Forged pistons on stock rods.

Posted by tom04841, Jan 15, 2009
Cylinder Head & Short Block - 4G63 cams, valvetrain, pistons, rods, stroker kits, 6-bolt swaps, hybrids, etc. Read this Forum's Strict Guidelines.

  1. tom04841

    tom04841 Proven Member

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    This may sound remedial, but does anything have to be done to a stock rod to run a forged piston? I know the pin is press fit from the factory, but once its pressed out, will the pins that come with the pistons slide thru the bore in the rod's small end, or does that need to be presed as well?
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  2. 300dollarGSX

    300dollarGSX Proven Member

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    It depends on what the piston pin requires. If it has a full floating pin, like Ross, you will need to have the rods machined. What type of pistons did you get (or are looking to buy)? Usually, instructions and requirements are included.
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  3. turboglenn

    turboglenn Proven Member

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    I was wrong..Sorry.. erased info to avoid the possibility of "net rumors" containing my mis-information.

    The rod that my pin fit throug is also a 1g rod, so that wouldn't make since why the 1g Wiseco pin slid right through it :/ (except for that they had JE pistons on them at one time..which could be the rod being modded for that

    I think maybe i've been too stressed to think for the last 3 days with all the things that hve went wrong on my DSM coupled with trying to quit smoking completely:(
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  4. 92awddsm

    92awddsm DSM Wiseman

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    The wrist pin in aftermarket pistons is the same diameter as stock. With stock rods, the pins need to be pressed. If you want to take advantage of full floating pistons, you either need to have the small end of the rod bored, bushed, and honed to size. With that said, you would spend close to the same as buying an aftermarket set of rods(eagle, etc).
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  5. tom04841

    tom04841 Proven Member

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    So which is it? Does the pin press into the piston or the rod? Just to clarify, i am leaning toward wiseco.
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  6. turboglenn

    turboglenn Proven Member

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    EDIT: I stand corrected - I didn't even have to press one out. Picking it up and looking at it while moving the rod was all it took. The press fit IS IN THE ROD, so go with orignial info.

    Now i'm off to work on my cr's issue again and will have to call said person who told me the press was in the piston :( I've probaly got something mixed up, so sorry for the mis-info.. off to edit original post

    Yea, i'm wondering now because the 1g rods i had laying that i stuck the 1g aftermarket (wiseco) pison on had been to a machine shop at one time, but supposedly nothing was touched on them, just checked and passed, and the wiseco pin slipped ight through.

    So, this l;eaves a chance that my 1g rods MAYBE had the small ends honed, but it's not on the receipt (but this is the same motor build that the first machiist screwed me on adn gave me back a junk motor)

    Since i'm more of a porche guy when it comes to "most motors assembled" i will go with the DSM wiseman for now, but i also have some stock pistons on stock rods down stairs, i'm going to press a pin out and see where the press fit really is. I was told it's in the piston becaue the bearing would sieze if the pin was press fitted to the rod...but now am confused..be back in a few after pressing the pin out of a 2g piston/rod combo.
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  7. 92awddsm

    92awddsm DSM Wiseman

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    It presses into the rod and floats in the piston. Aftermarket forged pistons use circlips to retain the wristpin and keep it from sliding out and scoring the cylinder bore when used with bushed, floating rods. Stock pistons rely only on the press fit into the rod to retain the wristpin. Aftermarket pistons can be used in stock rods with the pin pressed, just dont install the circlips that come with the pistons.
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  8. JamiesTSI

    JamiesTSI Supporting Member

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    Have the machinest drill an oil hole also. No need to bush the rod just go a .001" over the pin size. Apply a generous amount of lube to pin/rod bore when assembling.
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  9. 92awddsm

    92awddsm DSM Wiseman

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    The rod has to be bushed when using a floating pin. If not, the pin will gall or wear the rod excessively in a rather short time period. Thats like machining a rod to fit the crank without bearings.
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  10. JamiesTSI

    JamiesTSI Supporting Member

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    Use casidiam coated wrist pins.
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