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Hot Rods New Stromberg Big 97 Issues

Discussion in 'The Hokey Ass Message Board' started by Hotrodmeister, Apr 14, 2016.

  1. Hotrodmeister
    Joined: Aug 20, 2015
    Posts: 50

    from Virginia

    I recently bought three of the new Stromberg Big 97s designed for SBCs and similar engines. I have spent weeks trying to get them running and have also taken them to one of the best Stromberg guys in the country. After weeks of research, work, and money spent they still pour fuel into the barrels after the car is turned off. They flood the engine and just leak and leak. Stromberg apparently doesn't have a fix or an answer. They just simply sell a product that does not work. Don't waste your hard earned money and precious time.
    Last edited: Apr 17, 2016
  2. wex65
    Joined: Dec 19, 2012
    Posts: 1,100

    from WV

    I have zero issue with their performance. Got 6 (regular 97s, NOT Big 97s) on my nailhead and they run like a champ.

    Re the leaking...check out my thread. I think there is a fix...I dealt with Clive in Stromberg and Norm over at Comp Fuel Systems who were both extremely helpful in getting to the bottom of it.

    In short it appears to be residual line pressure causing the issue. Reducing that to 0PSI quickly after motor shutdown seems to be the cure.

    The Grose inlet valves just don't appear to do their job properly and if the line pressure remains at or close to 2PSI on a hot motor I found the fuel level rises for @2 mins after shutdown, causing leaks etc.

    In my thread you will see some videos showing the issue.

    Hope you manage to get things resolved. Feel free to shout if you need any input.
    ace5043, clem and slack like this.
  3. I have them on two engines, works great for me! I would bet there are thousands upon thousands of people who would argue with "worst product of the year"
    Last edited: Apr 14, 2016
  4. "stromberg apparently doesn't have a fix or answer"

    So you did call them and try and got some tech help?
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  5. oj
    Joined: Jul 27, 2008
    Posts: 6,179


    I've worked on them myself (the set in question) and it is a mystery. It seems to be a question of poor needle & seat design -they are sideways and all others are up & down. Low pressure seems to dribble right past them. The next step is to try a pressure relief as Paul suggested.
    uncle max likes this.
  6. rfraze
    Joined: May 23, 2012
    Posts: 1,995


    We had the same problem w/Edelbrocks on a 2-4 manifold and a "street fuel pump". They are very sensitive to fuel pressure above 5lbs. and would "waterfall" after shutoff.
    A fuel pressure regulator pretty much solved the problem.
    You might put a temporary fuel pressure gauge in line to see what you are dealing with.
  7. oj
    Joined: Jul 27, 2008
    Posts: 6,179


    Yes, it has a gage and aeromotive regulator set at less than 2psi with engine running, when engine is sitting with fuel dribbling the gage isn't showing any pressure.
  8. 35cab
    Joined: Jan 5, 2011
    Posts: 243


    Sorry to hear of the issue you are having and I have had no experience of these carbs, my experience is only with his regular 97s which has been very positive.
    If you have not done so you must speak to Clive, if there is a problem with any of his products he would want to know.
    Clive is a totally stand up guy, the research, time and effort he has put into the business and his product development is amazing and his customer service is excellent.
    I hope you get it fixed, but "scammed" "rip off" "worst product of the year" really?
    WiredSpider likes this.
  9. stromberg-97
    Joined: Sep 14, 2004
    Posts: 20

    from England

    Hi Everyone. We generally keep off the HAMB as a rule because I don't think it's right to promote our products on a social forum. However, our nomination for Worst Product of the Year has got our attention, and I thank all the guys out there who brought this to our attention and stood up for us in the comments above. We're all entitled to our opinions and I guess social media gives us all a platform to air them. I'm not about to get into a shouting match, or give everyone a load of corporate BS, so let's just get to the bones of the argument.

    Carb flooding is something that comes up on our tech emails every day, and in pretty much every case, the issue is too much fuel pressure, or the position of the fuel tank. A Model A Ford stock cowl tank, for example, will fully empty all your gas into your carbs on shutdown if you don't use the fuel tap - that's why Henry put it there! One guy had a tank mounted so high in his rat rod truck bed, that it was above the six 97s on the motor. He returned the carbs rather than fix the tank.

    Assuming none of the above, Hotrodmeister's problem sounds like fuel inlet seepage. Same for Paul (wex65) - see his helpful post above. And I am first to admit, this is a relatively new issue to us. After 10 years of making new Stromberg 97s - it's just never come up. Tony at Ross Racing Engines asked us first about the issue with Paul's car. We assumed it was heat percolation on shutdown, which is becoming increasing prevalent with higher percentages of ethanol in today's gas. When Paul was kind enough to take videos of the issue, we needed to dig deeper. Our consultant Norm Schenck at Competition Fuel Systems, Ohio explained it best. And I quote:

    "Fuel pumps retain fuel pressure after the engine is shut off, due to the check valves that are in the pumps...necessary items to make the pumps work. Also, bowl inlet valves and fuel pressure regulators do have fuel seepage even when they are fully closed. That seepage rate is usually well below the amount of fuel that each carb is delivering into the engine at the engine's idle speed. So when there is retained fuel pressure from the pump, after shutting off the engine from even a very short running period, the seepage of fuel into the carbs' fuel bowls continues until the residual fuel pressure is down to zero, thus overfilling the bowls with fuel. Depending on the volume of fuel in the fuel lines and regulator, this can be a considerable amount of fuel. To prevent this overfilling, we need to decrease the amount of time that the residual fuel pressure exists down to a matter of seconds. The seepage rate of the S Jet inlet valves is enough to cause some significant overfilling within minutes. Even the Holley fuel inlet valve design, with the rubber tipped needle, has a high enough seepage rate to have this problem caused by the residual fuel pressure. So this inlet valve seepage is not something that is peculiar to Stromberg S-Jet inlet valves... all carb inlet valves have it to some extent.
    The way to prevent the residual fuel pressure from being an event of too long a duration is to have a small fuel return line going from somewhere between the pump and the carbs back to the fuel tank. This assumes that highest fuel level in the fuel tank is below the carbs. This line does not have be large... an inside diameter of 1/8 or even 1/16 inch would suffice. Somewhere in the return line there needs to be a restrictor with a single hole in it of about .024-.028in. When the engine is shut off, the residual fuel pressure will be dissipated quickly through the return line and the restrictor, flowing the necessary amount of fuel (to lower the pressure to zero) back to the fuel tank. The restrictor size is important... it needs to big enough to dissipate the residual pressure within 15-20 seconds after engine shutdown, but not so big that too much fuel is being returned... potentially causing a fuel pressure drop when the engine is being run at full throttle, accelerating the car. The size range of .024-.02in for the restrictor hole has been found to work well.
    The connection point of this return line at the engine works best if it is somewhere in the fuel line system between the regulator and carbs. At the other end of the return line, going into the top of the fuel tank works best. On some cars, having the return line go to the top of the fuel tank is either difficult or impossible. The next best alternative is to have that end of the return line go to a T fitting that is in the fuel line between the fuel tank and pump, near the pump. The restrictor can go anywhere in the return line, and it can be something as simple as a small piece of 1/8in diameter brass rod, with the .024-.028in hole drilled lengthwise, pushed into a small fuel compatible rubber hose. Having the return line connected to a T near the inlet of the fuel pump can temporarily cause some fluctuations in fuel pressure until all of the air is purged out of the pump/fuel line/return line system... but that shouldn't take too long.
    Putting a fuel pressure gauge, even just as a temporary thing, is a good check and adjust the fuel pressure going to your carbs. With 6 carbs, 2 1/2 psi would be the max you would need, 2 psi would probably be fine. The final thing is to make sure that none of the lines carrying fuel are too near anything that generates heat, particularly the exhaust system of the engine.
    Where it is not possible to reroute fuel lines further away from heat sources, it may be necessary to insulate those fuel lines to prevent fuel boiling in the lines or in the carb bowls". Norm/CFS

    One final thing. We concede that the basic design of the Stromberg inlet valve is not the best, because, as OJ (above) says, they are a horizontal valve, and they rely only on the direct float pressure to hold the valve shut, with low mechanical advantage on the lever from a light float. We cannot fix that. It's from the original 1930's design. Equally, the 97 has a relatively small fuel bowl, with little space to accommodate extra fuel from seepage. Maybe this is another reasons 97s were called leakers from Day One? What I can say is that we swapped from a traditional needle & seat to a twin-ball 'grose-jet' valve because, in every measure, it was universally accepted to be a better solution. They have two stainless balls - 1/4 on the outside and 3/32 inside - pushed into a machine ground super-accurate seat. The valve ejects dirt as the balls spin.

    In a further effort to research this issue, we have sent Paul six new S-jets for The Gentleman's Coupe to see if this helps reduce the seepage. We are testing Norm's suggested brass restriction valves on our own cars with a view to making them widely available. And we will put more about our findings on our website Tech Center and our blog, the Stromberg Bulletin.

    So, to Hotrodmeister. If you want to work further with us to fix your problems, we're more than happy to help. The general solutions seem to be based on a shorter line between pump and carbs, reduced regulated fuel pressure, slightly lower float levels, and then the return line. If you want to return your BIG97s, we're also happy to refund you. Just email us. Scam and rip-off are not in the Stromberg business plan.

    Thanks for listening. Sorry this is so long. 'Worst Product of the Year' takes more than a little defending..
    slim38, Kenny P, harpo1313 and 53 others like this.
  10. Petejoe
    Joined: Nov 27, 2002
    Posts: 10,234

    from Zoar, Ohio

    Now that's a vendor who cares. Enough said.
  11. wex65
    Joined: Dec 19, 2012
    Posts: 1,100

    from WV

    I tried to avoid getting involved in the unfair negative tone of this thread but I will say this. The support I have had from Clive and Norm is beyond what I would have expected elsewhere and it is clear from the lengthy correspondence I have had specifically with Clive that he sincerely wants to get to the bottom of any issues his clients have and is willing to ship free replacement parts to that effect.

    He is reproducing a design that is 80 years old and trying to introduce improvements and I am cognizant of that and accepting of the fact that there will be small issues which I will work with him to resolve.

    The carbs perform excellently and we think we have identified the issue creating the small rise in float bowl level post motor shutdown. Once tested/proven I will have ZERO issues with them and already recommend them and Clive to others.
  12. flthd31
    Joined: Aug 5, 2007
    Posts: 561


    Thanks for chiming in. I run flatheads with multiple carbs in all my cars and have been dealing with seepage for 3 decades. It most certainly isn’t something your product invented. I chuckled when I read Wex’s thread a couple weeks ago. They may have thought they discovered something new.Now this thread pops up!

    I want to mention that my carbs are all original 97’s, not your new ones. This problem is as old as the design itself. Your perfect reproductions are so accurate that you inadvertently also carried over the 97”s weakness.
    I will add that I switch to your Stromberg S-Jet inlet valves and the problem was slightly worse. I went back to steel needles and lightly staked them (hold the seat part in one hand, give needle a light smack with a very light hammer, rotate and repeat a few times). This was the best solution so far.

    I also found, as you mentioned, that ethanol seems to make this problem worse. Last summer I ran ethanol free gas exclusively and it almost solved the problem completely. That’s not a realistic fix when on the road.
    I’ve also been brainstorming a restrictor bypass somewhere that would reduce line pressure short of a complete return line as Wex was mentioning.

    Look forward to any news from you on this and any product that you may come up with to help. Thanks again for the continued research.
    alchemy likes this.
  13. Don's Hot Rods
    Joined: Oct 7, 2005
    Posts: 8,319

    Don's Hot Rods
    from florida

    That is a very intelligently written, informative response by stromberg-97. Nice to see a vendor who cares and who took the time to write his side of the story in such a non confrontational manner.

    Instead of the OP posting "worst product of the year", it might have been better to come on and ask if someone has found a solution to this issue. I know we all get frustrated at times, but that is what forums are here to do, help others.

    Let's face it, you are dealing with 100 year old technology here, if you want troublefree motoring, put fuel injection on it, otherwise, learn to work with this old stuff.

  14. big duece
    Joined: Jul 28, 2008
    Posts: 5,704

    big duece
    from kansas

    Very well explained and spoken. Thank you for stepping in to help, I believe you cleared up some future issues for me that I have not dealt with yet. Now that's a GOOD vendor!
  15. oj
    Joined: Jul 27, 2008
    Posts: 6,179


    Very good of Clive to step up and clear the air, blaming mfgrs or customers isn't going to fix anything. This is a mechanical problem to solve, an interesting one.
    One thing I noted and wanted to mess with is the floats' pivot, where the pins passes thru the float it is held captive by a formed 'tunnel' in the sheetmetal. This tunnel is generous and allows the float lots of freedom in movement and possible deflection so when satisfied the floats' energy isn't fully directed at the needle & seat.
    We ran out of time trying things, its is a slow process from making a change, reassembling everything, driving up to temp, watching what happens and tearing it apart again. We also stuck a cam in it while this was going on, it was a long day.
    falcongeorge, wex65 and hrm2k like this.
  16. porknbeaner
    Joined: Sep 12, 2003
    Posts: 41,327


    For a product to be named the worse product of the year I would have to assume that hundreds of other products have been tested extensively and that the proclaimer of the product's viability/value is not just someone who has had a problem and wants to bitch about it.

    Perhaps it comes from years of trouble shooting but it seems to me if there is a problem with a part it is better to find a solution to the problem and not just bitch about it. Once a solution is found or while solving the problem the findings can then be related to the manufacturer so that they can produce a better product. Some manufacturers will just blow you off, but they seldom continue to prosper.

    NOTE: I do not have any investment or interest in the product in question or its manufacturer.
  17. town sedan
    Joined: Aug 18, 2011
    Posts: 1,106

    town sedan

    First, I don't have a dog in this fight. When I opened this thread I was expecting another Hoffman Companies rant....
    I wish all companies and proprietors were as stand up as Clive. Thank you sir for setting a fine example for us all to follow.
  18. Black Panther
    Joined: Jan 6, 2010
    Posts: 1,487

    Black Panther
    from SoCal

    Clive. ..stand up guy and company. Also wanted to thank you for that informative post...
  19. Dan Timberlake
    Joined: Apr 28, 2010
    Posts: 1,245

    Dan Timberlake

    I wonder if a scratch or microgroove in each of the fuel pump's check valve disks would accomplish something similar to the orifice. As long as the discs are accessible, and replacements are available.

    Or one of those fuel filters with the 3rd fitting for a return line.
  20. Blake 27
    Joined: Apr 10, 2016
    Posts: 534

    Blake 27

    DSC08703-001.JPG DSC08704-001.JPG DSC08705-001.JPG DSC08706-001.JPG DSC08707-001.JPG I had a similar problem with my Rochester carbs (fuel seepage after shutdown). Lowering fuel pressure didn't help.
    I contacted Larry Fulton at and he thought my problem was heat related fuel percolation. He sent me carb spacer heat insulators, gaskets, new longer studs, nuts and washers, everything I needed.
    PROBLEM SOLVED! Thanks Larry.
    harpo1313 and Jeff Norwell like this.
  21. bchctybob
    Joined: Sep 18, 2011
    Posts: 1,772


    I ran 3 old Strombergs on my '27 T for years and once I got the fuel pressure right they only caused trouble a few times when an occasional booger got past the fuel filter. The residual fuel pressure/percolation after shut off has been a problem on several of my other cars and not just the Stromberg equipped ones. In fact, I'm struggling with the new Edelbrock carb that came on the sbc in my latest acquisition - same issues.
    Stromberg-97's response was great. I was wondering how to bleed off the pressure after shut-off and now I have some ideas to work with. Thanks.
  22. porknbeaner
    Joined: Sep 12, 2003
    Posts: 41,327


    Fuel pressure is not why your eddie is percolating. 10-15% alcohol is why your eddie is percolating.
  23. Nobody has asked the OP, are these STROMBERGS from Clive? Edelbrock copies? OR Speedway Copies??????????
    sjm1340 likes this.
  24. alchemy
    Joined: Sep 27, 2002
    Posts: 14,553


    The OP is talking about the new big 97s, which are a real Stromberg product.
  25. bchctybob
    Joined: Sep 18, 2011
    Posts: 1,772


    Oh man, not much I can do about that!! I wonder how hard it would be to "unblend" this fine California gas? Calling all chemists..........
    Black Clover Custom likes this.
  26. Response from OP? And thanks to Clive for his response.
    X38 likes this.
  27. prpmmp
    Joined: Dec 12, 2011
    Posts: 1,007


    Last edited: Apr 16, 2016
    desotot likes this.
  28. David Gersic
    Joined: Feb 15, 2015
    Posts: 1,992

    David Gersic
    from DeKalb, IL

    After reading Clive's response, I want to buy some Stromberg 97s. I don't need them, got nothing to put them on, but damn it's nice to see a good tech heavy answer like that.
  29. 56sedandelivery
    Joined: Nov 21, 2006
    Posts: 5,854


    When I read about someones "issues" with a product, or anything else, they fuss about, the first thing I do is look at their post count. It's usually a pretty good gauge of what's really going on. Stromberg sounds completely reputable to me.
    I am Butch/56sedandelivery.

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