First Engine Rebuild 420a, I need some help

Posted by DeathJunior, Jun 17, 2017

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  1. DeathJunior

    DeathJunior Proven Member

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    Joined Jan 19, 2017
    Springfield, Missouri
    Alright so I picked up my first eclipse ever earlier this year and It has a spun rod bearings internally and I have no idea for how long they have been like that. However, I really don't trust the original owner to have taken care of it since he let it sit for the last 2 years and he told me the reason why was the ALT. The ALT is fine but the engine rattles around 4k and above. So because the rods are probably going to need to sent to the machine shop anyway and I had access to a fresh block with new crank bearings and fresh crank for 50 bucks I just decided I'd go with an all new or remanufactured short block that I would build in my garage. This means block, pistons, rods, and a freshly rebuilt head and cams. It also allows me to rebuild the majority of the engine outside of the car meaning I can move it around my driveway for a bit longer while I build.

    I'm starting on the rod and piston assembly asap and the first issue I'm running into is how the rods are supposed to go. My new pistons have a F for front and an STD and arrow point which way goes towards the front of the engine. However I have no idea which way the rods go and my haynes manual doesn't say anything about it. These are press in so finding out is fairly important because I really can't go back if I make a mistake. Here's hoping someone on here knows which way the rods go on a 420A. I'm assuming the print on the side of the connecting rod goes forward but I really don't know.

    Any help would be awesome thanks
     

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  2. DeathJunior

    DeathJunior Proven Member

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    Joined Jan 19, 2017
    Springfield, Missouri
    well alright apparently no one knows the answer guess I'm just going to wing it
     
  3. DannyE

    DannyE Proven Member

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    Joined Dec 2, 2016
    Charles Town, West Virginia
    Not to familiar with the 420a but I do believe that the letters/numbers face the timing belt side as in the 4g's, one thing you do not want to do is mix up the the rod caps because they go in a specific orientation. Hope this helps you some bud.
     
    My DSM:
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  4. dsmcrzy

    dsmcrzy Proven Member

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    Trenton, Ohio
    Are these stock rods?
     
    My DSM:
    1996 Mitsubishi Eclipse N/T

    Street Build

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  5. dsmcrzy

    dsmcrzy Proven Member

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    Trenton, Ohio
    Also have you taken the block to a machine shop to ensure the bores are true (straight) and don't need any material taken off? If they are still true you will need to do a home at the very least to help the rings seat properly.
     
    My DSM:
    1996 Mitsubishi Eclipse N/T

    Street Build

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  6. DeathJunior

    DeathJunior Proven Member

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    Joined Jan 19, 2017
    Springfield, Missouri
    They are refurbished rods that I ordered as a set of 4, they have been refinished and prepped. I already installed all 4 with the freeze and heat method and a 3D printed jig I made. I figured out orientation by using a post in the neon 420a forums. I checked with my machine shop and I got it right however I may take one of the rods to the machine shop just to have them press one of the wrist pins in just a bit further since its off center by about a millimeter and I'm shooting for perfect. This should be a straight forward rebuild though the crank in this engine is likely dead so I have a freshly remachined crank shaft waiting and a set of .025 over bearings prepped. I'm replacing the head, pistons, rods, crank, and I have a set of crower stage one cams on the way. I figure why put the old cams in a new head if I can drop in a slightly better set. Then I'll build an 8psi turbo setup for it once I've finished fixing the headliner and built the audio system for it.
     
    spyderdrifter likes this.
  7. spyderdrifter

    spyderdrifter Supporting Member

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    Colorado Springs, Colorado
    Good idea to get the wrist pins pressed a bit more. Can't go wrong with a double check :thumb:
     
    My DSM:
    1997 Mitsubishi Eclipse Spyder GST (sold)

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    T28   manual
    1996 Mitsubishi Eclipse GSX (sold)

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    1996 Eagle Talon N/T (sold)

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