Dymano Mounting bracket width discrepancy

for those with Series MM sidevalve cars produced between September 1948 and February 1953
Forum rules
By using this site, you agree to our rules. Please see: Terms of Use
Post Reply
gtt1951
Minor Addict
Posts: 978
Joined: Thu Oct 04, 2012 5:01 pm
Location: Farnborough, Hampshire
MMOC Member: Yes

Dymano Mounting bracket width discrepancy

Post by gtt1951 »

Colleagues,
I've been having some problems, as some of you may know, with my Low-Light 1950 project.
When refitting the C40 dynamo, that came with the car, I had to add about 4/5 washers to take up the gap.
C39 and C40 dynamos should be 145mm (approx) between the mounting plate holes.
I have checked my 1951 side-valve High-light (with the original aluminium water jacket/dynamo mounting) and the spacing is 145mm.
All my spare dynamos (both C39 and C40) are all 145mm, so I have, just now, measured the (what I took to be original) aluminium water jacket/dynamo mount on the Low-light and it is only 137mm
Distance between flange outers.jpg
Distance between flange outers.jpg (402.23 KiB) Viewed 1287 times
You should be able to see the pile of washers (just about) at the front mount.
My ESM repro is 145mm (but the threaded bolt holes are the wrong size (UNF instead of Metric 8 Fine).

So what on earth is on my 1950 side-valve? Anyone, out there, have any comparable measurement?
I know the earlier engines had an extension to the head casting, where the dynamo was fitted - but what was the spacing on that?

Has mine been ground down for some reason?

Any information gratefully awaited,

George.
P.S. this engine originally had a blanking plate where the water pump is now fitted.
Image
'50 Low-light with 918 Side-valve engine,
'51 High-light with Side-valve 918 engine,
'55 4-dr with 803 engine,
'56 Traveller with 1098 engine.
philthehill
Minor Maniac
Posts: 10768
Joined: Thu Jul 19, 2012 12:05 pm
Location: Hampshire
MMOC Member: Yes

Re: Dymano Mounting bracket width discrepancy

Post by philthehill »

A common problem even on the 'A' Series. It is not unusual to have to pack with washers between the dynamo mount flanges and the mounting bracket.

sparesman
Minor Fan
Posts: 326
Joined: Tue Dec 25, 2012 7:40 pm
Location: norfolk
MMOC Member: Yes

Re: Dymano Mounting bracket width discrepancy

Post by sparesman »

The original dynamo for an MM was a C39PV , maybe the end bracket thickness or the length of the body was different to the later C40 dynamo. Will measure my water jacket on my low mileage MM engine tomorrow.
Bryan
1934 Morris 10/4 in Dark Green / Black - BGO517
1953 S11 Traveller in Birch Grey - oldest survivor ? Export model now reg PPO924
1953 S11 Traveller in Black - 3rd oldest in UK PPX344
seriesmm_1
Minor Fan
Posts: 180
Joined: Wed Aug 10, 2011 3:52 pm
Location: Pembrokeshire
MMOC Member: Yes

Re: Dymano Mounting bracket width discrepancy

Post by seriesmm_1 »

Hi George,
just measured my water jacket & it is 145mm & fitted to it is as Bryan stated above a C39PV dynamo which fits great.
Regards
Brian R

gtt1951
Minor Addict
Posts: 978
Joined: Thu Oct 04, 2012 5:01 pm
Location: Farnborough, Hampshire
MMOC Member: Yes

Re: Dymano Mounting bracket width discrepancy

Post by gtt1951 »

The water jacket bracket on my 1951 High-light is 145mm
DSCN1427.JPG
DSCN1427.JPG (1.2 MiB) Viewed 1256 times
and it has the original dynamo with the rad fan mount on the end.
Only the low-light mount is the wrong size.
Image
'50 Low-light with 918 Side-valve engine,
'51 High-light with Side-valve 918 engine,
'55 4-dr with 803 engine,
'56 Traveller with 1098 engine.
sparesman
Minor Fan
Posts: 326
Joined: Tue Dec 25, 2012 7:40 pm
Location: norfolk
MMOC Member: Yes

Re: Dymano Mounting bracket width discrepancy

Post by sparesman »

Just measured my water jacket. It is 145mm.
If anyone needs one we have an old engine I can take it off.Half of ESM's price !!
Bryan, MMOC Club Spares
1934 Morris 10/4 in Dark Green / Black - BGO517
1953 S11 Traveller in Birch Grey - oldest survivor ? Export model now reg PPO924
1953 S11 Traveller in Black - 3rd oldest in UK PPX344
gtt1951
Minor Addict
Posts: 978
Joined: Thu Oct 04, 2012 5:01 pm
Location: Farnborough, Hampshire
MMOC Member: Yes

Re: Dymano Mounting bracket width discrepancy

Post by gtt1951 »

So were earlier engines fitted with different sized dynamo mounting?
8mm is quite a difference.
Phil, I too have noticed discrepancies in the mounts of the A-series engines. I also remember, years ago (probably not a Morris) of having a C39/40 dynamo with a built-in extension tube!

Looks like I'll have to find a "spacer" that is easier to fit then 4 lose washers.

Many thanks for the answers,

George.
Image
'50 Low-light with 918 Side-valve engine,
'51 High-light with Side-valve 918 engine,
'55 4-dr with 803 engine,
'56 Traveller with 1098 engine.
philthehill
Minor Maniac
Posts: 10768
Joined: Thu Jul 19, 2012 12:05 pm
Location: Hampshire
MMOC Member: Yes

Re: Dymano Mounting bracket width discrepancy

Post by philthehill »

Looking at the original photo the front mount appears to have been ground back to allow a dynamo of unknown style to be fitted.
Look at it this way - having the washers (front or rear) allows you to centralise the dynamo pulley in line with the crankshaft which is just as important than having the correct mount.
I remember those dynamos with the tube in the rear plate which allowed a degree of adjustment for centralising of the dynamo and using a variety of dynamo mounts. Nearly all alternators these days are fitted with the adjustable sliding tube in the rear mount plate.
Phil

Post Reply