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Twin Intake Cam Mod

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  • Twin Intake Cam Mod

    This article courtesy of Nate from Plastik Racing...

    Twin Intake Cam Mod

    What you need:

    Intake camshaft (make sure the cam lobes are within spec)
    Cam sprocket. It doesn't matter which sprocket, they're both the same.
    A grinder
    A marker

    First, you have to grind a nub off on the exhaust side of the head. The intake cam won't fit without it ground down.

    Where the nub is:


    Why you need to grind it down:



    Alright, this last pic shows how the cam is normally lined up, with the alignment hole and the pip on the sprocket at TDC.

    With an intake cam,you have to turn the cam so it's 180* out from what the exhaust cam would normally be. So you put the pip so it's at BDC, NOT TDC!. Then retard it 1 tooth clockwise.



    TIP:

    Draw a line from the pip to the exact tooth that's 180* on the other side. Then mark the tooth that is 1 tooth CLOCKWISE from your 180* mark. That is your new TDC mark.

    The redline shows the 180 tooth, and the yellow mark shows the {9} degree retard. Notice the pip mark on the top of the red line that shows the cam is at TDC

    I wouldn't expect a huge increase in power. I think it would give a decent boost in power, while keeping the idle smooth. It's no heavy grind, but it will do well if you want a small boost for cheap in your DD without the lopy idle of some cams.

    You'd be surprised what the extra 5* of duration and .01" of lift will do.

    Update with more pics:

    I've actually done this now, and I can say it runs smoother. Not sure about the power gains since I did a rebuild at the same time with other mods. It is very, very smooth though.

    Nub ground down:




    Cam sprocket remarked for timing. The black dot is 180* off from the stock timing pip. The punch mark/black line is one tooth clockwise. *THAT NEW PUNCH MARK/BLACK LINE IS THE NEW TIMING MARK.



    I'm not sure how you would do this in the car.

    1. Grinding the nub down with the head on the car would cause metal shavings to go all over your engine. That would not be good

    2. The sprocket has to be removed in order to turn it 180*. As soon as you do that, the tensioner will want to take up the slack. The tinyest little bit of slack given, the tensioner will take it up. You would have to devise a really cool way to not allow any slack.

    So you would have to remove the head, and disassemble it to avoid getting metal shavings all over it. Then clean it really good when you're done grinding.

    And you would have to remove the timing chain cover so you can draw back and hold the tensioner. Which, if you're removing the head, you should have removed the cover anyway.



    *EDITED for third gen*

    The nub on the head doesn't exist like it does on the 2 older generations. So there is no need to grind down anything

    see below for picture.

    [attachment deleted by admin]

    • SattySc2
      #10
      SattySc2 commented
      Editing a comment
      Click image for larger version

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      Look closely next to my pinky finger at the tip of the lobe. you can see where it was wearing. Its hard to see in the crappy phone pic. I dont know exactly what happened. All i know is the car wasnt pulling as much vacuum after 3 days of driving (150 miles), it had lots of metal in the oil, and when i pulled the valve cover it was sparkling and there was metal all over. It was obvious the metal was coming from that cam. Now that i recall though, The head i pulled this cam from was a 95 (i believe or 96 cant remember) and it had a vertical crack in the casting from the cylinder 2 ex. port all the way up to the lifter on the exhaust cam. It was wierd. I have never seen a dohc crack before. I took the intake cam anyways because thats what my dad said i could use and I didnt think the crack effected the intake side... has this happened to anyone else?

    • THUD
      #11
      THUD commented
      Editing a comment
      Out of curiosity did you grind the nub off while it was in the car?

    • SattySc2
      #12
      SattySc2 commented
      Editing a comment
      No head was off. And I blew it off with the air gun and carb cleaned the metal shavings off!
    Posting comments is disabled.

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