peeeot

Be proactive! Take two potatos and put them in your exhaust pipes. DO NOT rev the engine. OBSERVE. Pete

As Old Car Mark observed, the mufflers are made to fit one way... why would you install the mufflers backwords ?!!

Paul

I'll look into this. It seems unlikely that they are starving the engine with backpressure because I have hit it pretty hard at highway speeds (pulling past 4k rpm) with plenty of power and responsiveness in the past; however, I can imagine that perhaps being backward is raising the temperature in the manifold crossover and, by extension, the carburetor. Evidence suggests that the difference between trouble and no trouble MIGHT be 20*F or less.

I think whoever put them on backward did so because of the inlet/outlet configuration. They should've used a different muffler, obviously.

1954 Crestline Victoria 312 4-bbl, 3-speed overdrive

Also, this is an interesting read.

http://www.thecarburetorshop.com/Ethanoluse.htm

1954 Crestline Victoria 312 4-bbl, 3-speed overdrive

Another thought comes to mind, since this seems to be heat related. Have you checked all the vacuum hoses and diaphragms for cracks. Occasionally I've seen instances where they only leak while hot, or leak MORE when hot. If the engine is borderline lean it could be just enough to create the misfire. Re-set the carb float to the factory setting, The rich at idle condition should be cured with other methods and a low float setting will affect the mixture setting everywhere in the rpm range. You risk burning a piston or valve if you let it continue as is.

Frank/Rebop

Bristol, In ( by Elkhart) 

I have some updates after a brief break from this trouble.

First, about float setting: I had been setting the level at the end of the float just past the rounded corner, measuring from the raised seam around the circumference of the float. The manual says "top center" and my Carter info sheet says "top center at end of float." The last thing I did before today was to set the float to spec at the top center center of the float instead of the end. This lowered the level by a small amount, about 1/64". At the time I didn't notice any difference so I parked the car and walked away.

Today I made no adjustments but drove the car around the neighborhood to warm it up with plans to check valve adjustment hot and also to try to rule out exhaust crossover leakage inside the intake. It was still idling ok after my loop, just a bit slow, so I turned the speed up a bit and went for another loop. At this point everything was good and hot, but it was still idling in gear ok. After that loop I pulled into the driveway fully expecting a stall but it didn't. It was running in gear with no missing, but it was surging irregularly between 450-550 rpm. The only thing I changed since last week was slightly lowering the float, but I think the ambient temp is a bit cooler today too, so there's that.

Anyway, I tried to get rid of the surging by playing with the mixture and idle speed while idling in gear, hot (how nice to be able to do that for once!). What I found was that it was best if I completely closed one mixture screw and had the other out about .25 turns. If I completely closed both it would die. With the screws set that way, however, even in neutral the car would start and die immediately like old times. If I opened up the screws again, it would start and run, but was obviously too rich. The plugs are now consistently black and fluffy looking.

It is acting like the idle bleeds are clogged but they aren't. The throttle plates have to be open fairly far to admit enough air to make power for idling in gear, but the engine speed in gear is too low to effectively draw fuel from the transfer slots so the idle isn't stable. The mixture screws have to be cracked open to assist fuel delivery at that speed or it will stall, but they seem to emit only raw fuel without air premix so they can't be open very far at all OR they will cause a stall from over-richness. It is a delicate balance which, if set just right, lets the car run in gear, but not smoothly like it should. I cannot achieve adequate engine speed or power by closing the throttle plates and opening the mixture screws (which is to say, opening the mixture screws beyond .5 turns never results in an increase in engine speed).

The problem of intermittent missing under moderate to heavy throttle acceleration also has proven to be consistent. I'm pretty sure these problems are related. I have tried dropping the floats an additional 1/64" to the bottom of the spec range, but no change is evident at this point. Timing is still set at 10-12*, and reducing that number slows the engine while raising it increases engine speed. It shouldn't be this hard to set things straight.

1954 Crestline Victoria 312 4-bbl, 3-speed overdrive

PEEOOT, enjoy reading your journey on this, glad its not me, but if it were after what you describe, i would dismantle carb and blow out all passages etc, reset float level, restart car and reset idle mixture screws noteing any difference to before, then reset timing after establishing timing marks are correct then start from there, just what i am thinking and would do, hope this may help. bill.

  AussieBill            YYYY    Forever Y Block     YYYY

 Down Under, Australia

Two things, but first are you using quality points and not something like Blue Streak? Second did you check the point angle adjustment? This can be found in the FORD Factory maintaince manual. Also, have you checked to see that there are no wires broken inside the insulation? This is done with an OHM meter, and one culprit that I have personally had drive me nuts until I found it was the breaker plate ground wire that was seperated inside the insulation. The point angle adjustment is something that most people never think of.

312T85Bird

What?

Hi, sorry ive been off the site for a while. To your question of me, when I took apart my carb, I didn't really find any damning evidence for dirt in the fuel/carb. A tiny bit of weird grit in the bottom of the float bowls, but nothing that was like "oh wow, there it is!". But putting on a new carb (Eddy 500) made all the difference.

One other question, you mentioned early on that you didn't know how long the car was sitting when you purchased it (correct?) I would be suspicious of the quality of the gas in the tank as well; have you filled the tank since then? Flushed anything? Replaced the flex hoses, etc? Sometimes bad gas can cause goofy behavior also. Just a thought.

It seems to me like you are on the right track looking at fuel/fuel delivery.

Was hoping you were closer to IL; I would have loaned you a known working carb ...I have an eddy 500 and a holley 570 avenger sitting around that ran fine on my car.

Ron Grove

Wauconda, IL

peeeot,

Does your car have power brakes? Have your blocked off the vacuum hose to the brake booster? I've had boosters give me problems in the past.

JJ