Classic cars forum & vehicle restoration.

[peter scott]

[Ashley]

I've fitted a 3.4 to 1 axle in place of the original 3.727 to 1 and I believe R-R concluded that your car was slightly under geared by their standards, which would mean very low. Mine is 3000 rpm at 75 mph.

Ash

[peter scott]

True, but don't forget that standards were different pre-war.

Peter


---------------SS Jaguar 2½litre-- Derby Bentley--SS Jaguar 3½ litre
Price--------------£395----------------£1510--------------£445
Length------------15' 6"---------------16' 0"--------------15' 6"
Width--------------5' 6" ---------------5' 8"----------------5' 6"
Weight------------32 cwt-------------34 cwt---------------32 cwt
Max Speed-------87 mph------------88 mph--------------91 mph
0 -60 mph--------17.0 sec----------17.1 sec ------------15.4 sec
0 -50 mph--------10.6 sec----------12.7 sec-------------9.0 sec
0-30 mph---------4.7 sec------------4.9 sec--------------4.1 sec
30-50 in top-------9.4 sec-----------8.0 sec--------------8.5 sec
30-50 in third-----8.1 sec------------6.6 sec--------------7.7 sec
mph/1000rpm----20.16 mph-------22.12 mph-----------21.34 mph
Test mpg----------19 mpg-----------17.5 mpg------------17 mpg
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http://www.nostalgiatech.co.uk
1939 SS Jaguar 2 1/2 litre saloon

[Ashley]

The pre war Wraith was a superb car and rode and drove very much better than the Derbys although Rich says the MX was a lot better than the earlier cars. He's been involved in rebuilding quite a few when he was at www.alpineeagle.co.uk and is now www.richardjamesupholstery.com
The Jaguar I had did 90 relatively easily but was quite difficult to slow from that speed in that it started to snake and would bust the spokes in the back wheels if you weren't careful. I thought it was better proportioned than the standard Derbys too with a nice old engine.
The rods used to stretch rather than expand and I believe the same thing happens to Triumph motor bike engines.
Ash

[peter scott]

Yes, I've had to replace quite a few spokes (inspite of having renewed the lot 16 years ago) but mainly as a result of cornering rather than braking.

Have been looking through the photos on your son's website. Very impressed!

Peter
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http://www.nostalgiatech.co.uk
1939 SS Jaguar 2 1/2 litre saloon

[Ashley]

It wasn't braking with me either, it was getting up to 90, taking my foot off the accelerator and trying to cope with sometimes violent swaying. Some Derbys do it too and things can be improved by resetting the rear springs because they tend to sag and lose their tension.
Rich has done some famous stuff and is unusual in doing mechanical work as well.
Ash

[Ashley]

Here's the Bentley on the inside:





It is extremely comfortable.

Ash

[peter scott]

Looks immaculate.

Have you kept your Radiomobile original or converted to semiconductor and FM?

Peter
_________________
http://www.nostalgiatech.co.uk
1939 SS Jaguar 2 1/2 litre saloon

[Ashley]

I've repaired/restored them in both the Bristol and the Bentley but not converted them to FM. I had one done in KDA and it was crap so I decided not to make the same mistake again.
I have a good spare too.
Ash

[peter scott]

I used to run one from an under wing aerial in my SS. It was surprisingly good considering how shielded it must have been in there.

The RJF91 control box is not very intelligent so driving at night with the radio on was a bit either/or with other ancillaries like the heater blower or wipers but current drain wasn't the reason that I took it out.

I kept skinning my knuckles on it when changing gear.
http://www.jag-lovers.com/saloons/ss/ss10.jpg
http://www.jag-lovers.org/snaps/snap_view.php3?id=1117063708
Not a problem on the Mark VI though.

Peter
_________________
http://www.nostalgiatech.co.uk
1939 SS Jaguar 2 1/2 litre saloon

[Ashley]

The Bentley's have a special dynamo with plenty of reserve for most occasions, but the Bristol has a contemporary Lucas which is barely adequate.

R-R and B made all their own electrical equipment for years until they realised it was uneconomical so then they went to Lucas and made them set up a special department to make R-R bits and continued to be uneconomical!

They did the same with SU and their carburettors are different too.

Ash

[peter scott]

It wasn't a lack of dynamo output that was my problem but rather the way the RJF91 reacted to increasing load. Even lightly loaded it doesn't fully maintain the battery charging current as you increase the load.

Whereas when Lucas brought in the RB340 things were much better controlled and increasing the load current didn't decrease the battery charge current. Leastwise up to the maximum specified dynamo output.

I could hide an RB340 behind the dashboard but I really prefer to experience the car (largely) as it performed originally.

Peter
_________________
http://www.nostalgiatech.co.uk
1939 SS Jaguar 2 1/2 litre saloon

[Ashley]

I'm not sure what the Bristol one's part number is but the Bentley has an RF95 which is the original. I've carefully cleaned the contacts and set it by the book and it wrks perfectly.

The Bristol is the same type but has extra terminals that presumably are to assist the wiring process. It seems to work, I have a spare I think and I've noticed that with everything on the system is only just holding its own.

Maybe I should set it up too!

Ash

[scott_budds]

Lovely looking cars, I lust after something like one of those!

Buddsy
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Im looking for an Elan plus 2 for my next resto project...if you see one think of me please!!

[peter scott]

If you set the engine running at say 2000 rpm in the Bentley and note the charging current, what happens to it as you switch on various loads? Does the charge current decrease gradually as you add loads or does it maintain the same charge current?

Mine gradually decreases the charge as I add more loads.
I think it still holds positive with headlamps and heater blower but if I were running the radiomobile on top, that would put me into discharge.

RF95 internals look similar to my RJF91 but I don't know if the regulators have the same series and shunt turns.

Peter
_________________
http://www.nostalgiatech.co.uk
1939 SS Jaguar 2 1/2 litre saloon