Would anyone have a photo showing the pipe from the starting carb to the head on the 2 1/2 SS engine.
Unlike the 3 1/2 if appears not to have spacers between the carbs and head making this pipe short and with a tight bend?
Regards, Graham.
Hi Rob.
Excellent photos thanks.
I’m surprised to see it is not fitted the other way around with the olive and nut into the carb like the Mk V.
Sure is a tight fit.
Thanks again.
Graham
The SU books say - 1937-1939 2-1/2 litre SS Jaguar had Pair H3 Thermo carburetters (that’s how SU spell their own product) built up/configured to Spec No.357, renumbered post 1953 as AUC.357.
When you get a chance Rob, would appreciate a few more photos, they look nice original/untouched examples.
Roger
Sorry
But the float bowl tops are post war. Pre war tops had a bullnose shape where the banjo bolt goes in and the words " SU Adderley Park Birmingham" cast into the top This is usually the result of a PO over-tightening the banjo bolts and stripping te threads and replacing witha more moodern replacement. Sadly un-necessary as the bull nose tops can hve the thread extended as there isplenty of room [ unlike postwar tops] and a longer 38" BSPF bolt used
As shown here
New Addeley park tops are available from Burlen.
The didn’t have an over flow pipe [although that’s not a bad idea. But the float bowl top needs a sight mod to make the over flow actually work, otherwise it’s just a bit of decorative tube.
The strap over the solenoid is Later postwar. Originals were a wire clip
The pipe will need to be from a 2 1/2 litre I tink the 3 1/2 is not the same.
I do have somewhere the blue/ white transfers made for the air cleaners. [ for that extra concours point : >)
Hi Ed.
Yes I would like a pair of transfers if available. Let me know price etc and I will sort it out.
Cant imagine the strap being changed but who knows. My MKV has the wire loop so perhaps this is earlier?
Regards, Graham
Graham
I dig around and see if I still have some transfers, Ifnot teyare only printed ona homeprinter and carefully painted with clear over the top
The strap on you saolenoid is fromaround the XK ? MK VIi era, here is apic of an original 2 1/2 SS carb set up [ Bit grubby but orignal. The springs sometmes break or are lost > I had Bells Springs in Melb do a small batch but they’ve gone now.
I suppose its possible that some previous owner changed the float bowl tops on mine because he wanted overflow tubes.
So are we looking for date code stampings on the mounting flanges? I don’t see any.
Rob
There are 2 types of wire spring depending on which direction the holes are drilled in the starting craburretter. I think I can say your were replaced becuase of stripped threads. f one wanted over flow pipes on early crabs its only a matter of facing off the top of the float bowl lid to remove the horizontal slot, and usin the then appropriate shaped fibre washer
AS I said over flows area good thing, but also inserting asmall 1/8" capillary into the line between petrol pumps[s] and the float bowls will allow excess pressure to bleed back to the tank and avoid the tendency to over flow and flood.
I can’tsay abot 38 saloons , but 36/7 saloons and SS100s right through had all the wires under the bonnet in small separate conduits , inc te starting carb.
Rob,
The DATE CODE stampings start at A = 1945, although still not then universally used on all Carburetters and Petrol Pumps made. Don’t know much about pre-war SUs, so advice of what if anything on these SUs fotted to SS Jaguars would be a start. Certainly there is casting numbers on main body and float chamber, and possibly other cast aluminium parts, but there is all manner of different Specification Numbers that fully define the exact type of SU, whether single or pair or twin, and its complete make up to last nut, setscrew, washer, linkage, lever etc etc over and above just the main castings…………
1936 SS-Jaguar 2-1/2 litre 6 cylinder has a pair of HV3 to Specification No. 307
1936 SS-Jaguar 2-1/2 litre 6 cylinder COMPETITION has a pair of HV4 to Specification No. 333
1936 SS-Jaguar 2-1/2 litre 6 cylinder has a pair of HV3 (Thermostatic) to Specification No. 337
1937/9 SS-Jaguar 2-1/2 litre 6 cylinder has a pair of H3 (Thermostatic) to Specification No. 357
1938/9 SS-Jaguar 3-1/2 litre 6 cylinder has a pair of H4 (Thermostatic) to Specification No. 358
1938 SS-Jaguar 1-1/2 litre 4 cylinder has a single D4 to Specification No. 367
1939 SS-Jaguar 1-1/2 litre 4 cylinder has a single H4 to Specification No. 412
1940 SS-Jaguar 2-1/2 litre 6 cylinder has a pair of H3 (Thermostatic) to Specification No. 448
1940/48 SS-Jaguar 3-1/2 litre 6 cylinder has a pair of H4 (Thermostatic) to Specification No. 449
1945/48 Jaguar 1-1/2 litre 4 cylinder has a single H4 to Specification No. 459
1946/48 Jaguar 2-1/2 litre 6 cylinder has a pair of H3 (Thermostatic) to Specification No. 460
So that covers most of the SS Jaguar and Mark IV period, but suggests Rob’s, Ed’s and Graham’s carburetters are not all going to be exactly the same, albeit you would have to refer to the detailed Specification No. breakdown to see exactly what is different - may be major or may be very minor, albeit if just different Needles that usually doesn’t warrant a new Specification No.
Roger
Here is what I have found on my carbs.
Front. Stamped on top of flange (head side) M81997
Main body, Cast, 3275
Float bowl, Cast (small) 6211
Rear. Stamped on top of flange (head side) M82048
Main body, Cast, 3275
Float bowl, Cast (large) 3258LL
Here’s what I see:
front body side 3275
front body under piston 657A
front bowl 1159 J
bowl top 1160
no M number at all
brass piston 3174 with solid shaft, no provision for a damper
dome top cap says USE BICYCLE OIL
needle DS
rear body side 3275 (this number is upside down)
rear body under piston 657A
rear bowl 3258 LL
bowl top 1160
no M number at all
brass piston 3174 with solid shaft, no provision for a damper
dome top cap says USE BICYCLE OIL
needle DS
Is there a pdf copy of SU H3 Spec 357 anywhere?
Hi Rob.
Yes mine to say USE BICYCLE OIL.
Regards, Graham
Presumably Swallow side car combinations would use tricycle oil
2 Likes
As before, I don’t have a lot at all on pre-war SUs, although very comprehensive post-war.
So at this stage, nothing definitive on 2-1/2 litre 1937/9 (Spec No. 357) nor 1940 (Spec No.448), but I do have SU Spares Listing for 1946/48 (Spec No. 460) with the main caveat being my SU SPL for Spec No. 460 is c1953 issue, so although I expect unchanged from 1946/48 original, many of the part numbers now show BMC Part Nos with thus there AUC prefix. Most pre 1953 SU part numbers, simply received an AUC prefix from 1953 onwards, thus the paperwork started to be updated quickly, but where physical parts had the SU part number cast in, that remained unless there was a need to retool that part post 1953, then they added the AUC part number. Indeed this Specification No 460, has been renumbered AUC.460 for this 1953 issue, albeit the publication number is still NEL.191/27, which was later reissued as publication AUC9526.
See below, both the parts listing and the associated blown-up parts illustration for 1946/8 - Spec No.460.
Now the most important component is the main body casting, which both Rob (1938 - No.357) and Graham (1940 - No.448) have advised have the same main body casting 3275.
Note for No.460, item 1 - the Body-bare-front and rear is Part No. 3275
So this pretty well tells me this same Body 3275 is common 1937 to 1948 on the H3 type/size carburetters as used on all 2-1/2 litre SS-Jaguar and Mark IV (for want of a simplistic term).
But with all other items, you still need to work through part by part to see what has in fact changed 1937/9 to 1940 and then additional changes to 1946/8, and without a similar Parts List for No.357 and No.448 as this one for No.460 you really cant be sure. Certainly you can start from the MAJOR parts and down, and look for parts with cast in numbers, and relate them to be the same as the No.460, or not.
The Rear Float Chamber is noted as being 3258LL on both and indeed the No.460 advises item 46A Float Chamber - bare - with stud - rear is part no. 3258, which is a match (the cast in LL suffix is indicative of being a Low Level float chamber - which is independent of the 3258 match) . Now note, this 1953 issue Spec now shows the later MK II Solenoid, which is a major difference from the observed 1938 and 1940 H3s. So keep comparing part by part, and be aware that some different parts from what is in Spec 460 can often be identified from other Spec Listings other than Jaguar which is where I would start looking for the Front Float Chamber 6211 and 1159. And so on ….
Be easier if someone had SP Listings for 357 and 448.
Roger
In SU’s Information Sheets, List 121, there are a couple of referenced differences between the Specs of the pre and post war 2 1/2 Litre Jaguar H3 Thermo Carburetters:
Spec No. 357 2 1/2-Litre 6-Cyl 1937/9
Spec No. 460 2 1/2-Litre 6-Cyl 1945/8
The needles are different (No. 357: rich R.3, std 2, weak M.5 v No. 460: C.B, D.S, E.Q). The pre war set-up has one throttle lever (1201) but the post war rear carburetter has 3120/1 (Foot) and 4059/2 (Hand).
The Specs share the same bodies, suction chambers and pistons, float chambers and lids. Other minor possible differences are not detailed in the List e.g. holding up bolt which may be a different part/shape for different washers (felt v fibre).
I believe the pre war SU date code is similar to the now decrypted post war code (A = 1945, B = 1946 etc, suffixed with the month number).
The two numbers stamped on the flange of Graham’s two H3s are: M81997 and M82048. I have a pair of bronze HV5s, ex Lagonda LG6, stamped K45464 and K49973. This pair therefore predates the SS pair by a couple of years and ‘K’ is a couple of letters in the alphabet before ‘M’ so I suggest (as with post war) the first letter of the stamped code is the year and the second the month. The final four numbers are a sequence, unique to each carburetter (and dropped post war). In 1945 the letter for the year was reset to ‘A’, so pre and post war codes share letters but they do not equate to the same year.
Regards
Simon
I would point out that perhaps the part numbers refer to the purpose or spec of the item but not the atual appearance. AS for example so while spec 357 and 460 might on paper share the float chamber lid, the appearance [ and operation where different.
The Adderley park lids breathed through a slot across the top o =f the lid, to the outside, and had a fibre washer to accomodate this, the postw ar had vertical slots and a different fibre washer to allow breathing to drain tube
I would be careful of taking lists as gospel. I understand very early SS Jaguars had 1 1/4’ carbs. Likewise the hand throttle was not part of the carburretter but a lever on the accelerator cross shaft pulled by a cable
Different needles were at least partially explained by different air cleaners which resricted air fow differently.Which is whyLHD and RHD Mk IVs had different needles.
Ed, I fully concur with you. The spec sheets provide an excellent point of reference but the sighted detail carries the significant weight.
Some of the Adderley Park lids also had the tickler (I don’t know if this is the case for the SSs, and is your point exactly). The breather slot in the two lid castings is different but why might the design of the bullnose end of the inlet feed have changed?
I was recently looking at a 1/4” fluid diameter holding up bolt with a brass nut threaded to take a steel pipe threaded at each end. The later bolts are all steel and (presumably) the same part number.
Many thanks