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Discussion Topic:
Sticky valve
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Esteban34 |
09-28-2012 @ 9:14 PM
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Member
Posts: 30
Joined: Jul 2010
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After eight years I have my 34 Ford on the road. Drove it to work and Rotary this week. What a pleasure. But . . . Sticker valve is causing pops and farts. Rather embarrassing. Engine had not been run much for at least 30 years, but compression is good on all but one cylinder. Probably the one with the valve problem. Any ideas on how to unstick the valve. Am running SeaFoam and MMO In the gas. adonde vas, estas alli Esteban
This message was edited by Esteban34 on 10-1-12 @ 8:50 PM
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Esteban34 |
09-28-2012 @ 9:39 PM
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Member
Posts: 30
Joined: Jul 2010
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Sorry, meant this for the ford discussion.
adonde vas, estas alli Esteban
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supereal |
09-29-2012 @ 10:50 AM
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Senior
Posts: 6819
Joined: Oct 2009
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To confirm that a valve is the problem, run a dry/wet compression test on the low cylinder. Test compression, then insert oil in the cylinder and compare results. If the wet compression shows a large increase, the problem may not be a valve, but a broken or stuck piston ring, a leaky head gasket, weak or broken valve spring or retainer, or other cause. As you say only one cylinder is affected in an engine that hasn't run for that long, one stuck valve seems odd. Most stuck valves are due to carbon buildup from oil consumption, and only pulling the head and intake manifold to remove the valve assembly is a reliable cure. Most oils, etc, will not dissolve carbon.
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Esteban34 |
09-30-2012 @ 12:27 PM
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Member
Posts: 30
Joined: Jul 2010
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Thanks for the tips. My plan for now is just to drive it. It seems to be getting a little better. I put a nos set of c7 plugs in it yesterday. The plugs that came out were cooler and sooty. The popping through the carb seems to go away with a little choke. Maybe thinks will settle in.
adonde vas, estas alli Esteban
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supereal |
10-01-2012 @ 10:08 AM
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Senior
Posts: 6819
Joined: Oct 2009
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Sooty plugs and backfiring can also be due to a vacuum leak. Check all connections to the intake manifold, such as the wiper hose and distributor line. Squirting a bit of carb cleaner on suspect places can help. If the engine speeds up at idle, you have found the cause. Another cause is a worn carb throttle shaft and a throttle plate that doesn't fit the throat.
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Esteban34 |
10-01-2012 @ 8:49 PM
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Member
Posts: 30
Joined: Jul 2010
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Thank s Superreal, I will check those out. I think the carb is good, it's one of the new Strombergs, but it could be a vacuum leak. I'm try the carb clea near trick. Esteban
adonde vas, estas alli Esteban
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shogun1940 |
03-19-2013 @ 5:23 PM
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Member
Posts: 464
Joined: Feb 2010
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t hey have these little cameras on the end of flexible line, maybe you can find a garage that has one and look down the spark plug hole. or just squirt some pb blaster down around the valve stem
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40 Coupe |
03-20-2013 @ 4:18 AM
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Senior
Posts: 1678
Joined: Oct 2009
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You can also run the MMO in the engine oil, check the container for instructions. Beside helping to free a stuck valve it will assist in freeing stuck piston rings and help to stop burning oil. I am not recommending using it in the oil with every oil change but worth a try at this point. It will help to run the engine and not let it sit. You can also remove the spark plug from the cylinder and with the valve open spray a bunch of the MMO under the valve seats, let it sit for several hours and then run. If it doesn't get any better in a couple of weeks, it is possible the valve is bent, the valve spring broken or excessive carbon deposits on the valve seat. Before taking the engine apart do another compression test to see if there has been any increase in the low cylinder reading.
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jacky374 |
11-04-2013 @ 2:16 AM
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Member
Posts: 1
Joined: Nov 2013
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The problem may not be a valve, but a broken or stuck piston ring, a leaky head gasket, weak or broken valve spring or retainer, or other cause. As you say only one cylinder is affected in an engine that hasn't run for that long, one stuck valve seems odd. ------------------- http://www.itu.edu.tr/ http://www.ism.ws/ http://www.brain-dumps.us/MCSA-SQL-Server-2012-guide.html http://www.colorado.edu/ http://en.wikipedia.org/wiki/Aruba
This message was edited by jacky374 on 8-22-14 @ 11:21 PM
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supereal |
11-05-2013 @ 1:04 PM
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Senior
Posts: 6819
Joined: Oct 2009
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As you have located the offending cylinder, I'd pull the intake manifold and inspect the two valves of that cylinder. As the post above says,you may find a broken valve spring or other related problem. Old valve springs easily break after years of flexing, and the protective coating wears away. Sometimes the broken spring is hard to see, so pry it up and down to be sure it is intact.
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