Alan Herod

Thanks for posting the pictures. I don't believe the information about Euro cars being all Nikasil though (or Nikasil not having rib). Since I know the history of the car and it still has the original engine number, I find it hard to believe that anyone would have torn down a low mileage engine and put it back together with Alusil (according to the rib definition) unless labor is really cheap in Germany. Nonetheless it does have Allusils and it runs great, now with 160,000 miles on it.

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slate blue

Hi there 911 owners, I have some experience with the issues raised here. Alusil is the property of Kolbenschmidt and nicasil is the property of Mahle. Mahle also make their version of alusil. I don't believe either product to be greatly superior to each other.

The fact BMW has had trouble has got nothing to do with their quality but the fact that nicasil cannot cope with high sulphur fuels. Alusil has no problem in this regard. The reason that the nicasil is shiny is that it is essentially chrome.

The alusil is dull because it has a high content of silica aluminium. It is extremly tough and long wearing and with the 928 motors doing many hundreds of kms. Nicasil is easier to repair though. Both have low friction qualities. Alusil motors use chrome rings and chrome cannot be used in a nicasil motor. For a good rundown on nicasil go to US Chrome's website or Nicom. All the best.

Speedraser

If the BMW problems were purely fuel-related, we in the US would be seeing all kinds of horrible things happening to Nikasil 911 engines -- but we're not. Also, I believe 944/968/928 blocks are Nikasil, as are various Mercedes-Benz engines.

Tom F

Just to thicken the stew a little, my '83 Euro (original engine never opened except chain tensioner upgrade with 70,000 miles) has the vertical bar like the alusil in the picture, but it has 11 fins like the nikasil. I'm going to have the engine out this winter for some clutch work and SSIs. I'll probably do oil return tubes at the same time, so I'll see whether I can find the Schmidt or Mahle marking.

I have two sets of 3.0 nikasils around (one in another car). They both have 11 fins and NO vertical bar.

The manuals specify alusil or nikasil for all normally aspirated 3.0s and for late (like post '86) 3.2s. All turbos use nikasil exclusively. Same thing for euro 3.2s.

Alusil process first was used on the Chevy Vega. They had some teething problems as we know. Nikasil is clearly superior.

slate blue

Todd as far as you reasoning goes for the problems with nicasil being a bmw problem goes I think that reasoning is flawed for the following reason; the nicasil is supplied to both manufactorers by the same company.

The 944 928 968 all use alusil that I can garantee you, as I have worked on these engines myself.

Now on the issue of which finish being better I'll state I might be wrong here as I haven't confirmed this. I believe the new 996 turbo uses alusil and what I can tell you is that mercedes benz have been using alusil for the last ten years without any problems.

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Wil R. Ferch

Speedracer:
Let's not confuse the facts more than they are already ...all 944/928 engines are alusil.

Charlie...looking forward on word from your mechanic..are 3.0 and 3.2 cylinders the same?..the reasoning being I think both use the same 95 mm bore. The 3.2 has a longer stroke.

---Wil Ferch

Speedraser

Sorry, I guess my memory failed me regarding water-cooled Porsche engines. I am absolutely certain that I read in the motoring press that Mecedes-Benz used Nikasil at some point, but the info may well have been incorrect; does anyone know for sure? Nevertheless, there appears to be no doubt that the Nikasil works extremely well in 911 engines with "poor" US fuel -- why? Could temp alone be the answer? If so, are our 911 engines wearing rapidly during the warm-up period? I think it is unlikely that the only Nikasil engines sold in the US were in BMWs and air-cooled 911s -- does anybody know of any others?

By the way, I haven't crawled under my SC yet to look for vertical bars or fin count . . .

911pcars

The modular "Vee" engines produced by MB of late use an Alusil process where an aluminum-silicon alloy sleeve is molded into the pressure-cast aluminum alloy block. The cylinders are acid etched to leave silicon particles as the primary wear surface. This process is the same used by Porsche in their water-cooled engines.

Any longevity stories circulating yet? Maybe too early to tell.

Sherwood Lee
<a href="http://members.rennlist.org/911pcars" target="_blank">http://members.rennlist.org/911pcars</a>

Tom F

MB uses primarily alusil, and seems to acheive excellent results. Alusil longevity, including 911 motors from 3.0 onward, is not a problem. The 2.7 motor definitely had some issues, but the ring design is different on later motors. Whether it's ring design or cylinder manufacturing processes or modern oil I don't know for sure, but Porsche and its supplier for the alusil solved the problem.

MB has used nikasil for some of its "hot" engines, I believe. Everyone uses it for racing. I believe that nikasil has superior friction qualities as well as superior longevity. I would bet that this is why Porsche rated the 3.0 Carrera at 200 hp, and the virtually identical 3.0 SC a year or two later at 180 hp. Besides a change to breakerless ignition, the only difference that I can see is that nikasils were standard on the Carrera 3.0, interchangeable with alusils on the 3.0 SC.

On the other hand, I don't think that I can detect the difference with alusils in several 3.0 and 3.2 motors I've driven. You'd have to have perfect control over all of the other variables that affect power in order to judge.

Charlie Stylianos

Wil,

I have not had a chance to stop by Bob's place again since my last post. I will need to go by some time this week so I'll pick his brain again then. I have a feeling that the 84+ 95mm cylinders are the same from the pervious vintage and the casting marks would be the same. Thats just my guess. I'll see what Bob says.

-Charlie

jet911

Here's my findings FWIW. Crawled under my '86 911 over the weekend and counted 11 fins with 1 fin running perpendicular on each cylinder.

Regards,
Jim
'86 911

Ed Bighi

I counted 11 fins myself on mine, with a perpendicular fin. Strange. Or maybe the first fin is just some sort of flange. But I did not see one on the Alusil picture. Anyway, I did have mine re-rung at 140K since I had to replace some broken head studs. So I don't know what is in there. But I do have 210K miles now. That does not sound like I lot, but considering all the years of track driving that engine has, and how hard I drive, it is a lot.

Charlie Stylianos

Wil and all,

I talked to Bob again today and asked him about the 84+ 3.2 C/P's. He pretty much said that he has not had much of an opportunity (yet) to work on those engines as they are, for the most part, still running well. The couple 3.2's he has worked on he mentioned that the 95MM 3.2 cylinders have a different mounting surface for the head gaskets, but nothing specific to this Alucil/Nikasil debate.

3.2's.....Too new for Porsche Bob...another testament to their durability.

-Charlie

Bob's flat-six

Hi Charlie & Everyone: I have an 80SC that was overhauled and ringed a couple of years ago by a top porsche only shop ( NARW in Reseda Ca )And I remember the cylinders being Nicasil.I had to check though after reading this thread. I came up with 11 fins and the center rib? I'll check with Claus @ NARW to confirm.
Cheers Bob

dial911

FWIW....Just bought a brand new set of Mahle P & C's for my 3.0. They do have 11 fins *and* a center rib. My original Kolbenschmidts have 10 fins as well as a center rib.