Hello, I come here seeking help. This might be long, but I want to thoroughly explain what I have already done, to avoid rehashing the same things (as I have done myself for weeks now).
I have a 64 Deville that I received in non running condition. Old fuel had seized up some valves, and just about everything had to be taken apart, cleaned, and put back together.
The car only has 25,000 miles. Well, 25,300 as of today.
I've had a really tough time getting it to run properly. I had the heads cleaned up, a valve job performed, and hardened exhaust valve seats installed.
Compression is excellent and uniform across all cylinders, around 190.
I rebuilt the carburetor.
I disassembled and cleaned the fuel pump.
The fuel tank and sending unit have been replaced.
Obvious tuneup parts have been replaced with new.
First problem was that I was unable to get the idle down to 480RPMs in drive. All vacuum lines were disconnected and capped to perform testing. At first, I did have a leaking intake manifold gasket, I corrected that. There are NO vacuum leaks.
After that, I was able to get the idle down, but it didn't run particularly well. I adjusted the timing and dwell. The car falls all over itself when trying to accelerate, and stalls most times. No power.
I went and bought an Edelbrock 1411 750CFM carburetor, as I suspected trouble (and doubted my rebuild) on the original Rochester. I was able to get the car to kind of run with this carb, but only at idle. Before I installed it, I removed the intake manifold, drilled, tapped, and installed brass plugs into the exhaust ports beneath the carburetor so that I could run any carburetor. That's just a nasty idea anyway, but I digress.
I warmed the engine, and adjusted the mixture needles on the Edelbrock to get it dialed in, and began working toward lowering the idle to the specified 480 RPMs. It doesn't really run well down that low.
I managed to get to run long enough with the vacuum advance unhooked to get the timing set to 5 degrees BTDC, and set the dwell at 30 degrees as specified in the manual.
Back the car out of the garage- ok.. try to go, and it quits. Very frustrating.
So this morning, I thought, maybe the fuel pump isn't doing toowell. I don't have a gauge that goes low enough, so I just went and bought a cheesy electric fuel pump and some fresh hose, and hooked that up.
Fire it up, idles fine, kick down the idle when it warms up, fine, no problem. Try to go- and it quits.
So finally, I decided to start advancing the timing. Maybe this is the issue?
Now we're getting somewhere. It's now at least driveable. But something is just not right. It misses and spits and sputters under load, you have to feather the gas pedal to drive it. Once you're at speed, you can ease into it and drive it to 80MPH effortlessly... the engine is clearly good and strong. No noises, nothing- except random misfires and popping... not good at all :-(.
The advance mechanisms seem to be working. With the timing light, quickly 'blipping' the throttle causes the timing to retard as you'd expect with reduced vacuum to the vacuum advance.
Steadily increasing the speed of the engine results in the overall timing increasing.
As far as I know, all is correct here...
So what am I missing here? Why won't it run right, and why on earth should I have to advance the timing so much- that can't be right, nor can it be good for it long term.
I really want to drive this thing, hopefully someone can offer me some advice.
It is an honest to goodness 25,000 original miles. As stated, I'm friends with the original owner, and have known the history of the car. It has its original paint in nearly perfect condition. I can't wait to actually enjoy driving it!
I'm going to mess with the timing some more, trying some of the things I have learned here.
The crank pulley only fits one way, I was pretty sure, but a previous response solidified that for me.
The carburetor gaskets were a bit of an obstacle, but are no longer since I have blocked the exhaust ports beneath the carburetor. At first it was behaving just like a car with a stuck-open EGR valve- and no wonder!
It can run essentially any carburetor now, since there are no exhaust fumes that will be introduced into the intake manifold via leaks, or otherwise.
My goal is to get it running with all original parts, including the original carburetor, although I'm not above installing the highly regarded pertronix system. I have a 1973 Mercedes that is soon to see that upgrade, as well.
Thanks again, everyone,for your responses- I'll keep updating.
Ok. It's on the ported vacuum port.
I said to hell with the book, and just kept advancing the timing until it stopped backfiring, and then more until it started pinging.
I backed it off a little bit, and now it runs perfectly well.
Thanks to everyone for your help, I'll be back with more discussions relating to other parts of the car... but for now I have to go drive around!
Well, I'm not at 100% with the car, but I would say at 80%. It's driveable. Enough so that I put 87 miles on it today, and enjoyed it very much.
Advancing the timing beyond the point where it COMPLETELY stops misfiring results in severe detonation under load. I live in mountainous terrain, so this is not an option.
So I retarded the timing to the point where the detonation is minimal, and some of the misfires are back. There doesn't seem to be any happy medium.
On the ported vacuum, you can FEEL it come on. It's not ideal, the car is a little jerky with this Edelbrock. When you step on the gas gently, it starts to roll, and then the vacuum advance comes FULL on and there is this MASSIVE boost of power. I wish it was a little bit smoother.
It's definitely jerky and a little rough off the line. It's like it needs more timing off the line, and less timing at higher RPMs.
The engine seems most at home accelerating through the middle speeds- in high gear, it'll pick up speed effortlessly and smoothly... I was actually shocked at how much power and how quick this car is at speed- and how quickly it accelerates. It's impressive for such a large machine.
Also, with no advance at idle, it really kind of idles lousy.... It's tolerable, but I might just have to bump up the idle speed and play with the mixture a little bit to smooth that out. Maybe that'll help with the off idle jerkiness too.