See post #12.

If only we could stop buying all that junk but suppliers know that new carburettors are unobtainium. However, I bet there's still a good few original Zeniths out there somewhere just needing a rebuild and that's the obvious way to go although a Zenith in need of a rebuild will cost about the same as new Chinese junk.

I've had Webers, Zeniths, Zenith-copies and now back with a Weber and it runs beautifully in all weathers.

If you're having trouble when it's running hot - how's the engine cooling generally? I ask because I had no end of vapour lock issues on my S3 because a previous owner had fitted an electric fan. Once I got fed up with that thing and sourced an original metal 4-blade fan and a shroud, the constant airflow over the manifolds made a huge difference to the carb temp, even though the water temp didn't change much. I also made a rough heat shield to go above the inlet, but I don't think that helped a lot as it fell off somewhere on a drive and I didn't notice.  Neither did wrapping the headers help much - but the airflow did.

Wrapping cast iron headers can cause them to fracture. Stainless steel is ok though.
I've had a thermostatic electric fan on my 2.5 engine Series 3 for years and no problems with vapour lock with the Zenith.

Quote from: Alan Drover on Sep 15, 2023, 02:23 PMIf only we could stop buying all that junk but suppliers know that new carburettors are unobtainium. However, I bet there's still a good few original Zeniths out there somewhere just needing a rebuild and that's the obvious way to go although a Zenith in need of a rebuild will cost about the same as new Chinese junk.

What really bothers me is that the parts dealers KNOW the Chinese clones are garbage,yet they still offer them.

As to NOS... I know a guy who found one, and replace parts like the O-ring.  He said the difference between that one and his old one was like that between night and day.  He never said how much he paid for it, but he found it on eBay.

Quote from: Alan Drover on Sep 15, 2023, 08:32 PMWrapping cast iron headers can cause them to fracture. Stainless steel is ok though.

I didn't know that, guess I was lucky. Although in truth, you can't actually wrap Land Rover headers that effectively as the inlet is so tight.

Quote from: stevesharpe on Sep 14, 2023, 05:41 PMSo here are my further trials and tribulations with the new carb.
I fitted the Britpart zenith carb.  Nice easy fit and install as it goes the same was around as the old weber.

Started first time without any adjustment
Played with the idea mixture screw to get a lovely smooth idle
First test run - amazing! landcover pulled like a train - nice smooth transition from no throttle to small opening.
No heat soak or vapour lock like the weber - so very pleased.
After a day or so idle started to falter and revs dropped. Tried to compensate with idle speed screw but idle still really lumpy.
Played with the idle mixture screw but now it seems to do very little - idle is really lumpy and engine seems to be rich. Pulled out the mixture screw and gave it all a blow through  - no change
I have closed the garage door for another day as the frustration is getting to me
I can already hear some of you saying "I told you so about Chinese copies!" However, it was running unbelievable smoothly for a day
If you have any sensible suggestions then please let me know
Frustrated of Essex
Steve

Steve, when we met didn't I suggest getting an old original Zenith, and getting it refurbished by an experienced Company?
If I didn't, I should have.

Like many on here, I have been through the same thing as you have with an aftermarket Zenith, many years ago.
The only thing they are good for is throwing at pigeons, to get them off your vegetable patch.

It is why I keep a few original Zeniths for the sole purpose of having them refurbished if I need them.

I am rapidly coming to that conclusion!

I plan to bung the weber back on until I can find the Zenith solution
Many thanks
Steve

I keep 3 refurbished Zeniths and 1 in need of refurbishment just in case.

I have a donor Zenith I'd like to rebuild, but I had to get the donor to replace a spring that broke in order to rebuild the one on Grover.

In the pic you can see an arrow pointing to the part of the spring that broke.  Anyone know where to get replacements?

The only place I know is BFS in the UK but I suspect carriage will be horrendous. I've found it in the spares catalogue but it doesn't have a part number and is not included in the rebuild kit. Is there a spring supplier in the States that could help?

Are there any on the cheap Chinese copies that are usable?

If not, somebody must have one and it's so small it wouldn't be a problem to bung one in the post.

Larry

I've just been through the same process with my Zenith.  After several attempts at putting a 'service kit' in it I went through the same cycle of having it run perfectly for a couple of days then going rich again with the bleed screw ineffectual.

Problem turned out to be a warped case and top, ended up spending best part of a day lapping them with wet&dry on a piece of glass, along with the wrong spec o ring in the aftermarket 'service kit'.  Got onto a local seal supplier who supplied some viton o rings and it's been a sweet runner ever since.  The kit o rings were the wrong compound and were going rock hard after a couple of days leading to leaks even after the case and top had been lapped flat.  this may be the issue with the reproduction Zeniths as well.

With the o ring size I was kind of flying a bit blind, and assuming the size in the aftermarket kit was correct.  They were 1 3/16 x 3/32, which was a standard size.  Does anyone know if this is correct?  I suspect that while this size seems to work, it may be a little small, although the next biggest imperial o ring would be too big.

Was it a genuine BFS service kit?
I've had a look in my carburettor box but nothing. BFS returned all the replaced parts when they rebuilt my carburettors but no sign of them. I suspect they were ditched. I don't have a junk Chinese one only genuine rebuilt ones.
I thought of posting one if I had a spare but as it's metal I wonder if there are metal detectors at customs posts which it would trigger prompting a terrorist alert?

Quote from: Alan Drover on Sep 17, 2023, 11:14 AMWas it a genuine BFS service kit?
I've had a look in my carburettor box but nothing. BFS returned all the replaced parts when they rebuilt my carburettors but no sign of them. I suspect they were ditched. I don't have a junk Chinese one only genuine rebuilt ones.
I thought of posting one if I had a spare but as it's metal I wonder if there are metal detectors at customs posts which it would trigger prompting a terrorist alert?

I've posted plenty of small metallic items to the US. Not a problem - just state contents as "a spring" and state "of no commercial value" nothing more. Do not say that its a used automotive part - US Customs don't like that.