Vilhuer

I haven't seen MB aluminium V8 up close but have heard from people who have compared it's block to 928 block that even if some of it's specs look similar to 928 V8 it doesn't have anything to do with Porsche block. They both share same basic configuration with linerless Alusil cylinder walls and even repair liners sold by Kolbenscmidt are same but still engines are totally different.

928 design started in 1971. Porsche had first cast blocks on table by '72 and they were also testing cam belt drive then. Complete engines were running during '73. First design still used single carburetor but this was quickly replaced with Borsch K-Jet. I'm not sure when MB had Alusil engines ready and in use, Porsche could have started development earlier but was slower in bringing 928 to stores.

Dennis Wilson

Adrian,

Agree that cats were available later but during the 928 design decision they were an unknown. Had they been available, we would have seen a lot of oversquare and undersquare engines still being produced in 1973 by US auto companies.

Dennis

GT Jackson

As an aside, the 911 engine is not air cooled as one would think, but rather oil cooled with additional air cooling. So too is the 928/944 engine gets cooling from oil and while water cooling moderates rapid cooling and expansion of components. All that oil in the sump is just not for lubrication.

I believe that previous to the 928 block, all other aluminum blocks were sleeve fitted, while the 928 was not, making it a first of its kind.

Adrian

The primary source of cooling for the air-cooled 911 engines is a thumping great engine driven (belt) fan. There is no sump fitted to an air-cooled 911 engine, but an external oil tank. The oil certainly does provide some cooling, but the oil is also air-cooled via an oil cooler.
If the engine driven fan belt breaks the engine will overheat in a very short time. Of course if you run out of oil the same result will occur.
The 964 and 993 are fitted with an additional air-cooling system to back up the engine driven fan because the M64 series of engines ran a tad hotter than originally planned..

The statement about all previous aluminium blocks being sleeved is also incorrect. The first mass produced sleeveless silicon-aluminium (Alusil) engine block was the Chevy Vega engine in model year 1971.
Experimentation with sleeveless aluminium engine blocks date back to 1961 with Chevrolet, Rootes and Cooper Climax in England.

The 928 could lay claim to being fitted with the first mass produced sleeveless V8 engine, but I am not 100% sure about this either.
The 928 V8 is certainly way above and beyond the most reliable of the sleeveless engines (all kinds) of the time.
Ciao,
Adrian.

Jfrahm

*edit* whoops, too slow.

How soon we forget. The lowly Chevy Vega had a linerless high silicon aluminum engine block and tin plated piston skirts back in 1971.

http://en.wikipedia.org/wiki/Chevrolet_Vega

-Joel.

Normy

The M28 V8 engine is not a derivative of any other engine any more than a modern 1.8t Volkswagen engine is derived from anything horizontally opposed...

YES it uses technology and configuration from things that are not even quaintly similar. I make great sport of my Borla/Ott X exhaust; the combo results in a slightly raspy but singularly distinctive exhaust note. People who encounter the car for the first time do a wide-eyed left-right look as they ponder the rumbling car with slick curves. More than one has asked me if I've installed a different engine. This points out one of the things I like the most about the 928 car: the combination of sleek, sophisticated yet muscular lines and the bar-room brawler street hemi sound track. They don't seem to fit...

However, this just brings up something important to note: there are basically two ways to make a V8 fire: Flat Plane, like most Ferraris, which results in a car that sounds like a "rice rocket" Japanese sport bike, or Even Firing, which the M28 employs....along with all the various American V8 offerings.

-A few years ago, Honda decided to go the extra mile and put away their imminent logic and move away from two crank pins on their Harley-clone "Shadow" V twins and build a single crank pin engine just like their compatriots in Milwaukee. The result was a motorcycle that looked the same and not only was way more reliable and cost half what the Wisconsin bike cost...but sounded the same as well. Harley Davidson sued~

Wrong, says the court; you cannot copyright an engine sound. Thus it can be inferred that particular engine firing orders are just that- firing orders, and nothing of the sort is considered by the court to be proprietary. Same with configuration.

Aluminum block? Hello- it was a matter of when, not if! Linerless? Not a good idea in my mind, but they made it work. Good for them. Timing belt that turns the water and oil pumps? Same! Listen- everything is actually an evolution of everything else. The Cadillac Northstar engine has a lower engine block that looks VERY similar to the lower cradle that Porsche uses for our V8 engines. You can bet that gm bought a 928 out of the classified section of the Detroit News in the early 1980's and took the engine apart before they designed the Northstar. Why not? I would. "It works and works well, so lets learn something from it." Besides, immitation is the most sincere form of flattery. I never hesitate to bring up the rear-transaxle thing to the owners of C5 and C6 corvettes when I occasionally meet them. C4 owers were so sure this was a mistake.....

Anyway...the M28 DID turn out to be a modular design, in that Porsche turned it into the M44 four cylinder for the 924S/944/968 series of cars. I bet Porsche planned a V6 from the M28 V8, though I doubt they built one. Interesting fact, one that I read, but still cannot find in print again is that Ferdinand Piech wanted the 928 to be powered by a V10 engine. Said motor was to be derived from the design of two Audi 5 cylinder engines...engines which in turn were really just the orginal VW 847 [code for the original 1.5 liter VW Golf engine which is still that company's main engine today] with an extra cylinder added. This engine was designed on paper, but was nixed by Porsche heads. The paper V10 sat in VW files for years....until a few years ago. Now the VW Toureg rolls around Europe with a diesel version of this motor, and morons with more money than common sense sit about 12 inches in front of one as they tool around Fort Lauderdale in their Lamborghini Gallardos....

[I give them dirty looks; it doesn't matter. Most of the people who drive those have their cellphones stuck to their ear and are too self absorbed to look out their windows; That's fine- the majority wouldn't know a 928 from a '58 Buick anyway~]



N!

Steve Cattaneo

If you talk about uniqueness in the design of the 928 all aluminum engines, I think of the allusil bore running an aluminum iron coated piston. But that remains me of the 16-valve, fuel-injected Cosworth Vega of the 70s, which had an allusil bore running an aluminum iron coated piston.

The 928 V8 was a clean slate design, absolutely not !


GM introduces the catalytic converter, a technology it developed in the 1960s. All 1975 model cars sold in the U.S. and Canada were equipped with these catalytic converters to comply with the Federal Clean Air Act.

GT Jackson

Adrain: I hear to the contrary from 911 builder uppers, tearer downers and the like, that they can run with a broken fan belt. And if the oil is cooled by venting heat to the air, then a 928 water pumper by definition, would also be air cooled. But I'm in hot water here as I'm only passing along garage stories!
And so much for sleeveless . . . I'll take another piece of that humble pie. You just can't trust anything you read these days.

Adrian

Well you can tell these engine builders we will not be rewriting our books and I am sure Porsche will not rewrite theirs to accomodate this view.

On a more serious note, in the 911 world there are some disturbing things I hear that come out of certain garages and what they tell their customers. It's getting worse not better, despite the available literature on the subject.

On what you read and trust, the truth is out there.
Porsche history for some reason is more full of myth and legend based on opinion, rumour and lets be honest, made up stuff, that has morphed into fact and truth, than almost any other car I have researched.
Every brand has its myths and claim to fame, some correct, some not so correct, but Porsche has more than most.
A lot of this has to do with how the car magazines and their journalists wrote up their stories on the various Porsche models and versions. Much of what is believed today eminates from the original articles written way back when, and Porsche never corrected them. Often it was not what they wrote, but what they didn't write.
That is why I like these threads where facts can be swapped in an honest and friendly way, and people can make up their own minds or go off and do some of their own research.
Ciao,
Adrian.

Vilhuer

Porsche solved problem of casting of Alusil blocks by controling cooldown. Chevy didn't and this caused Vega engines to have uneven distribution of silicon making serious waranty problems for GM.

Seems MB started using Alusil (still use it in V8 and V12?) in '78 450 SLC 5.0 and AFAIK did not have same problem as Chevy. How they did solve it? Both 450 and 928 coming out at same time and using what appears to be similar engines it's easy to see how this can cause confusion.

Adrian

Erkka,
Actually Porsche did not solve this problem, Mahle did.
Mahle had been making the sleeveless individual Nikasil and then Alusil cylinders for the Porsche flat sixes since 1974. Nikasil was deemed too expensive so Porsche quickly reverted to Alusil.
The technology developed to create these Alusil sleeveless cylinders along with low pressure engine block die casting techiques solved the problems suffered by the Vega engine.
Mahle manufactured all the engine blocks for the Porsche 928 and I suspect they may have also looked after Mercedes Benz as well.
Strangely or maybe not, the test car used by Porsche for the first of the V8s for the 928 was a Mercedes 350 CSL. Bit of a partnership going here we didn't know about?
Often the efforts and breakthroughs of the supplier/vendor companies are credited to the manufacturer.
The real way it works is that Porsche Engineering approach a company, in this case Mahle and they say. "Well guys you know what you do for the flat sixes, we want the same done for our new V8", or as in the case of GKN in England with their new con-rods, they approached Porsche and said; "this is what we can do for you". Porsche was impressed and gave them the job.

For the record I have just been looking at the first drawings of the 928 from 1971, and it was envisaged originally fitted with a flat six using the VW EA-266 project components known at Porsche as Type 1966.
VW cancelled the 266 project and Porsche went on with their own design using a V8 engine up front.
For reference: Karl Ludwigsen Excellence was Expected, 2nd edition, Volume 2 page 764 onwards.
The first Porsche V8 was the Type 370 from 1948.
Ciao,
Adrian.

PS: The 928 block was made from Mahle 147 silicon-aluminium alloy.

chaadster

Whoa! Adrian... what is the Type 370? I thought the first Porsche was the 356 from '48, and from my reading figured that the small firm was pretty much fully engaged in trying to move the factory and produce those first 356s.

Are you saying that Type 370 was a V8 powered car, or just an engine, or an engine design? Of course, Ferdinand Sr. had designed or led development on 8s at Daimler, and was very involved with the Horch 8 at Auto Union, but I was unaware of any design for his own marque!

chaadster

Without meaning to speak for you, Bigs, I think there is a problem of definition here, as to what "clean slate" means.

I take it to mean that you were asking if there had been a Porsche (the company) V8 motor that preceded the 928 motor and from which the 928 was adapted. Others are taking "clean slate" to mean something analogous to "invented". Which did you mean?

Adrian

The Type 370 was just the V8 engine design.
The V8 was to go racing with I believe, but it never eventuated due to cost constraints.
By the way from the beginning every car, engine and transmission design were given project and/or type numbers by Porsche.
Ciao,
Adrian.

heinrich

The Tatra V8 -- was it sleeved? All-aluminium engine aircooled IIRC. FWIW 911's (air-oil cooled ones) run very much hotterthan 928's in my experience.