What I did today.

[VFRhugh]

Replaced the Tillotson with a Marvel-Schebler. What a difference!! The idle is smooth and slow. No tach so I don't know what it is now but very low RPM. Also no stalling at hard stops. Off idle throttle response is smoother than my old Tilly. Starts faster also. The GAV likes 1-1/2 turns out.

While I was at it I installed a hinge mount outside rear view mirror. Like everything else I've done it was a bigger job than you'd expect. After a little hammering it was obvious the old pin had worn a ridge that I couldn't overcome with brut force. Had to remove the door to drill each end enough the separate the hinge. Drilled out the remaining old pin using my drill press.

I'm learning more about these old cars than I'd planned after ten months of ownership. Good fun though.
😎

[DougVieyra]

VFRhugh : " . . . no stalling at hard stops."
________________

So, was this an issue with your Tillotson? I have heard of it being a characteristic of ZENITH carbs. but not of the Tillotson carb.

[VFRhugh]

Since this is all pretty new to me I don't know how a Tilly in good shape is on sudden stops. Mine was terrible. It could have been the float level but I didn't have any way to check it. Also I didn't want to start a rebuild with out a back up. I bought the Marvel on impulse. Fortunately it turned out good for me.
Hugh

[VFRhugh]

I noticed an app on my new iPhone called iMovies. Here's a little video showing the Tillotson that came with the car and running with the Marvel-Schebler installed. No more stalling or backfiring.
More than a little weird hearing my voice😳
Enjoy,
Hugh

http://youtu.be/yQrXaDK4BRA

[Marshall V. Daut]

Take a metal straight edge (not a wooden ruler or yardstick) and lay it across the top flange of the Tillotson now hanging on your garage wall. Make sure no gasket material is remaining. Use a thick feeler gauge and run it between the straight edge and the flange. You will probably find a big gap around the butterfly valve opening in the carb's flange, but nothing at the ends. In other words, the flange is drooping in the middle of the "saddle". This is very typical of the pot metal Tillotsons. They warp here, which allows unwanted volumes of air to enter. That affects the idle and in extreme cases of warpage, increases the likelihood of stalling because the engine's back pressure upon de-acceleration sucks in large amounts of air through this gap. That upsets the air-to-fuel ratio = stalling. No amount of fiddling with the float level will counter this inherent problem with pot metal Tillotsons.
Check out this suggestion and let us know what you find. 'Betcha a nickel the Tilly's flange is warped = the "smoking gun".
Marshall

[VFRhugh]

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I plan on attempting a rebuild on my Tilly but it's poor condition and what looks like a cut off bolt for a drain plug drove my decision to purchase the Marvel-Schebler. I've studied mrtexas Tillotson web page and realize there's more to it than meets the eye. Thanks for the tip.
Hugh

[MikeK]

That unsupported copper fuel line in your video is trouble. It will work harden from vibration and crack, possibly gushing fuel all over the hot exhaust manifold. Use a steel line.

[VFRhugh]

I've become aware of copper becoming "work hardened" only recently. The car had a beat up copper line on it when I bought it last spring. I didn't know any better and tried to make it look straight with another length of copper. It will be replaced next. I've got too much sweat equity, not to mention money, to watch my A go up in a ball of flame.
Warning appreciated,
Hugh

[CarlG]

Easiest place to get steel lines is at your favorite local auto supply store. Just ask to see their assortment of hydraulic brake lines. All sorts of pre-cut lengths to be had.

[bobpo1]

If your GAV likes 1 to 1-1/2 open, it sounds like your GAV seat made need replacing or am I missing something? Normally 1/4 open should suffice. But this applies to a Zenith. Maybe yours' is different. I'm not familiar with the Marvel-Schebler. Just a thought.

[Marshall V. Daut]

"Easiest place to get steel lines is at your favorite local auto supply store. Just ask to see their assortment of hydraulic brake lines. All sorts of pre-cut lengths to be had."

A poor man's way to bend a steel line without the proper expensive bending tool or without putting a crimp into it is to plug one end of the line, fill it with fine grit sand, and then plug the other end. Then you can safely bend the angle you need without damaging the line. The sand will keep the metal sidewalls from collapsing during the bending process. Once the correct bends have been achieved, remove the plugs, thoroughly blow out the sand with compressed air, and then run some gas through the line, followed by more compressed air. That should take care of any residual grains of
sand left inside the steel line.
I have been successful at times bending a steel line without this procedure - but I have also ruined lines by putting in unfixable crimps. Obviously using a crimping tool would be best if you have one or can borrow one.
Marshall

[CarlG]

Being the toolaholic that I am, I have a set of these for several sizes of tubing.

Now if I could only figure out how to do it right the first time, I wouldn't have to buy so much extra tube.

[Jim M]

Wow - I religiously read the posts every day and save the ones I think I might need to review later on. This one will go in my save bucket. My 29 Roadster is a work in progress but this last summer I tried driving it every day weather permitting (haven't done the top yet). I had noticed that every time I came to a stop sign the engine would slow way down and seem like it was going to stall although it came close but never did. It was one of those things that I put on the back burner hoping that more driving (had sat for about 25 years before I got it) would clear it up. I now have some research to do this spring when the weather gets good enough to drive. Thanks so much for the info!!!

[Marshall V. Daut]

"Jim M" -
If you have a Zenith carb, my posting about a warped flange will not apply to you. If a Zenith stalls upon sudden braking, then the problem probably does lie with the float, or in clogged passageways, both repairable conditions. My comments were only about the pot metal, warp-prone Tillotson replacement carburetor that so many guys are running.
Marshall

[VFRhugh]

Carl , I went to the dark side and installed hydraulic brakes early in the ownership experience. I purchased a tubing bender for that job. Still have a few lengths left over, maybe I'll get lucky and have one long enough.

Jim, My car is a lot easier to drive in traffic with a reliable idle. I now fear no quick traffic signals

Hugh

[duke36]

My Marvel GAV likes to be open 1/4 to 1/2 when warmed up with a new needle, and you may want to check the GAV needle and washer above the seat. Perhaps someone else will also provide info.

[w.michael]

Originally Posted by Marshall V. Daut

"Easiest place to get steel lines is at your favorite local auto supply store. Just ask to see their assortment of hydraulic brake lines. All sorts of pre-cut lengths to be had."

A poor man's way to bend a steel line without the proper expensive bending tool or without putting a crimp into it is to plug one end of the line, fill it with fine grit sand, and then plug the other end. Then you can safely bend the angle you need without damaging the line. The sand will keep the metal sidewalls from collapsing during the bending process. Once the correct bends have been achieved, remove the plugs, thoroughly blow out the sand with compressed air, and then run some gas through the line, followed by more compressed air. That should take care of any residual grains of
sand left inside the steel line.
I have been successful at times bending a steel line without this procedure - but I have also ruined lines by putting in unfixable crimps. Obviously using a crimping tool would be best if you have one or can borrow one.
Marshall

This method also works for bending copper tubing to make a worm for a liquor still--so I've heard. Wet sand.

W. Michael

[pgerhardt]

My 29 tudor runs wonderfully with its marvel carb. It ran ok on the Zenith, but suffered from stop-stalling.