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Technical Flathead Engine Builders, can this be saved?

Discussion in 'Traditional Hot Rods' started by EricVA, Mar 31, 2024.

  1. EricVA
    Joined: Jan 22, 2006
    Posts: 27

    EricVA
    Member

    HI, I have a Flathead Ford V8 that has cracks in the valve guide bores of the exhaust ports of the two cylinders next to the center exhaust passage. Is this block worth trying to save?
    Hope this link works, having trouble trying to import pictures

    https://www.youtube.com/shorts/iB-Xx0BX284

    Thanks for your advice
     
  2. EricVA
    Joined: Jan 22, 2006
    Posts: 27

    EricVA
    Member

    Ok so here are some pics of the cracks in the valve guide ports. Also I've found what look like casting defects on the crankshaft journals. Assuming both block and crank are junk?
     

    Attached Files:

  3. SS327
    Joined: Sep 11, 2017
    Posts: 3,260

    SS327

    You could try sleeving the lifter bores and getting the crank welded.
     
  4. dwollam
    Joined: Oct 22, 2012
    Posts: 2,533

    dwollam
    Member

    I had a Merc 4" crank ground years ago and they trun open a small casting bubble and told me about it and said it wasn't anything to worry about. Better than turning it smaller to hope to make it disappear.

    Dave
     
    alanp561 likes this.
  5. Those valve guide bores are dry,,,they don’t get any oil pressure .
    I’m pretty sure they are not near any water passages either,,,,so should be ok there as well .
    If they are leaking any pressure,,,,you might try having them sealed like Hand H does . They have some kind of sealer they apply into the water jacket system that saves a lot blocks .
    And ,,,,you might even try to machine the bores and install some kind of bushing ?
    I have even seen some builders that completely seal the guides on installation with an epoxy to keep the guides in place when doing a valve job .
    Unusual I guess but many guys do it and the blocks last forever .
    I’m sure it can be fixed ,,,,,they are not making any more blocks .

    The crank can be welded if it won’t clean up,,,,,they are cast steel,,,,they weld just like any other steel crank .
    If that’s all the damage,,,you are pretty good shape,,,,Flatheads are a different animal compared to other V8s .
    Low compression,,,low valve spring pressure,,,,not a ton of power in stock form .
    Even hopped up they are still around 120-130 or so,,,,unless you really start modify everything .

    That block doesn’t look too bad really,,I only looked at the pics,,,there are usually a few defects in these old engines,,,,but they can take quite a bit,,,,Henry designed them to last .
    If it’s a stock rebuild,,,,you can use the crank as is after grinding,,,they are not perfect many times .
    Not like a SBC at all,,,,,,they can run with some issues that another engine would fall dead .

    Tommy
     
    Last edited: Apr 1, 2024
    alanp561 and Budget36 like this.
  6. theHIGHLANDER
    Joined: Jun 3, 2005
    Posts: 10,400

    theHIGHLANDER
    ALLIANCE MEMBER

    Nice close up shots of the guide. Is that crack into the water jackets? What's going on in the video? A valve guide can be bushed easily. The crank? Turn it and run it. This isn't going to be taking the checkered flag at 12,000 RPM in Formula 1. I wouldn't weld it either, what if a minor faux pas happens in the weld and it chips away a little? It isn't necessary to fill em, let oil do it.
     
    Desoto291Hemi and chicken like this.
  7. CSPIDY
    Joined: Nov 15, 2020
    Posts: 739

    CSPIDY
    Member

    Video looks like a pressure check of the water jacket
    Have you had the block magnafluxed?
     
  8. Those are funny cracks - have never seen them like that . . . makes me wonder if this block froze with water in it?

    I see you had it pressure checked and it is leaking pretty badly in those areas. While you can sleeve those bores - it will be an expensive operation as nobody is going to be setup to do that work and it would have to be done in a milling machine that has a "saddle setup" for a flathead. Also, given that the valves are not perpendicular to the deck (the angle of the guide bore is not 90 degrees to the deck surface) the machinist has to get the angle just right (not easy to do without having a pilot that picks up the lifter and guide bores at the same time).

    I'd be more worried about the cracks you can't see (like in the exhaust ports).

    Me, I would probably find another block (after seeing your video)!
     
    Last edited: Apr 1, 2024
  9. Also, given that you're using air pressure in the water jackets to test for cracks - and you're seeing it come through the guide bores, there is obviously water around the guide bores. This is very important in that the water is used to extract heat from the guides, which extracts heat from the valves themselves. On the exhaust side this is even more important than on the intake side.
     
  10. wheeldog57
    Joined: Dec 6, 2013
    Posts: 3,583

    wheeldog57
    Member

    That is way beyond my skill level, good luck whichever way you go
     
  11. Flathead Dave
    Joined: Mar 21, 2014
    Posts: 3,994

    Flathead Dave
    ALLIANCE MEMBER
    from So. Cal.

    I would take it to a pro for an evaluation. At least have it magged.
     
  12. EricVA
    Joined: Jan 22, 2006
    Posts: 27

    EricVA
    Member

    This was an engine my father in law picked up that was "a runner". Granted this was bought and sold a couple times before we got it. He planned to put it in hi newly restored '39. I told him I would take it home and put it on a test stand I had to run some heat cycles on it before we put it in the car, so we avoid scratching paint if we ended up having to remove it if something went sideways. Well something went sideways. I had run it probably six different times, about thirty minutes each time until I noticed milkshake in the oil pan. While still warm I pulled the pan to peek around an see if in could tell where water was getting in. Not signs on plugs, with the pan off I could see water drops coming out around the lifters at Cylinder 3, pulled the intake, PUDDLES of water in the valley, I'm confused. Pulled heads, no signs of head gasket failure.
    Decided to buy block pressure test kit from Speedway, I've got lots of blocks I've collected over the years so I figure it would pay for itself. I pressurized the side with #3 cylinder and heard hissing in the lifter valley, narrowed down to #3 exhaust guide, pulled both #3 intake and exhaust valves/guides and the video shows the air rushing out of a crack that runs at least half the circumference of that guide bore. Spray a little windex and there it is!
    So, what to do. I don't have a machine shop in my area that I think could handle the repairs described so I'm gonna go with another block. This one is already bored .060" over already, I'll save the pistons and rods etc. And I might just do a home polish on the crank and see what happens.
    Sorry for long response but I am grateful for all of your input, just wanted a sanity check on this because I have never heard of a crack in a guide bore, actually multiple bores
     
    Desoto291Hemi likes this.
  13. I think you're making a wise choice!
     
  14. Kevin Ardinger
    Joined: Aug 31, 2019
    Posts: 925

    Kevin Ardinger
    Member

    It’s crazy how you can see from the pictures how porous those castings were. Pretty crude. It’s no wonder they crack and leak. I would definitely consider sleeving that bore and saving the block.
     
  15. ronnieroadster
    Joined: Sep 9, 2004
    Posts: 1,125

    ronnieroadster
    Member

    Sadly the block is not save able. There's no way the lifter bores can be sleeved even if you had the machining capability's to add a sleeve the crack will continue to be opened at the top and bottom areas out side of the guide hole area. Saving what you can from the block and putting another together is the best thing to do.
    Ronnieroadster
     

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