Technical 1978 124 Project

[smahaley]

Okay good people. I’m in a pickle.

That’s the crankshaft pulley nut. It is seemingly a non-standard size, based on what I’ve read - it is a 30mm. Let’s call it weird discovery #8.

I did a test pull on it with my breaker bar and the camshaft gears isolated because I had to take the flywheel off to have clearance for the engine stand.

The crankshaft budged - and the camshafts did not. I’m now in a zone of combined regret and fear that I’ve thrown the workings out of timing / clearance, AND am not sure how to safely arrest the movement of the crankshaft so I can pull hard and not worry that something skips and I bang up some valves.

TIA for your advice.

I could try to source some much longer mounting bolts for the engine stand, rehouse it, remount the flywheel and start from there…?

 

[Twink80]

Okay good people. I’m in a pickle.
View attachment 463387
That’s the crankshaft pulley nut. It is seemingly a non-standard size, based on what I’ve read - it is a 30mm. Let’s call it weird discovery #8.

I did a test pull on it with my breaker bar and the camshaft gears isolated because I had to take the flywheel off to have clearance for the engine stand.

The crankshaft budged - and the camshafts did not. I’m now in a zone of combined regret and fear that I’ve thrown the workings out of timing / clearance, AND am not sure how to safely arrest the movement of the crankshaft so I can pull hard and not worry that something skips and I bang up some valves.

TIA for your advice.

I could try to source some much longer mounting bolts for the engine stand, rehouse it, remount the flywheel and start from there…?

Firstly try to retime the engine otherwise there is a chance you may bend inlet or exhaust valves due to piston contact. Or remove the cylinder head off the block if you were doing this anyway.
A pneumatic impact gun may remove the crank pulley nut without putting a load of torque into the engine.
The nut requires a multipoint socket I think but others may know better
Why do you want to remove the crank pulley?
It you are not stripping the engine I would leave the crank pulley in place.

If you have removed the flywheel carefully inspect around the mounting holes for hairline cracks, high mileage engines are susceptible to this, advice I received from Guy Croft.

 

[Slotman]

124bc1 mentioned left hand, vs, right hand threads on the crank pulley in different years? Think it was something like from 82 on? Forgot the year of yours? Vicks Sells a block off plate if you go electric on the fuel pump if you decide to go electric..I still stayed mechanical on my recent fuel pump change..

 

[Slotman]

Just a screen shot, sorry I'm not a tech guy,

of 124bc s post about a smaller nut on the crank pulley, and different thread direction....because of the smaller nut wonder if your motor is an 83 or newer? Kind of sounds like it...if you have that bolt your crank would likely left hand?

 

[smahaley]

124bc1 mentioned left hand, vs, right hand threads on the crank pulley in different years? Think it was something like from 82 on? Forgot the year of yours? Vicks Sells a block off plate if you go electric on the fuel pump if you decide to go electric..I still stayed mechanical on my recent fuel pump change..

Thanks so much @Slotman - mine is a ‘78, and has this weird 30mm nut that I have not found mentioned anywhere (manuals or online) so I suspect some shady DIY. I will retime the engine and put an impact on it (thanks to a loan from a friend). Also will inspect the flywheel per your wisdom. I might just go ahead and take the top of the engine off as I suspect that will reveal a bunch of good intel. More tomorrow!

 

[124BC1]

Never fear, ******** is here! ,

I'll try to answer this query first tonight as @smahaley seems to be getting into a panic...

That crank nut is not the type I've seen used on Fiat crankshaft pulleys of that era, so may? have come from some other application and been fitted if e.g the original nut was lost/damaged.

The correct NUT has a 38mm hexagon, with a small lip/protruding ring on the rear face (possibly to locate on the timing belt gear) and thread size is
20 x 1.5mm pitch, with a normal RIGHT HAND THREAD. Here's a pic :-

To correct any confusion I may have introduced in a reply to another current thread by @ Slotman re- timing belt replacement, here's a pic of the later BOLT, this was used on 1983 - '85 124 Spiders engines, this BOLT has a LEFT HAND THREAD. I have no info to hand re. it's head size but from the pic it looks to have a much spanner hex. size than 38mm. Here's a pic:-

To further clarify, there is a difference between a NUT and a BOLT - some people seem to interchange them at random...
The nut has an internal thread, a bolt has an external thread.
So, when looking at the 'fastener' securing the pulley to the crankshaft, if you can see the crankshaft end in the middle of the 'fastener' and a little bit of the thread, then you have a NUT, if you can't see the end of the crank or any threads, then you're looking at a BOLT, Unless of course you're now looking at a *dome or *cap nut....
(*The early 124 Sedan (Saloon) did have a domed nut on the crank pulley but it was 38mm and a normal right hand thread).
(* Lada's, which were based on the 124 Sedan, had a crank nut with an unusual extension to allow the use of a manual 'starting handle', does anyone remember these?).

 

[smahaley]

(Laughing) thank you, sir! Yes, that helps as I was losing my mind for a bit - to have confirmation that, yes, I have some non-standard situation, and I’ll get the spec nut to replace this interloper once I devise a method for removal…

Onward…. And I’ll post pics of success or failure tomorrow.

 

[124BC1]

Very good advice from @ Twink80 (as usual!).
I'd certainly agree with either re-timing the valves (to avoid possible damage) or alternatively remove the cylinder head and then figure out a way to stop the crank from turning e.g. block of wood down No. 1 cyl. bore and a steel bar bolted above it to the block deck (top of block).

A couple of ways of locking the crank with the flywheel removed :-
1. Remove the oil pan (sump) and place a block of timber between one of the crank webs (i.e. next to one of the rod ends) and the cylinder block to prevent the crank turning.

2. The flywheel bolts on your engine are probably 12 x 1.25mm, these should be the same as used to attach the transmission to the engine, so perhaps you could borrow 2 of these bolts currently being used on your engine stand, insert them into 2 opposite holes in the crank rear (flywheel mounting) flange and then use a bar/lever to hold the crank from turning - using an impact wrench shouldn't require much opposing force to prevent the crank turning, unless of course, the NUT is extremely tight.

 

[smahaley]

Very good advice from @ Twink80 (as usual!).
I'd certainly agree with either re-timing the valves (to avoid possible damage) or alternatively remove the cylinder head and then figure out a way to stop the crank from turning e.g. block of wood down No. 1 cyl. bore and a steel bar bolted above it to the block deck (top of block).

A couple of ways of locking the crank with the flywheel removed :-
1. Remove the oil pan (sump) and place a block of timber between one of the crank webs (i.e. next to one of the rod ends) and the cylinder block to prevent the crank turning.

2. The flywheel bolts on your engine are probably 12 x 1.25mm, these should be the same as used to attach the transmission to the engine, so perhaps you could borrow 2 of these bolts currently being used on your engine stand, insert them into 2 opposite holes in the crank rear (flywheel mounting) flange and then use a bar/lever to hold the crank from turning - using an impact wrench shouldn't require much opposing force to prevent the crank turning, unless of course, the NUT is extremely tight.

Ooooh solid gold. Going to do one or more of these approaches tomorrow!

 

[smahaley]

I took the head off, just to make sure I didn’t crunch valves. Then applied the air wrench and quickly realized I should have done that from the start as the nut whizzed off with no engine rotation. Here’s what I have. I’m doing more reading as I get things apart. Notice #4 spark plug (on the right) and all the gunk in the jacket of the block. I’m sure wiser eyes will notice more and I look forward to your observations. My feeling at the moment is that I’m just going to go ahead with rebuild - checking everything.

 

[Twink80]

I took the head off, just to make sure I didn’t crunch valves. Then applied the air wrench and quickly realized I should have done that from the start as the nut whizzed off with no engine rotation. Here’s what I have. I’m doing more reading as I get things apart. Notice #4 spark plug (on the right) and all the gunk in the jacket of the block. I’m sure wiser eyes will notice more and I look forward to your observations. My feeling at the moment is that I’m just going to go ahead with rebuild - checking everything.

Doesn’t look too horrendous for a used engine. The valves took dry and the right sort of colour.
What are the bores like? Any vertical scratches are bad, any kind of lip at the top of piston travel is bad. As a guide anything you can feel with your fingernail as a start.
The pistons are std and have flat tops. Lancia Pistons are domed and have bigger valve cut outs and raise the compression ratio
If you post the part number on the cylinder head I can see if it features in Guy Crofts book and give you some more info
The part number is cast into the top side between the spark plug galleries
There is also a cast in part number on the block if you can post that too?
Good luck with the teardown, I guess you have checked you can obtain all the spares you need before pulling the crank out?
Oh and try to measure the crank end float before stripping apart.(can’t remember if you have auto or manual?)

 

[smahaley]

Doesn’t look too horrendous for a used engine. The valves took dry and the right sort of colour.
What are the bores like? Any vertical scratches are bad, any kind of lip at the top of piston travel is bad. As a guide anything you can feel with your fingernail as a start.
The pistons are std and have flat tops. Lancia Pistons are domed and have bigger valve cut outs and raise the compression ratio
If you post the part number on the cylinder head I can see if it features in Guy Crofts book and give you some more info
The part number is cast into the top side between the spark plug galleries
There is also a cast in part number on the block if you can post that too?
Good luck with the teardown, I guess you have checked you can obtain all the spares you need before pulling the crank out?
Oh and try to measure the crank end float before stripping apart.(can’t remember if you have auto or manual?)

Cool - will post part numbers and what is ‘crank end float’? I’ll check the US suppliers for internal bits before I go much further. I do want to get ahold of a valve spring compressor so I can look more closely at those…

 

[Slotman]

I believe Its " end play" as if you put a dial indicator with a magnetic base on one end of the crankshaft set to zero, and see how far it moves the opposite direction...that's what my guess is, that's what I did before and after when rebuilding auto transmissions but perhaps I'm wrong and it's play up and down with in the bearing?hopefully an expert will chime in soon..

 

[124BC1]

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2. The flywheel bolts on your engine are probably 12 x 1.25mm, these should be the same as used to attach the transmission to the engine, so perhaps you could borrow 2 of these bolts currently being used on your engine stand, insert them into 2 opposite holes in the crank rear (flywheel mounting) flange and then use a bar/lever to hold the crank from turning - using an impact wrench shouldn't require much opposing force to prevent the crank turning, unless of course, the NUT is extremely tight.

Small correction, upon further memory searching, I now think the engine to transmission bolts are possibly 12 x 1.5mm thread,
so won't fit the rear of the crankshaft where the flywheel attaches.
But iirc, the wheel bolts are 12 x 1.25mm thread so could be used instead.
Alternatively, there are also 12 x 1.25mm thread bolts used on the rear axle locating rods and
possibly also on the rubber coupling on the end of the transmission.
Also some spark plugs fitted to e.g. motorcycles and small engines have a 12 x 1.25mm thread size.

 

[124BC1]

---------------------------------
* Lada's, which were based on the 124 Sedan, had a crank nut with an unusual extension to allow the use of a manual 'starting handle', does anyone remember these?

In case anyone is interested, here's a few pics from various suppliers of the special crankshaft nut that allowed the use of a 'starting handle' on the older Lada cars - note the prices (Euro 1.00 = $1.08 approx.)



While on one of the Lada parts suppliers websites I came across this heavy duty version of the rubber 'doughnut' (Guibo) driveshaft coupling that looks like it might fit the Fiat124 Spider, might be useful for someone with a highly modified engine or for competition/racing use? (details below):-

I've just checked the price of this heavy-duty coupling it's Euro 69.72 (c. $75) +shipping - however all upgrading items on this LadaPower site are listed as out of stock until Mar31-2025, err...

On further consideration, I reckon it might be too rigid for normal passenger car use, resulting in vibration being transmitted into the cabin and given the price, I could buy 2 or more stock rubber couplings for less.

 

[124BC1]

Crankshaft end-float is the amount of fore and aft movement of the crank, it's controlled by 2 halfmoon shaped thrust washers, they're fitted, one on each side of the crank rear main bearing in the cylinder block. Here's a pic showing their location (the red arrows show where they fit):-


Here's a written description on how to check and adjust crank end-float:-

Here's a pic of the end float being checked using a dial- test indicator:-



Here's a pic of the end float being checked using feeler gauges (considered to be quite sufficient in many workshops):-

 

[124BC1]

I do want to get ahold of a valve spring compressor so I can look more closely at those…

No need to get a valve spring compressor to remove the valves. Here's a trick I use - I've seen it being used in some professional engine overhaul 'shops.

Remove the cam boxes with their camshafts but be careful as you lift the camboxes as the cam followers (tappet blocks) and their shims will try to fall out of the cam boxes (although the shims will usually remain stuck to their respective cam follower due to the oil film between the two), store these safely as it's timesaving to have the original shims in their correct locations if re-using the original valves.

Support the cylinder head on a couple of blocks of timber so that all the valves are free to move downwards.
Now, taking a pipe or socket, sized to match the diameter of the valve spring cap (i.e. outside diameter of socket
should equal the outside diameter of the spring cap), give it a couple of sharp whacks with a soft-faced hammer,
this will shock the valve open -do this correctly and sharply enough, and the valve retainers (collets) will pop free
and the valve spring cap and spring will now also be free - don't worry, there is not much pressure contained in
the valve spring (so not dangerous) and the socket/pipe will prevent the valve retainers going into orbit.
But please wear Eye Protection just to be safe.

You will need some sort of valve spring compressor to refit the valves - in the past, I've even managed by using a large C clamp
and a section of tube with a side cut-out to allow insertion of the valve retainers once the valve spring had been compressed enough.
Not much point in buying a special tool you might only use once (or maybe check out the AutoZone, tool-hire scheme?).

 

[Twink80]

I believe Its " end play" as if you put a dial indicator with a magnetic base on one end of the crankshaft set to zero, and see how far it moves the opposite direction...that's what my guess is, that's what I did before and after when rebuilding auto transmissions but perhaps I'm wrong and it's play up and down with in the bearing?

You are correc

Cool - will post part numbers and what is ‘crank end float’? I’ll check the US suppliers for internal bits before I go much further. I do want to get ahold of a valve spring compressor so I can look more closely at those…

I would highly recommend buying or making a valve spring compressor, ths valve collets are extremely fiddly to remove
You will need to tap the valve spring with a socket etc to remove any stiction. Make sure the head is supported and the valves can move to avoid bending the valve.
I made a valve spring comoressor out of a plate that goes under the head, a small tower out of box to make a pivot then a lever arm with a horseshoe shape collar to bear down in the valve while allowing access to the collets, a pick tool is handy for hooking out the collets
Make sure you measure the valve clearances before you start and note down carefully. Then keep all the correspinding parts together eg Cyl 1 ex valve, spring seats, collets, (you can leave the bucket and shim in the cam carrier as long as you dont mux up, they will fall out if you are not careful.

 

[smahaley]

You are correc

I would highly recommend buying or making a valve spring compressor, ths valve collets are extremely fiddly to remove
You will need to tap the valve spring with a socket etc to remove any stiction. Make sure the head is supported and the valves can move to avoid bending the valve.
I made a valve spring comoressor out of a plate that goes under the head, a small tower out of box to make a pivot then a lever arm with a horseshoe shape collar to bear down in the valve while allowing access to the collets, a pick tool is handy for hooking out the collets
Make sure you measure the valve clearances before you start and note down carefully. Then keep all the correspinding parts together eg Cyl 1 ex valve, spring seats, collets, (you can leave the bucket and shim in the cam carrier as long as you dont mux up, they will fall out if you are not careful.

Thank you - Yes, I can imagine a day, perhaps far in the future, when I am driving this car in good weather, and perhaps once a year I check the valves and need to do little adjustments. In this hazy golden future I would be re-using a tool that makes it easy to do such things. These are the stories I tell myself. I will get a tool!
Thanks for the great advice!

 

[smahaley]

Okay here’s today’s update:
1) oil pan. It’s got some dings in it but nothing that impedes the oil flow / pump. Leave it alone?

2) Cylinder head and valves. I procured a spring compressor and removed the intake valves. They all are black and crusty with buildup on the top, and caked a bit with burnt on business on the hot side. I soaked them for an hour in chem dip, rinsed and wiped a bit - some came off; perhaps more will with another round.

Salvageable or should I just go ahead and buy a new set? BTW valve guides seem smooth at first inspection…