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Camshaft journal clearance question

Posted by Kapok6, Sep 14, 2014

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  1. Kapok6

    Kapok6 Proven Member

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    Fort Worth, Texas
    I disassembled my head for a thorough inspection and cleaning. I noticed on the #1 intake cap and journal, there was a gouge with some high and low point, and some nice scuffing on the correlating journal. Some light scratching on the other journals too, but not as bad as #1.

    So I took some 600 grit paper to them, then some 1000 grit, then a rag with some aluminum polish. I was able to knock it down to where I can't catch it on my fingernails.

    Now I know plastigage isn't going to be very accurate on an aluminum journal in comparison to some iron main caps, but I wanted to try to get some kind of idea where I am.

    So all the intake journals measured at .004" with one being .0045". I then did the exhaust cam as sort of a control, and they were all between .003" and .004", (so .0035"ish). with one closer to .004".

    Now, the FSM gives a range of .002"-.0035."

    Am I screwed with the intake journals being about .0005 out of that range? I run 10w40 or 20w50 oil. Not sure if that makes a dif on cam journals the way it does on main and rod bearing clearances.

    Please no opinions here unless there are facts to back it up. Not looking for, "Yeah brah, your head is trashed, I would get another one, but I have no info or experience to back that statement up or explain why."

    Looking for fact based information on this.

    Thanks.

    -Ryan
     
    Kapok6

    Street Build 2K  0

    1991 Mitsubishi Eclipse GSX
    11.3 @ 130.75 · 1G DSM
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  2. Dericsh

    Dericsh Supporting Member

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    Joined Nov 25, 2002
    Pearl River, Louisiana
    I know this post is old, but did you end up running that head? I have a head with one pretty bad looking cam journal from what I think was starvation after an oil pump failure. I was considering cleaning it up and taking some measurements like you mentioned.
     

    Street Build 154  1

    1991 Mitsubishi Eclipse GST
    fwd · manual · 1G DSM
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  3. biglady112

    biglady112 Proven Member

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    Joined May 20, 2004
    Commerce City, Colorado
    I sand every head and have never had an issue to 1000whp and 10,000rpm. Almost every head I see now has some cam journal damage of some kind.
     
  4. Dericsh

    Dericsh Supporting Member

    331
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    Joined Nov 25, 2002
    Pearl River, Louisiana
    what do you use to sand it? Thanks.
     

    Street Build 154  1

    1991 Mitsubishi Eclipse GST
    fwd · manual · 1G DSM
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  5. biglady112

    biglady112 Proven Member

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    Joined May 20, 2004
    Commerce City, Colorado
    Just my finger and sand paper. I do 220grit then 320. I never go smoother than that and don’t have issues. Even bone stock cars like yours always seem to have issues. I have been doing it for about 15 years now.
     
  6. biglady112

    biglady112 Proven Member

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    I do both the cap and the head by the way.
     
    Dericsh likes this.
  7. Dericsh

    Dericsh Supporting Member

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    Joined Nov 25, 2002
    Pearl River, Louisiana
    thanks for the info- I posted a new thread right before you responded to this one but I’ll post the photo here too. do you mind looking at this one how bad it looks if you can tell I know it’s hard to see in a photo
     

    Attached Files:

    Street Build 154  1

    1991 Mitsubishi Eclipse GST
    fwd · manual · 1G DSM
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  8. biglady112

    biglady112 Proven Member

    1,206
    168
    Joined May 20, 2004
    Commerce City, Colorado
    Sand it and run it. Remember a groove is a low spot and not the end of the world. Maybe a little pressure loss but, you can get away with some deep ones if you have to. Not recommended or ideal obviously. High spots are where the problem lies.
     
    Dericsh likes this.

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