| 1934 Ford | -- 01-01-2011 @ 5:06 PM |
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My 21 stud V8 has been a wonderful car to always start easy and run super smooth and fast. We've driven it all over the country with a minimum of problems. Now it's acting up. The last 4 times I've started it, it has given me the same trouble. It starts on about 4 or five cylinders and sounds like it's cross wired. If I drive it a half mile it suddenly smooth's right out and runs perfect until I shut it off again. I think electrical, but the self part correcting baffles me. Where should I look first? All idea's appreciated.
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| ford38v8 | -- 01-01-2011 @ 10:08 PM |
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Paul, for a man of your experience and history to ask a humble question here on our Forum is certainly a testament to the help we've been able to give others. I'm quite sure you've already considered the answer I can only guess at, but here goes nothing: The fuel available today seems to have a varnish that is not as soluble as it was just a few years ago. Gasoline varnish is particularly effective in exposing the vulnerabilities of engine valve guides. A sticky intake valve can cause cross-firing and backfiring through the carburetor, while a sticky exhaust valve will backfire through the exhaust and cause a constant miss. Certain gasoline companies have all but acknowledged the fact in their advertising, claiming to have solved the problem with the detergents in their gasoline. As you may know, all gas comes from just a few refineries, with additive packages per customer spec delivered as the tanker is filled. This is all beside the point, except that the varnish is there to be dealt with for better or worse. With the Government mandate of reducing or eliminating certain properties and additives formerly contained in motor oil, the most well known of these being zinc, it is quite possible that this is a contributing factor to sticky valves. I for one am considering a zinc additive for this reason, where I previously had spurned its need in our flathead engines to prevent camshaft wear. There are some Diesel and Racing Oils that still have zinc, and some guys have also substituted a qt of MMO for motor oil, so this may work also. Whatever the chemical cause of modern day varnish, Many have found that an old remedy is still an effective solution (no pun intended). Marvel Mystery Oil delivered by way of a top oiler bottle, or 4 oz in the tank per fill up can help prevent the varnish. In the old days, we used to see huge billows of smoke emanate from the rear of used car lots while hearing a car engine racing. This was from pouring a product called "engine treatment" (or something like that) down a carburetor, but I wouldn't want to get caught doing that today. I wish someone would be able to verify conclusively the ideas I've expressed here, but I guess word of mouth is as good as it gets. When you do find the cause or the remedy, please get back to us with the fix? Alan This message was edited by ford38v8 on 1-1-11 @ 10:12 PM
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| 40 Coupe | -- 01-02-2011 @ 4:51 AM |
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I do not believe the car will start unless all the cylinders are fireing. How about a sticking valve. I would get it running and up to temp so it is running well and VERY slowly pour some MMO in the carb. You could do a compression test both cold and hot to verify. This procedure will cause the engine exhaust to pour out white smoke don't do it in the garage!
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| Texas40 | -- 01-02-2011 @ 8:20 AM |
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Get some Berryman's Chemtool and after your 34 warms up rev the engine enough to prevent stall and pour Chemtool down the throat of the carb. I have had great luck unsticking valves using the Chemtool. Then, if you drown it out (don't forget to turn off the switch)and let it soak for several hours, it works on stubbornly stuck ones. Sounds like yours just need a little dose to free up. I also use some MMO in my gas tank every fill up.
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| alanwoodieman | -- 01-02-2011 @ 9:43 AM |
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while it is still cold, check the fire at the spark plugs, is it a nice blue spark or yellow in color? are all cylinders actually firing? A bad distributor cap, moisture in the distributor which dries out could be a problem, a weak coil-try putting full voltage to the coil, does this change anything? On a spark plug engine misfiring can mostly be traced to an electrical problem. Just worked on a 59A engine that the owner said the problem was the coil, I pulled the plugs-worse collection of fouled plugs you have ever seen
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| supereal | -- 01-02-2011 @ 10:20 AM |
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Before you start pouring anything into anywhere, or swapping components, take time to diagnose the problem, or you will probably complicate it. To run, an engine needs three things: fuel, air, and spark. To check the first, look down the carb while you work the throttle. You should see two strong jets of fuel. If not, suspect a partially clogged fuel line or filter. To check the "air", run a quick compression test to see if any of the cylinders are low, usually indicating a valve is not seating. It is not common for several valves to suddenly stick unless there is an oiling problem. To check the "spark", hold each plug wire about half an inch from the cylinder head as the engine is running, and look for a strong, blue spark. Be sure to use an insulated tool to pull and replace the wires, or an unpleasant jolt may wake you up. If pulling the wire doesn't immediately cause the engine to run rough, or die, suspect a problem with that spark plug, plug wire, or distributor cap/rotor. Keep in mind that the firing order is 1-5-4-8-6-3-7-2, with cylinder #1 being the closest to the front on the passenger side. If any of the spark tests show weak or missing spark in two of the cylinders on the same side, suspect a cracked distributor caps, or one that has developed a carbon path between contacts. You may also have a cracked plug wire that is firing inside the metal conduit until it dries. These carbon paths collect moisture, and cause crossfiring until they are warm enough to dry out, which may explain why the condition improves in your engine. As the problem goes away after running, the coil is likely OK. A weak coil problem increases as the engine warms up. As the only practical way to determine if the condenser is at fault, is substitution with a new or known good part is to isolate it as the cause. Finally, check the voltage input to the coil at the terminal. With your voltmeter hooked up between that terminal and ground, wiggle the ignition switch and watch the needle of the meter. Old Ford switches tend to deteriorate from use, and lose firm contact, allowing the voltage to the coil to vary. If you find a low or erratic voltage at the coil, follow the circuit from the switch through the resistor, and the wires, themselves. If any movement shows loss, that part of the system should be replaced or repaired. Finding an intermittent car problem can take a lot of time and patience, but creating another problem by using the "shotgun" approach is a recipe for frustration and failure. Be methodical, and carefully check each possibility before you move on.
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| Pauls39 | -- 01-02-2011 @ 7:01 PM |
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Ditto to all that Super has stated. One additional thing to look at is the spark plugs. If all else fails try a set of new NGK's. If your plugs are old it would be a good practice to replace them anyway. This message was edited by Pauls39 on 1-2-11 @ 7:01 PM
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| TomO | -- 01-03-2011 @ 9:43 AM |
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40coupe, I have started my car many times with one distributer cap swinging in the breeze. I don't do this on purpose, but am easily distracted and for get to secure the cap before starting. Tom
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| 1934 Ford | -- 01-08-2011 @ 6:13 PM |
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Thanks guys. I suspected a sticky valve because I haven't been using an additive, but it sure sounded like the distributor went nuts. The self correcting part makes me want to check that first with a compression check, If it happens when I start it again next time. If it doesn't I'll add Marvel Mystery Oil or transmission fluid to the tank anyway. I've wanted to get back out there all week and find the real problem and fix it, but life takes time away from fun stuff like V8 Fords. I will post what I find as soon as I get out to the barn and and play a little. Thanks for all your suggestions. Paul
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| trjford8 | -- 01-08-2011 @ 7:49 PM |
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For those wishing to use oil with more zinc go to this website; www.bradpennracing.com. E-bay shows a case price of $67 plus shipping.
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