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Hot Rods Flathead machine costs

Discussion in 'The Hokey Ass Message Board' started by flatford39, Jan 23, 2016.

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  1. flatford39
    Joined: Dec 3, 2006
    Posts: 2,799

    flatford39
    Member

    So my 8BA has a good bill of health. I took apart a stuck motor and dropped it off at my machinist to clean it and magnuflux as well as pressure test. It came back as a good block that can be rebuilt.

    I read all these threads on here how expensive it is to build a flathead and with that in mind I thought that maybe I should do this. I have built a number of SBC and to be honest with you the costs aren't that far off.

    The machining breaks down to this.
    Clean and check for cracks $150.00
    Bore cylinders $260.00
    Furnish & Install cylinder sleeve $165.00 yes I need one
    Install new cam bearings provided by you $50.00
    Grind the valve seats $100.00
    Install new pistons to your rods $50.00
    Resurface all decks $175.00
    Total $950.00

    Now keep in mind that you must supply all parts and assembly is totally on you. By the time you are done you are going to have at least $2,000.00 in a rebuilt motor.

    Not much different than a SBC as long as you have the ability to build the motor youself.

    These are quoted prices given to me today by my machinist.
     
    Last edited: Jan 23, 2016
    bct likes this.
  2. Slopok
    Joined: Jan 30, 2012
    Posts: 2,949

    Slopok
    Member

    You will never spend so much money for so little HP gain, but I aint in no hurry! Hence the name.;)
    212.JPG
     
    1927graham likes this.
  3. tubman
    Joined: May 16, 2007
    Posts: 7,834

    tubman
    ALLIANCE MEMBER

    "Check it before you deck it!"
     
  4. walter
    Joined: Nov 4, 2007
    Posts: 635

    walter
    Member

    That sounds pretty reasonable. On a flat motor I align bored the crankshaft, did a balance job, ported and polished intake runners and exhaust ports, and trued up new heads. App. $5K
     
  5. flatford39
    Joined: Dec 3, 2006
    Posts: 2,799

    flatford39
    Member

    Yeah I agree...I told him i really don't want to deck unless I have something major going on. He is going to check it before milling.
     
  6. flatford39
    Joined: Dec 3, 2006
    Posts: 2,799

    flatford39
    Member

    Well you did more than I am doing and I suspect your final number is probably not that far off.

    The reason I posted this was to try and encourage people to try and save these engines. There is so much negative things written about the costs associated with a rebuild that I wanted to post some actual figures. I am not line boring etc. Just making a reliable weekend driver.
     
  7. image.jpg Try to avoid decking the block.Flathead v8 have a pretty thin deck and unless yours is warped or needing attention,I wouln't deck the block unless absolutely essential.
     
  8. flatford39
    Joined: Dec 3, 2006
    Posts: 2,799

    flatford39
    Member

    Thank you but there is some minor pitting that may need a pass.
     
  9. The 39 guy
    Joined: Nov 5, 2010
    Posts: 3,698

    The 39 guy
    Member

    I think the machining expenses is not the problem. It's all of those go fast things some of us like to add. If you buy a merc or scat crank,new rods,pistons,valves, adjustable lifters,rings,cylinder heads,intakes ,carburetors,distributor,starter water pumps,headers etc.
    You can easily spend well over 4 grand for 135 HP even if you build it yourself.

    Having said that I would not discourage some from building one as they are are a piece of history worth saving and besides they are fun even if they are not usually fast.
     
  10. Maybe not a lot of HP but they sure sound great!
     
    continentaljohn likes this.
  11. GordonC
    Joined: Mar 6, 2006
    Posts: 3,413

    GordonC
    ALLIANCE MEMBER

    Its interesting that you come up with a total number of about $2k. The guy who is building my flathead gave me an initial estimate of exactly that number to start. I am having it bored out an 1/8", putting in a 4" crank, and providing all parts needed. He is doing all the machining on the block, after sonic testing and magging, and will do all assembly as well. I have provided new pistons, new rings, new cam bearings, new oil pump, reground cam, new valves, seats, guides, heads, gaskets, water pumps, and so on. I have the feeling before this is finished it will come in probably closer to $3k or $3500, which is ok as I am not doing it to have a racy hi power motor. Just a unique old time motor in a car I would have built way back when if I had the resources at the time to do so.
     
  12. Other things that I think most people will need:

    1) Rods: Many times they do need to be rebuilt, new bushings, big-ends reworked, etc.. Truth be told, if you can buy a 'new' set from guys like SoCal, it is really WORTH it ($225). (Costs more to rebuild them, then a new set in most cases).
    2) Crankshaft Regrind: I don't see that many cranks that don't need to be reground and polished
    3) Balancing: I would sure have the assembly balanced - can sure make the engine run a lot smoother.

    Just wanted to add to what I see as typically needed . . .
     
  13. Travis T
    Joined: May 26, 2014
    Posts: 84

    Travis T

    I had $1800 in mine, all machine work with eight sleeves, but that was in 2000 or so. Only crack free block I could find before the internet.
     
  14. Mike51Merc
    Joined: Dec 5, 2008
    Posts: 3,855

    Mike51Merc
    Member

    Winter/Spring of 2007 I rebuilt my flattie for about $1200 in parts (bought by me) and $1400 machinist costs. Flatheads don't cost more to rebuild, they just deliver less horsepower/dollar from modifications.
     
  15. tubman
    Joined: May 16, 2007
    Posts: 7,834

    tubman
    ALLIANCE MEMBER

    I had a crank magged, cleaned, and reground .010-.020 last summer for $120.
     
  16. if there are any colleges around often they have engine building classes you can take. cost me $50 to machine my motor....
     

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