Results 1 to 18 of 18

Thread: Stromberg vs. SU carbs (discussion/advice)

Discussions of Triumph motor cars

  1. #1
    Senior Member
    Join Date
    Nov 2018
    Location
    FREDERICKSBURG VIRGINIA
    Posts
    88
    Thanks Thanks Given 
    2
    Thanks Thanks Received 
    1
    Thanked in
    1 Post

    Stromberg vs. H6? carbs (discussion/advice)

    I know, I know, I come on like gang-busters, disappear for awhile, then show up like a bad penny again.

    Been working on little things mostly, leading up to the big stuff (since some of the big stuff is still beyond my skill set). My TR is still right where I parked it, the engine is still on the stand, my seats are still not finished (awaiting Tack Strips, but that's just an excuse). Had a little downtime due to my neck, but have jumped back in with both feet, only to be waylaid by Dad (I did kind of volunteer some time ago).

    So I'm cleaning off the blaze orange paint on my air cleaners (really, someone painted them blaze orange, with a paint brush) and got some gloss black laid out on them when Dad shows up at the shop to visit (well check up on me I'm sure, since it is his shop. I call it a shop, though it's not a business shop, and more than a garage by a long shot). Well Dad looks over the small parts (side-screen mounts, bonnet locks, dimmer switch etc.) that I have de-rustified and painted (corrosion control being my main goal), and we get to chatting about this upcoming weekend (the swap meet at TRF) and he suddenly remembers he had something to show me.

    A set of Strombergs from a TR4 engine that he acquired many years ago. The story as I understand it is that back in the day, he swapped his TR3 engine for a TR4 engine or his car already had a TR4 engine when he got it, don't know exactly. Like a lot of folks in this hobby, things get accumulated over time until they no longer serve our interest or someone wants it more than we do and cross our palms with silver or gold. These have been sitting for some time with their manifolds still attached and though he took them to the swap meet at TRF last year, there weren't any takers.

    He mentioned to me about cleaning them up (besides dusting them off with a dirty rag, I wouldn't know where to begin, but I know not to paint them) or I could use them myself if I felt so inclined.

    So the question, or discussion revolves around this: What will slapping a set of Strombers on my original TR3 engine do for me? My current carbs are currently in a plastic bin, and for sanity's sake I was planning on rebuilding them (or having them rebuilt) so at least one set of carbs will get the treatment. The engine is out of the car, so yanking the old manifold and putting the other in looks pretty straight-forward. Dad says the Strombergs are easier to rebuild/tune/maintain. Let it be known, that I believe the current carbs are SU-H6s that were stock on that car. They certainly are not Zenith-Strombergs.

    Will they (the Strombergs) make my TR faster or give me more power?

    I read somewhere here about a carb setup that barely fit under a TR3 bonnet, is that the case here?

    Are they easier to rebuild/tune/maintain?

    Do they cost more to rebuild (if I go the route of having it done by those with more skill. Dad has done his, but last time cost him two kits I believe).

    Should I just clean them up and head to the swap meet? I'd post a pic, but ran out of time and won't be able to get pics of them before Tuesday.

    Thanks for chiming in!
    Last edited by RJCOX; 05-05-2019 at 06:59 PM. Reason: terminology upgrade
    I must keep telling myself, it's a journey, not a race...

  2. #2
    Luke Skywalker
    Join Date
    Jan 2007
    Location
    Winnipeg ,Manitoba,Canada
    Posts
    1,894
    Thanks Thanks Given 
    4
    Thanks Thanks Received 
    1
    Thanked in
    1 Post

    Re: Stromberg vs. SU carbs (discussion/advice)

    Older Strombergs are a nightmare. Get a couple of rebuild kits for your SU's.

  3. #3
    Senior Member
    Join Date
    Oct 2018
    Location
    Livermore, Ca
    Posts
    99
    Thanks Thanks Given 
    0
    Thanks Thanks Received 
    5
    Thanked in
    5 Posts

    Re: Stromberg vs. SU carbs (discussion/advice)

    The 70's Strombergs were better carb's in that they were less finicky. The SU's produce more power, so I'm told. I would stick with the stock SU's. You can rebuild them yourself. I just did with no major issues.

    Steve

  4. #4
    Luke Skywalker
    Join Date
    Aug 2010
    Location
    Strafford, NH
    Posts
    1,638
    Thanks Thanks Given 
    5
    Thanks Thanks Received 
    8
    Thanked in
    8 Posts

    Re: Stromberg vs. SU carbs (discussion/advice)

    I've had a bunch of cars with SU carbs and have always admired their simplicity and ease of maintenance. I only remember one car with Strombergs, a TR7 that I drove for 70+ thousand miles. I learned nothing about them because I don't think I ever touched them. So I guess that says something. Your TR3 will probably run fine with them but they just don't match the car. Rebuild the SUs or keep the bonnet shut.
    Tom
    1960 TR3A TS73117 (under restoration year 8, owned since 1964)
    1959 TR3A TS58023 (in case I never finish the one above)
    1969 Triumph Herald 13/60 (a whim)
    1970 Lotus Elan Plus 2 /0023/N
    1992 BMW325IC (fun to drive)

  5. #5
    Senior Member
    Join Date
    Nov 2018
    Location
    FREDERICKSBURG VIRGINIA
    Posts
    88
    Thanks Thanks Given 
    2
    Thanks Thanks Received 
    1
    Thanked in
    1 Post

    Re: Stromberg vs. SU carbs (discussion/advice)

    I'm feeling better already.

    But if the Strombergs were the newer carbs, what was the benefit?

    In searching around, the kits for the Stromberg (for both cars) look simpler (less parts) and certainly seem cheaper (factoring in two kits for the SUs). I must say, my SUs look better (must've seen some love recently by whoever painted the air cleaners blaze orange) than the Strombergs. They have been in my Dad's collection forever. Apparently he has a block, crank and heads floating around as well. If my skills progress I might undertake building (only if I become independently wealthy, or at least better off). We probably have enough spare parts to get a good start on building a spare engine/transmission.

    Funny, way back when I remember an english teacher of mine had a barn filled with old cars. Dad made a deal with him to bring one home. Sadly, that gent was killed later that year. Dad and a neighbor pulled and swapped parts in our driveway then resold the car for what they paid for it. That neighbor was the guy my dad bought the car from originally. Apparently he paid a whopping $100 for it. The neighbor's kids were using it as a fort and had busted out all the gauges. Funny how your memory works to remember things.

    I can't remember what I had for lunch today, but I can remember, in vivid detail, riding in my dad's TR with no doors or hood on.

    So, the general consensus so far, Keep the SUs. Easier to rebuild, maintain, not as finicky. Were there more than one type? As I'm looking for kits, what should I keep an eye out for? Is there a Master kit out there with everything you would ever need? I saw something like that for the Strombergs.

    Thanks for taking the time!
    I must keep telling myself, it's a journey, not a race...

  6. #6
    Senior Member
    Join Date
    Nov 2018
    Location
    FREDERICKSBURG VIRGINIA
    Posts
    88
    Thanks Thanks Given 
    2
    Thanks Thanks Received 
    1
    Thanked in
    1 Post

    Re: Stromberg vs. SU carbs (discussion/advice)

    Found the kit I think

    Moss 370-795? Probably more than I need, but hate to get into it and find out I needed something more than I got.
    I must keep telling myself, it's a journey, not a race...

  7. #7
    Obi Wan
    Join Date
    Feb 2016
    Location
    Macon Georgia
    Posts
    2,259
    Thanks Thanks Given 
    10
    Thanks Thanks Received 
    26
    Thanked in
    24 Posts

    Re: Stromberg vs. SU carbs (discussion/advice)

    Check for play in the shafts. If there is play you are probable better off sending them off to a rebuild shop as the bushes need replacing. Not a task easily done without the correct tools.

    David
    TR3A TS75524L

  8. #8
    Senior Member
    Join Date
    Oct 2018
    Location
    Livermore, Ca
    Posts
    99
    Thanks Thanks Given 
    0
    Thanks Thanks Received 
    5
    Thanked in
    5 Posts

    Re: Stromberg vs. SU carbs (discussion/advice)

    I rebuilt with a kit from moss that had the original cork seals. Then I learned of kits with more modern seals that last longer than cork.
    Check that out too.

  9. #9
    Yoda Geo Hahn's Avatar
    Join Date
    Sep 2001
    Location
    Mt Lemmon, Arizona
    Posts
    9,324
    Thanks Thanks Given 
    0
    Thanks Thanks Received 
    8
    Thanked in
    8 Posts

    Re: Stromberg vs. SU carbs (discussion/advice)

    I've had both - SUs on the TR3 and Strombergs on the TR4 and both were just fine. Easy to tune and maintain.

    The rubber diaphragm in the ZS (Strombergs) means the piston does not require as much precision machining - one less thing to wear.

    The float bowls on the ZS are a little less handy to undo and work with but not enough so to be a strike against them.

    The 'choke' on the ZS is much simpler and more trouble-free - using a 'starter bar' to raise the piston rather than lowering the jet like an SU.

    Mixture adjustment on the early ZS was basically the same as an SU - turning the nut on the bottom to adjust the jet carrier. SUs use a special wrench, ZS use a one shilling coin (or a quarter if you are a Philistine).

    I think once emission requirements had to be met the move from SU to ZS really took over as there were features on the ZS that lent themselves to the tricks that had to be done to meet Federal requirements (e.g. the temperature compensator).

    I'd be very surprised to learn that SUs produce more power - the principle involved in the same, the design similar and the throat is 1" vs 1" which might give an advantage to the ZS but may not be a noticeable difference in normal driving.

    Quote Originally Posted by RJCOX View Post
    ...But if the Strombergs were the newer carbs, what was the benefit?
    The story I was told was that BMC bought SU at a time when Standard Triumph was still independent. Maybe it was a matter of pride or maybe BMC was sticking it to STC for the SUs but STC encouraged Zenith Stromberg to develop a similar carb that would not infringe on the SU patent.

    No idea how accurate that tale is, just repeating what I heard as the explanation for why the ZS was developed.

  10. #10
    Yoda glemon's Avatar
    Join Date
    Jun 2007
    Location
    Nebraska, USA
    Posts
    3,283
    Thanks Thanks Given 
    9
    Thanks Thanks Received 
    5
    Thanked in
    5 Posts

    Re: Stromberg vs. SU carbs (discussion/advice)

    What Geo said, bad rap against Strombergs I think is mostly the later, much more complicated, emissions compliant version. The early ones are very similar to SUs of the same period, and in my opinion no more or less difficult to work on or tune.

    They were offered in alternating batches on TR4s and 4As. Contemporary reports say no discernable difference in performance or driving characteristics. As far as the question at hand, I suppose I would stick to the SUs on the TR3, originality and you might have to monkey with the throttle linkage to get the Strombergs to work.

  11. #11
    Yoda martx-5's Avatar
    Join Date
    Jul 2002
    Location
    Kings Park, NY
    Posts
    6,534
    Thanks Thanks Given 
    0
    Thanks Thanks Received 
    3
    Thanked in
    3 Posts

    Re: Stromberg vs. SU carbs (discussion/advice)

    Quote Originally Posted by Geo Hahn View Post

    I'd be very surprised to learn that SUs produce more power - the principle involved in the same, the design similar and the throat is 1" vs 1" which might give an advantage to the ZS but may not be a noticeable difference in normal driving...
    The throat size on the TR3 (H6) is 1 3/4", same as the ZS 175, which means 1.75", whereas the "6" in H6 refers to 6/8" plus 1". The H4 (4/8" plus 1") carbs were used on the TR2.

    As others have said, the early ZS's are fine, but personally, I still prefer the SUs.
    Art
    '58 TR3A TS236xxL
    '92 Mazda Miata -- Supercharged
    '07 Mazda RX-8
    '11 Mazda CX-7

  12. #12
    Jedi Hopeful
    Join Date
    Jul 2018
    Location
    Perth Australia
    Posts
    150
    Thanks Thanks Given 
    0
    Thanks Thanks Received 
    1
    Thanked in
    1 Post

    Re: Stromberg vs. SU carbs (discussion/advice)

    In both Roger Williams' books on restoring and improving the TR he says the Strombergs achieved the same power output as the SUs with less emissions. Strombergs were more tamper proof, being factory pre set. Might explain Tom's experience with the TR7.

  13. #13
    Senior Member
    Join Date
    Nov 2018
    Location
    FREDERICKSBURG VIRGINIA
    Posts
    88
    Thanks Thanks Given 
    2
    Thanks Thanks Received 
    1
    Thanked in
    1 Post

    Re: Stromberg vs. SU carbs (discussion/advice)

    I've been given lots of great advice and I am happy to say my SUs stay. Some conflicting advice (though not a conflict) was to install the carbs on the car and set them up and run the car and tune them, resorting to rebuild if I find a problem.



    Obviously that won't be very soon, so, disregarding the adage "If it ain't broke, don't fix it," I can do one of two things: Leave it as it sits (fairly pretty in it's dedicated Tupperware) or buy a rebuild kit and rebuild a set of carbs that may have already been rebuilt.

    Now what to do with a set of ZSs....
    I must keep telling myself, it's a journey, not a race...

  14. #14
    Jedi Hopeful
    Join Date
    Jul 2018
    Location
    Perth Australia
    Posts
    150
    Thanks Thanks Given 
    0
    Thanks Thanks Received 
    1
    Thanked in
    1 Post

    Re: Stromberg vs. SU carbs (discussion/advice)

    Build another car!

  15. #15
    Senior Member
    Join Date
    Nov 2018
    Location
    FREDERICKSBURG VIRGINIA
    Posts
    88
    Thanks Thanks Given 
    2
    Thanks Thanks Received 
    1
    Thanked in
    1 Post

    Re: Stromberg vs. SU carbs (discussion/advice)

    We do have most of a TR4 engine and transmission laying about. Also a bumper a part of a cowl and top frame

    Hmmm.....
    I must keep telling myself, it's a journey, not a race...

  16. #16
    Yoda Geo Hahn's Avatar
    Join Date
    Sep 2001
    Location
    Mt Lemmon, Arizona
    Posts
    9,324
    Thanks Thanks Given 
    0
    Thanks Thanks Received 
    8
    Thanked in
    8 Posts

    Re: Stromberg vs. SU carbs (discussion/advice)

    Is that blood all over the gearbox? Looks like some of my work.

    The ZSs should sell on eBay - I bought parts from TR4 ZSs to convert my 'non-adjustable' ZS carbs on my other car to be able to adjust the mixture.

  17. #17
    Senior Member
    Join Date
    Nov 2018
    Location
    FREDERICKSBURG VIRGINIA
    Posts
    88
    Thanks Thanks Given 
    2
    Thanks Thanks Received 
    1
    Thanked in
    1 Post

    Re: Stromberg vs. SU carbs (discussion/advice)

    I've seen what appears to be the same ZSs relisted over and over. I'll have to figure out what they are worth to someone.

    I think I'd prefer to trade them for something I want or need.

    I'll dust them off tomorrow and post a pic in the classifieds here and see what happens. They have probably been in my Dad's collection for a couple of decades.

    BTW, that red was someone's first paint on the transmission, and the silver was someone's second attempt. I'm seeing a lot of different colors on the engine. Blaze orange air cleaners, orange starter, blue generator, BRG oil filter. My headlight buckets were BRG, and the adjustment bracket was yellow, but under the paint was red on both of them.



    They will most likely make the trip to TRF for their swap meet this Sunday in Armagh PA. I wonder If I could get a set of wheels for them?
    I must keep telling myself, it's a journey, not a race...

  18. #18
    Senior Member
    Join Date
    Nov 2018
    Location
    FREDERICKSBURG VIRGINIA
    Posts
    88
    Thanks Thanks Given 
    2
    Thanks Thanks Received 
    1
    Thanked in
    1 Post

    Re: Stromberg vs. SU carbs (discussion/advice)

    Well, I spent the day cleaning parts, and painting parts, and loading parts into containers for the trip to TRF. The ZSs got scrubbed down (decades of dust and grime) and should probably get a good servicing since they've been sitting so long. I sand-blasted the intake manifolds and they look pretty good. All that nasty grime is history. Truth be told, I'd trade them in a heartbeat for a rear ****-pit rail. Found out mine was bodged together using some really soft metal covered in vinyl. Thought I would pound it into shape (back into shape) but did it with my bare hands. Still looks like doo-doo.

    Hope I can get something good for them. I believe the air cleaner I have (single unit for two carbs) can go with it, but it could be from a TR6.

    Wish me luck

    Ron
    I must keep telling myself, it's a journey, not a race...

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •