The mystery of a proper prop and terrible performance.

Discussion in 'Props' started by missinginaction, Jan 25, 2020.

  1. missinginaction
    Joined: Aug 2007
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    missinginaction Senior Member

    Step.......
    Pearl heat exchangeer installation.jpg

    by step.......
    IMG_20210517_142007111.jpg

    by step.......

    IMG_20210517_142541667.jpg
    Stay tuned.......
     
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  2. Mr Efficiency
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    Mr Efficiency Senior Member

    You are Mr Methodical, and that raises the chances this all comes together as a success.
     
  3. missinginaction
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    missinginaction Senior Member

    Thanks for the compliment Mr. E.

    As is almost always the case though there are unforseen issues that crop up. Take this morning for instance. I'd installed the exhaust manifolds yesterday and was staging everything for the riser installation. As I worked I looked over the area as I usually do. It occurred to me that there was almost no space between the inside edge of the exhaust manifold and the outside edge of the valve cover. There's a hold down bolt for the valve cover down there. "How am I going to get that bolt out if I need to someday" I thought.

    So the risers didn't get installed today. I did some other things and came home to do some research. It turns out this is a known problem with Barr manifolds for small block Fords and has been known for years. It seems that the only solution is:

    1. Pull the exhaust system off if you need to get to the valve train.

    or

    2. Install a header flange (used as a spacer) to get an additional 3/8 to 1/2 inch of clearance between the manifold and the valve covers.

    I've never needed to add a spacer before. The Barr manifolds are nicely made. I've used OSCO manifolds in the past on this engine and didn't have a clearance problem. I'll be calling a header shop tomorrow to get a little guidance on this. It seems to me that I'll just need two gaskets per side, the spacer and eight bolts that are 1/2 inch longer than the ones that Barr supplied.

    Sometimes it's a few steps forward and then one step back.

    MIA
     
  4. Mr Efficiency
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    Mr Efficiency Senior Member

    That sounds like a nuisance, but maybe there is a work-around the header shop can suggest ?
     
  5. missinginaction
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    missinginaction Senior Member

    Nuisance is right. The good news is that the manifolds should pop right off since the engine hasn't been run. I always use a copper based adhesive sealant between the gasket and the cylinder head and no sealant on the gasket side facing the manifold. The manifold bolts are only torqued to 20 ft/lbs. If my header flange as a spacer idea works it should take very little time to get things assembled once the flange is delivered.

    On the bright side this gives me an excuse to get a fresh pair of valve covers.

    We'll see how it goes.

    MIA
     
  6. gonzo
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    gonzo Senior Member

    If you have 18" clearance from the center of the shaft to the hull, a 18" diameter propeller would have 9" clearance.
     
  7. missinginaction
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    missinginaction Senior Member

    That's an old post Gonz. I made a typo when I posted it. Anyway, if you look above you can see the 17" DQ486 installed. I'm a little tight with about 2-1/2 inches of clearance to the hull but it is what it is. I'm pluggin' along and hope to be in the water in a couple of weeks. That means it'll probably be three.

    Regards,

    MIA
     
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  8. Ad Hoc
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    Ad Hoc Naval Architect

    If you have a 17" prop, the minimum clearance is 15% of prop diameter as clearance to hull.
    Thus 17 x 0.15 = 2.55 - so you're on the money.

    Recommended clearance however, is 20% = 3.4...so if you are getting around 2 1/2 -3"...that'll be about ok.
     
  9. gonzo
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    gonzo Senior Member

    That high-rise intake manifold should add a few horses to the old Palmer.
     
  10. missinginaction
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    missinginaction Senior Member

    Just happened to check in Gonz. Between the intake and the Barr manifolds (they have noticeably larger exhaust ports than the Osco's) hopefully she'll have a little more oomph. We'll see how it goes.

    That Weiand is just a dual plane for stock or mildly modified engines. I saved some weight as well.

    Like I said, we'll see.

    Have a great day!

    MIA
     
  11. missinginaction
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    missinginaction Senior Member

    Just a few more steps now........almost ready. This is the time that I always get stressed.

    IMG_20210612_173014575.jpg

    MIA
     
  12. 7228sedan
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    7228sedan Senior Member

    Looks great! can't wait to hear it...:)
     
  13. missinginaction
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    missinginaction Senior Member

    Just an update if anyone's following......besides 7728.......

    I pre-oiled her before I reinstalled the distributor. Checked the timing by spinning her over before I primed her and opened the fuel shut off valves. Stuffed as much water as I could into the heat exchanger, about 4 gallons. Checked everything over, twice. Added some prime and she fired right up. Settled into a nice smooth idle.

    I checked the manifold temperature, riser temp and felt the hoses. Everything looked OK but she was still warming up. Then......

    BANG! I took a couple of steps into the cabin and shut off the key. turns out that the hose I had attached to the coolant filter on the starboard side slipped right off. Just by feeling around I figured out that there was air and not enough water in the exhaust manifold, which turned to steam as the manifold heated up which created pressure which blew the hose off. No harm done but it did startle me.

    I drilled three 1/8th inch holes in the thermostat for bypass flow while the engine warmed up (and the thermostat stays closed). Maybe I need more bypass. More likely I need to get the air out of the system. Tomorrow I'll give her another run but will add water to the heat exchanger and through the coolant filters as well. My local O'reillys will have a few feet of Gates Green Stripe hose waiting for me in the morning. Since the hose that runs from the thermostat to the manifolds is under pressure I'm going to replace the Trident/Shieldflex hard wall hose I used in the current set up with a soft wall hose (without the wire reinforcement). I think the gates hoses will stay put a little better.

    Not quite there yet but a good idle is a good sign.

    MIA
     
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  14. Adler
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    Adler Senior Member

    Have you removed out of the engine's soft water circuit the thermostat device to be checked into a pot with boiling water ?
     

  15. missinginaction
    Joined: Aug 2007
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    missinginaction Senior Member

    Yes I have Adler. The engine had only been idling for a few minutes. Just as I shut her down I looked at the engine temperature gauge and it was only at about 110* F. The thermostat is brand new and opens at 160*. I'll have another crack at it in a couple of hours. Thinking about it overnight I think the most likely problem was air trapped in the manifolds. We'll know soon enough.

    MIA
     
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