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series 5 strombergs don't fit series 2?

Discussion in '"Stock" Alpine' started by mightyohm, Jul 6, 2020.

  1. mightyohm

    mightyohm Gold Level Sponsor

    Hey all. It's been a while, but I am working on the Sunbeam again, trying to sort out carb and exhaust issues.

    I decided to see if a set of series V Strombergs would fit my series II with 1725 engine. The carbs fit, but the air filter for the rear carb won't fit because it interferes with the fender brace.

    I'm guessing that the fender cross brace changed locations sometime between the series 2 and series 5? I found some photos of series 5 engine bays and it seems like the brace mounts to the firewall about 2 or 3 inches further towards the drivers side of the car.

    This photo shows the issue - the air filter is as far back as the cross brace will allow. You can just see the rearmost mounting hole on the rear carb, just to the right of the filter housing. The filter would need to move down and a couple more inches to the right in order for the mounting holes to line up.

    Surely I'm not the first person to run into this?

    Last edited: Jul 6, 2020
  2. alpine_64

    alpine_64 Donation Time

    Yes the early scuttle braves on the cars with the king pin front ends are a different location and length. Probably easier to find some of the offset filters use on the strimbergs on triumphs
  3. puff4

    puff4 Gold Level Sponsor

    ...and stop calling us Shirley.
  4. bernd_st

    bernd_st Bronze Level Sponsor

    Other than that clearance issue you'll be much better off using a pair of early Zeniths. Furthermore your Strom's don't look particularly good so it's hard to believe they will perform properly...
  5. Barry

    Barry Platinum Level Sponsor


    Don't know if the Strombergs are a good idea or not.

    A possible solution to the fender brace / air filter interference issue is a curved fender brace. Other than originality, there is no reason that the brace (less than a foot in length) has to be straight.
  6. mightyohm

    mightyohm Gold Level Sponsor

    Hah! Thanks for the laugh today.
    puff4 likes this.
  7. mightyohm

    mightyohm Gold Level Sponsor

    Yeah, they are grimy, but I think the internals are actually reasonably clean. This was just a test fit, anyway. I was planning to have them fully rebuilt before using them. I'm glad I checked the fit before sending them off to be rebuilt. My usual luck would be that I get the shiny carbs back and then discover the problem.

    I had no idea that the braces changed locations between years so this is a big surprise to me.

    Will the Zeniths work with a 1725? I have a pair of those as well but they are missing some linkage parts. I'm assuming jets would have to change, but wouldn't they be too restrictive for the larger motor?

    The motivation for running the Strombergs was so that I could run the stock series V manifold and PCV system. I have a stock 1725 so it all should work together. I also like the look and sound of the dual carbs, but at this point it might be easier to just keep the Weber.
    Last edited: Jul 6, 2020
  8. mightyohm

    mightyohm Gold Level Sponsor

    Thanks for the tip. I'll check those out.
  9. bernd_st

    bernd_st Bronze Level Sponsor

    It's always good to trial fit things before actually sending them for a rebuild. All done well so far. Yes, the Zeniths will work well on a 1725cc. Just the main jets may need slight adaption. Stable idle,excellent fuel consumption in combination with good power delivery...
  10. Alpine Addict

    Alpine Addict Platinum Donor Platinum Level Sponsor

    A better option would be to use a Webber carb
    Tim R likes this.
  11. Gordon Holsinger

    Gordon Holsinger Diamond Level Sponsor

    I had a friend who had that problem what he did was he adapted a pair of smaller su air cleaners to the strombergs if I remember correctly they had foam filters inside of a two piece housing.
  12. RootesRooter

    RootesRooter Platinum Level Sponsor

    Track racers often used to switch their Series V's back to Zenith's.
  13. alpine_64

    alpine_64 Donation Time

    I too like to keep twin carbs on them, looks much nicer when you open the bonnet at a show.. Or when you are staring at the next repair :p.

    The pcv setup wpuld be worth keeping which you cant do on the Zeniths unless you source series 3 setup.

    As a side note will you be fitting an oil cooler per factory SV spec? Apparently the 1725s gave the pil a much harder time for some reason, which may explain why the 1725 alloy head verisons of the rootes range were often fitted with oil coolers or alloy sumps.
  14. Tim R

    Tim R Silver Level Sponsor

    Considering the cost of rebuilding the Strombergs and then the ongoing pain of keeping them in synchronisation, replacing the diaphragms when they fail (thanks ethanol) etc isn't it worth considering the Alpine Innovations Weber carb conversion? Once fitted you get a carb that stays in tune permanently, performs better than the Stroms and will return over 40mpg on a run. Plus the firewall throttle rod mount will already be in the correct position. The car accelerates like a scolded cat, ticks over steadily at a much slower RPM than the Stroms could ever manage and I have never managed to reach the top speed it will deliver! You can get rid of the PCV at the same time.
    Getting rid of the Strombergs on our Alpines and fitting the owner's club carb was the single biggest improvement we had ever made.
    Just a thought.

    Attached Files:

  15. alpine_64

    alpine_64 Donation Time

    Tim, i think he wants the twin carb look for his weekend car... I get that.

    The dgv is certainly a nice set and forget upgrade but its certainly not as nice looking.. and for me the Ai setup while apparently well engineered ( bar the pcv pickup issue it has) it is aesthetically very challenging ( thats as politely as i can put it )

    Also he wants the pcv and isnt the current recommendation to remove that from the Ai setup as it causes stalling issues?

    Dads car runs the dgv ... Rarely had a problem ( execpt the electric choke when first installed) but its just not something to proudly look at in an engine bay....

    Id say bugger the fuel and go 2x DCOE .. Looks, performance, sound.. Dependable....but thirsty (ish) no pcv... new scuttle brace or none.. And more expensive... But what a way to waste some money :D

    I think with a set of either triumph filters or some aftermarket SU ones he can resolve the clearance issues.
  16. Tim R

    Tim R Silver Level Sponsor


    You are probably right, at the end of the day I suppose it depends on what someone wants from their car and what they want to do with it. Personally I have never liked DCOEs because almost every set up I have seen has been lumpy and difficult to drive at low speed (great flat out though). Some people swear by them and tell me that they have them set up to be smooth and progressive but that hasn't been my experience.

    Tim R
    bernd_st likes this.
  17. RootesRacer

    RootesRacer Platinum Level Sponsor

    I have PCV on my DCOE setup...
  18. alpine_64

    alpine_64 Donation Time

    Hey jarrid, yes i should have said it can be done.. The holbay motors had a pcv ...
    Out of interest did you make a balance tube for your manifold or did you just draw the pcv off 1 runner?
  19. alpine_64

    alpine_64 Donation Time

    Tim.. When the world finally gets back to normal... Come on down and drive mine :)

    Ill be honest its not 100% perfect like fuel injection...but ive yet to srive a dgv that was either. Carbs will always have a weak point somewhere... Like of you snao accelerator open from down low.. Or if its setup for cruising and you want upper level performance....
    Its what gives the car character and how you drive to the car...

    A friend of mine had my alpine for a year and he changed the e-tubes in the dcoe's from the f16s to f8s as he said the car loaded up to much when moving around at parking maneuvering speeds.. Id never had an issue.. But i probably drove around that problem and was focused on mid range punch.

    I didnt notice the change at low speed but noticed the car lacked its usual mid range punch (where the fatter f16s overcame the transition of the switch between the idle circuit) and when i mentioned it to him he told me about the switch in jetting. It lost some of its lovely punch.. But did gain 5mpg....

    I drove the car on sunday 165miles.. It did 36mpg on the twin doces.. Which i think is decent... Oh i do have a high output bosch electronic ignition and coil which helps.. Keep meaning to fit a multispark crane controller.. Figure that would help torque down low and also eek out a few more mpg... But Jarrid would be better advice on that than me.

    Anyway.. We digress.

    I think he wants the classic sports look and feel of twin carbs.. And i suuport that.. The aesthetics of these things is one of the appeals of classic cars to me.
  20. RootesRacer

    RootesRacer Platinum Level Sponsor

    Balance tube. A lot of trouble.

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