Engine Idles ruff
 

I finally got my 58 Buick Special Running and it idles ruff. When I rev it up it seems to run fine. I do have some sputtering out of the tail pipe. I need help on what to check. I had the Gas tank cleaned, new fuel pump, carb rebuilt, timming set and new plugs point and condenser. what should I check next. Desperate. Big D

Could be a vacuum leak, but how did you set the point gap and plug gap also ?
You might have a bad plug wire, dist cap maybe even a cracked plug.
If the idle mixture screws on the carb are not right, too rich or too lean it could give you a rough idle.

Hanky,

I set the spark (new ones) gap at .032 the manual called for .030 - .035, I replaced the cap, rotor and points and I set the timming and set the points though with a feeler gauge. I am going to get a dwell meter and set it to 30 degrees. I set the two idle screws by backing them out about two turns. I did check for vacuum leak on carb and intake did find some of the bolts loose and tighened them. The exhuast does sputter at low idle and leaves a black mark on the floor. The engine sat for 10 years so that might b eexpected. Any other ideas Hanky.

Thanks

BIG D

Hanky,

I did notice that the Thermostatic Coil on manifold is missing. Will that cause a problem?

The butterfly inside where the coil is missing was to divert exhaust heat under the intake section to help vaporize the fuel when the engine was cold.
If you haven't adjusted the idle mixture screws they are adjusted by doing one at a time and turning the screw in until the engine falters then out until the engine idle speed is affected and placing the setting in the mid point of the range . Do that with both screws.
You need to make sure the choke blade is fully open when warm. I don't remember if the choke coil was electrically heated or if they used a tube from the exhaust manifold to get heat up to the choke coil.
This sure takes one back a bit !

Hanky,

Do I need to have the thermostatic coil in the manifold? Or should I just make sure it is open and wire in that position. With out this will it make the car run ruff? Do you think I should change the plug wire just to be safe? What would make the exhaust sputter when idleing? Thoughts?

Big D

If the sputter is consistent and regular it may be a cylinder misfiring. In that case you could short out each spark plug one at a time and you will get a double misfire until you get to the bad cylinder . At that time you will notice no difference when shorting out that plug. All that will do is tell you which cylinder has the problem which could be a bad wire, plug or something related to that particular cylinder like a valve problem.
If you take one step at a time you will be able to pin it down. Did you adjust the idle mixture screws as suggested ?

Hanky,

I did adjsut the idle mixture screws and it did not seem to help to much. I did spray some carb cleaner and that helped alittle bit. How do I short out the plugs for each cylinder. I am planning on changing the plug wire since they are not real expensive. I already just replaced the plugs again because they were really carboned up. Probably since the car sat for about 10 years without running. I am planning on putting some sea foam in the oil what do you think about that? Should I make sure that the thermostatic valve in the exhaust manifold is open that then wire it that way since I cant find a new coil for it.

Thanks, Big D

If I may,
The best thing you can do for the oil is , change it with a new filter.
If the car sat for any extended period of time some dry gas in the fuel tank might do more good.
Spark plugs can tell you a lot. When you removed them for the second time and they were full of carbon , that tells you the engine is getting extra fuel.
Either the choke is not opening all the way or the idle mixture screws are open too far or the carburetor is allowing too much fuel in. If one of the plugs was more carboned up and possibly wet that is the misfiring cylinder and it could be the wire that is defective.
To short out a plug when the engine is running , use a good insulated screwdriver with a wire connected to a good ground and the other end connected to the shaft of the screwdriver. Place the screwdriver next to the sparkplug boot on the plug and the spark should go to the screwdriver instead of to the plug. You will be providing a shortcut to ground and the cylinder should not fire and produce any power.

Many cars in those days drove around with the thermostatic butterfly frozen closed due to rust , so don't be too concerned with that right now.

Hanky,

Thanks and yes all of the plugs were really carboned up.. I have the idle screws about 2 to 2/12 turns out. I will check the choke. We did rebuild the carb and it seems to be okay? When we move the cam to fast idle on the carb it seems to run pretty good. When it heats up and drops off the fast idle cam then the car eventually goes to a lower and lower idle until the engine dies. I did replace the old vacuum hoses that I could find and also replaced the ones on the wipers since it uses vacuum.

Thanks,

When you rebuilt the carb, did you replace the needle and seat for the float ? You should have, and of course then you would have had to adjust the float level according to the specs provided in the rebuild kit which were spelled out for each carb number. Did you do that critical step? If the float level is set too high, the engine will run rich and could possibly be the cause for the symptoms you are seeing. What engine do you have in the car? I'm trying to recall, the straight 8's had a thermostatic butterfly , but I don't recall if the V 8's had one.
They didn't have unleaded gas in those days and the needle for the float had neoprene rubber for the seating surface. Neoprene did not hold up to unleaded fuel so they had to switch to "Viton". What was the name of the manufacturer for the rebuild kit ?

Hanky,

I did replace the gaskets, accelerator pump and the needle and seat and set the float level. The carb kit came from Cars Inc. I have a 364 nailhead in my car.

Good Morning,
It appears you did everything right. Just have to find why it's running rich.

Hanky,

I have a new question. I pertains to windshield wipers on my 58 Buick Special. I am having a hard time to get them to work. I hooked all of the hoses up but it seems like something is missing. Do you know if there should be a vacuum line coming from down by the oil filter up to the wiper motor? According to the manual they make mention of it but I only could find a metal plug in the side of the crankcase and no line? Any drawings on how these wipers get hooked up from the wiper motor to the glass supply bottle etc.

Thanks

Big D Also my car with your advice is going better and thanks.

Many of those vehicles had what was called a double action fuel pump.
One half (the lower half) supplied fuel to the carb and the other (upper) half supplied constant vacuum for the wipers. This could be how the extra fuel is getting into the engine. If you look at the fuel pump and it looks like two sections then that's what you have.
The only thing I can recall that used a glass supply bottle was when someone added a so called water injector to the vacuum system to add moisture to the incoming air. I think it was more of a gimmik than of any real value.
Without the extra vacuum source from the upper fuel pump section when you stepped on the gas the throttle blades opened up an there wasn't enough vacuum to operate the wipers and they would stop working so they did that to fix the problem.

Interesting. I think the bottle is used for fluid for the windshield. Also I did replace the fuel pump but it is just a single action one that was supplied by the auto parts place as a replacement pump. I do believe the old pump was the style that you mentioned. Do you think I should try and get one that was like the orignial? What are your thoought on that or does it matterl

It depends on what you want. If it were me and I was able to get the kit to rebuild the old pump I would do that if an exact replacement isn't available otherwise if you drive it in any kind of rain you will definitely see the wipers stop when you step in the gas.
If you say the bottle is for the washers, you should know since you are there and I'm not ! I just can't remember if they used plastic or glass for that purpose. If you take a hose and run it from a manifold vacuum spot to the wipers they should work providing the wiper motor is functional. They worked better if you removed the top screws and made sure there was a supply of grease to seal the paddle that worked in the bowel. They weren't really that complicated compared to today's vehicles..

Hanky

I have a new question if you dont mind. I found that I have an exhaust manifold leak on the drivers side where the manifold connects to the cross over exhaust pipe. I saw exhaust puffing out. My question is does this connection have some type of gasket? I see it has to bolts holding them together and not sure if there is some type of gaskets between them.

Thanks,

They used an asbestos sealing ring to seal the connection. Many of today's vehicles still use a sealing ring referred to as a donut.

Do you know if you can still purchase the donut for these manifolds? If so from who?

Thanks

Your local auto supply store should be able to get one for you.
If not, try Googling , "Walker exhaust systems".

Hanky,

Dumb question which is the largest vavle on the 58 Buick Special Exhaust or Intake?

Big D

Hanky,

Thanks and yes all of the plugs were really carboned up.. I have the idle screws about 2 to 2/12 turns out. I will check the choke. We did rebuild the carb and it seems to be okay? When we move the cam to fast idle on the carb it seems to run pretty good. When it heats up and drops off the fast idle cam then the car eventually goes to a lower and lower idle until the engine dies. I did replace the old vacuum hoses that I could find and also replaced the ones on the wipers since it uses vacuum.

Thanks,

Big D,
No such thing as a dumb question, that's how we all learn !
The intake valve heads are larger than the exhaust valves.

mairraa,
the symptoms you describe all point to the engine flooding with excess fuel.
That 2 1/2 turns is only a starting point and they need to be adjusted to each individual engine. Did you do the adjustment procedure for the idle mixture screws I had mentioned earlier?