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Thread: Stamping Rods

  1. #1

    Default Stamping Rods

    Want to stamp connecting rods #1-8...
    Is it better to stamp (punch) with rod on bench or on journal?
    Thanks,
    Ed
    Last edited by ThunderStruck; 06-22-2018 at 06:25 PM.

  2. #2
    FEP Senior Member BMW Rider's Avatar
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    If they weren't marked, we typically did it before disassembly to ensure everything was kept correctly sorted.

  3. #3
    FEP Power Member 306gt's Avatar
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    stamp the rod and the cap before taking it apart.
    85 G.T. All motor
    337 c.i.d 11.44-120 mph

    1984 1/2 G.T. 350 (13.01-106 mph)

    1984 G.T. (Daughters car)

    1986 G.T. (Son's car) (12.99-105 mph)

  4. #4
    FEP Super Member erratic50's Avatar
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    We would always use a fine center punch and make our marks on a flat surface of the rod cap before disassembly like the others said above. I haven’t messed with it in years, but lord knows I helped my dad and others put together more engines than I care to think about when I was a kid. (And many were NOT Fords - lol).

  5. #5

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    Thanks,
    But these are new rods...

  6. #6
    FEP Senior Member BMW Rider's Avatar
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    No real need to number them then as long as you keep the caps together with their respective rods. The only other concern is if the pistons have been individually fitted to the cylinder bores. The numbering is more for ease of keeping everything sorted for reassembly.

  7. #7

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    Quote Originally Posted by ThunderStruck View Post
    Thanks,
    But these are new rods...
    So what would be the purpose in numbering them then? That will be left for the next guy that rebuilds that engine when he/she takes it apart.

  8. #8
    FEP Senior Member BMW Rider's Avatar
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    Numbering is to help keep the caps and rods matched and to keep pistons in their bores into which they are fitted. In production, there are variances in the machining of individual components. No two piston are likely to be exactly identical in dimension, that is why when you read specs for an engine there are fit tolerances. Usually a set of pistons will be selected to be very close in range though. On a production line, that was not always the case. Blocks were bored and honed, then pistons selected to fit within the range of tolerances. It would not be unusual to find differences of a couple thousandths in any given engine. If you were to disassemble and rebuild that engine and inadvertently mix up a larger piston in a tighter bore or vice versa, the results may not be ideal. With the caps and rods, they are sized as a unit, meaning they are bolted together and then the bore is honed to size. If a cap from another rod were mixed up, the bore would be very unlikely to line up correctly and bad things would surely result. Same goes for the main caps, they are bolted in place then align bored as a unit.

    If you are building the engine and taking care to fit each piston to the bores, then numbering the rods will help to keep everything sorted as you go through the build process. You could easily stamp each rod out of the engine, just be careful in how you secure them to ensure you are not doing damage. Using a piece of aluminum bar or pipe as an anvil to slip the rod end on so the hammering forces are not potentially deforming the bore would be one idea.
    Last edited by BMW Rider; 06-24-2018 at 11:21 AM.

  9. #9
    FEP Super Member gr79's Avatar
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    Default mark the parts

    Some like to pre number or id new right away. Others do it later. If they remember to.
    Easy to dismiss or overlook details when engine tear down and build procedures are unfamiliar tasks.

    Select fit is common for certain critical parts. More now than ever. Color, bar, stamped, casting codes.
    Say when a crank is ground. Factory or machine shop.
    Bearing size selection usually immediate before part leaves area to help eliminate measuring errors later on.
    Engine plant crank depts have machines to inspect, measure, record, mark. Same with block area.

    Best reinstall any engine part to be reused where it came from, like crank bearing caps.
    Marking or id them is key, especially if all look alike.
    Similar to tagging wp bolts during disassembly which have to be reinstalled in correct spot.
    Bag assy parts separately, like oil pan bolts from valve cover bolts.
    Also mark orientation when important. Certain parts ng assembled backwards. Stuff like that.

    Nothing like a leftover or missing bolt or 2 after engine is done.
    Or guessing 'how or where did this go'?
    Last edited by gr79; 06-24-2018 at 03:49 PM.

  10. #10

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    Quote Originally Posted by BMW Rider View Post
    Numbering is to help keep the caps and rods matched and to keep pistons in their bores into which they are fitted.
    Just going to go ahead and cut that down to the most import part and add that I totally agree. What he said^^^^. So there is absolutely no reason to number anything before it gets installed. You do fit these to the bores they are going in etc. all of that is true. If your builder removes all 8 of the piston assemblys after they installed all of them, find a new builder. There is No reason to number these during the build of a new engine.

  11. #11
    FEP Senior Member BMW Rider's Avatar
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    Quote Originally Posted by homer302 View Post
    Just going to go ahead and cut that down to the most import part and add that I totally agree. What he said^^^^. So there is absolutely no reason to number anything before it gets installed. You do fit these to the bores they are going in etc. all of that is true. If your builder removes all 8 of the piston assemblys after they installed all of them, find a new builder. There is No reason to number these during the build of a new engine.
    I always fitted the pistons to their bores when I was honing the block, thus they needed to be numbered to keep them sorted for correct assembly later on.

  12. #12
    FEP Super Member erratic50's Avatar
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    Forged pistons tend to rattle at startup unless tolerances are precise. Annoying but not catostrophic. Ring gap is far more important - especially if boosted or sprayed.

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