Rubber mounted crankcases

[Reckless Rat]

Just curious... does anyone know when exactly the factory changed from the bolt down crankcase to the rubber mounted one please. Is there a chassis or engine number reference?

On top of that, I see that the earlier rubber mounted cases had the feet drilled at 1/2" whilst later ones are drilled at 5/8ths" - I guess that's where the anomaly comes in relative to the centre rubbers. Would this coincide with the introduction of the "low frame" crankcases or was it earlier?

[David Stepney]

According to Wyatt: rubber engine mountings were introduced on 22nd August 1933 (together with synchro box, modified head and stop/tail lamps) from chassis no: 179368.

Looks as if the modified rubber mountings were introduced when the Ruby was in July '34, as, on 1st December 1934, the sports engine is recorded as having mountings with larger sleeves and washers. However, it appears that on 3rd June 1935, further modifications to the engine mounting studs and bushes were introduced from chassis no: 224721.

Wyatt is silent on exactly what these mounting mods entailed.

[Reckless Rat]

Thanks for that, David. The reason I asked was that my RP should have a bolt down crankcase, but the current engine is a bitsa, with a low frame crankcase dated 1935 (M238xxx) I do however have a spare case from 1933. It's got the rubber mountings but the narrower drillings. It has an engine number at M181xxx so it must be one of the early ones as I reckon it's from September 1933. It was only when I was checking the case over that I noticed the difference in the diameters on the feet.

[DavidK]

i have crankcase 1789xx a bolt down type; so one of the last before rubber mounting.
Seems to agree with what David Stepney found in Wyatt.

[David Stepney]

Thanks for that, David. The reason I asked was that my RP should have a bolt down crankcase, but the current engine is a bitsa, with a low frame crankcase dated 1935 (M238xxx) I do however have a spare case from 1933. It's got the rubber mountings but the narrower drillings. It has an engine number at M181xxx so it must be one of the early ones as I reckon it's from September 1933. It was only when I was checking the case over that I noticed the difference in the diameters on the feet.

 You're welcome.

I don't think that  your estimate of the date of your spare crankcase is far wrong. As you may recall from previous correspondence, I am in the happy position of being able to put the build date of my car into the third week of June '33 and my engine number starts 177xxx. DavidK's post would seem to lend support for your estimate.

[Archivist]

As is often the case, such questions can be answered by examining the Archive web site. In this case:

http://archive.a7ca.org/wp-content/uploads/IC_A7_BA.pdf

and scroll down to the Index card marked Engine for New Models..

[Reckless Rat]

The chassis number if my RP is 176617 which, if David's car is properly dated would place mine at around the end of May to the beginning of June 33. Quite by chance, when I registered the car here in France several years ago they issued me with the number 8633 YH 30. I guess 8th June probably isn't far off the mark...

[David Stepney]

The chassis number if my RP is 176617 which, if David's car is properly dated would place mine at around the end of May to the beginning of June 33. Quite by chance, when I registered the car here in France several years ago they issued me with the number 8633 YH 30. I guess 8th June probably isn't far off the mark...

RR, that may be more accurate than you imagine. The reasoning goes as follows:-

1. The early type Hardy Spicer prop joint was fitted from 14th June 1933 starting with chassis number 176687
2. Between 5th January '33 Chassis No: 167588) and 21st September '33, Chassis Nu: 180260) 12,672 Sevens were produced, equating to an average of 311 per week.
3. My chassis No: is 176805; i.e 188 chassis after the propshaft joint change. RR's car is 70 chassis before this change.
4. 14th June 1933 was a Tuesday. I understand that the factory did not build cars at the week end, this being reserved for maintenance work.

Therefore: my car was probably built either Friday 17th June or or Monday 20th. Similarly RR's car was probably built built at the back end of the previous week (i.e about the 9th or 10th June)

Incidentally, both RR's and my car are standard saloons! My own car was registered in Fife on 4th July 1933 as FG8659. On 26th August 1973, the file of papers was transferred to Cheshire County Council. However, and unfortunately Cheshire achives have no record of the Registration number, so it appears that the file has been lost. As it happens, I have a continuation RF60 logbook issued by Aberdeen CC on 2nd July 1958 and thus have the history of the car since then. However, the first 25 years of its life remain a mystery.

[Reckless Rat]

Amazing!

As far as previous history of my car is concerned, prior to the early 80's it's a complete mystery. The documentation that came with the car ( log book) bore no resemblance to the car either age, engine number or chassis and it was subsequently voided by the local dvla office and issued with a different age related number. The closure of local dvla offices and the digitalisation / loss / destruction of records has led many to a dead end. Hey-ho! At least the car is still here and going well, despite a number of bits the rivet counters would not be happy about. Standard (!) Saloons rule, OK.