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Degree Cams 4G64 w/4G63 head Question?

Posted by VETDRMS, Mar 12, 2011

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  1. VETDRMS

    VETDRMS Proven Member

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    Vancouver, Washington
    I am about to wrap up the build on this motor and wanted to verify I set everything up right.

    I am using an OEM Galant DOHC 4G64 belt and Fidanza 4G63 adjustable cam gears. I found a few threads on marking these 1/2 tooth off for use on a 4G63. I made these marks and installed straight up at TDC they lined up pretty well.

    I degreed the cams using the centerline method as recommended by GSC. The nose of the cam is pretty flat so it was hard to find peak lift, but as long as you stop at the same point on either side of the lobe on the dial indicator it shouldn't matter, right?

    The intake cam was right on at a measured centerline of 107*. The exhaust cam, however, when installed straight up was also on a 107* centerline. I had to advance the exhaust cam gear 3* to get it to the correct centerline of 113*?

    If the difference in deck height caused by milling the block/head was the cause of this, wouldn't both the intake and exhaust cams needed to be adjusted by the same amount if the cams were ground correctly? (from what I have heard GSC's cams are usually dead on). The block is at a zero deck and a decent amount of material was removed from the head and I am using a .066" gasket. I was surprised to see the intake cam right on.

    Here is how everything lines up at true TDC with the exhaust cam advanced by 3*:

    CamsDegreed.jpg

    At true TDC both dowels are angled slightly in toward each other. Everything look ok?

    Thanks!

    Travis
     
    Last edited: Mar 14, 2011

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  2. dsmarmy777gst

    dsmarmy777gst Proven Member

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    Looks good to me. That looks like how mine matched up, so I'd say your good to go! What cams are you running on this build?
     

    327  0

    1996 Mitsubishi Eclipse GSX
    · 2G DSM
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  3. VETDRMS

    VETDRMS Proven Member

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    dsmarmy I am running GSC S2-R custom cams. Here is the cam card:

    S2RCamCard.jpg
     
  4. Absit

    Absit Proven Member

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    Slightly unrelated, why do they advertise duration at .040 instead of .050 like every other cam card I've looked at? Got a picture of the cams outside of the engine?
     
  5. dsmarmy777gst

    dsmarmy777gst Proven Member

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    Decatur, Illinois
    274s also i see, weird. There is another thread ive been involved in about degreeing the adjustable cam gears for better driveability on our 274 regrinds(i also have the same cams). Hopefully you dont have those issues.. So i'm definitely interested to see how it runs/idles with the exhaust retarded 3* and the intake zeroed out.
     

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    1996 Mitsubishi Eclipse GSX
    · 2G DSM
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  6. delta448

    delta448 DSM Wiseman

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    Joined Jan 13, 2006
    Waynesburg, Pennsylvania
    As long as that's what GSC recommends for their cams, you're set.

    4g63 camshaft degreeing

    Advertising mostly. It makes the cam sound better to someone who is fixated on how large a number something is. This is also why some other brands have extremely aggressive cams for what they're being advertised as. But some manufacturers like to use the metric system (since the US is about the only place still using anything else), so the preferred measurement there is 0.1mm, which is very close to 0.040".
     
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  7. VETDRMS

    VETDRMS Proven Member

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    Vancouver, Washington
    Delta: Thanks for answering those questions. GSC does recommend the centerline method so I would think their cams are symmetrical. The measurements at .040" were a little off and so was max net lift but I think I may have had some amount of lash in my solid lifters. There is no way to adjust them once the cams are in which is really frustrating so it was trial and error. The measured valve lift was .447", or about .013" short of what is listed on the spec sheet. Also, as I understand it, any angular mismatch between the measuring device and the centerline of the valve will impact the max lift and readings at .050". It seems the centerline method, at least on cams that are symmetrical, is a more fool-proof method to measure cam/crank phasing.

    I just wanted to confirm my method for installing the belt initially was correct. I lined up the modified marks on the gears when first installing the belt. I understand that the higher deck height will pull the cams about 1 tooth in the advanced direction, but isn't the 1 tooth longer Galant belt supposed to make up for this?

    Thanks!
     
  8. delta448

    delta448 DSM Wiseman

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    Waynesburg, Pennsylvania
    If you have feeler gauges, a set of digital calipers and plenty of known thickness shims, setting zero lash shouldn't be trial and error more than once.

    It is easier, but I wouldn't use it without being absolutely sure that the cam being used is symmetrical.

    The DOHC 2.4 belt's tooth count was simply a matter of deck height and optimal auto tensioner range. The cam gears were differently aligned and marked for that engine in order to correct the cam timing. Any differences in the belts would be negated by the revised cam sprocket timing marks Mitsu used on that engine.
    So since you're using adjustables meant for a 63, the marks will be off of zero by the amount the OEM sprockets were different between the two engines, assuming there is no other measuring error or machining tolerance error present in the system.
     
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  9. VETDRMS

    VETDRMS Proven Member

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    I did not have any shims, which would have made the process much easier. I had to move the cam, pull the rocker arm, remove the lifter, adjust, reinstall and test again to get as close to 0 as I could. If I do it again I will just measure the lash with a feeler gauge and set lifter height with my calipers. It would be nice if the adjuster on the BLE solid lifters was accessible when installed.

    I checked the centerline several points on either side of max lift and the calculated centerline was the same so it should be symmetrical.

    Thanks. :)
     
  10. dsmgsx98

    dsmgsx98 Probationary Member

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    Did you know that that cam is advanced 3* not retarded
     

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    1998 Mitsubishi Eclipse GSX
    · 2G DSM
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  11. VETDRMS

    VETDRMS Proven Member

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    Vancouver, Washington
    dsmgsc98 Yes, I fixed it on the link forums but forgot to here, thanks.

    Ok, I re-did everything to make sure it was right. I set zero lash by adjusting the BLE solid lifters, installing the rocker arm, cam, and two camp caps and made sure I could not fit a .001" feeler gauge and confirmed that the roller turned with no force on the cam. It was trial and error to make sure the valve was not opening off the base circle but after a little while I got them both set as close to true zero lash as possible.

    Once that was done I could accurately measure the valve open and close events and compare them to the cam card.

    Here is the cam card:

    S2RCamCard.jpg

    Here is the valve timing per my measurements:

    Intake:
    • Opens: 8* BTDC
    • Closes: 44.5* ABDC
    • Max Lift: 0.454"
    • Centerline: 106.875 @ +/- 0.050" from peak lift
    • Duration @ 0.040": 232.5*
    • Duration @ 0.005": 263*
    • Duration @ 0.000": 273.5* (seat-to-seat)

    Exhaust:
    • Opens: 50.5* BBDC
    • Closes: 2* ATDC
    • Max Lift: 0.451"
    • Centerline: 112.75 @ +/- 0.050" from peak lift
    • Duration @ 0.040": 232.5*
    • Duration @ 0.005": 263*
    • Duration @ 0.000": 273.5* (seat-to-seat)

    So, the duration @ 0.040" appears to be about 3* less than advertised. The intake cam opens 3* late but closes when it is supposed to and the exhaust cam opens when it is supposed to but closes 3* early.

    I am used to the advertised duration being measured at 0.005" for the domestic cams I have degreed, but it looks like GSC uses true seat-to-seat duration for their advertised duration.

    On my setup the exhaust cam needed to be advanced 3* to be on the correct centerline and the intake cam was right on straight up.

    I believe I can stop worrying about this now. Thanks for your help! :)
     
    Chepeturbo likes this.
  12. Chepeturbo

    Chepeturbo Probationary Member

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    Joined Dec 25, 2018
    Managua, Central America
    Belt with 1 more only affect in tensioner adjust travel.1 complete tooth requires only to set marks properly...when 1/2 tooth requires a more complex compensation.
     
  13. Chepeturbo

    Chepeturbo Probationary Member

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    Joined Dec 25, 2018
    Managua, Central America
    Hello..new here ...never degree cams before .got a pair of used regrinded cams from a parted 2g and installed in my engine.would appreciate a lot any help .need to find values and learn the procedure with centerline method..
     

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