VCCA Home Forums TECHNICAL - 1945 AND EARLIER 1916-1922 - Model 490 Repairing a Zenith T-4 carburetor for a 1922 490 s

Hello everybody

My name is Bjorn Lindell, i come from Sweden and I am new to the forum.

I am currently working with a 1922 Chevy 490 or rather with the engine.

That it because it is fitted to a 1920s rail speeder that was built by the Swedish firm of Ljusne Voxna verkstads AB.
That probably makes this contraption the world’s only “Chevy 490” that run on rails.



Originally the speeder had a totally different engine but I guess it broke.

So in the 1940s the railroad replaced the original engine with a 1922 Chevrolet 490 Superior engine with the Zenith T-4 updraft carburetor.

The original car most likely was scrapped sometime before the war and I have yet to find records of it.

Now I am having problems with the carburetor as it needs its float valve and seat replaced. No problems there as I am in contact with the carburetor shop for a repair kit.

But the real problem is the Venturi or Choke tube.

As often is the case I am told it has swelled and started to crack and disintegrate.
Unfortunately it has also managed to partially crack the cast steel part of the carburetor body in which it is inserted.
So this winter I need to get hold of an experienced welder to repair the cast iron body piece and also to remanufacture a replacement choke tube.

My question is if any of you have had this problem and have made these repairs. Especially things to consider when remanufacturing the choke tube would be greately appreciated.



Yours / Bjorn L

A VCCA member from Oregon, Bob Hughes, has made venturi and other parts for the Zenith O-4 and T series carburetors. Some or all those parts can be obtained through the Filling Station.

Hi Bjorn.
The cast iron body can be TIG welded by a competent welder.
That is an interesting picture of the Rail speeder. Thanks for posting.

I braze the broken bodies. Takes some care to get them right and have the venturi fit the bore but they can run well if the job is done right.

What a lovely rail car and most probably the only one in our Nordic countries! I have not heard of any other rail car of this type even in USA.

Where do you live, Bjørn? I have a 1916 car with the same carburetor and am living in Oslo.

Hope you can get the crack repaired soon.

Hi Solan

Thanks :-)

I live in Uppsala but the heritage railroad is situated in Jädraås just east of Ockelbo, http://www.jtj.org.

I am tasked with having this thing running for the annual show at the Swedish Railroad museum in Gävle on the 14-15 September.

So you can see it there if you like, or in Jädraås on any summer Sunday when there is traffic.

/ Björn

Hi Chipper and jack39rdstr

Thanks for the good information. I missed that the Filling Station had so old carburetor parts. I will get some stuff from them.

Unfortunately they do not have the choke tube for the T-4. So the only way i guess is to ask Bob Hughes if there is some other channel for purchase.

Otherwise I will have to manufacture it locally, actually that would be kind of fun to do.

Not that I would machine it as it requires a CNC Lathe and expertise in its use but researching the shape and making the drawings would not be impossible.

/ Björn

Hey, Bjørn. I can lend you a ready overhauled carburetor so you can run the rail car at those dates. In the meantime you can repair the original one. If you miss the flexi hose and exhaust stove I can supply you with that for a low sum. Those two items are needed for making the carburetor air "hot" enough to give right working temperature.

I am leaving early tomorrow morning and do not come back until late Sunday, but thereafter I can send the items needed.

Send me a message here and I will follow up.

Just remember that the 0-4 and T4 Carburetors are not the same.
The 0-4 was used from 1916 to 1919 and was all cast bronze/ Brass. The 1920 to 1922 T4 has the Cast iron upper body part, which was prone to the crack illustrated in the pictures.

Yes the carburetors are built from different materials but internally they are very similar.

Hi Solan

Thanks for your very generous offer. :-)

I have recived your e-mails and will replye to you via e-mail.

/ Björn

Hi Bjorn,

Did everything function the right way Saturday and yesterday?

Anty pictures of the running rail car?

Here are the YouTubes links from the railway meeting showing the engine of the Four-Ninety rail car running in Sweden. Turn on your sound too.





Hope you like them.

It might just be the video capture rates, but when they rev the engine up # 1 intake valve seems to be "hanging up" and looks like the rocker arm is hammering the valve.

Thanks Jack.I will pass the comments along to Bjorn. They know already they will need major maintenance during this winter to make the rail car a easy driven and good runner again.

Hi everybody and thanks for your help

The “car” performed well at the Swedish railroad museum but the engine sound seamed
increasingly raw and clunky to me. That sound doesn’t come through properly on the YouTube clips.

When we checked the engine afterwards one can feel a quite noticeable rotational play in the flywheel
before you feel that you move the cylinders.

Remember that this engine don’t have a gearbox attached just the engine and flywheel so it’s easy to rotate the flywheel that way.

Also when I checked the oil pump for pressure and flow there were no oil flow what so ever.

I suspect that the crankshaft bearings are not in the best of condition and bad lubrication won’t have helped.

So this winter the engine will have to be totally overhauled.

Yours / Björn

Sending you an email today.