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ZS Carb is GONE!

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Dozuki

Dozuki

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Just wanted to share that I successfully replaced my Zenith Stromberg Carb this weeked. The replacement was not one of the usual suspects (IE Weber), But a good ol' trusty HS6. Fits like a champ with a few minor modifications to the carb and to the heat sheild using a Dremel tool and a drill.

Man, this makes one heck of a difference, the car is actually kinda quick now. And the choke works like a choke should =). The Mixture is about right with a DX needle and Longflo air filter. (The mix was way off with my ZS) and the car will actually surpass 5000 rpm. I couldn't ever get it past 4500 with the ZS.

I used one carb from a set of carbs off of a Volvo 1800. The carbs came with new jets and 4 different needles. All in all it cost me about the same as a manual choke conversion for the ZS, and that wouldn't have even sorted the A/F ratio problems with the ZS. I should have pictures soon and possibly a full write up in the near future.

-D.
 
Congrats!! You know what they say... a happy car is a happy car /ubbthreads/images/graemlins/smile.gif
 
ooo.. I wanna see this ... I wonder if a "test only" inspector would notice the difference in CA... sounds like an interesting conversion... /ubbthreads/images/graemlins/smile.gif
 
I doubt anyone in an inspection station would know what the heck they were looking at no matter what kind of carb is in an MGB.
 
Very cool! Now you've got me considering an HS4 for my Midget. A single HS4 sounds like less of an undertaking than a dual HS4 conversion, though that would be nice.
-Dave
 
Okay, here are some pics:
H6-2.jpg

Carb with over view of engine bay. I never said it was pretty in there /ubbthreads/images/graemlins/grin.gif
H6-3.jpg

Top view. Note the choke cable at the front of the carb. This was the only major modification to the HS6, drilling out the hole so the choke cable fits SNUG (3/16" bit for a Moss T handle choke cable).
H6-1.jpg

Throttle side view, here you can start to make out the cut that was made to the heat sheild for the ZS throttle linkage mounted to the HS6. The side of the ZS throttle linkage where the throttle shaft bolt is had to be ground down so the bolt could grab some threads. After that it fits to the throttle shaft WITH the HS6 linkage. I bent the return spring hole on the HS6 linkage, but it didn't actually have to be done. The other end of the throttle return spring is connected to a wire loop around the Master cylander right now. This works fine, but a more elegant way could be devised. If the induction heater doesn't work (I don't think it does) this would be a good starting point for the return spring fastener; attaching the spring from the HS6 linkage to the induction heater.

My car has no emissions hooked up, so this was all fairly straight forward. Doing this swap on an emissions equipted car will require some more thinking as this carb doesn't 2 emissions connections that the ZS does.

-D.
 
lemme guess... those would be the crank-case breather watchamacallit, and the vacuum connection that's next to the butterfly valve on the ZS... The vacuum connection can probably be taken from one of the other points on the intake. So i guess that leaves the crankcase thingiemabob to deal with.

Would moving the vacuum connection to a different point on the intake effect the ignition advancing at all... anyone know?
 
so the HS6 just bolted right onto the MGB ZS manifold without any modifications to the bolt pattern?

Also, I was just reading on a different board and some people were mentioning HIF-44s... I normally only see people talking HS4s here... what's the diff between the HS4 and HIF-44? I assume the diff between the HS4s and HS6s is the HS4s are 1.5" and HS6s are 1.75"... but HIF-44?
 
It just bolts right up. The only modification is to the heat sheild to clear the old ZS throttle linkage. I Modified it with a dremel tool.

The HS4 is 1 1/2" and the HS6 is 1 3/4" that is correct . The HIF44 is a 44mm bore (I believe that 1 3/4" is 46mm). An HIF44 should bolt right up to the single ZS manifold as well. That is the carb that Moss and VicyBrit sell as the single carb (SU) replacement for the ZS. I never did find a used HIF, but I did find used HS6's. The HIF has an intrigal float bowl, a differnt choke mechanism and some other differences. I've not played with an HIF yet so I can't be very specific.

-D.
 
How'd you get it so shiny and purdy? I want to start working on my HS4s to get them cleaned up and ready for a rebuild. (or should we do the rebuild first?)
 
IT Has a chrome cover over the bell JB.---Keoke
 
What about a plastic spacer to move the carb out about 1-1/2" from the intake?

Next thing you need to do is whack out that siamesed exhaust manifold & install an original MGB 3 into 1 with head pipe!
 
Or just go and get a header, JetHot coated, and volumetric efficiency is achieved!

I guess the "inspectors" would kinda notice that tho, huh?

"darn their eyes."
 
They might, but I don't think they'll care if the car passes the test and appears to have the emissions components in the right place... heh
 
You might want to get a header...I think the last one we did, we had to dent the middle run of the header so the ZS intake would fit over it....separating the siamesed manifolds is easy though.
 
Hmm... I didn't know the manifold could divided. any info or pictures on that one??
 
ah... but do you know of a header that has EGR fittings for a 'B? I need to retain it, and since I don't have a welder or access to one for that matter, I'd have to pay someone to fab the necesary bits to retro fit an EGR valve to a header. Something I plan on doing somewhere down the line, but certainly not right away. It's times like these I miss living in FL... heh
 
ah! Adam9000_9 on this board has already done it! /ubbthreads/images/graemlins/smile.gif

I found the thread a few months back and bumped it up... lemme see if I can find it again...

Here we are:
https://www.britishcarforum.com/ubbthread...true#Post106126

and the link to their pictures page for the "mod":
https://community.webshots.com/album/129331308VoeHCi

Not really a step by step, but you can pretty much see that the exhaust portion was cut from the intake and they were sepparated. /ubbthreads/images/graemlins/smile.gif
 
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