1948 IFA F9 Replica Project - Part Three. The Chassis

From what we read about the technical development from F8 to F9, we know that the F8’s front axle construction was too weak and small for the new 27hp engine and its inline mounted four-speed gearbox. The F8’s cable brake system also needed to be completely renewed and changed to a hydraulic operated system in order to make it more powerful, especially in the front axle. These changes were implemented in the war-time Werner car and the pre-series F9 from 1948 were also supposedly equipped with all these updates. For the project my thought was to obtain a chassis as shown in the IFA F9 parts list from 12/1951.

1. Chassis. After extensive searching and consulting with my German DKW-enthusiasts, it became obvious that it would be impossible to find a vehicle frame as shown in parts list 12/1951 and I would need to fabricate one. From careful study of the chassis-picture shown in the 'DKW F9 Technical Description', issued 1948 by IFA in Chemnitz, the IFA F9 vehicle frame from 1954 seemed to be the most similar, so I obtained a vehicle frame from a 1954 car and then rebuilt according to the picture of chassis in the 1948 DKW-brochure and the 1951 F9 parts list from Zwickau.

To recreate the early bracket mounting for the front leaf spring I used one from an F8, but mounted in reverse to the driving direction. It was essential to be sure before starting that the F9 gearbox could pass between the two side parts of the F8 spring bracket. As revealed in the photos, this was possible, but it's a very tight fit with only a few millimeters distance between gearbox and spring bracket frame. We will encounter many more occasions of very tight clearances around the front axle and engine throughout the project.

2. Wishbones and Shock Absorbers. In order to be able to withstand the heavier weight and loadings, the wishbone triangle arms of F9 were set wider than the F8, but initially only one arm of the triangle was changed, the other still being the same part as in the F8. The same asymmetric form of the wishbone was also used in western Germany in all F89Ps and the F91 until 1955, however, from the beginning in 1950 these were equipped with silent block bearings and with different shock absorbers. The asymmetric wishbone from Zwickau in eastern Germany was still equipped with brass bushing as in the F8 even though this form of construction was already out-of-date in 1950. Possibly this, and the use of new shock absorbers, was one of the reasons why Zwickau quickly gave up using the asymmetric form of the wishbones.

The car's telescopic shock absorbers were originally manufactured in Schweinfurt in western Germany by FICHTEL and SACHS for the KdF-beetle and were no longer available in eastern Germany after 1951. I once saw one of these early Tu26 shock absorbers stamped with the mark 'IFA' on it, handmade with brass solderings, so clearly they reproduced them in Zwickau on their own after 1951. Due to the extreme rarity of these shock absorbers, only very few DKW-enthusiasts know about these technical details.

3. Brakes. The 1948 IFA brochure still showed wire operated mechanical brakes, but it was easy to use the complete wheel brake sets from the DKW F89P for my F9. The main brake cylinder is a newly produced spare-part for the Mercedes-Benz Type 170 (1948–1952), which fits exactly into the F9 chassis without having to change any mounting details. The diameter of all brake cylinders for the IFA F9 and DKW F89P are the same - 25.4 millimeters.
Winfried Kuhl

For comparison - The 1951 IFA F9 Chassis (from the IFA spare parts list)

The 1956 IFA F9 Chassis (from the IFA repair guide)

You can see that the front axle mounts and wishbones are different in the later version.

Above is the chassis of the contemporary DKW F89P from 1954. The F89P was also derived from the DKW F8 and shares a common heritage, but there are lots of different details.

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

The IFA F9 Project Part Two. The Engine - https://dkwautounionproject.blogspot.com/2021/09/1948-ifa-f9-replica-project-part-two.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

1953 Overview of the development of the IFA F9 - https://dkwautounionproject.blogspot.com/2021/09/1953-deutsche-und-auslander.html

1954 IFA F9 Ersatzteilelist - https://dkwautounionproject.blogspot.com/2021/12/1954-ifa-f9-ersatzteilelist.html

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