Porsche 8 Cylinder Engines before the 928

[Buchanan Automotive]

This is something that I find interesting ( Early Porsche engines ) and in this case 8 Cylinder , a lot of people do not know just how far back 8 cylinder Porsche engines go , most people think of air cooled flat 4 or flat 6 engines , but 8 cylinder ?

There were two completely different 8 cylinder Porsche engines that Porsche made from 1960 , one engine type ( the first 8 cylinder engine ) had two important variations , it took all of 1960 & 1961 to get this engine's power up to a competitive level & was ready to race in 1962

 

The first 8 cylinder engine was the type 753 , it was a 1.5L( 1500cc) flat 8 (2 valve DOHC ) engine designed to go into Porsche's only ever "pure" Formula One car in 1962  ( car type 804 ) , it only raced a few Formula One races in 1962 & it even won the French Formula One race & that was the only time , Porsche withdrew from Formula One to concentrate on sports car racing

Whats technically interesting about this 8 cylinder engine was the way it drove its DOHC ( double overhead camshafts ) via bevel drive shafts ( a bit like a 1960's/1970's Ducati motor cycle engine )& similar to Porsche's 4 cylinder Carrera "Fuhrmann " DOHC engines , so this means it was very time consuming to make & to get everything to stay together , everything had to be shimmed to get the correct preloads for the multiple bevel drive gears & their respective bearings & expected preloads & clearances ( cold & hot ), so there was a lay shaft driven by the crankshaft and this layshaft in the crankcase also drive the two ignition distributors & the crane drive ( take off ) for the large top mounted cooling fan , from this intermediate shaft ( centre / top of engine crankcase ) two of the bevel drive shafts went off at 90 degrees to the centre of the cam boxes to drive the inlet cams ( L & R ) with their respective bevel gears . shims / bearings & then from the inlet cams & going off al another 90 degrees , but this time straight down are two more bevel drive shafts going to the exhaust cams with their respective bevel gears / bearings / shims 

Magnificently complicated , but durable if all the clearances & preloads are massively time consumingly done

 

This above 8 cylinder engine ( one year only raced as a 1.5L ) was modified over the next few years for use in sports car racing & had grown to 2.0L with mechanical fuel injection ( engine type 771 ) & then later as a 2.2 L engine ( engine type 771/1 ) , these 8 cylinder Porsche engines were used in sports car & hill climb & Targa Florio competitions & were very successful in Porsche car Types = 718 , 904 , 906 , 909 , 910 ,  One of the standouts for me is the  1967 Porsche 910/8 Bergspyder , this Porsche ( Hill climb special ) weighed in at 410KG( Total car weight) its 1,981cc 8 cylinder NA engine gave 270HP at 9,000RPM 

So these beautifully complicated 8 cylinder Porsche engines competed and won numerous sports car / hill climb events from 1962 to 1968 , the last hurrah for this engine was victory in the 1968 Sebring 12 hour & the Targa Florio in a Porsche 907 & then off to the Porsche museum for this engine & the last Porsche engine to use the bevel / shaft drive DOHC

 

In 1968 came the 2nd new 8 cylinder Porsche engine , the 3.0 Litre 908 engine type 300HP to 360HP  in NA form , this was the a simpler chain drive to the DOHC ( much less expensive to make as compared to the type 771 ) and being air oil cooled it was still only 2 valves per cylinder , this engine went on being used in competition right up where this engine was eventually turbo charged ( like its big brother the 12 cylinder 917 engine ) which kept its ability to keep competing in events for years & years , a de tuned version of this 3.0L 8 Cylinder engine was installed into 2 separate Porsche 914's for evaluation purposes .    One 914/8 was built for Porsche's chief technician at the time Ferdinand Piech ( this one was not street registered as the engine was full race trim ), the other 914/8 was given to Dr Ferry Porsche for his 60th Birthday , this was more suitable for road conditions and was fitted with carby's & air-filters and produced 260HP 

Not surprisingly , in late 1968 Porsche experimented & developed water cooled 4 valve cylinder heads for the 8 cylinder 908 ( 3 litre engine ) , but at this stage in late 1968 Porsche was way too busy with the 12 cylinder 917 race car project , thats because the rules governing engine capacity for racing at ( Le Mans etc ) had changed from 3 liter  to 5 liter capacity & so the development of the 3 liter 908 engine was put on the back burner & the bigger 917 ( 12 cylinder ) engine now took precedence as a possible candidate for outright race wins 

My favorite 908 variant ( purely on looks & sound ) is the 1969 Porsche 908/02 Spyder , what a stunner 

Then there was a 928 transmission layout / design & shape link with the above as well , there were two very special Porsche's , one an hill climb experimental race car , the 1968   909 Bergspyder & the other the 1970 Porsche 908/03 Spyder (Targa Florio race car ) , both these race cars had their 8 cylinder engines pushed even further forward , naturally this meant the drivers legs / toes were well over the front axle line with a mid engined layout ( very dangerous but we are talking 1968 & 1969 / 1970 ) , this allowed an even better weight distribution so this meant for the first time Porsche had a new transmission built ( 5 speed with LSD ) where the diff was at the rear of the trans ( gearbox in front of the diff ) , in fact it looks very very similar to the later 928 5 speed manual transmission , even the end plate is extremely similar 

 

The above is just a condensed version of events in the history of Porsche 8 cylinder engines , so do not think that Porsche was going against the grain in building the 928 ( 8 cylinder) engine , the 928 was just the logical extension of what Porsche learnt about 8 cylinder engines in the decades before & the liquid cooling was the next logical step in to regards to emissions and mechanical noise control , much like how Porsche's famous racing 6 cylinder engines in the late 1970's had to go with water cooled cylinder heads( 934 & 935 ) & finally in the 962 Le Mans cars etc they received ( mid 1980's ) fully water cooled race engines & the water cooling enabled the use of 4 valves per cylinder because before that ( water cooled heads ) Porsche found in racing 4 valve per cylinder heads that were air cooled just could not cope with the heat ,plus you add emission controls & mechanical noise controls for road cars , hence why all Porsche from 1999 are water cooled 

 

The 928 was the beginning of the new era

 

Regards

Bruce Buchanan

Buchanan Automotive

 

 

 

[micknine01]

Interesting, thanks for sharing Bruce

[ANF]

The 908 is one of my favourite Porsches! Although I do prefer the coupe version

The one that Porsche brought out to Australia a few years ago is very nice too!

Good info Bruce

 

[Timm]

Hey Bruce, do you know anything about this? Came across these pics a while back, apparently an abandoned attempt by Kremer of fitting a turbocharged 32V 928 engine in a 962 if I can remember correctly. Unfortunately I haven't been able to find any more information about it since.

A turbo 32V 928 engine like this in a 904 or 908 replica/tribute is what I dream about at night

The above image is from the book "Porsche 956/962 The enduring champions" by Peter Morgan, so if anyone has that book, I'd love to get a picture of the accompanying text for the image.

[ANF]

I have that book Timm and no doubt you may have copied those pics from what I posted previously? On here somewhere and RL as well?

It was done by Kremer and presented to Porsche as a solution for 962 to battle Jagaur and Mercedes, unfortunately Porsche did not have the $$$ to pursue. It would have been a beast! I will dig it out later and maybe copy a few pages for you.

cheers

[Timm]

I have that book Timm and no doubt you may have copied those pics from what I posted previously? On here somewhere and RL as well?

It was done by Kremer and presented to Porsche as a solution for 962 to battle Jagaur and Mercedes, unfortunately Porsche did not have the $$$ to pursue. It would have been a beast! I will dig it out later and maybe copy a few pages for you.

cheers

Ah yes, I probably must have come across one of your posts then. That would be great, I'd love to read a little more about it cheers.

Makes you wonder what it could have been like...from the couple of turbo 928's I've read about on RL, and Porsche's own boat engines, 700 to 1000hp seems to be no issue for a boosted 32V, especially if it were to be a purpose built race engine in a chassis that has space for nice exhaust manifolds and intake plenums.

I wonder if it would have sounded anything like these awesome beasts:

 

 

[ANF]

Some 908/3 action

https://www.youtube.com/watch?time_continue=87&v=klptXsXwCjI