203 sites

The Autocar noted the advanced design of the head and valve system and noted Peugeot had patented it in 1948 but did not call it a crossflow head. Edward Eves who was later Midland editor had a 203, was close to Tom Knowles and was their continental expert.
There I've been over the years dismissing designs as not having cross flow heads because the inlet and exhaust manifolds are on the same side but all that mattered was the internal airflow of the head. Without the engineering plans hard to classify according to airflow but some of those L heads would fit the bill. I'll stick to my definition and that of many Peugeot people over the years. What difference does it make? Well the temperature of the inlet mix is much different when they are together which is why designers of arctic duty vehicles do not use cross flow heads. Whatever, the 403 head was much more efficient when fitted to the 203 block.


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About 40 years ago my every day transport was a 203C fitted with a 403 engine. It went surprisingly well and had no trouble keeping up with Sydney traffic. However, I decided it did not look right when the bonnet was lifted. I therefore I fitted the ogiginal 203C head but had it fitted with slightly larger 403 valves and the stronger 403 rocker gear. It still went well and I could not feel any "seat of the pants" difference in performance.
Quite a lot of performance difference with 203's. You sometimes meet a good condition 203C with performance not much below a 403. My early 203 has a very high second. Very different to Basil Moran's 1951. That car seemed low geared and would pull on a hill. With my high second on a steep hill if you don't keep the revs up it can die in second. There are a couple of locations I'm careful with. A 403 would just pull. The first 203's were pushing to get to 72 but the later ones were getting 74 and three seconds quicker to 50. Basil who was a back yard dealer handled a 1956 he sold to NSW for the Redex Re-Run and it performed very well. No real difference to the 403 engined 203 he was preparing. My gearing is so high I sometimes wonder if I've scored one of the 21 tooth diff wheels but it climbs the Pentlands in third as well as my 403's. Where you saw the extra torque of the 403 was on a long grade where the 203 would get winded and the 403 would breeze past.


1000+ Posts
Basil complained about the 203s engine when first put together, not enough performance, I used the pistons and liners from a rebuilt engine that hadn't had much use but it seemed that some bore corrosion was affecting things more than expected. Basil took a long drive to a farm where there were two brand new piston and liner sets. Still with a bit of corrosion but managed to get a good set out of the two and then the car went as expected. This was done in the weeks before the event when I was flat out with that, so a bit busy!
Got to give this site a rest for a while, will be back when I have more time.
My 203 is original and unrestored just as it was when bought from Miss Pratt in 1974.
The owners of three of the four 203's in the photo are deceased.


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The problem with posting on the internet is having to waste time with distractions. For the record the definition of a cross flow head from all motor engineering authorities I can find is one that has the inlet and exhaust ports on the opposite side of the head. The 203 head design is a reverse flow head. Do some research.
For the record the 403 Sept has a power output of 54 bhp gross compared to 49 bhp gross for the 203. Torque went up from 66 lb ft to 68 lb ft.
Compression ratio was raised from 7:1 to 7.4:1. Fuel consumption improved by 5% to 17% and a top speed of 75 mph claimed.

peter munro

l have an oil leak at the back of the gearbox on my 1951 203 sedan & it looks like it's coming from the speedo cable inlet
any ideas on how to fix the leak...
There's an O ring on the "speedo drive socket". Question is, with the grub screw out, is it possible to ease the socket out? Of course the socket itself may have an internal failure that would allow oil to exit.

peter munro

thanks russell, l have two spare gearboxes in my shed, l will have a look at the speedo drive socket in one of the gearboxes to see how to take the speedo drive socket out.


New member
Remove the speedo drive setscrew and its locking nut from the gearbox. The drive assembly will pull straight out but may require a twist or two to loosen it. The oil is most probably leaking past the O ring. The ring is part no 2645.01 and its dimensions are 16.9x19.6x2.7.

peter munro

thanks Commerciale, l will try to remove the drive assembly next week, it's to cold in the shed today to work on the car , it might snow tonight...
+ thanks for the parts number...


Thanks Russell for sharing the history .Stewarts garage in Delegate claim they sold 16 203 in 1953/54!!! also claim they got the first batch of 403s as a reward, which turned out to be a back hander as they had many problems , there were 2 of the early 403 still in the district in the 70s
Yes, those early semaphore 403's didn't have a good reputation in the used trade.
It's always interesting and valuable to get early Peugeot documentation that pops up in odd places.
I have a 19 page Peugeot book supplied by the Peugeot After Sales Department to someone at Sochaux. It is dated January 1950 and provides the "caracteristiques 203, 203 L and 203 U." It has the detailed specifications of the cars, paint, upholstery, equipment of the different models, diagrams and useful things such as two pages of photos showing how two men in dustcoats can correctly fold the roof of a decouvrable.
I also have a copy of the Peugeot Repair Times Schedule Renault supplied to agency workshops in the late 1960's. It includes 403 and 404. Always interesting to see the various times and compare your own performance. Times seem to make allowance for a fag or two. Four hours for a head gasket, 6 hours for a clutch plus an extra 90 minutes on a 403U, 3.5 hours for a major tune up, 19 hours for a complete re-wire. A complete engine overhaul is 27 hours.
I was going to put up a lot of early Peugeot info. Next was a piece on the 203 body design, the concern it caused to Peugeot and the snub to the Peugeot design team by employing Batitsa Farina for the 403. But the fate of this site is uncertain and I have no interest in providing free material for unknown commercial interests. I shall stick to the written word. I am working on a manuscript concentrating on the 203 but I will only publish if commercially viable. There are always unseen costs and problems before the book is printed. I could bring it out as part of a larger second edition of Peugeot and Australia. I printed 220 copies of Peugeot and Australia and sold most through this site, Automoto in Sydney and Motor Book World in Melbourne. Sydney still has three copies and Melbourne one. A publishers agent would have sold more of course and promoted the book through a number of stores but the total market for Australia would only be three or four hundred. People interested in Peugeots of any age are a diminishing number and those interested in the early models and the minutiae of the company are disappearing at an alarming rate.
The advantage of using a publisher is they often provide an online page for updates to the book and further material. But low volume specialist publishing is a very small field. Not my world. If I do publish again I'll sell through Automoto in Sydney which is high priced but actually pays for its stock and has an exceptional collection of rare motoring books.
Nearly ten years since Mike Mattison (catshamlet ) passed.


Now he was an interesting character drove his much modified 203 from Kendal in Cumbria onto some interesting roads in Yorkshire in April 2011
Mike was going to bring his car out for a re-run around Australia in 2013 and I was to be his co-driver. I stayed in touch with him until a couple of days before he passed and he remained his usual cheery self. I remembered him in the preface to my book.
The NHS treated him well, they brought a special bed to his house so he could remain at home as long as possible and for the last week he went into the MacMillan Hospice.
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