Hello everyone this is my first post so if I am in the wrong place Please advise. I recently changed my 265 engine for a 350. I was having issues with stuttering when I would run her for about 35 minutes. It was as if she was starving for fuel. So far I decided against going to an electric fuel pump. I bought a good Carter 6 PSI pump. Removed the fuel sender to replace the filter sock with a new replacement but of course I ordered a 5/16 instead of 3/8. I left it off. Later I re-grounded the fuel tank as my fuel gauge is sometimes a little flaky I put a good fuel filter on the fuel line. Made sure my fuel lines were clean Insulated my fuel lines with racing insulation in the engine bay. I am running strictly the highest octane fuel from a reputable garage no additives. Oil with Zinc in it. Took the Carb off adjusted the floats Cleaned the carb. She actually was not bad as she was only a couple of years old. Put in a new 1 inch Carb lifter so less heat near the bowls since it seemed like heat was one of the contributing factors. New Pvc valve Pulled the ignition switch extended the wiring with new wire in the right gauge soldered it and heat wrapped them. Replaced the ignition switch. Cleaned all of the bulbs while I had it out. Darn forgot to put in the kilometer conversion plate Later Borrowed a friend of mines MSD distributor Put lighter springs on his MSD distributor rewired everything that was a mess and re loomed. I will put the original MSD in Thursday am. I still have the same problem. It seems that as soon as I put the engine under load say 2200 RPM she starts to buck and fart. The only thing left is to have an Exorcism done. I have totally run out of ideas?
Depending on the engine, you are most probably better off with the 3/8" line...you didn't order. It won't affect anything..."over time", but overall performance may be affected with the smaller line, again, depending on the state of tune the engine is in. Did you change the coil for another ? The distributor won't have any "time related" problems, but the coil will. How's the "cars" ignition wiring ? If the wire's are original to the car, you may have hidden electrical problems. Check the wiring from the switch to the coil. Good luck. Mike
Do you have a fuel pressure gage where you can see it? If the fuel pressure drops when it 'bucks and farts' then you know it is fuel supply, if the pressure stays normal then carb or ignition.
Danny do you realize that old saying was from the times people shared their bath water? The kids were always the last to get a bath. And of course the baby was the last with the poopy ****. Your jumping around your problem like a fart in a skillet. I agree. One thing at a time. Slow down and give us time to help.
Did the 265 stutter? Maybe a half dozen times when misfiring was real sensitive to throttle position it has been ignition related for me. - Wet or Carbon tracked coil towers - Carbon tracked crazy long spark plug connectors in an old Peugeot hemi http://ebayapi.loc8apartltd.netdna-cdn.com/00/s/MTIwMFgxNjAw/z/hhYAAOSwq7JT01cH/$_1.JPG -Bad plugs in the leaded fuel days ========================== Most recently a fancy German ceramic spark plug terminal that must have been hit, and broke inside, but the thick rubber covering made it seem like it as intact. http://caferacers.files.wordpress.com/2009/10/bmw-r100-1984-cafe-racer-017.jpg?w=480&h=360 The spark was slowly making a carbon track across the busted ceramic face to the metal shell under the rubber. Over not too many miles the problem got progressively worse. .Since it was a 2 cylinder and the ignitions were linked when on spark shorted both cylinders fell flat. My wife secretly took the bike to an Indie Beemer dealer, who did all kinds of tune up stuff. He rode the bike to our house, and was confounded. On the delivery trip It ran well until the throttle was opened JUST a LITTLE too much, when it started to cut out. Just like for me, before all the work. I got thinking about previous throttle sensitive missing ordeals and did a resistance test of the plug wire ***emblies which made it REAL obvious there was a problem . Infinite resistance on the bad one. A $4 NGK replacement plug boot and it runs rock solid ( unless I forget to turn on the gas).
What carburetor? Stock or performance cam? What transmission? Freshly, rebuilt 350? Used 350 in known good condition? Used 350 in "god knows what" condition? How much manifold vacuum at idle? Have you done a compression test?
On that car the gas cap has to be vented to let air in the tank to replace the fuel being drawn out by the fuel pump. They usually run longer without stumbling or dying if the fuel level is low than if it is high. Basically when the fuel pump creates a vacuum in the tank the fuel doesn't flow. you let the rig set a while and air is drawn back in the tank and you can go again. Quick experiment. The next time it acts up get out and open the gas cap and see if air rushes into the tank and or you hear the sides pop back out on the tank. It can and will create enough vacuum to **** the sides of the tank in. If you open the tank and no air rushes in life is good as far as the tank venting goes and you move on to the next thing which I would suspect might be the coil acting up after it gets warm. Most things like dirt in the carb, bad wire, bad cap or what not are going to act up all the time or under certain load conditions. something that acts up after a certain period of time stands a good chance of being heat or fuel tank venting related. One last thought. Did you check the inside of the tank to make sure there wasn't any trash in it? Years ago we had a problem with a car that was brought to us when I was in high school autoshop that had befuddled most of the mechanics in town. Car stalled or acted starved for fuel at times and ran great at other times. Turns out that someone had stuffed a shop rag down the gas filler at some time or other and it was floating around in the tank and every once in a while would cover up the fuel intake in the tank causing problems. We only found it after pulling the tank to look at the fuel sock.
The Jalopy Journal
