Swollen pot metal venturi's

[Jeff/Illinois]

Fiddling with some Zenith carbs I picked up, two of them have pot metal venturi's that are swollen and seized in the carb castings upper and lower. They were 'apart' somebody had to break them to get the halves separated??

I used the old tried and true method of putting heat on one of them w/ a MAP torch, then quenching the assy. in a bucket of cold water. I was able to carefully pick at the venturi then back in the heat/bucket of water then pick away again.

I was being very careful trying not to booger up the thin casting in the lower half that the venturi sits on but I still broke a small piece off, about an inch long before I finally got it out. Not enough to ruin the carb but my question is, is there a better way to get these out w/o damaging anything? There's not much to get at them from the bottom side. Top half was a cinch. I tried to turn them to get them loose they were too tight in there.

Thanks.

[pgerhardt]

The venders sell a tool to pull out the venturi. It worked well for me.

[Mitch//pa]

here is a tool

[aermotor]

MAP is not hot enough, put the O2 and acetylene to it and the pot metal will drip out long before the cast metal is affected.

John

[Steve Wastler]

Made my own puller from a carriage bolt, a couple washers, a socket and a nut. About a minute a side, no damage and works great...

[Larry Jenkins]

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Just bust it out. Sometimes twisting it back and forth with a pair of water pump pliers works too after soaking it with Liquid Wrench.

Snyders makes a great, totally machined venturi.

Larry

[larrys40]

With the throttle shaft removed I use a 1 1/4" OD piece of galvanized pipe along with a 1 1/2" for removing the venturi in the top half which is usually the problem.
Remove the throttle shaft and insert the 1 1/4" on the intake end of the upper half and center the 1 1/2" piece so that the venturi half will go into it in the bench vise. Use it like a press and the venturi piece will come right out. Usually no heat, no fuss. Just presses out. I may take a photo and post later on of my method. I agree with vince.. that melting them out seems plagued with potential dangers. I would rather heat and quench if you want to do it that way.

Larry Shepard

[Tom Wesenberg]

When using heat on the venture be sure to wear a full face shield or you may get some splatter in the face. I have the best luck with heat and a cold water dip.

A Dremel with a grinding bur would also work to notch the side until it can be broken easily.

[Jeff/Illinois]

Thanks for the tips good ideas. Didn't realize they sold a tool to remove them I've never had one stuck before I guess! I was looking at Bert's web site and I see they sell a machined aluminum replacement. Looks like a good idea.I did have the fore sight of at least wearing safety glasses and still had a small bit 'pop' and land on my cheek!

Facial cheek not butt cheek!!

[29FordRoadster]

Jeff/Illinois, In his pamphlet "The Model A Ford Carburetors", Paul Molter suggests heating the carb in an oven at 350-400 degrees for thirty minutes then wrap the carb in paper and place in a freezer for an hour or two. I did this last week and the venturi just fell out. He also suggest loosening the body bolt a thread or so and tap the head of the bolt with a small hammer as it gives, loosen the bolt another couple of threads and tap again. This also worked well for me. Of course, you MUST have the permission of your wife to use her oven. Wayne

[Benson]

Hammering, chisels, drilling and hacksaws are a bad idea.

1. Hammering many times breaks off the "shelf" where the venturi sits.

2. Chisels gouge the inside of the bore of upper - lower castings and break off the "shelf" which is only an 1/8th inch thick.

3. Hacksaws many times create deep grooves in bore that cause massive vacuum leaks and sometimes air leaks around the throttle plate.

4. Drilling is same same problem as above

The safest way is to use the tool ... whether purchased or home made.

$17 v.s. the price of a good core is cheap!

Good cores are getting harder to find.

Avatar is Three Window Coupe with Crate Motor and low profile/Low Rider tires!!

[Bruce Lancaster]

I also made a puller for a B, very similar to process for A. I spent about half an hour at Home Depot in the plumbing and hardware sections, and ended up with a short pipe nipple as the body of the thing, a piece of threaded rod, and a stack of big washers. Only actual work I recall was grinding a divot in the top of the nipple to clear something. Worked fine, but was so clunky and ugly I bought the commercial one later on.
Decent puller allows the originals to be saved.

[Jeff/Illinois]

Originally Posted by 29FordRoadster

Jeff/Illinois, In his pamphlet "The Model A Ford Carburetors", Paul Molter suggests heating the carb in an oven at 350-400 degrees for thirty minutes then wrap the carb in paper and place in a freezer for an hour or two. I did this last week and the venturi just fell out. He also suggest loosening the body bolt a thread or so and tap the head of the bolt with a small hammer as it gives, loosen the bolt another couple of threads and tap again. This also worked well for me. Of course, you MUST have the permission of your wife to use her oven. Wayne

Wayne I dug around last nite and found that booklet, forgot I had it, and did read what you suggest. I think I'll avoid the oven trick or at the least, use my neighbors when they go away to visit their son who is stationed overseas in the USAF next month! They asked us to 'house sit' didn't say I couldn't stink up their kitchen and oven

Appreciate the responses I have filed them for future use. Next question see new thread!!