347 Pistons and Rods

Discussion in 'Technical' started by Elephant, Apr 10, 2020.

  1. Elephant

    Elephant Member

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    I scored what I thought was a 302 roller block this morning and turns out it’s already been used as a 347. It’s already been bored and notched and came with the pistons, rings, and rods. I’m looking for opinions or experiences with the following:

    Icon 9922-030 FHR forged flat top pistons
    Eagle I-beam SCR-5400-CB forged rods

    The rods are hard to find info on. I got a couple forum hits but they’re old like 2002 so maybe they’re predecessors to current forged I-beams?

    After I clean them up some I can make sure I don’t see any major defects or anything but so far they look good. Would anyone reuse the rings or just get new?
     
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  2. Rick

    Rick G8I operations

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    Good news, you still got a 302 block, it's just been bored .30 over. You mentioned it's a 347 so I assume it came with a 3.400" Crank. Since you have it apart and assuming the cylinders look good I would just give it a lite hone and replace the reings and bearings. Find a good set of heads and you have yourself a nice little motor.
     
  3. Elephant

    Elephant Member

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    Thanks for all that info Rick! Sorry I didn’t mean to imply I didn’t have a 302 block, just that I thought I was getting a stock 302 block and not one that was already bored and notched. The pistons and rods were a nice bonus!

    It didn’t come with the crank so I’ll be getting that new. I also want to pop the cam and crank bearings out before I take it to get cleaned and magnafluxed.
     
  4. Rick

    Rick G8I operations

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    No biggy, sounds like you got it all sorted. A nice set of heads and your good to go.
     
  5. Elephant

    Elephant Member

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    Well bad news. Upon closer inspection I noticed one of the rods is bent and there is some damage to the skirt of the piston. Doesn’t look to be near the rings. Is it possible to buy a single rod and single piston? If not, if I order a whole rotating assembly will it even fit the bore?
     
  6. 71gold

    71gold Frank Cooper Supporting Member

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    is this a roller motor?
     
  7. Elephant

    Elephant Member

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    Yes it is
     
  8. Rick

    Rick G8I operations

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    Bent rod that explains why it didn't come with a crank, a bit of a set back for sure. But since your gonna be balancing your new crank you'll problly need a new set of rods to balance out. Pistons can be ceramic coated to fix the skirt, but might be cheaper to just buy a new set of Hypers . Since your not gonna be making a lot power parts should be fairly inexpensive.
     
  9. Elephant

    Elephant Member

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    I'm going to chat with the machinist today when I drop the block off. Before I buy anything I'm going to wait to make sure the inspection and magnaflux goes well.

    I confirmed I can get a new rod from Eagle. The piston isn't produced anymore but they offered to get my a similar one if I get them the weight. I'll see what happens with the machine shop first.
     
  10. 71gold

    71gold Frank Cooper Supporting Member

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    any reason you can't start over with known good parts...block, rotating assembly?
     
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  11. Elephant

    Elephant Member

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    Just $$$. About to drop some coin on heads and saving where I can but only if it makes sense. Not trying to make it prone to explosion by skimping.
     
  12. baddad457

    baddad457 Member

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    Don't be so sure. If those are the older Eagle 5.4 rods, they don't make them any more. Do they have a bolt & nut, or are they capscrew rods ? I went through this a couple years ago with my 331 when I bent a rod (HYDRO LOCK) The newer rods are lighter by about 20 grams. I didn't want to replace the whole set, so I came up with a solution. I added 20 grams by cutting a SBF head bolt bushing down to that weight, then pressing it up inside the piston pin. Piston weight can be adjusted if the piston is heavier by drilling into the flats on the bottomside. You'll also need to weigh the rings too. Total weight of the piston, pin, rings, bearing and rod need to match what you have now. A new crank also throws another variable into this, the whole assembly will need to be balanced as well.
     
  13. Elephant

    Elephant Member

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    Eagle confirmed I can get a replacement. The piston I definitely can’t. Machinist today said he’ll measure everything out and let me know what I need to replace. Should be in good shape.
     
  14. baddad457

    baddad457 Member

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    Yea, that's what they told me too. They were wrong. Like I said, if you have the nut/bolt SIR rods, they don't make these any longer. All they have are the lighter capscrew rods.
     
  15. Elephant

    Elephant Member

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    I'll double check those!
    A larger setback is that the block I took to the machine shop is no good. The main caps don't match the motor and the cylinder wall clearance is too big. I'm working on another block as we speak.
     
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