SU H2 hydraulic dampers

[AEX 31]

Dear all,

I’ve been wondering about the carburettors on AEX 31. They are H2 like they should be, however they haven’t got any dampers. Maybe this is correct but as far as I understand for the SU H-type - the addition of the hydraulic piston damper carburettors were introduced as early as in August 1947.

So I’m curious what kind of carburettors other early Aces or Acecas out there have? That could be expected to be original.

The carburettor bodies on AEX 31 are branded PDC 3229.

Grateful if anybody could shed some light on this.

Regards Jonas

[nicksonsticks]

Hi Jonas,  for loads of info on SU carbs you could try burlen fuels www.sucarb.co.uk
They still manufacture most if not all of the original components even down to the small tags with the part number stamped on.
They were really helpful on a previous project so well worth a call.
Kind regards Nick

[AEX 31]

Hi Nick,

Thanks for the tip. I think I did ask them when I had these carburettors restored at Burlen. However this was roughly 10 years ago so I’m definitely going to ask them now.

Still if anybody with an early Ace could inform me if they have dampers or not on their carburettors I would love to hear about that. Thinking about it, does anybody know if the 2 litre saloon cars had dampers or not?

Thanks.

Jonas

[nicksonsticks]

Hi Jonas, could you post a photo of your carburettors?

[B.P.Bird]

Jonas,
I am sure your carburetter specification is correct: AE 22 came with original carburetters and they do not have the hydraulic dampers. I wonder if there was a change later with the CL, CLB & CLBN sixes ? For that matter I wonder why SU introduced the hydraulic dampers. I could speculate that it was more about comfort than performance - you can see the dashpots responding to the inlet duct pulsations and this does make a characteristic noise as the dashpot pistons and springs dance merrily up and down. Perhaps the addition of oil damping to air damping was  simply to introduce a bit more civilisation ?
Anyone out there know their S.U. history and can educate us ?
Barrie

[AEX 31]

Hi Nick and Barrie,

Please find some pictures of my carburettors enclosed. Externally they do look identical to any other H2 carburettor that has dampers. Interestingly enough I just spoke to a friend that has an early Aceca, I.e. from the spring of 1955, and that car doesn’t have any dampers either.

I realise  is that I might be totally wrong since I assumed that later cars have dampers. This is an assumption based on the fact that I have bought a number of carburettors that were supposed to be from later Ace’s, and they all have dampers…

To try to answer your question Barrie, I did read on an MG forum that MG changed to H2 carburettors on the TC’s, with dampers in August 1947. The reason was that during hard acceleration the (xpag) engines sucked too much air resulting in a too weak mixture. I’m obviously no expert and I have no other evidence for this.

Obviously the Weller engine is also a different beast compared to the MG TC engine.

I also believe the question has to be changed a bit, did any later AC’s with the Weller engine have SU carbs with dampers?’

Jonas

Note, the top image shows the solid piston.

[B.P.Bird]

Jonas,
Would there be a special reason why you want the hydraulic damper ?
Barrie

[AEX 31]

Barrie,

No, I was merely wondering if 31 had the correct type of carburettors, or rather suction chamber pistons!

Part of the reason is that the first time I saw 31 was in 1981, after it had been “restored” by the then owner, that also at the time, owned roughly 30 prewar MG’s! I have been pondering over the possibility that he might have made a change…

Since the dampers were introduced even before the war. But since two early UMB engine owners have come forward, I’m sure that it’s correct.

The question if later Ace’s and Aceca’s came equipped with H2 carburettors with hydraulic dampers still remains, surely there have to be someone on this forum that knows about that.

Thank you.

Jonas

[kicksey]

Hi Jonas

I am also following this thread with interest as I have carb issues and I am thinking about getting them refurbed by Burlen,  my setup looks very similar to yours although not as polished on my 1955 Aceca AE513

Regards

Chris

[AEX 31]

Chris,

Thanks for your input. I actually had the carburettors for 31 restored at Burlen something like 6-7 years ago. As far as I can understand they did a good job and they work okay.

I do occasionally have some running on issues that could potentially come from a butterfly or butterflies not closing as much as they should.

I did notice, for instance, that Burlen didn’t match the right dashpots with the correct pistons when reassembling… They are all marked 1, 2 and 3…

However I’m slowly planing to make a spare engine and this time I will try to restore the carburettors myself. Burlen haven’t got any “solid” pistons so when restoring one has to keep the original ones, if that is important to the restorer!

But still nobody on this forum that knows if later, AC engines cars came equipped with SU’s with hydraulic dampers or not?

Please, if anybody knows about this, do post.

Thanks

Jonas