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MG MGB Technical - What do I do with my Stromberg?

I am a recent owner of a 1977 B roadster and love it to death. However, not being the best mechanic in the world and basically knowing how the car should run, I feel that I have a serious performance problen linked to that wonderful invention called the Zenith Stromberg Carburettor.

When it is cold, it is very hard to start. When and if it fires I must keep the revs high until the engine is warm or else it will stall and not start again. (acts like it is flooded)

My accelleration is sluggish. I have seen better on a Bug.

I am thinking about rebuilding the carb or replacing it with something. On rebuilding it, does anyone know where I can get a good manual/

If I replace it, should I use Weber or SU. I have heard that there is a possible fire problem with Weber but I really do not know.

If I change does anyone know where I can get details?

Any help will be greatly appreciated.

Thanks to all and Merry Christmas.

Bob Anderson

Bob Anderson

I would get

1. SU/Zenith/Weber carburetor manual from Moss Motors or
Amazon or VB. Covers up to approximately 1975 models of the
carb. Coverage of the autochoke is accurate up to your year.

2. Haynes MGB manual -- covers basics of later Zenith carbs
and gives tuning instructions.

3. "Those Damn Zenith Strombergs" available in the
technical manual from www.universitymotorsltd.com. Also
do a google search for this article.

It sounds like your autochoke is not working -- I would replace
the bimetalic spring/heat mass with the manual choke conversion
from Moss or VB or other sources.

Poor acceleration could be due to lack of oil in the dashpot --
take off the damper cap, if no resistance is felt when threads
are within 1/4" of the carb, then not enough oil -- use 20W/50.

Before any of this, I would check compression, ignition and
timing before playing with the carb.

Carefully check your local smog laws before considering
SU or Weber conversion. Good luck!
Ronald

All great information.
I have the Haynes MGB Manual but as you said it covers the basics.
I'll go and get "Those Damn Zenith Strombergs"
Dashpot is OK, I keep that one checked regularly.
Ignition ok, will check timing and compression before I continue and I like the idea on a manual choke but I would like to have a go at fixing the auto choke if it isn't too hair-raising.

Thankks very much for the help,

Bob
Bob Anderson

Bob, as Ronald noted, check your local smog laws, then, if you legally can, chunk the ZS in the nearest trash can and go with SUs. You will need the complete intake manifold from the gasket to the air cleaners, along with an earlier exhaust manifold or aftermarket header. I would also change to an earlier distributor, they are curved for much more power. You'll be amazed at the difference.
Ken Lessig

Hi Bob,
If it is your autochoke, I went through the same thing on both midgets and MGBs. The last time I got frustrated with these things, about two months ago, I did some studying and ended up putting together some info on the water choke mechanism. Just yesterday I uploaded it to my website. You can find it at:
http://uslink.net/~jasko/choke/ZSchoke.htm
If you look at it, I'd appreciate feedback. I don't claim to be an expert, either with the choke or with writing articles. In fact, anyone reading it is welcome to give me their comments. May be best to send them right to my email address so Bob's thread isn't hijacked.
Rick
Rick Jaskowiak

Gentlemen, this is wonderful information, and Rick, your web page on the choke is absolutely terrific, I recommend that anyone who wants to understand the choke go and read it.
Hope you don't mind, I copied it to my PC but will not distribute it. If you need any money for it please let me know.

Bob.
Bob Anderson

The site is great but the photos didn't come up...just a little box with different colored squares in the top left corner of the photo area
Tony Barnhill

You weren't the only one, Tony. I don't know why it would work on some and not others. When I tried Netscape I had to refresh once to get all the pictures. I tried both from home and work with no other problems, and evidently Bob could see them. If anyone has a suggestion let me know. Maybe I did something wrong.
Rick
Rick Jaskowiak

Bob,

If you search the archives, you'll find a lot of great information regarding the pros and cons of the Weber vs the SU. You won't find very many fans of the Stromberg.

The "possible fire problem" is with the Stromberg, not the Weber. The Stromberg has a nasty habit of leaking gas from the plug on the bottom of the float onto the hot catalytic converter. Engine fires seem almost inevitable with the Stromberg.

I've found the Weber to perform very well and be maintenance free for at least the first 100,000 miles. You set it and forget it. If you decide to go Weber, call Bob at Brit Tek ((800) 255-5883). He's helpful, knowledgeable, and has good prices.

I've found SUs to perform the best of the lot (when properly set up) and they look great. They'll require more attention and maintenance than the Weber, but tinkering with an MG is part of the fun.

Whichever carb that you go with, I'd strongly recommend using K&N air filters. They last forever, filter the best and give you a bit more power.

Good luck!
Steve


Steve Lipofsky

Nope...refreshed, went to different computer...still can't see photos...bet the article is great with them though
Tony Barnhill

Guys, be patient on the pictures in Rick's Choke article. They all come through eventually (23 pistures in all. Print it directly from the web page. I was unable to save the pictures. Persevere with this. It is a great article
Bob Anderson

Rick. One of the best illustrated technical articles I have seen. I don't have
a car with a Stromberg but will bookmark the site for future reference. Clifton
Clifton Gordon

Nope, can't get photos...don't load...just see the little microsoft emblem....but, i can get the photos on his home iste...nice looking cars...wish i could see the zs photos
Tony Barnhill

If switching the carb, I would tend towards the multiple SU setup, but there is another alternative. If you want a safe, easier way to solve the ZS problems with little effort, how about one larger SU? They make a SU that is exactly for this application and I would think it better pennies spent than on a ZS rebuild. No true experience hear, but just about everything I've read here or otherwise points to this solution over the ZS. Anyone try this in person?

Just .02
Luke
Luke Staley

Ric
You did a top job of your site. All the pictures came up immediately.
I have a Stromberg carb on my 79 MGB & it works well
Keep up the good work
Jeff
jeff jorgensen

Rick...since our last e-mail, it worked from the link above also...so, the code you changed corrected the problem....I'm gonna add you to my links page Monday when we do anopther update
Tony Barnhill

This thread was discussed between 13/12/2001 and 14/12/2001

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