I could really use some help.

My 1964 Model 62 is running poorly.  The car is 100% stock and has 47,000 miles on it.  I put the car away two weeks ago and it was running fine.  I started it up yesterday and it was a different story.  It seems to run fine at highway speeds but when I pull up to a stop sign it feels like it is running on 7 cylinders.  It doesn't stall but comes close.  Trying to figure out what could have happened in two weeks time !

Yesterday I did the following:

  • Changed out plugs, wires (put in 7mm wires) and cap.  Made no difference.  Plugs were burning hot and white.
  • Bypassed fuel tank and ran the car on an external tank for a few minutes.  Made no difference.
  • Looked for a leak in vacuum hoses using both carb cleaner and propane. 
  • Checked vacuum at it is holding steady at 15 pounds at idle.
  • Checked timing.  All good.
  • Cleaned points.

I borrowed a dwell meter and I'm going to install a new set of points.  At this point I am just throwing parts at the car.  My Dad would not approve.

Any suggestions?  Maybe a carburetor issue ?

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With the engine at operating temp, do a compression test to see what you have to work with.

Any mechanic who is even half good at his job, will perform a compression test first.

If the compression is good, then set up the ignition system side of things, then go to the carb and set the idle mixtures after that, if the problem persists, remove the carb and overhaul/clean it. 

I checked compression tonight.  Ranged from 166 to 179.  That sounds good to me.  You agree ?

Plugs are white, you are running lean. Possible clogged carb idle circuit or just lean. If it were your fuel filter, you would run out of gas above idle. 

Compression test was good.  166 -179 depending on cylinder.  Wires were good.  Getting spark to all cylinders.  Changed fuel filter.  Still running poorly.

Next move is to install new points.

I haven't changed points and set timing on an engine in 40 years.  Can anyone point me in the right direction ?  I also have a dwell meter.  Really appreciate your advice.  I live in suburban NJ and unfortunately there are no more knowledgeable guys in my neighborhood then me ! (that's sad).

One more note:

I was driving it today and noticed that when driving around town it was stumbling but when I got out on highway and out my foot in it the car really ran fine.  I keep thinking it's a carb issue.

How is the accelerator pump? With the air cleaner lid off the car, look down the carb and give the throttle a stroke. You should see a stream of raw gasoline squirt into the front two throttle bores. It sounds like the stumbling could be the car going lean as you open the throttle and there is no compensating fuel squirt to get the rpm up. Check that.

I believe the factory says 30 degrees for the dwell angle. If you have a timing light with dwell built in, set the dwell then the timing. If your timing light is a digital unit, you can dial the advance you want into the light as follows. Loosen the distributor clamping/hold down nut until you can rotate the distributor with some resistance. Find your timing mark on the harmonic damper and highlight it in white if you can. Mark the zero position on the degree pointer tab or damper. Not sure where it is on a 63. Disconnect the vacuum advance hose from the distributor dash pot and block off the hose. Connect the light with the inductor on the left front cylinder, number 1. Connect the light to power and start the engine. If you are running regular grade gasoline, set the advance on the light to 8 - 10 degrees and point it at the degree pointer tab. Rotate the distributor very slightly one way or the other to bring the mark on the damper to zero on the tab. If you are running premium fuel try 10 -12 degrees. Lock down the distributor and check your dwell again. You adjust the dwell through the little widow on the distributor cap with I think, a 1/8" allen key. If your light isn't digital then you will want to line up the advance number you want on the tab and damper instead of zero. You can check if the vacuum advance is working by plugging the hose back in and checking your timing mark again. It should be way in advance of any markings available on the damper or indicator tab.

Ignition timing and fuel octane go hand in hand. A lot of folks think that high octane fuel is more volatile than regular grade gasoline but the opposite is true. It has additives in it that slow the burn rate down giving it a chance to release energy over a longer period of burn. Think of diesel engines that burn even less volatile fuel, they have great torque and ignite their fuel really early with very high compression, not spark plugs. 

With high octane fuel burning slower, you can start to ignite it sooner hence the more advanced ignition settings. The reason the fuel is lit off early is so that the peak amount of combustion pressure is obtained just as the piston reaches top dead centre. If you light it off too late you lose peak pressure and a good portion of the fuel ignited is wasted. All the good of the longer burn is lost as it happens after peak pressure. The right mixture is important too. A lean mixture actually takes longer to burn completely than a moderately rich one. Think of the fuel molecules as basket balls on a gym floor. The optimum ratio has all of the basket balls spaced 14.7 units apart. With the space being air to give the right fuel air ratio. When the fuel lights off the flame front travels very quickly. If there are fewer basket balls, the flame created by each one has to fully burn before it can spread to the next basket ball. Pack them in too close and the opposite is true, they are lighting each other off before they get to their peak burn temperatures. 

So with a lean mixture, you can have more ignition advance but you are giving away power which in turn actually wastes the fuels efficiency. If you are running too rich you will have to dial back the timing which is also a waste of fuel and power. So the timing isn't a fixed number, it is based on what your engine needs given it's fuel delivery system, it's quality of spark and very importantly, altitude above sea level. Most carbs come jetted for sea level to 1,000 feet or so. Folks living in higher altitudes will have to reduce jet size to compensate for the thinner air, unfortunately, giving away some power. I'm at 3,500 feet ASL. Bummer.

Today's fuel is actually a lot better than what was available when our cars were new and in my view, the factory numbers are a guide line and not fact. There is a lot to tuning an engine and with all of the varying differences in each one of our cars, there is no one tune that is exact for all of them. They are all individuals and need to be tuned to their condition and location as in altitude. Just my humble opinion. If you got this far, hopefully I didn't bore you to death!

 A couple more things, I should mention that too much advance is really bad and can damage the engine but I think everyone is aware of that, I just want to state it. 

Another often miss understood thing is vacuum advance. First up, the vacuum advance pot is calibrated to the specific car and option package that goes with it, they are not freely interchangeable. For example, two Chevelles, same year with 350 ci engines, one has a two barrel carb and a turbo hydro 350 trans, the other an LT1 cam, higher compression ratio, four barrel and a 4 speed. These cars will have different advance pots. Fortunately our cars only have the one part number because there are hundreds for GM alone.

The vacuum advance is designed to allow the engine to run a significant amount of advance in low throttle high vacuum situations like idle and highway cruising. Under these conditions the engine needs a lot of advance because it running at a much leaner fuel ratio and in order to use that fuel properly, needs longer to light it off so that peak pressure arrives at the right time in the pistons stroke. When you put the engine under load and need to open the throttle the manifold pressure increases meaning there is a drop in available vacuum. The drop in vacuum allows the spring in the dash pot to overcome the weaker vacuum signal and pull timing out of the ignition system which allows the denser charge of fuel to light when it should and not cause the engine to ping. So, a freely moving, properly working dash pot is an often over looked but critical component. 

Lastly, the stock mechanical advance springs are too stiff for today's better quality gasoline in my opinion. This is another waste of fuel because as rpm goes up the stiff springs prevent the mechanical advance from adding timing to compensate for the faster engine cycle. That means a lot of the fuel is burning after peak pressure. The factory springs are a serious "err on the side of caution" affair. 

Well, we've probably got Robert's head spinning by now so I better quit with the monologue!  

Sitting at my bench with a cold beer. Can I get an Amen !! 

Just got down changing the points, using a dwell meter and setting the timing.  A real education.  Didn't really make much of a difference.  Idled better but when I put it in reverse or drive it would start running rough.  Just about gave up for the night when I remembered I had new fuel filters on my bench.  The old ones did not look bad but the glass bowl didn't seem to be full when running.  Changed both of them out and all seems well.  Rainy night here but ran it up the street and back.  No issues.   Timing set at 5 degrees now.  Going to push that to 8 degrees in the morning just to check how performance is.

Want to ensure all that are reading that I do perform maintenance on the car.  I'm taking good care of this car for the next guy.  Thanks for all the advice.  You guys are a great resource.  I used to be able to call dad but he is long gone.

 

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Sounds like that beer is well earned! Is that PH 16 filter going in an Alpine?

Thanks.  Yes the PH 16 is for the my 1962 Alpine.  You are a real detective to notice that.  My dad was a mechanic.  When I was 13 I started hanging out with the wrong crowd.  Dad figured if he got me involved in cars it would get me away from the "bad influence".  We bought a rusty Alpine for $400 in 1978.  His plan didn't work (I still hung out with the troublemakers) but I did learn about cars.  I took that car to my senior prom.  Still have it today.

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Nice. My first car was a '62 Alpine a year later I got a '65 Tiger. I still have it today and am in the process of restoring it. I'll never get rid of that car.

I didn't even know there was an additional filter in the Carter.  I cleaned it.  Thank you.  I'll check the plugs again in a few weekends and let you know about rejetting the Carter.  I don't mind messing with the carb. 

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