1966 Ford 200 idling problems.

[Anonymous]

Hi Everyone--I am new to the board and was reccomended here by the Stang.net guys. I am having trouble with a Ford 200 in a 1966 mustang

I just finished putting a long block in car. It fired right up and I was able to set the Dwell and Ignition timing and the idle mixture on the carb. However, the car idles extremely rough below 1000 rpm (my chiltons book says i should set the idle at 575 rpm and I cant get it below 800 without it stalling).

When driving and I come to a Stop--the car vibrates from the roughness A Tach shows that it also varys idle speed from 900 to 1100 rpm. The roughness smoothes out above 1000 rpm. The car accelerates and runs smoothly on the road. I have also put a vaccum guage ont the intake and it reads 14 lbs at idle.

I have the following new items on the car; fuel pump, (rebuilt carb), points/condensor, coil, spark plug wires,

I have checked for a vacuum leak by spraying carb cleaner all over and physically looking for a leak but cannot seem to get any response. Any thoughts as to what i should try next? Any help would be greatly appreciated. Thanks! --John

 

[CZLN6]

Howdy John:

And welcome. You will need to recheck all prelininary settings of the Carb, The distributor, initial advance verifying that TDC is really TDC. Verify that the Spark Control Valve in the carb is sending the correct vacuum signal to the distributor and that the vacuum diaphram on the distributor is functioning.

If the carb was rebuilt by a rebuilder (Someone other then yourself) be suspicious. Rebuilts are seldom clean, accurately assembled or adjusted.

There are some ideas to get you started. Good luck.

Adios, David

 

[Anonymous]

what do you have the initial timing set at? also I would play around with the idle mixture, remember you need to adjust the idle mixture when you change the idle speed, it took me a long time to get mine set well.

 

[Anonymous]

You can find some older posts that talk about the harmonic balancer getting old and the outer ring slips. The index ring timing mark when lined up with the pointer should place the #1 cylinder at TDC. If the ring has slipped the engine will not be at TDC and your spark timing will be off. This is what David is referring to when he mentioned checking TDC on the engine. The other common problem is the vacuum advance cannister on the distributor gets old and will not hold a vacuum. Disconnect the vac line and plug it at its source. Then suck on the vac line to the distributor and see if it holds vacuum. With the engine running, if you suck on the vac line, you should see the engine idle increase and the timing should advance if it is working properly.
Doug

 

[Anonymous]

Thanks for the advice guys--Here is an update as of last night.

Timing is right on 12 degrees BTDC--correct according to Chiltons--Dwell is 40 (again right on per Chiltons)
I have confirmed the vacuum advance on the distb is correct and operational
I have fiddled with carburator adjustments and they don't seem to make any difference.
I double checked the harmonic balancer and I don't think it is slipping. The TDC still is accurate.

Here is what I learned.
I originally thought that the roughness was at idle only; but after listening to it run for 1/2 hour I now know that is is inconsistant. Sometimes the idle smoothes out for a minute--then goes back to being rough in an instant. At higher speeds the roughness is tougher to detect but it is still there and cuts in and out. (eg. If the idle is smooth and you accelerate the higher speed is smooth as well and vice versa) I checked the plug wires by pulling one off at a time and they all cause the engine to pull down. I also checked compression (just out of curiousity) they are all from 165 to 175.

Does this sound more like elctrical? Could I have a wire somewhere in the electric system that is grounding? Whats a good way to trace something like that? Any other thoughts?-- About the only thing I haven't replaced on this thing is the distributor itself. This thing is driving me nuts! Thanks again

 

[Anonymous]

Just curious, how did you check TDC? Did you pull a plug and use a piston stop to see if piston was at top of its stroke? Or did you pull the valve covers to check valve positions to ensure that the #1 cylinder was on the compression stroke?

The balancer may not be your problem anyway. Do you have the stock Loadamatic type distributor and a carburetor with the Spark control valve?

 

[Anonymous]

Yes, I pulled the valve cover and used the valve position to determine TDC accuracy.

I believe the distributor is the original with vaccum advance. The carb is a single barrel with a vaccum port that runs to the dist.

 

[JackFish]

I just finished putting a long block in car.

What's the story on the engine, where did you get it, and did you break it in?

 

[Anonymous]

I had the original car engine block and head rebuilt by Midwest Engine--a local guy in wichita, ks who came highly reccommended. The engine has new everything except cam/crank and block. The engine had obviously been rebuilt several times because it had 40 overs pistons in it and Midwest had to go to 60 overs to clean up the cylinders.

I have been taking the car out and varying car speed from 20 to 60 mph on the highway to seat the rings (this was Chiltons suggestion for breaking the engine in).

 

[pedal2themetal45]

I've heard of a lot of people haveing a prob with the Dizzy.. Is it still the load-a-matic. that uses two lines?? Maybe hooked up wrong.. how about the fireing order?? 180 out?? or one or two out. old plug wires??
The reason the carb adjustments don't do anything is because the idle is too fast and your past the idle circut. You'll have to get the idle down to get that to adjust.
Good luck
tim

 

[mugsy]

The original engine in my '65 would idle at 19" to 21" Hg; and the darn thing had 250K miles ! The 14" Hg seems low to me .

Put the vac gauge back on and play with the idle mixture screw. You want highest vac reading.

Also, have you verified that the spark plug wires are on in the correct order? (don't ask me why I'm asking you! )

tanx,
Mugsy 8)

 

[Lazy JW]

Yes, I pulled the valve cover and used the valve position to determine TDC accuracy...

Ummmm....not quite sure that this tells you what you really need to know. TDC of the PISTON in the CYLINDER is the critical data point. The position of the valves is dependant on several factors that can contribute to considerable error when trying to detirmine TDC by your method.

I wouldn't jump on the TDC bandwagon just yet though. I'm wondering if your valve adjustment is too tight. This can certainly cause the problem you are describing.

Any 40 year old distributor is also highly suspect. The shaft can get loose and wobbly, the little cam that operates the points can wear un-evenly. The breaker plate also needs to be PROPERLY grounded.

As David mentioned above, you do need the proper vacuum signal from the carb, but for idle you don't need it at all. That engine should idle like a sewing machine. Keep us posted and Welcome to the forum.
Joe

 

[Anonymous]

Thanks for the advice guys--I've got the day off tomorrow and I'm gonna fiddle with it some more. Based on what you've said I think I will check the valves and the distributer. I'll let you know how it goes--thanks again.

 

[Anonymous]

take some pictures...we love pictures

 

[Anonymous]

Sounds like a sticking valve. You might feel the coil. Maybe its getting too hot mounted to the block? You could check each wire with a timing light for consistent spark.
Vacuum also sounds a bit low. My 66 rebuilt block still pulls 19 - 20 vacuum.

 

[Mercury Mike]

I'm having the same problem, but getting black smoke. Thinking it's my carb. My timing was a bit advanced so I got it right where it's supposed to be, but it won't idle right if I don't boost the idle up a bit. I'm going to switch out my carb and see if it runs any better. Also, what octane gas do you use?