| carguy | -- 07-16-2010 @ 6:42 PM |
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When I install new plugs the engine (original '34) runs well but they too soon get fouled and the engine starts to run poorly with a significant loss of power. I have had the coil, distributor, & carb repaired and new plug wires. The compression seems OK at 110 - 120 for each cylinder. I have not yet removed the intake or heads. Before I start tearing into the engine is there something else I should do?
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| Pauls39 | -- 07-16-2010 @ 7:13 PM |
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Hook up a good vacuum gage and see what it will tell you. The points may be worn or the timing retarded. The exhaust may be partially plugged. The valves may be worn or out of adjustment. Your carburator may need adjustment. Use the gage to pinpoint problems before you start tearing the motor apart. You might try disconecting one plug wire at a time listening for a drop in RPM. If there is no decrease, that cylindar is not doing its job. Rebuilding an engine because the distributor or carburator is faulty, is expensive and largely a waste of time.
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| supereal | -- 07-17-2010 @ 9:19 AM |
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Are you adding anything to the gas? Constant use of Marvel oil, or other additive, will foul plugs eventually. It is a good product to use occasionally when a sticking valve is suspected, but adding it constantly to fuel as a preventative measure is asking for trouble. That is why the highly advertised automatic "upper lube" oiler accessories went out of style years ago. We still see them at swap meets, and I've been told they are being made again.
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| TomO | -- 07-17-2010 @ 9:45 AM |
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Plugs can become fouled due to too much idling or low speed driving, not driving the car long enough for the engine to reach operating temperatures, weak spark, oil leakage past rings,etc. Here is a link to photos of spark plug conditions and causes. Compare your plugs to one of the photos and if you have any further questions, come back here for answers. http://www.spark-plugs.co.uk/pages/technical/diagnosis.htm Tom
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| 37RAGTOPMAN | -- 07-17-2010 @ 2:09 PM |
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how old is the gas,? this stuff they sell today gets old fast,and will create problems, also try running the engine without a aircleaner, or a different one and see if that may be the problem..a dirty or clogged air cleaner is like running with the choke on,and will foul the plugs, see if you are getting a strong blue spark out of the distributer,and make sure the condensor is grounded and tight, with a mirror and a flash light, with aircleaner off look down though the carb and see if it is dripping gas, does the exhaust blow black smoke out the back while running,? let hear how you made out, 37 RAGTOPMAN and KEEP ON TRUCKIN,,!!!
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| carguy | -- 07-21-2010 @ 7:54 AM |
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I havn't yet tried all of the suggestions but I did compare the spark plugs I recently pulled with a set that I pulled a year ago. The interesting thing to me is that the fouling is not uniform, running from normal to dry fouled to heavy soot, and that the recent set of plugs look almost exactly like, cylinder by cylinder, the plugs I pulled a year ago. Both sets of plugs are Champion D16. And, I don't have very many miles of use in the last year.
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| supereal | -- 07-21-2010 @ 9:38 AM |
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As you have covered most of the tests, compression, etc, and replaced the plug wires, finding the cause of a rich mixture is likely in the fuel system. It could be a partially clogged air filter, a misadjusted choke that is not opening or closing fully, or the now common problem of a leaky power valve gasket. Even though you had the carb repaired, that doesn't mean it is OK. The replacement power valves have a rounded shank, allowing incomplete sealing. Remove the carb, set it on the bench, and with the bowl full of fuel. leave it to stand overnight. That will tell you if there is leakage that otherwise can't be detected. With the compression reading you quote, tearing down the engine isn't likely to do much except cost time and money.
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| Pauls39 | -- 07-21-2010 @ 9:50 AM |
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What did the vacuum gage/test show? Is your carburator a 97 or 94? That will make a difference in the type of power valve you have. You may have a leak in the intake manifold which would account for some of the plugs being darker than others. A sticking intake valve could also upset the mixture on other valves. Run some tests and let us know.
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| sturgis 39 | -- 07-24-2010 @ 3:00 AM |
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GO TO A HOTTER PLUG.I HAVE NOT HAD GOOD LUCK WITH CHAMPION PLUGS. I WENT TO SMALLER JETS AND NKG PLUGS WITH EXTENDED ELECTRODES.THE PLUGS LAST ABOUT A YEAR NOW. This message was edited by sturgis 39 on 7-24-10 @ 3:09 AM
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| 1934 Ford | -- 07-24-2010 @ 8:19 AM |
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I gave up on the champion D-16 and switched to the Autolite 386. Much cleaner running plug and better looking too. Cost $1.44 each at Advance Auto Parts when on sale.
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| supereal | -- 07-24-2010 @ 10:24 AM |
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Going to a hotter plug may help, but because some of the plugs are OK, while others are fouled, the problem must be solved, rather than covering it up. A wet/dry compression test will tell you if the offending cylinders have a ring, valve and/or guide situation. I'd bet on stuck rings, not rare in old engines. Long snout plugs usually help lightly driven cars. We use Champion RJ14YC in place of the H-10's, which tend to foul easily.
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| oldford2 | -- 07-25-2010 @ 1:40 PM |
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Bob, I have the top oiler (MMO) attached to our 46. I also put 4-6 ozs in the gas tank every 3rd tank or so. We just took a 1500 mile trip to Nova Scotia in 85-90 heat @ 55-60mph and the plugs look great. Nice light brown (Champion H-12 gapped 32-35). I know, Champions stink but I love them. I don't believe top oilers are the main cause of plugs fouling. John
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| supereal | -- 07-25-2010 @ 2:52 PM |
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John: The top oilers are OK if they are adjusted properly, which many are not. I know we had more trouble than was necessary "way back then". The only benefit that could be had from those was lubrication of the intake valve guides. If the valve chamber is clean, and oil pressure is sufficient, the guides get plenty of oil. That is why the later straight valves have seals on them. I was surprised to see the oilers reproduced. I've never been a fan of the "miracle in a bottle" stuff, as it usually just greases money out of the wallet.
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| oldford2 | -- 07-25-2010 @ 3:57 PM |
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Bob, The AMPCO lubricators that are being sold now are not reproductions. Apparently this guy found a stash of hundreds (?) of them. They are very nicely made and come in the original boxes and instructions (1952). John
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