M60 Engine Questions

[wishihad50k]

I am looking at buying a 1995 BMW 540i w/ 6spd. The vehicle has aprox. 125,000 on it and is in pristine shape. That being said I have done a lot of research regarding the nikasil vs alumisil issue. I have not been able to get a good look at the block in order to find out which it is. I did however check with my local bmw dealer and bmw usa and both had no record of the vehicle ever having a block swap done under warranty. So my question is.. If I do a leak down test and find that the cylinder bore is normal, what is the chance that it is going to go bad in the future, now that our gas has far less sulfur in it? Also was there any production date in 1995 that the 540i came from the factory with an alumisil block? The car was originally purchased here in CO. and has remained here its whole life, does that make a difference? I did talk to the orig. owner who put most of the mileage on it and he said that he always used premium gas. I would appreciate any advice you guys can give me! Thanks!

[BuckNaked]

I came across some stuff that must be true 'cuz I read it on the internet, I will pass it on anyway...
Nikasil took a while to figure out, since the conditions behind the failures weren't readily duplicated in BMW facilities in Germany. At first the bad short blocks were replaced with new Nikasil early in the recall. That did no good.
The date of 9/95 comes up as being the first builds that go to the US with Alusil.
The engine casting numbers will tell which M60 engines are Nikasil and which are Alusil.
The casting numbers are as follows
(3.0 liter for 530i) Nikasil M60B30 1 725 970 or 1 741 212
Nikasil M60B40 1 725 963 or 1 742 998
Alusil M60B30 1 745 871
Alusil M60B40 1 745 872
Alusil M62B44 1 745 873 (Note all M62 motors are Alusil)

I came to find out there are other casting numbers for Nikasil, but if you can remember to look for 871 on a 3.0 liter, or 872 on the 4.0 liter, or 873 to appear in the sequence, you know you have Alusil. And an 873 is the 4.4L!!!
Rumor also has it there was 4.4's stuffed in a 540 or two.

...and it wasn't the octane level, rather the sulfur content that cooked the cylinders.

There are people who are out there putting 250k on a Nikasil, so all rules apply to used vehicle purchase.
Look specifically to the idle. It is near impossible to get a car with failing cyliders to idle smoothly. The car will rock at idle. Get a leakdown test if the car runs well and you are serious about spending good money on the purchase.
The sulfur levels in todays fuel have been dealt with but you still need to stick with quality suppliers.
The 120,000 mile mark seems to be a milestone for an OEM Nikasil block. If it ain't shakin' by now you should be good to go.

[wishihad50k]

Production date is 9/94...

[yaofeng]

Be safe. Do a leak down before committing. If it passes, you will have no problem. Sulfur content of gasoline sold in the US is now at between 15 to 50 ppm. This is a far cry from 300 to 500 ppm in the 90's.

Being an engineer who services the refining industry, I have personal knowledge of the effect of the federal regulation on cleaner fuels. Many refineries had to install new Reformer Units (to produce hydrogen gas) in the last few years to extract sulfur out of the gas stream.