Crank pulley nut....

[itiejim]

I'm trying to remove the nut holding the front pulley onto a 2 litre Alfa Nord Twin Spark engine - with no success. I have a trusty piece of English oak blocking the crank and, even with a 3' bar, I can't get the bl@@dy thing to move.

I don't have an impact driver, though I could bung the whole thing in the boot and take it to someone who does. Alternatively, is it safe to apply some heat and heave a little? I really don't want to damage the crank

[Evoluzione]

Left hand thread?

[itiejim]

Pretty sure it's not, I've tried giving it a heave in the opposite direction anyway though.

[Evoluzione]

A bit of heat should be ok and might help, obviously as long as it doesn't get too hot!
Impact wrench is best, local tyre fitters are favourite for that. The action is less damaging than large bar and wedging the crank.

[PeterBurgess]

What can often help is a good thump directly onto the end of the bolt head with a hammer/club hammer via a drift, try not to hit it where you can damage the driven sides of the bolt head. This often loosens the 'stiction' of the bolt threads. Don't be shy with giving it a good wack!

Good luck and don't hit your thumb.

Peter

[stevieturbo]

The most old school, way of doing it. Is lock the breaker bar against something sold, be it the ground or a chassis leg. And operate the cars starter motor. Ensure the engine is disabled from running though.
That usually cracks most undone.

But you need to be 100% sure whether it is RH or LH.

Italians can do weird things.

[Evoluzione]

stevieturbo said:

Italians can do weird things.

I knew someone who didn't realise Lancia used L/H on theirs, they put so much pressure on it they snapped an M14 12.9 grade bolt clean off....

[itiejim]

Thanks folks, I'll try a bit of heat and then take it to a friend with an air impact wrench if that doesn't work.

Unfortunately I can't try whacking it as it's a not on the end of the crank rather than a bolt threaded into it.

[PeterBurgess]

Is the bit about Italians the start of a new thread

I just bought a 1971 Gilera 50 trail bike ( always wanted one when I was a lad but had to put up with a step-thru ( hence my inferiority complex I reckon) Riding it round my yard I thought, this is sluggish in first gear for a 7 bhp pre restricted monstah engine. Changed into second and stopped almost dead as I had gone up into first....Hadn't realised the Italian 'way' was one up, neutral, the rest down as opposed to the more familiar ( for me) one down, neutral and rest up whether left or right foot change.

tried to post a pic but it said server error

Here is a link to a page with a couple of pics http://www.peter-burgess.com/gilera50trail.html

Peter

[stevieturbo]

itiejim said:

Thanks folks, I'll try a bit of heat and then take it to a friend with an air impact wrench if that doesn't work.

Unfortunately I can't try whacking it as it's a not on the end of the crank rather than a bolt threaded into it.

A bolt screwed into a bolt ? I guess that stands more chance of being a RH thread....but you just never know !

If you can acquire a MAPP gas torch that should impart enough heat ( that's the yellow gas cans, B&Q etc used to sell them, or plumbers merchants should do too. Usually used for brazing air con pipes etc )

[itiejim]

It's a nut threaded onto the end of the crank. I think that if my butane torch isn't enough though, then I'll take it in to try with an impact wrench.

stevieturbo said:

A bolt screwed into a bolt ? I guess that stands more chance of being a RH thread....but you just never know !

If you can acquire a MAPP gas torch that should impart enough heat ( that's the yellow gas cans, B&Q etc used to sell them, or plumbers merchants should do too. Usually used for brazing air con pipes etc )

[stevieturbo]

Weird setup. So can you see if it is a LH thread or RH then ? There must be some threads exposed ?

If things are really that bad, get a nut splitter onto it, or cut the nut off.
That should remove all risk of damage to the crank.

And plenty of penetrating fluid left to soak in for many hours.

[DocArbathnot]

PeterBurgess said:

Is the bit about Italians the start of a new thread

I just bought a 1971 Gilera 50 trail bike ( always wanted one when I was a lad but had to put up with a step-thru ( hence my inferiority complex I reckon) Riding it round my yard I thought, this is sluggish in first gear for a 7 bhp pre restricted monstah engine. Changed into second and stopped almost dead as I had gone up into first....Hadn't realised the Italian 'way' was one up, neutral, the rest down as opposed to the more familiar ( for me) one down, neutral and rest up whether left or right foot change.

tried to post a pic but it said server error

Here is a link to a page with a couple of pics http://www.peter-burgess.com/gilera50trail.html

Peter

Blimey I had forgotten all about those. The cool kids had them, I had an NSU Quickly (which wasn't)

[itiejim]

Yes, it's definitely a RH thread.

[CNHSS1]

longer breaker bar? ive had a 5ft jack handle tube to undo in the past. They often release with a decent 'crack' sound, but never needed to use heat, often not possible anyway as there are seals etc in the vacinity on most engines

[itiejim]

Not really worried about the seals as they'll all be changed anyway, I'm a bit reluctant to put any much torque through through the crank though and I am hoping to re-use that!

[Steve_D]

If you need to take it somewhere for an impact driver try a lorry tyre fitter. The guns and air system they use are a step up from any other garage.

Steve

[CNHSS1]

itiejim said:

Not really worried about the seals as they'll all be changed anyway, I'm a bit reluctant to put any much torque through through the crank though and I am hoping to re-use that!

theres nowt you can do with a longer lever or compressed air nut runner gun that will worry a crank imho. the loads and stresses on a crank are larger than Billy BigBiceps and a scaffold pole...

but hey, your engine, your stuck bolt ;-)

[itiejim]

Success!! About three minutes with an air impact driver did it!