I was hoping you could help me. My Lincoln (430) was having carburetor issues, at least so I thought. I bolted up a new 600cfm Edelbrock and am having similar issues. Popping thru exhaust and run on sometimes. Any help or direction will be appreciated. New plugs, wires, points, condensor.
Hello Geri –
Your symptom information is a little sparse so other than common and accurate tune up diagnosis and the possibility of timing chain issues etc., I am going to refer you to our January 21, 2013 blog question and reply below:
1965 Continental Is Sluggish
I have been working on a customers 65 Continental for a couple of months now. He brought it to me saying it shut off on him one day and when he started it back up it was running rough and had little power. I have have been through this thing in and out, top and bottom. Did all the usual diagnosis stuff and have changed parts as I have found defects. The car was running rough at idle and would break up real bad when trying to accelerate, popping back back through the carburetor and smelling very rich. The first thing I did was rebuild the distributor, it wasn’t advancing and the plate was very corroded. That didn’t help at all. I pulled the timing cover to check the chain and marks and that was fine so I pulled the intake and discovered the lifters were seizing in the bores. I cleaned the bores, installed a new camshaft, lifters and timing chain set. While I had it that far down I sent the heads to the machine shop and 500 bucks later they were fixed with a few valves and all new springs. All the rockers are free and pushrods not bent. After all that the car idles as smooth as a brand new car, but still have no power and can barely accelerate. New coil, 12 volts to the coil, new cap and rotor, timing set at 10 degrees ( have tried it from 6 to 16 degrees), 5-6psi fuel pressure at the carb, new helper fuel pump near the tank, compression is 130-140 on every cylinder after warm-up. After all this the car still has very little power, breaks up during acceleration and is still slightly popping through the carburetor at WOT. You can see a mist of fuel with a flashlight coming out of the top of the carb while power breaking it at half throttle. I’ve hit a brick wall with this one, its the first 430 Ive ever worked on, I’m too far in it to stop now. Any ideas or advice? Thanks so much.
Greetings Andy –
After reviewing your letter several times and reading what you have done so far with this engine and assuming that all of your work has been done correctly as per the engine’s specifications etc. I can offer the following. The factory exhaust systems on these engines use a ” double wall” exhaust pipe. These of course are the pipes that bolt up to the exhaust manifolds and continue on to the next flange connection rearward. It is not unheard of for the inner pipe to develop a separation in such a way as to severely seal up the exhaust on one side enough to cause the symptoms that you are describing. When this occurs the outer wall remains intact and no exhaust leak is heard. Because of the exhaust heat factor this final “plug up” can take place in a very short period of time as your customer has described to you. If the vehicle has the original style pipes on it you should remove them for a careful internal inspection.
Two other items to be aware of when tuning or servicing this era of engine are…The damper pulley on the crankshaft can separate from the rubber damper material and give you an incorrect timing reading. These are available rebuilt. The second is that the vacuum advance units on the distributor are well known to seize or rupture and become inoperative. These are available new.
I hope that the above helps you and I would ask you to let us know here at Lincoln Land what you find.
1965 Continental Is Sluggish – Update
Bill I can’t thank you enough for the advice, I unbolted the exhaust just before the muffler’s and sure enough the passenger side exhaust pipe was clogged shut. I ran 2 new pipes from the manifolds to the mufflers and the car runs perfect!! I’ve run into double walled exhaust pipe problems before but 99% of those cases were on Honda’s. I had no idea these Lincolns were manufactured with it and probably never would have checked it.
Does that sound at all similar to your problems? It will be necessary for someone to perform precise and meaningful diagnosis in order to avoid replacing parts that are not faulty.
Run on is usually caused by too fast of an engine idle but correcting your main concern may also eliminate the run on. Let us know what you find out.