The 356 engine development, part 1 - introduction

The 34 hp 1131 cc Porsche type 366 engine used in the very first Gmünd Porsches was very similar in concept as the 1085 cc engines for the Berlin-Rome cars

When the war was over Porsche had re-located to Gmünd, Austria and plans for an own sports car started to take form. Almost all of Porsches work had been done for customers, thus they didn't possess much in terms of intellectual property to base their sports car on.

The whole Berlin-Rome program, including the type 115 engine, was designed with Volkswagen Werk as customer and the Sturmboot program was done for the German military forces. Thus, Porsche did not own these designs.

The lack of own intellectual property was a problem already before the war as Porsche was not allowed to use kdf-designs as a base for any private sports car project. Thus Porsches stillborn attempt of a sports car in 1938 (type 114) had to be designed from scratch.

After the war the situation was a bit different. Volkswagen Werk was now run by the British forces who heavily relied on Porsche knowledge to keep developing the beetle. Also there were some overlap in the staffing. Gustav Vogelsang, the chief engineer for engine development at Volkswagen in the 40's, seems to have worked in parallel also for the Porsche company. According to the book "Porsche - Origin of the species" by Ludwigsen, Vogelsang fled from Germany to join Porsche in Gmünd late 1944, but seems to have re-located to Fallersleben, and his position as head of the engine development at Volkswagen,  some years later.

So when it came to re-use Volkswagen parts Porsche had a friendly counter part to negotiate with. But when it came to the  re-use of wartime designs I imagine the situation was more tricky. This is only my speculations, but having Ferdinand prisoned in France for war time crime was probably not a good starting point for negotiations to re-use military designs for commercial purposes.

But, as they had the knowledge, the easiest way was probably to do new drawings using new project numbers. It might not be a coincident that the first attempts to develop a new Porsche sports car engine looks more or less like a re-make of the Sturmboot program.

Stay tuned for part 2 and I'll explain more!

The origin of VW tuning – Type 174A, 1942-1943

The Type 174A engine. From this angle it looks like a pretty normal kdf engine with dual carbs.

The last in the row of Sturmboot prototypes is the 174A. In the specifications I have seen it is said to be a normal kdf-engine, but with higher compression, larger intake valves and dual carburetors. But, was there perhaps something else done?

I want you to put yourself in the shoes of the Chief Engineer for the Sturmboot engine program. Your first attempt, 170, was a rather simple execution: Slap a Roots supercharger on to an existing engine. Simple, but in the end too heavy for the application.

Your next try, 171: An engine that is totally re-designed only to be able to get hemispherical combustion chambers. A nice solution from a design point of view, but tooling up for a entirely new engine, aimed for a very narrow application, would have been insane.

So, what to do next? Obviously there is a resistance in increasing the cylinder volume* and there is also a belief that hemispherical combustion chambers is the way to increase power in a normally aspirated engine (perhaps it was also deemed as a necessary measure to be able to raise the compression with the war-time fuel). On top of that, the new engine must reuse as many kdf parts as possible.

If only there was a way of tilting the valves while still retaining the overall lay-out of the kdf engine. Hmmm…. Wait a minute! If I tilt the valves in the other direction? Never mind the intake valves, perhaps only tilting the exhaust ones would be sufficient to get a much better combustion chamber? If we can find a way to get the pushrods on the exhaust side to work despite the angled valves, we can have a nice high compression engine, reusing most of the kdf parts. Then we only need tooling for new heads and we don't even need to touch the casting of the case! While we're at it we can add dual ports on the intake side for better flow, much like the early E60 engines from the 1930's.

This, ladies and gentlemen, describe the design principles of the type 369 head, a design that would follow Porsches pushrod engines in all 356 and 912 up until the late 60's.

Viewed from this side we see that this is not normal kdf-heads. They have dual ports and very different valve covers (I did the yellow high-lightning for illustrative purposes).

Look at the picture above of the type 174A. I have highlighted the shape of the valve cover and the dual port intake. Then compare it with the very early type 369 engine found at the Prototyp museum in Hamburg. I think the similarities are striking.

An early type 369 engine from the Prototyp museum. Compare this to the previous picture. To me it seems as the type 174A was the true father of the Porsche 356 heads.

Could it be that the 369 engine launched by Porsche in the late 40's was a carry over from the war time type 174A? Phil Carney (356 Registry vol 32, nr 6) writes that it's "quite possible" that the type 369 heads "were initially designed during the war". Not exactly heavy evidence, but I can't find any information that goes against my theory that the type 174A and 369 heads are closely related.

Again, any additional information that can support, or destroy, my theory is very welcome. To me the sketch of the type 174A is a good indicator that the Porsche 356 pushrod engine had its origin in the Sturmboot motor type 174A from 1942/1943.

*The cylinder volume was already increased a bit from 998cc to 1131cc, but I see no attempt in going further.

The origin of VW tuning – Type 174, 1942-1943

This is the only type 174 picture I have seen. Not a 100% normal kdf-engine as you can see.

As said before the type 174/174A is somewhat of a mystery. In this post I'll try to cover the first one, the type 174.

Looking at the technical data it looks like your normal post-war 1131 cc with 25 hp and a 5,8:1 compression ratio. But the only picture  of a 174 I have found show some strange things.

First there is a bulky device where the distributor should be, which seems to be some kind of magneto device. "Normal" kdf-stationary engines did have a bulky magneto device somewhat similar to this one on the type 174, while the type 171 had a Scintilla device of the type used on post-war stationaries. I guess they tried out different types during the war before they settled for the Scintilla type.

Technical data of the type 174/174A.

The second thing is the carburetor that looks a bit different from other ones from that time. It it's a Solex 26vfi II with dual float bowls that was also tested on the Schwimwagens*. Perhaps it was an attempt to try out a carburetor more suitable for use in a boat application? 

And that's all for the type 174. I have no more at this point in time. Next up is the 174A.

*Edit note: I did update this blogpost with additional information from Dieter and Lucian. Thank you!

The origin of VW tuning – Type 170, part 2

The first version of the type 170 featured a top mounted Roots supercharger, the photo was taken in March 1943.

This blogpost was supposed to be about Sturmboot prototypes type 174/174A, but when asking my source some follow up questions I received some more very interesting information. So until this new information is digested I will wait with the174/174A post, but until then I have some new findings related to type 170 I want to share.

As it turns out, type 170 were built in two versions: One with the Roots supercharger on top of the engine and one were it's axial mounted in line with the crankshaft. The first one is labelled version one and the photo is dated March 1943. The latter does only say type 170 and 1943, with no further details.

The new photo material of Sturmboot prototypes I got show different versions of prototypes and even complete units that appear ready for the sea. This put my statement in earlier blogposts in a new light. Probably no one knows for sure anymore how many prototypes were made.

The second version had an axial mounted Roots supercharger. Could this have been the engine that ended up in Ferry's kdf cabrio? To me it seems like the earlier version above would have been more practical...

The origin of VW tuning – Type 170, 1942-1943

Basic data for the type 170 engine dated 1943. As can be seen the original compression ratio of 5.8 was retained despite the use of a supercharger (Gebl.).

In 1942 three new project numbers aimed for the same purpose saw the light of day at the Porsche Designbureau: 170, 171 and 174. The background was a problem with the Sturmboots (a kind of simple motor boat with a very long propeller shaft) in which dirty water did clog the cooling system. The idea was to replace it with an air-cooled engine, but the only one in production, the kdf, was not powerful enough. Thus, Porsche  Designbureau was consulted to fix the power issue.

In this blogpost I will focus on the first one, type 170. It was a pretty normal 1131cc kdf engine, but with a Roots type supercharger mounted axially behind the crankshaft. Remember my reference in the last blogpost to Barbers book "Birth of the Beetle"? What he claims to be a type 115 engine looks very much like a type 170 mounted in a car. Also looking at the timeline it makes sense. According to Barber, the first version of a kdf engine with axial Roots compressor was completed in September 1942 which is more in line with project number 170 than 115 that is dated to 1939.

This is the only picture I have found on the type 170, I have chosen to zoom in on the axial mounted Roots type super charger (the rest of the picture was of poor quality anyway)

From a business point of view my belief is that the type 170 should have been killed already before the drawing stage. The engine was far to heavy for its purpose due to all the parts surrounding the supercharger. But, perhaps Porsche did proceed with the project just so he could put the high power engine in Ferry Porsches private kdf-cabrio? Who knows…

The origin of VW tuning – Type 115, 1939

Cut-away of the cylinder and head of the type 115. As can be seen it has a single overhead camshaft with a 74 mm bore and 40 mm intake valves. The bore size, with a 64 mm kdf crank makes 1101 cc. A rather odd displacement for a conpetition engine.

In the list of Porsche design numbers we can read that type 115 was a kdf based 1,1 litre engine with overhead cams, hemispherical combustion chambers and supercharger. Thus, a pretty advanced engine for its time, and as such a very interesting one for this blog! Perhaps it can also be seen as the grandfather of the Carrera engine?

Cut away drawing in which we can see the bevel gears and the shafts driving the over head cams. Even though the Carrera engine has twin cams per head the drive principle of the type 115 is not too far off.

But what was the background? Was it even intended for a kdf type car? Did it ever really exist?

Reading Chris Barber’s excellent book “The Birth of the Beetle” it is easy to believe it was a running prototype as a picture of what is supposed to be a type 115 engine in a kdf-wagen is published. However, looking closer at the picture we see a supercharged kdf engine with normal cylinder tin and what appears to be a standard case. For once the otherwise very correct Mr Barber seems to be wrong. What we see on the picture is a "normal" kdf-engine with a Roots type supercharger. As far as I know there are no known pictures of a completed type 115 engine.

The background why the project 115 was started I know very little about. My source has been able to measure the original engine block (yes it still exist) and confirms that if fits on a kdf-type transmission. He further claims that the case is very similar to its kdf sibling aside from the rear of the engine where the cam drive is. Thus it seems reasonable to believe that the type 115 was somehow connected to the kdf (race car) program rather than Porsches private sports car project (As the kdf-program was state owned Porsche was not allowed to use such parts in his own endeavors).

The supercharger is of a centrifugal type throwing out air in one pipe for each cylinder bank.

Another view of the rather unusual supercharger

The assembly drawings I have access to are dated 28.8.1939 and 1.9.1939, only weeks before the Berlin-Rome event. My immediate conclusion was that the engine must have been aimed for a future race after the famous one. But, my source who has interviewed mr. Kaes, cousin of Ferry Porsche, claims that the documentation sometimes were made afterwards, thus the date doesn't mean that much. In any case my guess is that the Type 64 needed a more "normal" kdf-engine for Berlin-Rome due to propaganda reasons and that type 115 was aimed for a future race.

If there ever was a running engine, or even a complete one, I don’t know. But, it seems that most of the parts were manufactured at least. According to my source, Otto Mathé saved the parts when he emptied Porsche’s shelves of old prototype stuff in the 40’s. It would be a thrill to see those parts come alive one day!

The first page of the drawing lot that this blogpost was based upon.

The origin of VW tuning – Introduction

 Together for the first time in a long-long while! In 2015 the Berlin-Rome car IIIA0701 (ex. Mathé) was finally re-united with its original engine 38/43, a mildly tuned E60 kdf engine.

A little over a year ago I did write about the origin of the ”V-heads”, that is the very special cylinder heads used on the type 367 Porsche prototype as well as on one of Peter Max Müllers race cars. Since then I have come in contact with a long time kdf-collector based in Central Europe who have provided me with very interesting information.

As it seems, my expression “V-heads” was not a good one. What I thought was basically versions of the same head proved to be three very different designs. But my guess that the design principles of a V-headed VW/kdf-engine stems from the time of the Berlin-Rome Wagen seems to be correct though.

Reading in books and articles there are a lot of confusing and sometimes contradictive information related to this mythic car and the race that never happened. Some state very detailed information that, upon a closer investigation, turns out to be totally wrong.  However, I will focus on the engines only and try my best to avoid using unreliable sources.

All VW/Porsche history writers tends to agree that the engine that in the end made it to the sleek Berlin-Rome car was a tuned version of the normal kdf engine using dual carbs. A qualified guess is that the engine needed to be recognized as a kdf-one for propaganda/marketing purposes. The Berlin-Rome Wagen needed to be perceived as a sports version of the peoples car rather than an exotica.

A teaser for the next blog post in which the technical specifications of the Type 115 will be revealed.

But, it's doubtful if this whole race car program was started for just one single race. Most likely they had future events in mind. In parallel with the preparation for the September 1939 Berlin-Rome race Porsche did develop a far more exotic engine based on the kdf platform. This project, type 115, will be the topic for my next blog post. Stay tuned.

*Images courtesy of my anonymous Central European contact

The blog will soon re-open!

Thanks to a generous blog-reader in Central Europe I have come across some very interesting material related to the early attempts of making high performance versions of the kdf/VW engine. Thus I find it's now time for me to re-open the blog!

Above is a teaser. It's a part of an engine drawing from Porsche dated 1 September 1939, the very same day as German did invade Poland. In upcoming blog posts I will tell you the story behind this drawing and how the off-springs of this design did affect the post-war racing scene.

To be continued

Norrtälje VW marknad 2015

I dag var det återigen dags för VW marknaden i Norrtälje. Som vanligt dök en del intressanta bilar upp. Själv tog jag mig dit i den egna bilen. Den nya motorn lufsade på bra på motorvägen, men var inte 100% smidig på lägre varv. När jag kom hem ställde jag om blandskruvarna, något jag borde gjort om redan efter jag justerade flottörnivåerna. Resultatet blev en mycket smidigare motor i de lägre varvtalen. Nåväl, här är några axplock av vad jag såg:

Denna fina 356A var begåvad med en SAAB Monte Carlo ratt. Ganska lik Nardi-rattarna, men den smala delen på slitsarna är bredare på SAAB:en. Hur som helst är denna ratt en personlig favorit!

Jag är normalt ingen "buss-kille", men denna trio såg bra ut ihop.

Fin korallröd 56/57:a. Plus i kanten för korrekt lackade fälgar!

56:a Ghia som byggts om någon gång i tiden med VW typ 3 bakljus. Nu i ett stolpe-in-på-besiktningen skick… Totalt tre lowlight kunde ses på mötet 56, 57 och 58!

Riksmötet - en nyare favorit

När det gäller nyare 356:or är färgen Slate Grey i kombination med röd inredning min absoluta favorit. Precis som den här C-modellen.

Riksmötet - en av favoriterna

En av mina absoluta favoriter på riksmötet var Mickes 54:a som ni såg i bakgrunden i ett tidigare inlägg. Visst älskar jag en perfekt originalbil, men min personliga preferens är nog ändå något som är varsamt och tidstypiskt tillbusat. Som denna pre-A med 120 hästar och Carrera lucka.

Riksmötet del 3

Även 356 ägare modifierar sina bilar, ibland med samma metoder som används inom VW-svängen. Ovan ser vi en Porsche 1500 från 1954 som försetts med en ljuddämpare från Abarth, vilket också var favoritavgasleverantören för femtiotalets VW-trimmare.

Ända sedan tidigt 70-tal har VW ägare älskat att sätta Fuchs-fälgar på sina bilar. På 356:or är de dock sällsynta idag. Här ser vi Martins fina 356C med utsökt renoverade 4,5" 911S 1967-only smidda Fuchs fälgar. Även däcken är av klassiskt snitt: Michelin XAS 165HR15. En eloge både för att han lackat dem korrekt och för att han har modet  att låta dem sitta på sin bil!

Riksmötet del 2

En intressant bil på riksmötet var denna Devin D. Modellen producerades mellan 1958 och 1963  och bestod av en rörram med glasfiberkaross. Den gick att köpa som ren kit-car utan drivlina, eller så kunde man välja VW, Porsche eller Corvair motor. Detta exemplar hade, som ni kanske kan gissa av sammanhanget, en 356-motor. Den lät dessutom riktigt vass med en kam som hade runt 300 graders duration.

Bilen i bakgrunden är inte dum den heller, en 1500S från 1954 som busats till med Carrera lucka och en 120 hästars motor med tredelade blocket.

Riksmöte

 Dagen som gått ägnades åt ett gästspel på Porsche 356 klubbens riksmöte. Av den stora mängden fina bilar var det ett par som verkligen stod ut lite extra. En jadegrön 56:a Carrera samt en radiumgrön 51:a.

Ett synnerligen vackert par!

Fyndläge 1965?

Radannonser i äldre tidningar är intressanta. Som intresserad av antik VW-trim kan man till exempel få en bild av vad folk verkligen körde med under en viss tidsperiod.

I nr 16 1965 av Auto Motor und Sport finner vi till exempel denna annons för en ganska speciell Hebmüller, (VW's ultrasällsynta 2-sits cab från tidigt 50 tal). Med Porsche 1300 motor, dito bromsar och en del annat godis, var den nog tämligen unik redan då.

Tittar man på mer "vanliga" trimmade VW's finner man bland annonserna påfallande många Karmann Ghior och typ ettor med Okrasa TSV1300 motorer och Porsche bromsar. Det verkar nästan ha varit standardförfarande bland de tyskar som ville ha en snabbare VW i mitten av 60-talet.

Enligt mitt synsätt utgör detta år, 1965, brytpunkten mellan den äldre typen av VW trimning och den modernare. Hösten detta år kom VW med egna dubbelportstoppar, bubblans motor växte till 1300 cc och typ 3:ans till 1600 cc. Med tillräcklig effekt i standardutförande minskade gissningsvis behovet att trimma nya bilar. 1965 kom att bli sista året för Okrasas TSV1300 sats.

Parallellt utvecklades eftermarknaden och vildare vevar, cylindrar och förgasarkit blev vanliga. Till exempel är det runt denna tiden Weber IDA48 slår genom som trimförgasare på VW motorer i Californien.  Allt som allt skedde nu en förskjutning från behovet att trimma sin vardagsbil till en mer hobby-betonad trimning för buggies, drag-racing etc.

Förhistorisk Fuchs

Under förra veckans motorhistoriska exkursion fick jag en kasse Auto Motor & Sport anno dazumal av Mats i Linköping (tack!). I ett reportage från 1965 års IAA i Frankurt upptäckte jag då dessa udda Fuchs fälgar.

Tydligen visades alltså tidiga prototyper av fälgarna  redan i samband med lanseringen av Porsche 911 Targa. Alltså nästan ett helt år innan fälgen officiellt lanserades på 911S.

Den skarpögde noterar att fälgarna inte har någon svart dekorfärg, som på produktionsfälgarna, istället är öppningen mot bromsarna betydligt större. Man kan gissa att ändringen tillkom för att förbättra fälgarnas styrka. Sedan är produktionsmodellens centrumkåpa betydligt snyggare än prototypens, om ni frågar mig.

Designmässigt hämtades inspirationen från den tidens amerikanska eftermarknadsfälgar, vilket den USA-bilskunnige läsaren säkert kan se. Konstruktionsmässigt hade Fuchs redan erfarenhet av smidda aluminiumfälgar från projekt där de konstruerat hjul till flygbara stridsvagnar.

Som alla vet blev Fuchsfälgen en designikon och eftersom den är smidd istället för gjuten, som är det vanliga i personbilsbranchen, så är den dessutom extremt lätt och stark.

Frukostklubben

I lördags var det dags för säsongspermiär för tidningen Klassikers frukostklubb. Sporrad av ryktet att bloggkollegan Niklas skulle premiärvisa sin 356:a såg Ghian och jag till att vara på plats i tid för portarnas öppnande klockan sex på lördagsmorgonen.

Niklas bil är en gammal ärrad räser som han låtit göra ordning för gatbruk. Med sportigt motorljud, inga kofångare och lite tävlingsdekaler gav den ett sympatiskt helhetsintryck.

Jesses blå 912:a var kanske ingen nyhet, men väl en mycket vacker bil som jag gärna delger er bloggläsare!

Mer om träffen här: http://www.klassiker.nu/traffar/morgontidig-succe

Vive la différence!

Det är alltid intressant att studera produktförändringar genom åren och fundera över varför man gjorde på ena eller andra sättet. Ofta är det ganska uppenbart, men inte alltid. Kanske vill man öka tillförlitligheten, förbättra prestandan, få bilen mer attraktiv eller helt enkelt göra tillverkningen billigare.

Här ser vi ett exempel i den senare kategorin. Fram till 23 januari 1958 hade Porsche 356 en plåtbit fastskruvad i baktrumman för att ta hand om eventuell olja som rymt från drivaxelrören, Förutom kostnaden för själva plåtdelen tillkommer en monteringsoperation samt borrning och gängning så biten kan skruvas fast med en M8 (som också kostar pengar). Dessutom, om Klaus i monteringen har en dålig dag och missar att dra skruven ordentligt kommer det att skramla till ordentligt i baktrumman när nybilskunden pressar bilen i kurvorna.

Men, från 24 januari 1958 ersattes plåtbiten (på engelska kallad "oil-slinger") med en fiffigare lösning. Nu löstes uppgiften genom en annorlunda bearbetad bromstrumma istället. Samma funktion med den enda praktiska skillnaden att hålet för överskottsoljan nu går ut närmare centrum. En mycket smartare lösning som sparade pengar åt Porsche och eliminerade en potentiell felkälla. Bra där.

Ovan ser vi en nyare trumma överst och den äldre typen närmast kameran. Ni kan se röret för överskottsoljan peka snett uppåt typ klockan två. Den övre trumman har i stället bara ett hål borrat genom trumman (syns inte så bra på bilden). Baktrummorna på bilden blev över vid min renovering då jag hade bättre ämnen att utgå från.

Färdigbromsat

I dag fick jag tillbaks en fräsch nyrenoverad 356A trumma från Mats i Östergötland. Han har bland annat krympt in ett nytt gjutjärnsinlägg samt spricktestat trumman med ultraljud. Jag fick också tillbaks de två andra framtrummorna jag skickat med. En blev helt underkänd, den andra var en "kanske". Av tre ämnen blev alltså endast en godkänd.

Enligt Stefi.G i Tjeckien, som säljer ringarna, så kan man inte svarva ur aluminiumet speciellt mycket innan man krymper i en ny ring. Tar man för mycket har trumman inte nog hållfasthet att klara det nödvändiga krympmåttet. Med andra ord är de flesta trummor som har hyfsat med korrosion mellan gjutjärn och aluminium icke renoveringsbara. Är det bara lite korrosion, eller att man helt enkelt är inne på tredje svarvningen, så funkar det. Stefi säljer ringar i olika överdimensioner så man inte behöver ta bort mer material än nödvändigt.

Trumman på bilden är den absolut icke räddningsbara. Men, den var lömsk. Korrosionen var längst in, så trumman såg rimligt OK ut vid en okulärbesiktning. Men, så fort Bil och Industribromsar satte svarvstålet i ringen så sprack den. Troligtvis hade den svarvats en gång efter korrosionen startade vilket tunnat ut materialet i det korroderade området.

Ringen ovan är från en av de "bättre" trummorna, men ser trots det ganska anfrätt ut. En del Porschefolk är tveksamma till att lägga in nya ringar, men gör man det seriöst (som Stefi/Mats) och dessutom spricktestar, tror jag det ändå är minst så säkert som 55-60 år gamla otestade.

Tack till Mats för all hjälp!

Förgasarrenovering, del 1

Så har turen äntligen kommit till förgasarna. Mina Zenith 32 NDIX från en 1959 års 1600N hade originalbestyckningen kvar och verkar ha klarat sig både från större slitage och vedbomekaniker. Så renoveringen av dessa ganska fräscha förgasare får väl betraktas som så kallat "mysmek".

Renoveringssatserna jag använde kommer från Stoddard och är tillverkade i USA. Såvitt jag kan bedöma verkar kvaliteten god. Munstycken rengjordes och blåstes ur. På utsidan försökte jag balansera bevarande av patina mot rent-och-snyggt. Det blir ingen blästring av husen således.

Nästa steg är att ställa flottörnivåer och accpumpens volym. Dessutom behöver jag lista ut rätt bestyckning. Så här långt har jag bara gjort en teoretisk betraktelse över Porsches originalbestyckningar samt kollat på vad Claude's Buggies rekommenderade för deras NDIX-baserade förgasar-kit för VW. Tomgångsmunstycke på 50 verkar vara rätt ingångsvärde, men 115 i huvudmunstycke känns i snålaste laget för dagens alkoholutblandade soppa.

Vi får se hur det blir i praktiken när det är dags för provkörning.