1948 IFA F9 Replica Project - Part Two. The Engine

In Part Two of the IFA F9 Replica project, Winfred Kuhl explains the development of the post-war F9 engine and his search for an early example

Prologue – it was recognized at the outset of the Hohnklasse project in 1938 that DKW’s workhorse 700cc twin-cylinder engine had reached its developmental limits. The CA700 engine, generating 20 horsepower, used in the F7 and F8 cars was operating at its peak. The company had attempted to develop the engine further by uplifting its capacity to 550cc per cylinder, but performance left a lot to be desired and the resulting ZW1100 engine was relegated for industrial use only.

Having decided on the development of a new three-cylinder engine, Director of Sales, Carl Hahn, demanded the construction of a test engine as cheaply and quickly as possible. The engineering team achieved this by cutting one twin-cylinder engine in half and grafting a third cylinder onto a two-cylinder engine block. This resulted in an engine with a slightly asymmetric piston layout, with the two outer pistons being mirror images. The asymmetric layout was not ‘planned’ per se, but an incidental feature of this tactical development process. This asymmetrical layout was then copied into later prototype engines, the pre-production series and all later post-war DKW 3=6 engine series right through to the retirement of the Munga in 1968.

In the east however, in the aftermath of the war, developments took another path. The 'IFA-Bible' (Plaste, Blech und Planwirtschaft by Peter Kirchberg, 2000) tells us that the triple cylinder engine block design went through several significant changes. Chemnitz engineers had discretely salvaged whatever was salvageable from the wrecked F9 cars at Saupersdorf, which was not much. Behind the backs of the Soviet occupation authorities, parts, tools and design documents were retrieved from where they had been hidden and planning began on restarting vehicle production. However, having lost virtually all of their machine tools as a result of seizure by the Soviets, the engineers were forced to improvise. In order to make serial production easier, the engineers simplified the engine block construction and symmetrically aligned the layout of the pistons. This change allowed IFA to use three identical pistons, while DKW would continue with two identical and one mirror-inverted (DKW 1939 - 1965). A critical factor driving these changes was the need to convince the Soviets that IFA would be able to quickly recommence car production, and thereby avoid liquidation of the company. Approval to recommence car production was granted at the beginning of 1947.

The second change affected the clean-up openings for the exhaust ports and the transfer ports for the fuel mix, which were removed completely. This change would also occur in Ingolstadt too, for the two-cylinder block of the F89, but not until after 1950.

Attracted by the better designed prewar-version of the F9 and with my expanding knowledge of the intriguing technical details, I began to focus more of my attention acquiring a prewar engine, hoping that maybe more had been produced than the three pieces mentioned in the 'IFA-Bible'....

In all my years visiting markets for oldtimer car parts in the eastern part of Germany - and this was over 30 years! - I never saw a single early IFA three-cylinder-engine for sale. It surely would have attracted my attention as it would have more than 8 bolts in the engine-block for the attachment of the head or an engine with a distributor for the three cylinders' ignition cables. However, these engines were always rare due to the extremely low production numbers of the early IFA F9 and the fact that early engines would later have been replaced by more modern ones. At the time though, I did not know anything about these engines and only became interested in them in 2012.

Using the internet, I was able to get an idea of what the original engine and gearbox would have looked like. Then, after much searching, I found an early IFA-engine for sale in Chemnitz of all places! This was the first engine that I purchased, and it turned out to be the most interesting because the cylinder head and the distributor gear mechanism were very early products, documented in the spare parts list from December 1951 as 'old version.'

Much later, the same seller offered an F9-gear box which obviously came from the same car as the engine I had bought because it was very early too. It was equipped with bearings from the West German bearing manufacturer, Fichtel and Sachs, in Schweinfurt. This means this engine was built at a time when the border between the two parts of Germany wasn't complete closed and trade was still possible. The border became increasingly restricted during 1951 due to the western Allies’ plan to weaken and boycott the eastern European countries whenever possible, after Stalin definitively denied the west further access and influence. The so-called 'Cold War' had begun...

Due to my job as a manufacturer of wooden bodies for prewar DKWs from 1999 and 2020, I made the acquaintance of lots of DKW-fans from all over Germany. Most of them were from eastern Germany, because - another effect of the 'Cold War' - in eastern Germany many wooden bodied DKWs remained in daily use right into the late eighties. Some of them even crossed to the west after the internal border with western Germany opened on the 9th of November 1989, where they became curiosities in car dealers' lots. Consequently – necessity being the mother of invention - the eastern Germans were much more skilled in using and repairing old cars than their western counterparts and that is why the hobby of restoring cars is much more popular in the eastern part of Germany than in the western one.

From the time I became interested in the F9, I used all my connections and friends from the DKW clubs, meetings and parts-markets to search for a prewar F9-engine as mentioned in the IFA-Bible and as can be seen in the F9 at the Audi Museum, Ingolstadt.

Then in 2014, I got a tip from someone that he saw such an engine block in a shop window in a little town somewhere between Zwickau and Chemnitz. When I showed up there, it was immediately clear that the owner did not want to sell the engine, but he was otherwise very nice and allowed me to take photos while he told me the story.

The house had been a DKW-workshop in the years 1935-1962, run by his grandparents and parents. The engine had been found under a wooden floor during renovating works on the house in the 1980s. It emerged that the grandparents had hidden it there from Soviet soldiers, who were 'fond of each piece of metal they could get in their hands' in those days. The engine had then been forgotten until it was rediscovered during the renovation.

In the Auto-Union Veteran Club magazine 'Clubnachrichten' Vol 172 April 2018, Audi Tradition historian, Ralf Friese, advised that the DKW pre-production engine blocks received serial numbers 429801V - 429900V and at least 49 examples were built.

The engine from under the floorboards however is stamped number 525269V, significantly far from the official series. We know that this is not a serial production engine as it is stamped with V, for the German word Versuch, meaning ‘Research’, which means this engine was destined for experimental purposes. In July 2018 I confirmed with Thomas Erdmann, the historian from Audi Tradition, that there was no way to relate this number to any experimental projects at Auto-Union before 1945....

Is it possible that this engine drove one of the three pre-series F9 that were constructed in Zwickau in 1948? This is what we will talk about in the following chapters.
Winfried Kuhl

The 1951 engine fitted in the chassis.

The IFA F9 Project Part One - https://dkwautounionproject.blogspot.com/2021/08/1948-ifa-f9-replica-project.html

The IFA F9 Project Part Three - The Chassis - https://dkwautounionproject.blogspot.com/2021/09/1948-ifa-f9-replica-project-part-three.html

The IFA F9 Project Part Four - The Body - https://dkwautounionproject.blogspot.com/2021/11/1948-ifa-f9-project-part-four-body.html

Development of the IFA F9 - https://dkwautounionproject.blogspot.com/2020/07/the-development-of-ifa-f9.html

1954 IFA F9 Ersatzteilelist - https://dkwautounionproject.blogspot.com/2021/12/1954-ifa-f9-ersatzteilelist.html
1956 IFA F9 Owners Repair manual - https://dkwautounionproject.blogspot.com/2020/07/the-development-of-ifa-f9.html

79Oktan have an exclusive reprint of Peter Kirchberg's "Plaste, Blech und Planwirtschaft" here: https://79oktan.de/shop/detailview?no=B0018