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Technical 49 mercury flathead build reliable?

Discussion in 'Traditional Hot Rods' started by ottos, Apr 3, 2014.

  1. ottos
    Joined: Jan 25, 2011
    Posts: 251


    Hey guys, Looking for some info on what isn't reliable on 49-53 flatheads ? I hear this from time to time about Them being reliable and I may get a car with a 49 flathead 8 and wondering what is done to make them dependable for long drives and such. Any info would be appreciated.
    Last edited: Apr 3, 2014
  2. tiquer
    Joined: Oct 21, 2010
    Posts: 65


    How on earth did anyone get anything done with there ford cars or trucks for the 20 years the flathead was produced?? With such a POS for a motor how did ford truck get to be the number one in sales in north america from1948 up?? I am 62 years of age and drove so many flat head powerd fords I cant even remember how many except they were just old still running cars and trucks and not even one ever let me down on the side of the road that i needed help to get home. End of Rant sorry
  3. suede shoe
    Joined: Jun 16, 2012
    Posts: 44

    suede shoe

    I've been driving my '51 Ford with '51 Merc flathead for over 20 years with very few problems. I had a water pump go out on it one time which required a tow home, and a couple of vapor locks, but that's about it. I think an electric fuel pump is supposed to cure the vapor lock problem, but I just used the old jug of cold water trick on it.
  4. ottos
    Joined: Jan 25, 2011
    Posts: 251


    Good to hear . I did hear some suggestions about water pumps online here.
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  5. J'st Wandering
    Joined: Jan 28, 2004
    Posts: 1,597

    J'st Wandering

    What can go wrong? You have ignition, fuel, and cooling. Change distributor to a Chevy style. Use an aluminum timing gear instead of the fiber one. If concerned about replacing parts, Carry a spare fuel pump and a pair of water pumps. I also carry a spare generator but you can usually limp home on a dead generator. If you carry spares, you will never need them.

    That should cover 90% of the problems. The motor is as reliable as any other or better. The problem is that you can not stop into the corner auto parts store and pick-up the parts listed above.

  6. low51fan
    Joined: Nov 17, 2013
    Posts: 66


    glad I read the post thanks for asking ottos
  7. RICK R 44
    Joined: Dec 13, 2009
    Posts: 448

    RICK R 44

    very reliable, have put over 75000 miles on mine. Lots of speed parts and up grades available. 3 upgrades I would do are, electric fuel pump, replace distributor (Several options available) convert to 12 volt. New water pumps and rebuild kits have modern sealed bearings. I use a home reworked Chrysler 318 dist., so I carry a spare that I have never used, a pair of rebuilt water pumps that I rebuilt myself (again never used ) and a spare starter. Used the starter once when the bendix spring failed.
  8. ottos
    Joined: Jan 25, 2011
    Posts: 251


    Thanks guys. I build engines myself and since I never was exposed to flathead Fords I was curious about this. Like I said I'm going to get a 49 Mercury Flathead and I just wanted to see what the problem was and before I'm stuck on the side of the road I will do those upgrades. The motor I'm getting has high performance upgrades and it's been rebuilt but a very long time ago but never ran that includes a cam ,intake ,heads and headers.
  9. Bruce Lancaster
    Joined: Oct 9, 2001
    Posts: 21,683

    Bruce Lancaster
    Member Emeritus

    Good, solid wiring concentrating on the engine and charging circuits...good fuelpump, nowadays a backup electric one mounted in car might be wise because we are still figuring out the havoc caused by ethanol gas on pump diaphragms. Do some reading, learn how it works, build the carb need to understand the parts that real world mechanics no longer even recognize. Spare regulator...currently available ones seem to be flaky!
    Distributor...properly sorted stocker can be perfectly reliable, but has poor Chevy conversion covers all the bases. Points must be top line from a good brand like Echlin, as thoroughly crap ones are available. People talk like points require constant maintenance...when they were the norm, any good ones only needed checking after about a year of normal driving and they should last much longer on a lightly used hobby car. I am real damn old, and have never had an actual failure of a point, even on noticeably worn ones so long past their prime there was almost no gap remaining!
    EVERYTHING ignition MUST be carefully purchased, because every single component is now produced in several grades...nearly unusable Chinese, seconf line parts from good companies, primo grade from good companies. Do not skimp on parts that can leave you walking.
  10. tubman
    Joined: May 16, 2007
    Posts: 4,411


    Anyone doubting the reliability and durability of a Mercury Flathead should watch a movie called "The Long, Long Trailer" starring Lucille ball and Desi Arnez. They pull a full-sized house trailer across the country with a '53 Mercury convertible, with an automatic transmission, no less.

    I have driven my '51 Ford for the last 27 years, and it has never left me stranded. This included a round trip from the Twin Cities to Chicago for a car show. About 10 years ago, I took the box of spare parts out of the trunk because I needed the room. They're still sitting on the shelf.
  11. Ole don
    Joined: Dec 16, 2005
    Posts: 2,915

    Ole don

    After a good modern overhaul, a flathead is as reliable as anything on the road today.
  12. Glenn Thoreson
    Joined: Aug 13, 2010
    Posts: 78

    Glenn Thoreson
    from SW Wyoming

    I'm 70 years old and have had quite a few old flathead Fords in my time. I still drive a '42 with a '53 Merc flathead. The engines are very reliable. Like anything else, it all hinges on how it's used and cared for. Bolt on parts that need replacement now and then are the fuel and water pumps, generator and regulator, points and condenser. There are high quality parts out there that will far outlast the originals, however.
    Sealed ball bearing water pumps take care of that issue. An electric fuel pump mounted near the tank takes care of any vapor lock or failure. I use mine only rarely in extreme hot weather or to prime the carb after sitting for a long time. My opinion on ignition and electrical system is convert to 12 volts and run an alternator and electronic ignition for maximum reliability and performance. Be sure to provide plenty of cooling capacity and you will get years of reliable service. Good luck.
  13. Mike51Merc
    Joined: Dec 5, 2008
    Posts: 3,787


    I think this whole "unreliable" thing comes from people who want to just turn the key and go, time after time. They think that a modern driveline will give them that so they swap out the old stuff for new stuff.

    The truth is that these old cars require maintenance and sometimes they get finicky. If you can't do maintenance or diagnose tricky problems it's kind of tough to own one of these things (and that goes for all old cars not just flatheads). A good part of this forum is devoted to helping sort out problems with old stuff.

    Flatheads are no less reliable than any other 50 year old technology. It just won't get you 100K miles without maintenance like your new car will.
  14. choppedtudor
    Joined: Nov 28, 2009
    Posts: 650


    you can just drop that unreliable flathead off at my house..I'll give ya a nice rice-burner for
  15. rotorwrench
    Joined: Apr 21, 2006
    Posts: 633


    On the cars of the pre war and imediate post war era (that's WWII for the young folks), they required more frequent maintenance than cars of the modern era. You needed grease guns, oil squirt cans, dwell/tachs, feeler guages, and other tools most folks these days don't even know existed. If you followed the lubrication and maintenance schedules, the old cars would last a long time with little or no trouble.

    Modern cars are driven until the bearings go out or stuff quits since nothing is manufactured to be serviced much any more. If the check engine soon light doesn't come on then it keeps going down the road and sometimes even if the light does come on. When the rods are knockin, you know it's probably way past time for an oil change.
  16. tommy
    Joined: Mar 3, 2001
    Posts: 14,758

    Member Emeritus

    Too many repeated wives tales by people that have never driven one. I couldn't even get mine home and off the trailer before I was told that they ALL overheat....not mine! Try one and you will like it. Not tire smokers but they will go down the interstate with the best of them and look cooler doing it.
  17. big bad john
    Joined: Aug 11, 2010
    Posts: 4,727

    big bad john

    Reliable?.......Hell ..I take my 37 ford anywhere in the lower 48
  18. Gerrys
    Joined: May 1, 2009
    Posts: 328


    Condition and quality of parts used to build the engine will determin how reliable any engine is.
  19. suede shoe
    Joined: Jun 16, 2012
    Posts: 44

    suede shoe

    That was my problem and why I towed it home. The water pump went out at Back to the 50's, 300+ vendors and not one flathead water pump. I do have a spare fuel pump in the trunk.
    I had to wait till Monday when Little Dearborn was open. I don't think I would have wanted to change it on University Ave. at 11:00 p.m. anyways, too many idiots driving around there.
    Last edited: Apr 5, 2014

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