Lotus Elan

Stromberg /Weber head

PostPost by: lottex » Sat Sep 06, 2014 6:37 pm

I appreciate that the following subject can be quite a contentious issue...
Can anyone shed any light on the Stromberg/ Weber/Dellorto carb argument.
I remember a conversation with Miles Wilkins who assured me that in his opinion, one of the most powerful factory twin cams produced was the late model Stomberg S4 SE engine, However , Lotus customers prefered the look of the Webers, hence the switch back for the Sprint, and Stombergs hated cold weather, but that's another story....
The reason I'm asking this question is that I've got a big valved Stromberg head stamped with the letter H, whereas on a Big Valve Weber head , It always seems to be stamped with the letter N. What does the H represent? I'd be grateful for some enlightenment on both counts please....
Thanks, Pete
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PostPost by: Europatc » Sat Sep 06, 2014 7:01 pm

Hello Pete i'm not positive but I believe its Super SE weber domestic early elan 1968 apparently rare 123bhp
im sure someone will know better
all the best
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PostPost by: 69S4 » Sat Sep 06, 2014 7:47 pm

Well I don't have the benefit of having spoken to Miles Wilkins but I do have the data page of his twin cam engine book in front of me and according to the chart there H stamps were to be found on the 1968 super S/E Weber head as well as the 69 S/E Stromberg head. Neither of them are "Big Valve" but both of them are "High Compression". Power wise they're both up on the std spec engines that preceeded them but down on the big valve engines that came after (105 vs 118 vs 126 (roughly)). All of this for UK spec engines.
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PostPost by: lottex » Sat Sep 06, 2014 8:33 pm

Thanks Guys for the input. My vague recollection re what I'd been told was that the most powerful factory Stromberg engine pushed out a max 128bhp , with a smoother delivery than a Weber head. Why therefore are these engine's frowned upon?? Is it simply a question of carb aesthetics....?!
Thanks again, Pete
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PostPost by: cal44 » Sat Sep 06, 2014 8:52 pm

I'm sticking to Strombergs on all my cars. Yes, Webers look the part but I'm not smart enough to know the difference with hood closed..................
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PostPost by: adigra » Sun Sep 07, 2014 12:01 am

I don't think there are any tangible reasons to the Strombergs being less popular, they just don't have the racing heritage/cache of the Webers and Dellortos.
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PostPost by: rgh0 » Sun Sep 07, 2014 12:24 am

For a road car in the 120 hp region the Strombergs ( without emissions controls) versus Webers discussion is one of minor points such as

Aesthetics ( most prefer Webers)
Hot starting ( Strombergs can be troublesome in some circumstances)
Running on ( Strombergs can be troublesome)
Icing ( Strombergs can ice up in damp cold weather)
Smooth torque delivery in the midrange ( Strombergs better)
Instantaneous throttle response ( Webers better)

Most of the above issues can be minimised or cured by good tuning of either type of carb and it really gets down to personal preference. Weber heads are worth far more than Stromberg heads so the market clearly prefers the Webers. For racing when developing engines over 140 to 150 hp Webers is the only way to go but up to 140 or 150 hp in a road car there is not much in it IMHO

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PostPost by: lottex » Sun Sep 07, 2014 12:44 pm

Thanks to all for the input. Isn't it about time a magazine did an impartial road test of 2 such Elans ?! Just for the record, I am putting the stromberg type H head inc valves carbs & cams up for sale as I need to source and fund an early Mk1 head for an S1 project.
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PostPost by: Spyder fan » Sun Sep 07, 2014 2:05 pm

lottex wrote:Thanks to all for the input. Isn't it about time a magazine did an impartial road test of 2 such Elans ?! Just for the record, I am putting the stromberg type H head inc valves carbs & cams up for sale as I need to source and fund an early Mk1 head for an S1 project.


If two brand new cars were available from the factory, one fitted with Webers and the other Strombergs then perhaps a meaningful comparison could be gained. This far down the road after over 40 years you really have to go with the consensus of opinion that Webers are superior to Strombergs if only from a desirability perspective.

I always thought that Strombergs were perhaps a better carburettor to have if only from the point of view that there's less to fiddle with and cock up and less chance that a previous owner had changed all the jets and emulsion tubes for the wrong stuff.

I have seen a friend struggle to get his weber headed car running right, only to find out it was previously Stromberg headed and that the advance curve was all wrong :roll: a previous owner had really cocked that one up no doubt a result of Weber envy!
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PostPost by: 69S4 » Sun Sep 07, 2014 2:47 pm

Rohan's list covers most of the up and downs of Weber vs Stromberg except the Stromberg is a bit more economical as well. Probably not a big issue the way most of the cars are used these days but, as they say, every little helps.

The running on, hot starting and icing are all pains in the Stromberg posterior :( and have often made me consider whether a box of matches might be the next accessory I'll buy to improve the fuel tank's functionality. :lol: There are ways round most of these (or at least ways to minimise them) but whether the grass is greener on the Weber side of the fence I don't know. I'm sure they have their problems (off idle stuttering etc) but the Strombergs could probably have done with a bit more development time for TC use. They seem to work well enough in Volvos and other cars of the period so I'm sure it could have been done.

Re side by side tests, the Brooklands Elan book has 20+ test of Elans (inc some +2's), both Weber and Stromberg fueled. The Stromberg S/E's do seem to come out pretty well but none of the tests mention stuff like hot starting, icing etc. I've wondered whether much of this comes in with, well, lets call it "wear and tear" :lol:
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PostPost by: a d price » Mon Sep 08, 2014 9:12 pm

I have had two 3 litre volvo engine marcos cars fitted with strombergs. Never had any problems with them on the volvo straight six engine- no icing , no running on etc.. Same carbs on my S4 elan and they dont seem to stay in tune for long. What I cannot understand is that the car might be in perfect tune, leave it in the garage for a month and it needs tuning again! When I use the car regularly it runs fine. I think there is a moral there somewhere
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PostPost by: StressCraxx » Tue Sep 09, 2014 3:07 am

a d price wrote:What I cannot understand is that the car might be in perfect tune, leave it in the garage for a month and it needs tuning again! When I use the car regularly it runs fine. I think there is a moral there somewhere


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PostPost by: RogerFrench » Tue Sep 09, 2014 4:17 am

I have a Stromberg Europa TC (de-Federalised) and a Dell'Orto Elan. Comparisons are a bit skewed, since the Elan also has a Vegantune-tuned engine, and the Europa, though Big-Valve, is still a low-compression motor. Also, the Elan has had an engine rebuild, the Europa hasn't.

My part-subjective, part-practical view is that for the most part the Europa is less fussy, the Elan possibly quicker but not so as you'd really notice. However, I do live in Texas, where the Stromberg issues are probably minimised.
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PostPost by: gus » Sun Sep 14, 2014 1:52 pm

In 30 years and ~100k miles I have never had running on problems, hot start or icing problems

Strombergs physically wear out eventually while webers will not. the also require more regular maintenance, diaphragms etc.

the stromberg head is supposed to flow better and IIRC drain oil better

On a stock motor I think strombergs are better, but if you are upping the horsepower, webers are more tunable
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PostPost by: rgh0 » Sun Sep 14, 2014 2:01 pm

gus wrote:the stromberg head is supposed to flow better and IIRC drain oil better





A Stromberg head may flow better on a flow bench but as the ports are Siamesed it does not breath as well in real life on an engine due to overlap between the adjacent cylinders breathing through the same inlet. The casting inside the head is identical to similar age Weber heads as far as I can see so I don't believe oil drainage will be any different.

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