Technical Removing crank pulley nut

[ErikK]

Anybody got a magic way to remove the 38mm crank pulley nut with the engine

in the car? I blocked the engine from turning, easy since the head is off. When I apply the big breaker bar I can rock the whole engine on the mounts but the nut does not budge. It is right hand threaded yes? I have soaked it with penetrating oil. It feels like I'd break a motor mount before the nut would loosen. And even with the radiator out there is no room for an impact wrench, the crossmember that supports the radiator is right there. Somebody must know a way...?

 

[bugsymike]

Anybody got a magic way to remove the 38mm crank pulley nut with the engine View attachment 482293in the car? I blocked the engine from turning, easy since the head is off. When I apply the big breaker bar I can rock the whole engine on the mounts but the nut does not budge. It is right hand threaded yes? I have soaked it with penetrating oil. It feels like I'd break a motor mount before the nut would loosen. And even with the radiator out there is no room for an impact wrench, the crossmember that supports the radiator is right there. Somebody must know a way...?

Not particularly on a 124 Spider, but what I find is locking the engine more effective by removing the starter and putting a small spanner across the teeth and turning the engine till it jams, then in your case with your long bar in it's best position exerting maximum force, have some one hit the long bar as high up as possible whilst missing the hand putting on the force, with a large hammer/mallet.
This provides the shock that you are unable to do with the impact wrench.
Another more destructive method is a large blunt chisel and big hammer on the nut at one side to drive the nut undone as a last resort.
Alternatively as you are nearly dismantled anyway, remove the engine and apply the impact wrench.
By the way the reason for locking at the flywheel is it acts directly on the same crankshaft rather than acting against the leverage of the con rod and piston which have the affect of reducing your effort by jamming the top of piston.
Another thing I have found is a 3/4 inch long bar has less bend/flex in it than a long 1/2 inch one, even with a reducer if required at the socket end. I also use impact sockets as stronger than normal bi hex type.
In extreme cases I have even added a short length of scaffold tube for even more leverage. In no case has this damaged the flywheel teeth, although I would say make sure it is well engaged with the spanner.
Yet another solution may be if possible to remove the engine mounts and drop the engine lower so the impact wrench can access the crankshaft nut.
You could also try some heat on the nut, sometimes people use loctite and this relaxes it's grip.
I have worked for many years on my own self employed and usually one of these methods will win. Good luck.

 

[portland_bill]

I agree with Mike, locking the crank directly is better than blocking a piston. Blocking the piston can lead to pressure damage on that big end bearing, which could create a problem later, if the shells are not being replaced.

A long time ago, I owned an Argenta (132 facelift) with the 2l twin cam engine. When changing the cambelt, I struggled to undo that crank pulley nut. With the engine in the car, I could not get an impact wrench at it, unless I removed the radiator, ane lifted the engine. Even then it would have needed a long extension, which reduces the impact forces. I never did find out if it was a left hand thread, but this is unlikely. Being automatic, locking the crank at the starter ring gear i spotentially risky, as it is just a flex plate, and with enough force can distort. I never did get the thing off. I did find that I could manipulate the cam belt around the pulley, without damage to the belt.
If you are just trying to replace the belt, that might work. If you need to replace the front seal, sorry, I've not helped.
I think an impact wrench is needed. Which will mean lifting the engine above the crossmember, or out completely. Sorry.

 

[puntodad19]

As above really, but check epar for "nut" ( is it a nut ?). If it is a nut, some threads on the crank may be visible, unless it is a "special" nut...

Would a long extension "miss" the cross member and still allow the socket proper alignment, so all torque goes into nut and not "ride off" ?

Farmers are quite ingeniouse.....

So long 3/4 inch drive ( or bigger ) extension sticking out of the front of the car properly in line with nut etc....

Place a jack "pivot point" or fulcrum close to long extension drive end, long breaker bar set to say 10 o clock, so downward force goes to ground but torque goes thru system to nut.....


Does the sump have a gasket and is it easily removable ?

Probably easier all round to raise engine enough to get a good impact drive, either electric or pneumatic...

Research epar first would be my initial action I feel....

That dexion type angle looks as if it would bend, only two head bolts is a bit risky I feel.....

I don't think I would use that method of preventing crank from rotating especially using an impact gun.

What does elearn suggest ?

There must be a fiat service locking tool ?

 

[jackwhoo]

Nut for crankshaft front Fiat 124 Spider (66-82), Coupé, Fiat 125, 128, 131, X 1/9, Lancia Beta

Nut (M 20 X 1,5) belt pulley crankshaft front SW 38 right-hand thread 1400-2000 Until Bj. 82 ( from 83 article no.:1162087) 38 nut article no.:1163210

shop.arnold-classic.com

 

[puntodad19]

Nice...I presume the raised spigot fits inside the pulley ?

New nut available ?

Size and pitch is mentioned....

 

[s130]

No experience with the 124s but on our Strada/Ritmo Abert 130TC 1998 cc - Engine 138AR2.000. has a LEFT HAND thread.

Note check if you have a nut or a bolt!

See this info.

 

[bugsymike]

OP did say nut, but I know some people are not aware of the difference.

 

[ErikK]

It is definitely a nut. Yes I can get the timing belt out without removing the pulley, I have done this many times. Since the car has been sitting for 30 years I thought I would replace the crank and intermediate shaft seals "while I am in there". But since it turns out not to be easy I think i'll leave it alone and see if it leaks much. Thanks for all the good suggestions.

 

[124BC1]

@ErikK

Old school method is to place a socket with breaker bar on the nut with the handle end resting on the ground/floor and hit the starter. As this crank pulley nut has a RH thread the handle end should be towards the driver's side (assuming car is LHD). I agree with others above that 3/4 inch drive tools would be preferable, you could also use a ring spanner (box-end wrench in the U.S.?) but might have to prop it up on a block of wood depending on its length.
Don't forget that 38mm is almost the same as 1- 1/2 inch.

Along with the methods suggested by others above concerning how to possibly get an impact wrench onto the crank nut - here's another possibility - as the cylinder head has been removed, if you loosen the engine mountings then release the rear transmission mounting crossmember (lower it gradually as required using a floor jack), the engine can be tilted by quite a large amount being careful to avoid anything being strained e.g. hoses, cables etc. -iirc, you might then be able to get an impact gun onto the crank nut using an extension through the air intake grill, or remove the grill and use the impact gun directly on the nut.

There was a Fiat factory tool for loosening the crank nut (Fiat S.A.T. A.50121) (afaik S.A.T. stands for Special Application Tool ).This was a short wrench, essentially like a flat bar welded to a reduced depth socket with a block on the end i.e. a 'slugging' wrench, designed to be struck with a hammer.
Iirc, the nut is tightened to 88 lb.ft, so shouldn't be too difficult to loosen.

As regards possibly damaging an engine mount - these may need to be replaced anyway after 30+ years. The original mount were rubber with a compression spring inside (these often split), later mounts were solid rubber - replacements are readily available and not expensive.
I wouldn't rely on a 30+ year old crank seal to still seal when the engine is re-woken - it would be a pity to have to re-do this job because of an old seal.

 

[ErikK]

I applied over 200 ft lbs and it did not move. But I like your idea of a short wrench and a big hammer, I've probably got a 1 1/2" box end wrench in my bin of big tools. And your point about the motor mounts is a good one, they're pretty easy to get to now with the head off.

I'm hoping to not have to pull the trans and do the rear main seal, we'll see. I did so many clutch jobs on 124's back in the day, it would not be tough. But why borrow trouble?

 

[124BC1]

As no doubt you're aware, It always takes a lot more torque to get a nut to start to loosen that what it was originally torqued to, add in a bit of corrosion and it gets even harder.
In your situation, I still think a suitably propped bar and socket plus a jab of the starter should work just fine, often did it back in the day and it never caused any damage - but your car so obviously your choice.

 

[puntodad19]

Car been asleep 30 years, time for some tlc...a stitch in time etc...

 

[bugsymike]

I applied over 200 ft lbs and it did not move. But I like your idea of a short wrench and a big hammer, I've probably got a 1 1/2" box end wrench in my bin of big tools. And your point about the motor mounts is a good one, they're pretty easy to get to now with the head off.

I'm hoping to not have to pull the trans and do the rear main seal, we'll see. I did so many clutch jobs on 124's back in the day, it would not be tough. But why borrow trouble?

The only thing I can add in addition to what was said previously is the mallet I use in those extreme cases is generally a Number 4 Thor copper mallet which can provide quite a firm impact.

 

[Pugglt Auld Jock]

The only thing I can add in addition to what was said previously is the mallet I use in those extreme cases is generally a Number 4 Thor copper mallet which can provide quite a firm impact.

I think it's pretty much all been said above and I agree the method of blocking the nut and shocking it with the starter motor works well. It's pretty much a "do or die" though because once you turn that key it's total commitment! Although, having said that I had one, many years ago, which simply stalled the starter! As folks on here will probably have gathered, I'm a great advocate of applying shock intelligently to loosen seized fixings. So all I can add to this conversation is that, as you're intending to replace that seal anyway, I'd give it a few cycles of heating and cooling to try to use thermal shock to "crack" the hold. An oxyacetylene torch works best of course but I've had to give mine up the bottles due to my insurance company refusing to insure my house if I kept it! So I now borrow a blowtorch from a friend which runs MAP gas and has a number of different torch sizes to allow fine or course flames to be chosen. You don't need to heat it to anything like red heat, just nice and "toasty" does fine. In situations like yours I've had considerable success with a dedicated "freezing" release oil as the cooling agent, but just throwing water over it works quite well too. Give it several heat/cooling cycles. This is the stuff I've had some success with: https://www.opieoils.co.uk/p-235091...ZH_EdbgCHY97DmiaMy70TySJ1xXWqB0qMTCrtv8x1bh8g When using it you need to apply a good long spray each time to get max effect from the freezing component. A quick squirt doesn't do any more than a normal releasing oil, needs to be maybe a quarter of the can each time you use it to get a proper freezing effect. It's quite expensive stuff, but I've had some quite reassuring success with it.

By the way, I'm also in agreement with the suggestion to not try blocking the top of the piston like that. Like Mike, I would favour jamming the flywheel - a very traditional way to do it and, as long as you take care to use something suitable and position it so it can't slip, I've never done any damage doing it this way. Having said all that though, my preferred method would be a nice big impact gun and I'd be tempted to work things, even to the extent of removing the engine from the car, so I could use it. I've learned over the years, that when you try to avoid doing something like that because of the "bother" factor, after you've made things much worse, by rounding off or otherwise damaging something, you really wish you'd just done what your gut was telling you was the best way to do it!

 

[Pugglt Auld Jock]

I intended to say above, but forgot, that, especially if using an impact gun, it helps a lot to initially start by giving it a quick "rattle" in the "doing up" direction before trying to undo it. I'm pretty sure I've seen posts from others from time to time advocating this and, although it seems counter intuitive, this technique often works well.

 

[Slotman]

i removed mine about 6 months ago..removed the radiator first then just used my 220lb air impact with a socket and mine came loose with out blocking anything on the motor..

 

[Pugglt Auld Jock]

i removed mine about 6 months ago..removed the radiator first then just used my 220lb air impact with a socket and mine came loose with out blocking anything on the motor..

Having wrestled many times with tight nuts and bolts using lengths of scaffold tube and the likes of a "T" bar It was an absolute revelation as to how easily a decently meaty air impact gun sorts something like this out.

Edit. Only thing I'd add is that if you need to use an extension then use one which is specifically for an air gun as I've found standard extension pieces greatly reduce the force applied to the socket.