Post Number: 68
|Posted on Saturday, 23 February, 2019 - 03:57: |
Could someone cast any light on a rare special feature on few 50/60’s Bentley’s and R-R described as High Frequency Horns & Horn Muting Switch and exactly what was/is its function?
Post Number: 87
|Posted on Saturday, 23 February, 2019 - 08:34: |
The parts list TSD547 on page L27 list the switch UD2183, cars for Switzerland.
The name would suggest the purpose.
Post Number: 69
|Posted on Monday, 25 February, 2019 - 21:08: |
Yes the only three examples in question are first delivery to Switzerland…why this Swiss regulation?
Not necessarily clear because they have the dual factory wind horns and a special feature ‘high frequency’ horn…would they sound simultaneously? or would the switch mute the lot or only one of the two…?
Posted From: 188.8.131.52
|Posted on Monday, 25 February, 2019 - 06:16: |
As David has stated the Muting switch was fitted as standard on cars delivered for use in Switzerland at no extra charge. However this could be purchased as an option in other markets at extra cost. In 1965 this option would have cost you £ 1.16s 3d with tax.
The Muting was usually intended to silence high frequency horns during darkness in Alpine villages, a requirement in at least some Cantons. These high frequency horns were, themselves offered as an option.
Often the Muting switch option was taken up along with SB553 which was the option to fit a changeover switch to allow the horn button to flash the headlamps. This latter option was largely superseded when the headlamp flasher was incorporated in the direction indicator as standard on S3 Bentley and SCIII RR, except for USA deliveries.
All these horn and headlamp schemes were developed by Stanley Bull’s department at the London service centre. Drawings showing each layout were prefixed SB.
(Message approved by david_gore)
Post Number: 143
|Posted on Tuesday, 26 February, 2019 - 12:11: |
The headlight flasher was introduced as standard sometime during the production of the SCII / S2. I'm sorry I haven't researched the exact date, but my D series car has it, so do the E series also, and then of course all of the SCIII / S3s.
Post Number: 70
|Posted on Tuesday, 26 February, 2019 - 19:32: |
Thanks for the input and history of this little feature…however still unclear as to which of the three horns is muted by the switch… only the ‘special feature’ frequency horn? and would normally all three horns sound by pressing horn button?
Interesting bit of history about the switch alternatively flashing the headlamps…
Neither my S2 nor the SCIII have the indicator flashing option…
My inquiry is directed to the S2 which has the switch but at some point was disconnected yet standard horns working and when trim pad was removed, found a loom of three wires taped together…by testing with switch nothing other than off or on…discovered small frequency horn has no wiring…furthermore the three wires from under the capping rail are not original factory wiring…
As a bit of a purist, if it’s a factory option, preferably should function as intended…
Posted From: 184.108.40.206
|Posted on Friday, 01 March, 2019 - 23:31: |
David / Felipe
David thank you for the reminder of the change point for the headlamp flasher I had not intended to get exactly into that demarcation due to the number of exceptions. However, for the record the company change point for the headlamp flasher fitment was B415 DV on the standard Bentley S2, almost at the end of production of that model.
That change alone resulted in some 29 changes to wiring looms across the model range. Almost simultaneously a change was actioned for the new Italian lighting regulations and a complete change of instruments took place. In addition the switch modification required a change of the gear change quadrant and cover. If that was not enough the position of the horns and wiring varied according to whether the car had a fresh air intake, air conditioning or none. Not surprisingly these last Bentley S2 cars were a little hit and miss regarding options and USA, Swiss, Italian and some deliveries to South East France had different specifications .It seems most of these differences were encompassed in the S3 models, when one could say the changes were now standardised.
The markets where headlamp flashers were illegal, including USA, were accommodated by blocking the flasher points in the new switch with a UR 5480 separator, which can be easily removed to convert the switch back to a standard UR 5273. I think Felipe’s SCIII may fall into that category, if the headlamp flasher does not “work”.
Felipe….. in the 60’s and 70’s I often drove in Switzerland and right through the 60’s I was a fleet and plant engineer operating various cars, trucks, including Bentleys, traveling between England and Milan in Italy. In fact I had at least one car on this route every week of the year. At that time I was extremely aware of all the European driving regulations, but 50 years later the passing of time blunts the memory cells, so take the following accordingly.
It was mandatory to blow the horn on any blind Alpine corner in Switzerland, but between the hours of 22.00 hrs to 07.00 hrs it was illegal to use a horn and flashing headlamps were mandatory.
As normal horns were not really sufficient to provide adequate warning in Alpine conditions high frequency dual tone horns were usually fitted.
It was illegal to use a triple tone horn as these were reserved for Swiss post buses, and they used the triple tone horns that blasted out a few bars of the Williem Tell overture, and you did not need telling the post bus had priority up or down hill.
As an aside, we all thought that Swiss Post Bus drivers were suicidal as they took the right of way or priority as definite, even if you were approaching uphill on a 1 in 6 incline to a 90 degree bend. They would blast around the bend on your side of the road, and the Williem Tell overture might be the last music you ever heard.
At that time on many Alpine bends the guard rails did not exist or were low to allow the rear or front overhang of the bus to sweep out into mid-air, all before the current new Gothard tunnel was built. If you survived the first shock you would fairly quickly fit headlamp flashers and high frequency horns.
I can tell you how our cars were wired. The high frequency car horns were too loud and harsh to use anywhere but in Alpine conditions and so demanded a muting switch. We wired the changeover switch to interrupt both sets of horns, both low and high frequency but allowed flashing headlamps when the horns were muted. I seem to remember we arranged this using a headlamp dipper switch and a separate flasher switch. Another foot dipper switch selected low or high frequency horns when desired. From memory we used head lamp flasher switches from Ford Classics’ type cars and we converted both R type and S1 Bentleys’ besides Ford Cortina, Austin A55 / A60, Sunbeam Alpine and Hillman Super Minx Estates. The reason for using a separate flasher switch (sometimes) was because we did not always want to utilise the horn button for headlamp operation.
Having converted a variety of cars and trucks I do know that you need to ensure you do not have a cross over or back feed on the flasher switch when you are running with the headlamps at night. Some cars are wired to allow headlamp flashing only on dip beam.
I cannot comment on how the ex- factory Bentley S2 is exactly wired, but I can provide some details of the Bentley S1 horn button operation of headlamps or horn. The S1 conversion assumed that only one set of horns were fitted. Remember other countries, including the UK made it illegal to operate a horn at night, or when stationary and did not require high frequency horn types. An extra horn set is easy to tag on to the general arrangement.
The RH 739 change over switch was positioned in the hand brake bracket to the right of, and above the handbrake (RHD cars). The master connection of RH 739 was connected to C1 of the horn relay, the existing red / yellow cable was removed from C1. The red / yellow cable coming from the horns was coupled to one of the two now vacant positions on RH 739. The other vacant switch terminal was wired to connect into the headlamp dipper switch main feed at the 18 way junction box.
If two horn sets were fitted only the high frequency or low frequency horns would be operated by the horn button, not both sets. A switch would be used to allow you to switch over to the desired horns. If you did not have this selector switch you would have no low frequency horns available for daytime town work, as you would not want daytime high frequency operation in towns, day or night. However, when selecting to change to headlamp flashing using the horn button, then both horn sets would be muted.
I have tried to explain why the high frequency horns were fitted for the Swiss market and why it was necessary to mute them together with the advantage of switching the operation to action the head lamps. I have also explained how we as an operator retrofitted this arrangement and also how the factory wired the cars for Bentley S1 derivatives, I am fairly sure S2’s will be the same. I trust you will be able to extract something from this information.
(Message approved by david_gore)
Post Number: 145
|Posted on Sunday, 03 March, 2019 - 23:16: |
As usual Norman your knowledge is amazing and invaluable.