International Lancia Forums

Hi forum,

Can anybody discuss the advantage/disadvantage of nitrating the fulvia crankshaft?
Regarding that 1,6 crankshafts are very precious, I am affraid it could be a dangerous work.

Carlos

The 1600 Fulvia crankshaft is nitrided, which was the reason that the factory stated that the crankshaft could not be reground. 1300HF crankshafts were also nitrided.

Of course we all have... and Vandervell produced shells down to -40 thou which I would say was a little optimistic, given the normal depth of nitriding (c. 30 thou). 20 thou is OK though in my experience.

For the process special nitriding steels must be used, the best known being EN40B (to hell with the BSI and Euro numbers - I prefer the ancient EN system). There were three in the EN40 series: A, B and C; C is the most de luxe including vanadium in the alloy. Incidentally I happen to know that F1 cars use EN40 type steels for their crankshafts although the metal is very high purity, being vacuum-smelted.

There was one other: EN19 and I understand that it is the Italian equivalent of this alloy that was used.

To re-nitride a crankshaft, it is necessary to grind off all the old nitride (so I understand). Nitriding is a slow process: to replace about 40 thou (0.040" - 0.16mm) would be costly.

Paul

Thank you Paul for your info.

I really did not know about Fulvia factory nitrided crankshafts.

Well, since my crankshaft is std, I will just clean it.

Carlos

Yes,

You are fortunate to have a standard one. Do you know how to remove the blanking plugs correctly? This is essential.
Paul

Paul,

I would be glad if you can tell me the right way.
I removed the plugs once in a 1,3 crankshaft, and if I remember, it was a very hard job.

Carlos

Well, firts the problem with 1600s is that the plugs are not available so must be conserved. (1300s can use BETA sump plugs!)

The procedure is that one must "undo" the "staking" i.e. where the plug has been centre-punched at the edge; the punching extends to the crankshaft itself, which is very hard, so a special drill is needed.

If you do not have a tungsten carbide drill, then you can do what we used to do: modify on a grindstone, a masonery drill. These have tungsten carbide tips and are cheap! Grind it so that it resembles a normal metal drill. Once you have removed all the staking - by drilling sufficiently deeply - you should be able to unscrew the plug with a suitable hex key (14mm same as sump plug).

When replacing the plugs after cleaning, use Loctite 271 (red) to secure the plugs

Paul

Thanks again Paul, for your advices.

I will get a set of 1,6 plugs from Omicron (just in case of damaging the original ones).

By the way, any advice on inside cleaning procedure?

Carlos

OK.

Cleaning?

AT Evo, we would often leave the crank overnight in the tank that contained the carbonised oil remover. This is an industrial product, based on methylene chloride (similar to paint stripper); we would then wash with water and blow-dry.

Failing access to this, I would simply go at it with paraffin or diesel fuel and a small scraper.

Paul

How about ultrasonic cleaning. Works wonders

Superb I should think; all you need is access to the equipment!

Paul