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Discussion Topic:
47 MERCURY FLATHEAD OVERHEATING
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LARC |
11-12-2015 @ 2:56 PM
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Member
Posts: 19
Joined: Jun 2015
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Dear forum: 47 Mercury is overheating in a short period of time even when it is parked. I was checking overheating problems and their solution at this forum as well at the link: http://www.vanpeltsales.com/FH_web/flathead_overheat_troubleshoot.htm which indicates 17 possible causes for overheating. Both sources were very usefull. I live in South America, so the car is not using thermostat. I think the problem could be the radiator cap (see picture attached), but I am not sure what should be the pressure, I think it is 7# because this number is stamped in the cap and I guess this is the original one but I have seen picture in internet that says it is 4#.I replaced the cap for a 15# cap by mistake and it was a mess. The rigt pump started leaking! I think the other cause of overheating could be the engine timing, it sounds great but anyway I think I have to use a stroboscopy lamp to be sure it is running perfectly. Finally, many people is advicing me to resurface the heads but it would be my last option. I´m sorry for my poor english and thanks for listening me! Regards! LARC
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TomO |
11-13-2015 @ 7:33 AM
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Senior
Posts: 7243
Joined: Oct 2009
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Have you checked to make sure that the engine is really running hot? A candy thermometer can be used to check the coolant temperature. A bad sending unit can make you think that the engine is overheating. You should have a 4 lb radiator cap. A bad radiator cap only causes overheating at highway speeds. The most common cause of overheating is a plugged radiator. Next would be worn water pumps, followed by excessive debris in the block. Ignition timing is set by the point opening time. You can use this procedure on Van Pelts site to check your ignition timing. http://www.vanpeltsales.com/FH_web/flathead_engines_distr-timing.htm Unless you are having a leaking head gasket, resurfacing the heads will not cure an overheating problem. If it was my car, I would start by having the radiator cleaned professionally, by someone familiar with antique radiators. If you have any of the cooling tubes closed off because of a previous leak, you will have to have a new core with louvered fins installed.
Tom
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LARC |
08-31-2016 @ 12:36 PM
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Member
Posts: 19
Joined: Jun 2015
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Dear Forum: Finally, my 47 Mercury is not overheating. The theory said that in the distribuitor we have to djust the breaker gap to .014 to .016 inch but in did not work in this case. Intead I adjusted the breaker gap to .024 inch and the overheating problem is gone! Thanks all of you for you support and TomO for your recommendations. Regards! LARC
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ken ct. |
08-31-2016 @ 1:57 PM
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Senior
Posts: 1513
Joined: Jan 2010
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I dout if a flathead would even run with .024 point gap. Are you adding the two sets together to arrive at that figure ????? ken ct.
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LARC |
08-31-2016 @ 2:45 PM
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Member
Posts: 19
Joined: Jun 2015
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Nop, .024 each one!
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TomO |
09-01-2016 @ 9:39 AM
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Senior
Posts: 7243
Joined: Oct 2009
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Larc, You need a total dwell of 36 degrees to fully saturate the coil and develop a good spark. A point gap of .024 will not allow this to happen. I tend to agree with Ken CT that the engine would run very rough with that setting. Are you sure that you are using US feeler gauges, not metric? Do you have access to a dwell meter? If so,please check the dwell.
Tom
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