The Stovebolt Site Forums The Shop Area Engine Shop 216 Carb Isolator

Hello everyone,
Had some problems with my truck ('38 half ton) not idling, so I bought a carburetor rebuild kit and jumped right in. Now I'm ready to reinstall the carburetor (Carter W-1), and found that the new Isolator that I bought doesn't quite match the old one in size. The ID of the new one is about 1/8th inch smaller in diameter, and it's also a little thicker.

The extra thickness is preventing me from getting the oil filter bracket on over the bottom flange of the carb. I figure I can probably sand the isolator down a little if I'm careful enough to keep it flat.

For the smaller ID, I'm concerned it will act as a restrictor. I'm not sure how best to make the ID larger without really hacking it up. I don't have any fancy machinery, so the best I could do would be something like a drum sander, and just sand around the ID to open it up. Any other suggestions?

Also, the old one had a cone in the center that went down into the intake manifold. I supposed it acted like a venturi and maybe helped with the airflow through the carb. The new isolator doesn't have this. I'm not sure I can install it in the new one, since it was kind of a press fit in the old one. How important is that thing?

Thanks.

Is the old isolator too bad to re-use? If not, put the old one back on. You could have a local machine shop alter the new one to match the old one and install the cone - but it would be a little pricey depending on their labor rate. Good luck with your project!

Thanks. I'm afraid I mangled the old one when I was taking it off. There was quite a bit of crud around the base of the carb and top of the manifold, and I wanted to clean it off. Should've been more careful taking the old isolator off. It would have been worth the effort.

You will be fine using the new one without the smaller center cone. That acted as a governor and was used on the Bigger Trucks. I think if you use a belt sander to thin down the one you have you should be fine. Don

Thanks Don. I sanded about a tenth of an inch off of it, and put a thin gasket on each side of it before I put the carb back on. I installed a glass bowl filter ahead of the carburetor, and after a few tries, fired it up. It ran well, but I didn't take it out on the road. It was around 50 here today, but there's a lot of water, sand, and salt on the roads, so it'll be a while before I take it for a spin.

In the mean time, I hope to get the air cleaner painted.

Already noticed some sediment in the filter. Will need to pull the tank and get it cleaned out before too long.

Thanks again.

you stand a good chance of needing to get a new tank, I fought mine for a year. It cost less to buy a new one than it did to boil out my old one, but mine was a 53, I don't know about 38. This is a fairly common problem