LewUnderCar

Great info...I appreciate the heads up for sure!! For once, thanks to you guys, I haven't taken something apart and created a disaster.

Thank you. I'll give that a try. Lew

My 1931 LaSalle 345 Steering wheel horn button lever is broken and wondering how to disassemble the unit and also if anyone knows of a source for replacement. Thanks for any info, Lew

After further inspection trying to find a "flap near where the 2 manifolds join and is/was controlled by a lever on the dash" I see only the item in the photos attached, which located toward the front of the left exhaust manifold. I found a drawing in the "Shop Manual" describing the heat/spring actuated valve. I bet it is stuck which would correlate to the high temp of the left hand side exhaust passage. All these weeks searching through manuals about the carburetor, I never thought about the exhaust manifold having a valve so far from the carb! I've been preaching "Never assume anything" for so long I forgot to take my own advice.

Thank you for that very helpful explanation...I checked the two tubes with an infrared thermometer tonight with the engine at idle and was surprised that one crossover tube was 450F and the other was 220F (the exhaust manifolds read 450F.) This is probably another dumb question, but am I correct in understanding that I will install my blocking "plates" at both sides where the tubes enter the exhaust manifolds? (like making a gasket with no hole in it for both flanges?) I can't wait to start twisting on those old corroded bolts...I imagine, if like every other thing it touch, this will indeed turn into a "big project" as you say. (maybe I can just fill in the tubes with JB Weld....ok just kidding. Maybe my wife's cornbread batter?)

Thanks again for the numerous ideas and suggestions regarding why my '31 V8 LaSalle will start, idle and rev, but within 10 minutes, at anything over 1/2 throttle (in nuetral or driving down the road) she stumbles (seems like runs out of gas) and dies. Then she won't start for at least 10 minutes (cool down). I am sure Ed is right...I likely have multiple issues. After checking / eliminating several items suggested, including replacing the coil, I'm beginning to think the primary problem is heat related. (Viv made some very interesting comments on the subject previously) Does anyone have a suggestion as to how to eliminate (disconnect) the heat exchanger tying the Johnson to the exhaust manifolds? My fan belt is pretty lose to, hard to watch from inside the car...maybe that's aggravating things. I wonder if I can get any clues by using an infrared thermometer...I'm now realizing my temp gauge does not work. Any rebuilders out there? Thanks so much for any help, I'm amazed at the generosity of time & knowledge. Lew

Thank you very much...greatly appreciated information & guidance. I checked the compression today and all cylinders are in the 100-110 range. I keep looking for the "Auxiliary Air Valve" lever described in several tune up documents I have for the Cadillac LaSalle 1931 carbs...I do not see it...maybe mine was replaced with some other year? My Block number (in the 800,000's) seems to indicate it is a very early 1931 engine, which makes it odd when I try to determine what instructions to follow in my "National Service Manual", that says 1931 cars start with block numbers 900,000. Still trying to figure out why my old timing light won't fire despite being powered by a separate 12V bat. and not sure if I know what to do if it does decide to fire. (I've read that old dudes like me should challenge our brains in an attempt to keep the cerebral juices flowing. Me trying to wrap my pea brain around 6V positive ground electrical circuits is more than challenging for me).

Thank you for the feedback...I'll check exhaust as well as compression.

I have been very interested in all the great information posted about Cadillac-Johnson carbs. I have a 1931 Lasalle V8 Sport Coupe that unfortunately has never been able to leave my neighborhood under her own power, and my wife is quite "over" coming to tow me home. I try to start the LaSalle every couple of months, and when I do it starts right up, idles well and revs while in neutral. Every time I try to take her for a spin it seems she tops out at about 10 mph (won't accelerate beyond that) then in a block or so starts to miss, backfires through the carburetor and dies. She won't start again until cooled down. The previous owner removed the vacuum tank and installed an electric fuel pump & pressure regulator. He had the carb rebuilt and the receipt shows numerous new parts plus being engine tested for performance. The stock exhaust manifold to carb heating tubes are still in place. Maybe there is too much heat for modern fuel? The car has been sitting and I also wonder if old fuel residue could cause such a dramatic lack of performance like I'm experiencing, or if it is something more serious. One time (has not happened again) after a backfire through carb & die episode, fuel continued to pour out from the bottom of the carb until I shut off the fuel pump (I will heed the advice of Ed and others on steps to prevent disaster!) I assumed it was a stuck float, and after tapping the carb the problem went away. Maybe this was unrelated to my primary problem? Maybe I just need a bigger hammer? The backfiring through the carb also makes me wonder if I have a timing issue. Any help or ideas would be greatly appreciated. I love the car but would love it more if I could drive it more than a block.