way they are, which suprises me because they are both the correct part number.

Run a straight edge ruler from both pulleys to see the alignment line ... bolt up and see what needs shim to correct ...

If I had to replace belt after 1 year - that would be last replacement I would make - I would find out why its not lasting ....

Belts should only fail due to age ... not misalignment.

Pity I'm not closer to you ... I'd be down to look and help sort.

 

[MontyMariner]

alloy tube of 8mm ID / 10mm OD and cut sleeves to centre your bolts

Not sure what alloy you have in mind, but my inclination would be to use steel tube.

 

[IanCC]

Run a straight edge ruler from both pulleys to see the alignment line ... bolt up and see what needs shim to correct ...

If I had to replace belt after 1 year - that would be last replacement I would make - I would find out why its not lasting ....

Belts should only fail due to age ... not misalignment.

Pity I'm not closer to you ... I'd be down to look and help sort.

I am up in Scotland. Yes done all the straight edge stuff. The alternator pulley is slightly twisted otherwise it's correct. I have shim washers down to 0.1mm but not really needed until i can get it straight.