From a 74 RS 3.0. Why did Porsche stop using twin plugs for their race cars? Was there a reliability or maintenance issue? The seller of the car claims 9.8:1 and 230 HP - only a 20HP increase over the 2.7 we all know. Didn't Porsche get more than that on their twin plugged sixes in the 60's?

http://forums.pelicanparts.com/uploa...1393880615.jpg

Is that the original motor? The RSR's still used twin plug as did all the racing models since the 550 Spyder until the 4 valve water cooled cars. Except maybe the 934.

The greatest of them all.

Very good details of the engine's development in Hans Mezger's book. I wish they had made more of them as I really want to own one for display purposes, but they are difficult to find.

This looks like driver, Lorenzo Bandini. My Father was actually at the 1967 Monaco GP that claimed his life.

Max - this is from the seller (1974 Porsche 911RS 3.0 (Significant Le Mans and Tour De France History) SOLD | Road Scholars)

"1974 Porsche 911RS 3.0 VIN: 91140609032 Motor: 6840051 Color: White with Gold script and wheels

Fully documented two owner history, numbers matching and significant race history with current FIA papers.

In the year 1974, Porsche produced a total of 109 Carrera 3.0. From the total number of units produced, only 54 cars were built to ‘RS’ specification while the remaining 55 where finished as ‘RSR’ race cars. The chassis numbers started with 9114609017 through 9114609121 while the engine serial numbers began with number 6840001.

The next evolution was to see Porsche achieve not just success but dominance in 3-litre GT and Touring class racing. Developed directly from Porsche’s experience with the modified Carrera that won the 1973 Targa Florio, Porsche achieved 2,993cc displacement by increasing the cylinder bore to 95mm, still retaining the 70.4mm stroke used since 1970. With 9.8:1 compression ratio it produced 230hp at 6,200 rpm and 204 lb-ft torque at 5,000 rpm. The body owed much to the Porsches built for the International Race of Champions series organized by Roger Penske."

Perhaps I just don't know what I'm talking about - which is often the problem...

Were the RS's not considered "race cars"? I always thought they were, but if what you say is correct then it makes sense as I can't remember seeing a stock 73 RS that had twin plugging. I need to get a hold of that RS book they talk about to see why they stopped. I mean, in '66 Porsche was able to get 225 HP from a 1991 twin plugged carbureted six and this 3.0 only makes 5 more? What am I missing? Longevity?

1965 904-6

http://forums.pelicanparts.com/uploa...1393958303.jpg

Any idea what this is? From an email I got about Leno's collection but with no description. I count 6 belts on the main pulley - airplane? Can't fail? Round in shape...

http://forums.pelicanparts.com/uploa...1393958370.jpg

Longevity in terms of that power was made at 8,000 rpm or more, and drive-ability. Not to mention that the noisy megaphones wouldn't work on the street, and street motors need air filters, etc.

So then was the 3.0 RS above (and for that matter the 2.7RS's) built for the street?

2.7RS yes (at least the touring version, less so the lightweight and even less so the RSH), RS 3.0 was more just for homologation. Motor was street, everything else was basically like the 2.8RSR.

Not sure why you reposted Paul, but that motor is certainly a thing of beauty.

That said, now that I look at it, and in light a few previous posts, it occurs to me that that is not the 4 cam that I thought it was. First is see no twin dizzys, no twin plugs, and now I see no DOHC's. Beautiful nonetheless.

can find very little info on this engine-
besides that it is 3L....

Looks like a standard 356 engine with a custom fan shroud

I reposted only because I forgot I had already posted it before. :(

But it got some folks looking at it closer and that's good. ;)

2.8 MFI RSR

http://forums.pelicanparts.com/uploa...1394067852.jpg