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How dependable is a flathead?

Discussion in 'The Hokey Ass Message Board' started by Mike Britton, Jul 16, 2012.

  1. OK guys, I'm going to take advantage of the fact that there are more "real world" flathead experts here on the HAMB than anywhere else.
    I have a shot at buying a nice, nearly bone stock 47 Ford Super Delux tudor. If this happens, my O/T glass 29 roadster/454 will become swap meet fodder, and I will actually have a traditional hot rod.
    I came into hot rods in the late 50's, and for the most part, here in North Texas the flat motor was already out of favor. Lots of Olds and Cads, and lots of small blocks. I worked on a couple flatheads in the machine shop, but wasn't around them enough to know how well they worked when they were in good shape.
    Whether or not the 59AB that's in this tudor can be made dependable will affect the amount of money I'm willing to spend on the car. I have a nice 350 on a cradle in the shop, but I'd like to keep the flathead for many reasons, cost, cool factor, etc,etc. I'd lots rather spend my money on stuff like a new interior, and better brakes.
    The flathead runs like a sewing machine now, and with new water pumps would be 100%.
    Can I depend on this engine for 100 mile round trips in the Texas summer? I've heard horror stories about the cost of rebuilding a 59AB, how does it compare to a small block?
    Would I be better off jerking the old flatmotor out and putting the belly button in?
    What I have to do to make the tudor a reasonably dependable cruiser obviously affects what I'm willing to give for the car, so bear with me, on this question that may not have an answer.Thanks, Mike
  2. Is your small block a crate motor? If not I doubt that it counts as a belly button although anything without one is an alien. ;)

    I guess dependability depends on the flathead. Are we talking built to the hilt flathead or stock flathead? They did get driven cross country for a great number of years and I don't doubt that many of them made it from Oklahoma to the central valley during the dustbowl.

    If it is cruising that is o=important to you then the flatty put up in shape will probably do you just fine but if it is performance that you are interested in then maybe a valve in head engine would be a better choice.

    Flatheads are not cheap to go though if it needs gone though if it costs you 1500 to go through an SBC a flathead will cost you 3K min and up to 5.
  3. Ole don
    Joined: Dec 16, 2005
    Posts: 2,915

    Ole don

    That question is like asking how bright is the sun. With new water pumps, and a new core in the radiator, if the heads were torqued correctly, then re-torqued correctly, if the fuel system is good and doesnt vapor lock, if the block is crack free, it will be dependable.
  4. J Twitero
    Joined: Apr 15, 2011
    Posts: 105

    J Twitero
    from Minnesota

    I cant say for your 59AB directly, but the 8BA in my '52 has been dead nuts reliable. I also swapped the water pumps (one was seeeping at the weep hole when I got it home so I did both while I was at it) and got the radiator checked by a local shop, also needed a fuel pump as the diaphragm dry-rotted, but otherwise nothing but tune up bits (carb kit, plugs, cap, rotor, coil, wires, oil/filter changes).

    Mine has a shade over 85k on the clock, and as far as I can tell it has never been "opened up" other than the things I have done to it. I have driven it 180 miles one way for weekend trips no problem, and given cash for gas and time off would have no reason not to hop in and drive it coast to coast tomorrow. I would say if your basics check out (compression check, has oil pressure, no ominous noises, etc) and going over normal maintenance items, go for it!

  5. hotrod40coupe
    Joined: Apr 8, 2007
    Posts: 2,559


    The biggest enemy of a flathead is cracks. If you were to completely rebuild the flathead with traditional speed equipment, a SBC is cheaper. I know guys that have $15,000 in flatheads and they can still get beat by a SBC.
  6. TERPU
    Joined: Jan 2, 2004
    Posts: 2,270


    Flatheads are pretty Damn reliable. If left Stock and driven with restraint. It'll run forever. But when you start Hot Rodding them like everything else you find the weak spots quickly. Flathead longevity is a cruising mentality. Drive it like a Chevy and well, it'll do its best but eventually the little guy just won't take the strain. Things like 2x2's and well tuned stock distributor, even a mild cam will do it wonders. They hate high compression and high RPM's for very long. Water pumps suck to change in the car so do it while it's out. 9 or 10" clutch and 2.5 lines of advance on the Distributor will make it purr like a kitten. They don't even need mufflers just straight pipes out the back. Good news is when it breaks adapters for a Y-block are easy to come by. Y-Block now there's an engine!

    But the look is like nothing else.
  7. nwbhotrod
    Joined: Oct 13, 2009
    Posts: 1,243

    from wash state

    Bone stock flat head still running 6 Volt pos ground Elect system. I drive the snot out of this car it has Mitchel Overdrive the flatty loves it and so do I if you want to chat about the Mitch pm me

    Attached Files:

  8. Thanks guys.
    I'm not after performance as much as a fun weekend cruiser. If I want performance, I'll take that big block and build a T-bucket!
    The small block would have to be "calmed down" a bit, it's a .030 over 350 ,11/1 Keith Blacks, Crower 292 deg. flat tappet cam, mildly warmed over heads.
    I understand the vague question. I guess I'm pondering whether I could live with the flathead or not. If the flathead wouldn't make a decent cruiser, I'm not sure I want to get into some can of worms. There are lots of other weekend cruisers out there.
    The old motor runs great, and if we could keep water from running out of the water pumps, ( a reasonably easy fix) it would be trouble free.
    BTW, the car has been converted to 12 volt, which I like. The lights are much brighter!
  9. 48FordFanatic
    Joined: Feb 26, 2011
    Posts: 1,335

    from Maine

    I think Flatheads are about as dependable as a politician.
  10. One of the sweetest engines I ever had was a 312/ 3 deuce in a 54 Crestline!
  11. yblock292
    Joined: Oct 10, 2006
    Posts: 2,937


    my 40 coupe is still running a flathead, me and my gal drove her to dewey to the straykat 500 few months ago, 100 miles from my house cruised 60 all the way, never got hot and got a whoopin 10 miles to the gal.
  12. I sent my old Deuce 4 door down the road a couple of months ago but after driving the car long and hard for 12 years the old Flathead engine never skipped a beat.

    My only problem was I needed a 5 speed instead of the 3 speed tranny when I was climbing those long stretches in the North Carolina mountains heading to Tennessee,,every day driving was no problem. HRP
  13. yblock292
    Joined: Oct 10, 2006
    Posts: 2,937


    running a 46 flatty in my 29, never been apart, but would recomend replacing waterpumps with new ones and having someome with a distributor mach go though the distributor, timing makes all the difference in the world
  14. Koz
    Joined: May 5, 2008
    Posts: 2,308


    I'm doing the same thing. Building a fresh 8ba to put in my new roadster. My Dad used to drive the snot out of his '34 tudor with an 8ba with a nice cam and trips on. Took Mom and the kids all over the country in his rod and had very few problems. My Dad was a super good flatty mechanic and I wish I had him to help me with this thing, (and everything else). Biggest problem I ever remember was getting popped for running the straight pipes so he carried a pair of "racketbusters" under the seat and put them on when he got pulled over! A bunch of times the cops just let him go.

    The only problem I remember was it ate fuel pumps. He carried an extra at all times but they were usually junk yard sourced. Nothing an electric pump won't cure.

    The coolest car I ever drove was my old club brother Dans' real deal duece roadster with a warmed 59ab/ '39 box with Linc gears. Pure hot rod porn. I've been Jonesing for a flatty ever since. Whatever you do keep the three speed box. They just feel perfect!

    Go for it.
  15. in 1963 ,i was in tech school , went home for weekend with a guy in a 50 fd f1 flathead was just a rootin tooting crusing so sunday we head back to school about 150 miles
    one cyl drops off, 2 cyls drop off and so on down the road then we go into coast and finally get it pulled to wahpeton nd with a chain:eek:
    me being mr mechanic i tear it down after school only 8 exhaust cracks
    my first mizerable flathead story
    had a 85 hp in my wrecker and went to a y block they really fit and makes a world of difference for depedability and keeping on running and that was a 239 y block the hook ups were even somewhat the same :D
  16. JunkYardFrog
    Joined: Dec 8, 2010
    Posts: 215

    from CA

    My grandpa owned a '53 Merc. We put over 200K miles on that flathead. Sure wish I had it today!
  17. Texas Eli
    Joined: May 28, 2012
    Posts: 40

    Texas Eli

    Most flatheads of this era were only good for 60-80K before they were worn out. How do I know this? Back in the 90s my father and I bought a few dozen '46-48 Ford parts car from an old salvage yard with 1955-1962 license plates on them and 60-80K on the clocks!
    I think it was probably more economical to replace the 100 HP flathead with a low-mileage 130+ HP overhead than rebuild the worn-out 59AB.

  18. 62rebel
    Joined: Sep 1, 2008
    Posts: 2,816


    that's a good observation, BUT... for the most part, the cars in question were just back-row survivors doing their last little bit in those days. the owners of those cars never changed oil, never changed plugs, and once it quit on them, they bought another fifty dollar back-row survivor....

    we (i HOPE) don't do shit like this anymore. we put good oil in and change it regularly; we keep on top of ignition and fuel issues, and we pay attention to what the car is telling us! we're scraping the veritable bottom of the barrel these days, trying to source decent old iron, so we're having to go back and rethink salvaging blocks we would have scrapped ten years ago....

    i think a strong stock flathead is as dependable as you make it.
  19. CutawayAl
    Joined: Aug 3, 2009
    Posts: 2,144

    from MI

    If the engine is in good condition and it isn't overworked, a flathead can be pretty reliable. But all things being equal, a decent SB Chevy, or most any other newer engine in good shape, will be more reliable than the flathead.
  20. metaldave
    Joined: Aug 27, 2011
    Posts: 81

    from michigan

    Had a 53 ford with 100,000 miles on it . Used to rev it up till the rods hammered. I am still ashamed. They didnt have a good oil filtering system.The cam operated the fuel pump and when the bump on the cam wore down the fuel pump wouldnt work right . One problem is that now you cant get parts at your local parts store. You can get anything but it will take a week by mail.
  21. 100 mile round trip is nothing.Go for it.
  22. Koz
    Joined: May 5, 2008
    Posts: 2,308


    Full flow oil systems are available for the flatty and relatively speaking, not that expensive. Most of the guys around here don't even run the filter, just change the oil more often. Only about 10% of the oil gets filtered in a flatty anyway.

    As Metaldave says, electric pumps are the way to go.
  23. David Chandler
    Joined: Jan 27, 2007
    Posts: 1,101

    David Chandler

    Well, when that was all they had, I think they were considered dependable otherwise Ford would have gone out of business. My father told me that fuel pumps were a problem, and he used to keep a new one with him. And he ended up nearly on top of Mt Washingon when he had to install it. Also he said that the cure for worn fuel pump lobes were to punch out a piece of leather from a belt and install it to take up the slack. I had one and my only problem was getting it to start. It turned out my battery was too small, and didn't have enough amps. Other wise it ran like a clock. If yours runs smoothly and dosen't burn excessive amounts of oil, I'd run it until it got tired, then swap it for an overhead, if that's what you really want.
  24. Rusty O'Toole
    Joined: Sep 17, 2006
    Posts: 9,445

    Rusty O'Toole

    They weren't that great in hot weather when new. In stock condition, they tended to overheat, a hot rod more or less guaranteed to overheat. One reason they are all cracked around the exhaust valves.

    Unless you get one of those NOS French blocks the newest flathead is now almost 60 years old. If you want reliability without too much hassle or expense, don't buy a flathead.

    Don't buy the car, hold out for one with a Chev engine. There are plenty around. Don't waste your money on a flathead only to take it out and throw it away.
  25. Its 65 years old so its life will depend on how its been treated over the years. Keep the speed reasonable at about 60, fresh oil in it and check the water level in the radiator religiously. You might try a 4 lb. pressure cap on it and a recovery tank. I'd also run a lead additive in the unleaded gas if you plan on running it hard down the highway very far. I burned a valve in my '40 Tudor that way. Run it til it dies and then put the SBC in it with an adapter or a S-10 five speed and an open driveshaft. The flatty would love that trans too but that's a lot of work to adapt it.
  26. Yeah, why bother with an old car at all? Just go buy a new 2012 something..:rolleyes:

    Flatheads are as reliable as you make them....mine in my F-1 is dead reliable, it is fairly stock though. Electric fuel pump, Bubba's dizzy, rochester 2g carb. It's probably the most dependable rig I have right now....
    Getting ready for an 1100 mile trip with it next month....
  27. StrickV8
    Joined: Dec 20, 2005
    Posts: 1,021


    x2! have done two 800 mile round trips in a stock rebuilt Merc.
  28. jimbousman
    Joined: Jul 24, 2008
    Posts: 543


    Just like almost any other motor, flatheads have there known weak spots especially in stock form. Siamese rod bearings, iffy fuel pumps, water pumps, ignition, poor rear seals, poor oil filtration etc. Those who have driven them know what they are and they also know all of these issues are fixable. There are an ample number of suppliers out there using new materials, better technology and years of experience to make a flathead rock solid.

    That said they are a period piece and require a more tinkering than a button motor. Do your research, build it right, take advantage of all the available improvements and it will serve you well.
  29. Saxon
    Joined: Aug 9, 2008
    Posts: 2,157

    from MN

    Yeah id have to disagree. In its stock config it runs the best. The deal with flatheads an modern day driving is gearing. Not fance stuff. If you want to complicate it, it will need to be fine tuned.
  30. hombres ruin
    Joined: Nov 21, 2006
    Posts: 3,301

    hombres ruin

    I don't know where this crap about the flathead being some sort of unreliable, fragile, can't drive it anywhere, engine come from. It's a damn work horse, like any other engine treat it right and it will serve you well.its pure vintage at its finest and nothing beats that!

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