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Weber downdraft Carbs

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ACMAUI Andy Herrera
Gig Harbor, WA, USA   USA
Hello all,
I bought a 69 TR6 and it had Stromberg carbs that were supposedly rebuilt by an expert in eastern Washington, anyway, they may have worked perfectly, but the connections and other parts had massive vacuum leaks and were clearly not synced. I have had these in the past and just don't want to deal with them again so I'm going with the weber downdraft kit from redline and some home made cable linkage and home made accelerator bushings on the accelerator pedal bar. My question to any who have made the weber conversion, is did you hook up the hose to the cooling system? I have the original green hoses (replaced by PO) and I hate to cut them to hook up the new manifold and there is not a lot of room on green hoses to cut "T's" into them for the new lines. I will only run this in the summer, so I'm not sure I need them. Still have the manifold cooling system hook up. Any ideas or thoughts?

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Krom Avatar
Krom Paul K
San Rafael, CA, USA   USA
Andy-
As this horse has already been beaten to death, i’ll try to be brief. Yes, I run Weber down draft DGVs and I run a hose setup through the p-trap manifolds. I fabricated copper Tees at the water pump outlet and the heater inlet so I am getting flow through the original manifold as well as the p-traps. Just copper pipe elbows cut with a dremel and soldered together. Nothing fancy. Before I did, running just through the original manifold, the car was hesitant coming off idle. This seems to have effected a positive change. Search the threads on this site for lots more detail and photos.
PK

Tracker1 steven archuleta
Columbia, USA   USA
You WILL be sorry!!!!! I did it "once" and never again!!!! Be smart and leave well enough alone...

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ForgedRbest Greg L
Slidell, LA, USA   USA
Hi Andy,
My 6 came with the Weber DGV's. The previous owner had installed them. They ran alright. The biggest issue was sitting at a long light the engine would load up, flood and quit, unless you kept revving it. This was due to the goose neck adapter that connects the DGVs to the TR6 manifold. Prolonged idle allowed raw fuel to accumulate at the bottom of the goose neck, thus causing the flooding condition. The only cure was to keep the engine revving when you were sitting still. I threw in the towel and converted to triple Strombergs with Rick Patton's TB injection kit. If you really want it to run good, start when you point the key at it, and get better fuel economy, look into fuel injection. Otherwise get someone to rebuild and setup your Strombergs for you. When done right those are great carbs and the car will run damn well with them.

Fogspawn, CA, USA   USA
1974 Triumph TR6 "Machine"
Good Z-S are not to be sneezed at, don’t
toss your Zenith-Stonehenges owing just
to low threshold of frustration.
w

POW Peter Wirth
HEBRON, NH - New Hampshire, USA   USA
In reply to # 1595196 by ACMAUI Hello all,
I bought a 69 TR6 and it had Stromberg carbs that were supposedly rebuilt by an expert in eastern Washington, anyway, they may have worked perfectly, but the connections and other parts had massive vacuum leaks and were clearly not synced. I have had these in the past and just don't want to deal with them again so I'm going with the weber downdraft kit....

Those Stombergs get bad raps from folks who just don't know what they are doing with carburation in general. Massive vacuum leaks and not synced are not indications of poor carburetors but rather poor install and maintenance. The exact same maladies can infect even the horniest of twin/triple Weber set-ups. Weber carburetors are great instruments that have their very own tuning procedures that if not understood and followed will also result in frustration. Be wary of 'kits'. - Pete

Fogspawn, CA, USA   USA
1974 Triumph TR6 "Machine"
the one time I tried weber dcoe on MGA,
compared to Z-S this Tr6... for setting up
and getting right the Z-S wins... if my
Stroma were to disappear or be incorrigibly
damaged... and could not find suitable replacements,
then is time to look to SU and others...
(including Webers)... but synchronication (balancing air)
and vac leaks are easy to take care of... not
enough to condemn them...
I had both MGA and TR at same time... I removed weber,
mounted the SUs back and tuned them up, ran fine...
gave the weber to the Italian car repair shop
next door...
That said, KROM has made a successful DGV conversion.

poolboy Avatar
poolboy Ken D
Sandy Hook, MS, USA   USA
You can't compensate for the need for a good periodic carb rebuild by turning screws..



ZS carb repairs
kencorsaw@aol.com

LFMTR4 Avatar
LFMTR4 Lou Mijares
Scottsboro, AL, USA   USA
What POW said. You’re throwing the baby out with the bathwater because you don’t know how to adjust the ZS’ and keep vacuum lines intact. Do you know how to set and synch Webers? ZS’s are easy to synch once set.

You’ll have the same issues with Webers if you don’t synch them and have vacuum leaks. If the carbs need to be rebuilt to bring everything back to the start line, send them to ZS expert in Mississippi and they’ll run way better without loading up.



Edited 1 time(s). Last edit at 2019-02-09 03:41 PM by LFMTR4.

Tonyfixit Avatar
Tonyfixit Tony M
Duncan, BC, Canada   CAN
"I bought a 69 TR6 and it had Stromberg carbs that were supposedly rebuilt by an expert in eastern Washington, anyway, they may have worked perfectly, but the connections and other parts had massive vacuum leaks and were clearly not synced. "

That so called rebuild could mean anything or nothing. With a proper Stromberg rebuild the car should run fine.
The downdraft Webers in themselves are fine carbs, but the manifolds that are required to fit them to our engines are a disaster!

For years now I have refused to attempt to tune a Triumph engine with DGV's fitted. Not out of any spite, just that the pitfalls make the task all but futile.

Please! Save your money and talk to Poolboy.

YTJOHN Avatar
YTJOHN Silver Member John F
Yorktown, NY, USA   USA
I've used both Strombergs (TR4) and Webers (TR6) and both worked fine when correctly jetted and tuned. On the 6, I skipped the extra cooling line on the manifold as this car wasn't used in the winter (after reading all the threads Paul mentions). As to the much criticized "goose-neck" manifold design on the Webers, recall those Chrysler 300s with the cross-ram intake manifolds back in the 1960s. That set-up had a quad carb hanging out over the exhaust manifold on each side of a 426 CI V8. The manifold goose-necked over the valve cover and into the intake ports on the opposite cylinder bank!

One other thing: don't trust those green hoses.

tirebiter Jeff Garber
Dighton, MA, USA   USA
Don't believe all the hype you read in the sales brochures. It's not a simple bolt-on precedure. The Weber kits are notoriously set richer than need be, just to make them work on all TR-6s. You will have to spend a fair amount of time and have a goodly amount of expertise to make them work correctly.

Or just bolt them on and crank in a lot of extra ignition advance like so many have done before. Use a vacuum gauge to find the best idle if you want and then cross you fingers and hope the timing is not too far advanced ... once you are done.

In my experience, the manifolds are not the problem at all. It's the jetting - and all the other precision calibrated parts - they come with in the kit. Also, the lack of any way to advance the ignition timing upon throttle opening/vacuum signal hinders their use on most TR-6 engines a LOT !

ACMAUI Andy Herrera
Gig Harbor, WA, USA   USA
Thank you! I can't believe I didn't think of that! The main reason I was hesitant to install the hose is the lack of space to cut in "t's". I'm sure I have the copper in my plumbing kit to do as you suggest and it is the elegant solution I was looking for!

ACMAUI Andy Herrera
Gig Harbor, WA, USA   USA
Thanks for all of your responses. Many were as expected, and still respected. The main reason I am changing is that I had a S'berg set up on a right hand drive Austin Sprite bug eye and I only drove it for a few months in the summer, and even then infrequently, and it seemed each time I had to work on the SB's. I believe the Webers will be less problematic with sitting for months. I could be wrong since I've never used these particular models, but have found other downdraft webers to be pretty robust. Time will tell. I'm not trying to keep the TR6 all original, I just like them and enjoy driving them when I have time. I'll keep the original parts for a future owner, unless I get a good offer on the SB's, in which case they are gone. If the down drafts don't suit, I'll go to the three side draft webers. It's only $$$$.
Thanks all!

Tonyfixit Avatar
Tonyfixit Tony M
Duncan, BC, Canada   CAN
I have never seen Strombergs on an AH sprite let alone a Bug Eye. Are you sure they weren't SU's?

On DCOE Webers the small money is in buying them, setting them up to run efficently takes time and $$$



Edited 1 time(s). Last edit at 2019-02-15 01:12 AM by Tonyfixit.

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