hacker-pschorr

You need to research how the Vega block was cast compared to the Porsche / Mercedes engines:

https://rennlist.com/forums/928-foru...l#post13256866

FredR

Jerry,

I was intrigued by some of the comments in this thread so did a Google on it and found an interesting article in Wkipedia. Alusil is indeed referred to as a "hypereutectic alloy" of aluminium and silicon with 78% aluminium and 17% silicon - no reference to what the remaining elements are. I am familiar with the term hypereutectic but absolutely no memory whatsoever of what it means other that it is a reference to the condition of the crystalline structure.

The alloy was conceived in 1927 and surprise surprise it was developed by Kolbenschmidt. What was a bit more surprising is that not many engines have been made with this stuff and the ones that are were made by Porsche, Audi, BMW and MB with the others lagging behind Porsche by quite a number of years. The first Porsche with Alusil was the 928 and by a few years or so it seems.

Welding this stuff should not be a problem in terms of structural integrity but whether or not it can be welded and leave a surface that can be etched to replicate the performance of the cast material is doubtless another matter altogether. I suspect the problem is not that it cannot be done but rather there is not the economic return to research/develop weld procedure specifications that can generate the requistite mechanical properties to support internal combustion mechanics.

Even more interesting was the statement that BMW migrated from nikasil because of corrosion issues caused by sulphur content in fuel and that was in 1996!

Rgds

Fred

Strosek Ultra

As said it is a factory exchange engine. I do not know if or where the thin sleeves can be obtained. Probably it is Porsche made sleeves for repair purpose.
The upper part of the sleeves is flanged (OD 108 mm). You have to get a KS blank sleeve part no. 89 880 190 and machine the sleeve yourself or have someone to make it for you.
http://www.pierburg-service.de/ximag...199_en_web.pdf
Åke

hacker-pschorr

Mercedes hit the market first with the 1977 450SL M116 engine.

Strosek Ultra

BMW had problems in certain markets like North America and Australia due to high levels of sulfur in the fuel.
Åke

hacker-pschorr

So did Jaguar.
I've talked to some Jaguar guru's who cannot believe my mothers 97 XK has close to 200k miles on the original engine (never even taken apart to update the cam chains). It was delivered to Appleton, WI and spent it's life in NE Wisconsin where we have sulfur free (or reduced) fuels compared to places like Chicago where Nikasil issues are more common.

Strosek Ultra

Jerry, in this particular case I would grind out and weld the crack in the cylinder. Bore out the cylinder and install a thin wall alusil sleeve (OD 104mm, flange OD 108mm). Bore and hone the cylinder to specs. However as Mr. Brown say it is always a risk involved in welding the engine block. I had a block welded once by a very skilled welder and it seems to work fine. It was a crack at the front main bearing. Following the welding I had to do a lot of machining like flycutting of the girdle mating surface on the block, inline boring of the mains and machining out and installing a bush at the oil pump housing.
Åke

FredR

Indeed, I thought they started with the 117 series engines but apparently they changed the 116 series to aluminium albeit in 1978 according to the reference I picked up.

Never been too interested in MB with their generally staid designs. I loved my last UK based car - 1986 BMW 535 straight six [cast iron block] - that was a lovely motor in its day and still relatively new when I owned it back in 1989 [they were very cheap s/h in the UK].

Rgds

Fred

Strosek Ultra

Fred, your interest in MB will increase with age. As they say in Germany, "Mercedes Benz ist ein Auto für alte Männer" which for you guys not familiar with the German language means that MB is a car for older men.
Åke

FredR

Åke,

This is very true. At the current rate of progress reckon that by the time I reach 100 I may well want one!

There are only two MB models that interested me, one being the Gullwing [and we know how unobtainable those are] and the 560 SEC of the 80's vintage. After that I feel MB lost their way somewhat when they went into the mass market. They scoffed at Lexus when that was launched back in 1990 and ended up eating humble pie. Nice cars of course but questionable value proposition. Much preferred BMW and then of course Porsche when I had some $$$'s to join the club. Even Porsche's are generally ugly cars [928 excepted of course] but once you drive them they are something else. The Cayenne is ugly as sin but what a drive- especially when you have 520 BHP and a shed load of torque on tap. The Panamera is real ugly duck but again awesome when you drive one.

I do not see a MB in my immediate future but who knows?

Rgds

Fred

Imo000

Try out one of the big engined AMG models and report back.

ptuomov

Or three.

Strosek Ultra

For some unknown reasons Tuomo, which is quite a young guy, do drive a Mercedes. Maybe he has some comments about his choice of car? Myself I qualify when it come to age and I have the means but I have realized I have too many cars and too many ongoing projects in order to find time for one more car like a MB.
Åke

jcorenman

Or a big-engined 928 ...

hacker-pschorr