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541R

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by DavidW » Thu May 09, 2019 8:45 am

Hi all
Need a tad of help. I have 'accidentally' tripped over a 541R and I am trying to identify which engine it has. From the research I believe it could be either a DS7 or DS5. How can I figure out which one and which is more desirable and why
Thanks
David
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by Frankoid » Thu May 09, 2019 8:56 am

The DS5 engine has the exhaust pipe on the near side with triple carbs, and the DS7 has the exhaust on the drivers side with twin carbs. In the 50's the DS7 was considered the faster engine but engine parts are harder to find. Hope this helps..
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by DavidW » Thu May 09, 2019 11:02 am

Thank you. Much appreciated
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by DaveT » Fri May 10, 2019 8:20 am

In terms of desirability, there were only a few hundred DS7 engines made by Austin, around 50 of which were used in the first batch of 541Rs (1 in the last interceptor). The production run of the DM7 / DS7 Austin princess was only around 200 cars. It has been suggested that the engine suffered from severe overheating and quite a few early 541Rs have subsequently been fitted with XK engines either to overcome this or to overcome poor spares availability.

The cylinder head design of the DS7 provides better engine breathing with no siamesed ports vs the DS5. The result of this being higher quoted BHp figures and higher top speed in the contemporary road tests, although road testing of the 541R with DS5 engine (circa 143 cars vs the circa 50 with DS7) seems to have been ignored by the press - it was a slightly backward step after all. Both engines are pushrod overhead valve with inlet and exhaust ports side by side on one side of the engine (I.e. not cross flow)

So reliability and spares availability vs power output - it is clear that a DS7 engine that has seen almost constant use throughout its life is unlikely to suddenly develop overheating problems due to the design of the engine, but a DS7 restoration project could uncover unresolvable engine issues...possibly explaining why the car was taken off the road in the first place.

Re power output, the race prepared 541R seen in recent years competing at goodwood etc has a highly developed DS5 engine, so it is possible to make up all the difference and some. A DS7 engine could be given the same treatment but with spares being short on the ground and the knowledge in race preparing early Austin Healeys being slightly less relevant, I am not sure this would be a good idea.

Other thoughts welcome.

Dave
Dave Turnage
Colchester

JOC 8674
JOC 541 Registrar
541S, 100/1061
541R, 6002/387 (now in lots of pieces!)
Alvis speed 25 DHC
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by Frankoid » Fri May 10, 2019 8:39 am

Do you know how many DS7 engined 541R are still running with their original engines Dave, and does it make any difference to their monetary value?
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by DaveT » Fri May 10, 2019 12:22 pm

Hi Francis, I do not "know" how many DS7 engined cars are still running, but I have just looked down the list and suspect that there could be as few as 10 that have actually been on the road, or are close to being on the road in the past couple of years. If anyone thinks I am wildly wrong, than that would be a good thing, so please let me know what you know!

I think a jag (or BMW!) engined 541 is likely to be worth about 60 to 75% of a similar car with the correct engine. I know of one originally DS7 engined car that has recently had the XK engine removed in favour of a DS5 and I would hope that this will be worth about the same as a similar but original DS5 541R. But that is just my opinion.

Dave
Dave Turnage
Colchester

JOC 8674
JOC 541 Registrar
541S, 100/1061
541R, 6002/387 (now in lots of pieces!)
Alvis speed 25 DHC
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by Frankoid » Fri May 10, 2019 12:51 pm

In August 2014 (I think..) between Brixton and Dulwich in south London I saw a shabby looking Red 541 R go past. I think the exhaust came from the off-side, but I was rubbing my eyes in disbelief at the time!! I couldn't make out the number plate either....
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by DaveT » Fri May 10, 2019 5:38 pm

According to Calver's book, there were only 4 reno red DS7 engine cars (317, 320, 327 & 330) and one imperial crimson (342). I know one of them (#317) was not mobile in 2014 (but now being restored), and #342 is alive and well in Canada, could be one of the others... unless you only saw the roof as being red, in which case it could be the prototype 541R (London - Paris record setter), pictured here:

viewtopic.php?f=7&t=9172&hilit=paris


Dave
Dave Turnage
Colchester

JOC 8674
JOC 541 Registrar
541S, 100/1061
541R, 6002/387 (now in lots of pieces!)
Alvis speed 25 DHC
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by Frankoid » Fri May 10, 2019 6:47 pm

It was not PEA 541, it was red (or crimson..) all over and looked like it had not been cleaned for 20 years! If it was not 317 pre rebuild (was it in the south London area?) it could have been one of the other 3.
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