Repair my crankshaft

biketeacherdave said:

Yes the early ones had an issue think it was todo with the fuel more than anything.

Click to expand...

Possibly. BMW and others all tried the same technology and all had the same issues. The fuel should have been OK by then but I wouldn't want to bet how pure it was.

Grrrrrr said:

Possibly. BMW and others all tried the same technology and all had the same issues. The fuel should have been OK by then but I wouldn't want to bet how pure it was.

Click to expand...

A cylinder that fails due to petrol can only be described as crap.

biketeacherdave said:

Yes the early ones had an issue think it was todo with the fuel more than anything.

Click to expand...

Hi sulphur content in the fuel was the main cause of the issue. Well reported failures in both BMW engines and early jags.

biketeacherdave said:

Hi sulphur content in the fuel was the main cause of the issue. Well reported failures in both BMW engines and early jags.

Click to expand...

Funny that high sulphur petrol did not seem to damage Nikasil or Alusil used on Porsche engines.

Datatek said:

Funny that high sulphur petrol did not seem to damage Nikasil or Alusil used on Porsche engines.

Click to expand...

BMW would replace the block if it failed and that didn't have the issue so there must have been something wrong with the linings as the later/replacement ones were fine.

I had a 996 C4S, they have their own special way of ruining the bore linings! Mine was fine (just to be clear) but I remember a lot of forum guys experiencing issues with bore scoring.

Also, I got talked into the LN Engineering ceramic IMS bearing, now that really is a pile of ****e! £600 for the bearing, lasted 5 weeks and was leaking oil through it. Warranty is a US one so it's 30 days! Euro Car Pricks Parts were the UK importer so we took it up with them and they begrudgingly replaced it. Lasted 3 months, leaked oil. Took it out, binned it and got a double row IMS bearing from Porsche for a fraction of the price (I know right?) and never had a bit of trouble with it. Oh, AND, it turned out that the ceramic bearing has a life expectancy of around 20k miles which was about 18 months for me at the time, the words the specialist used were "Never have to touch it again" when selling, they have not been forgiven!

You may be wondering why I changed the bearing in the first place. Well, It was part of the purchase of the car and it needed a new clutch and flywheel so while it's off, you may as well... Yeah, wish I hadn't.

Rant=Off

Datatek said:

Funny that high sulphur petrol did not seem to damage Nikasil or Alusil used on Porsche engines.

Click to expand...

Yeah, I was never convinced but there was clearly an issue of some sort.

Grrrrrr said:

Yeah, I was never convinced but there was clearly an issue of some sort.

Click to expand...

Quality control would be my bet.

Datatek said:

Quality control would be my bet.

Click to expand...

My suspicion is that the copyright ran out and various companies tried it themselves but there's something about the technique not described in the public documents or it is in the heads of the teams that developed it. It probably appeared to work or did work under lab conditions but wasn't reliable enough in production and after 20k miles or whatever the coating had worn off.

A quick Google reveals Nikasil was created by electroplating nickel to the aluminium with silicon-carbide suspended in it. Surface chemistry is a specialism in itself: the bonds between the molecules do really odd things at the surface and with that sort of mix all sorts could happen depending on just about any variable you can think of: concentrations, temperature, particle size, acidity, catalysts, voltage, you name it. Aluminium is pretty reactive and nickel often acts as a catalyst so that's a bad start. I wouldn't be surprised if they used some fluorine compounds in there somewhere with the silicon as they tend to be very stable.