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Camshaft swap now not running!

This is a discussion on Camshaft swap now not running! within the Internal Engine forums, part of the LSx Technical Help Section category; I just installed a G5X1 cam 114 LSA and Crane 1.7 variable rockers and tried to start it. The car ...

  1. #1
    Member stephen02ws6's Avatar
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    Camshaft swap now not running!

    I just installed a G5X1 cam 114 LSA and Crane 1.7 variable rockers and tried to start it. The car will turn over but it seems like it turns over faster than normal. It isnt trying to fire at all and backfired though the intake a couple times. It is getting spark and fuel just not starting. Could it be that the rockers are tightened down too much and leaving the valves open? I talked to the shop i am taking it to to get tuned and they said it might be the tune. I know it needs to be tuned just i need it to start to get it on the trailer. Could it be that the valves staying open or the tune? Could there be something unplugged?

  2. #2
    Sounds like a low compression issue. Are you sure the cam is installed correctly? If so, suspect the rockers holding the valves open. Hell, suspect them anyway - why did you put aftermarket rockers on? Waste of money...

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    TJEA Retirement Home Dr.Crash's Avatar
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    Quote Originally Posted by stephen02ws6 View Post
    I just installed a G5X1 cam 114 LSA and Crane 1.7 variable rockers and tried to start it. The car will turn over but it seems like it turns over faster than normal. It isnt trying to fire at all and backfired though the intake a couple times. It is getting spark and fuel just not starting. Could it be that the rockers are tightened down too much and leaving the valves open? I talked to the shop i am taking it to to get tuned and they said it might be the tune. I know it needs to be tuned just i need it to start to get it on the trailer. Could it be that the valves staying open or the tune? Could there be something unplugged?

    mine had almost the same thing and it ended up being the cam positioning sensor. i replaced it and it started up no problem. maybe check there first (pluged in) they with an electrical tester you can check the resistance. Good Luck

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    Find someone with autotap and start looking for missing signals if possible. The backfire sounds like a valve issue though. Havent dealt with lsx engines much though.

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    Member stephen02ws6's Avatar
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    ya the cam is timed right. the way it is turning over it almost seems like there is no compression. i thought about the cam position sensor too. havent checked that yet. i have autotap. i hooked it up but didnt check the sensors and there wasnt any codes.

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    Member stephen02ws6's Avatar
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    what do you guys think? think it could be the valves staying open?

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    long and strong Willfully Armed's Avatar
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    CPS has nothing to do with the valves staying open.

    I would bet the cam is installed 90 degrees out of time.

  8. #8
    Member stephen02ws6's Avatar
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    cam is installing right. dot to dot all lined up. the cps will make the "timing" off, which might cause the backfiring. but the way it is turning over fast it seems like the valves are open.
    Last edited by stephen02ws6; 02-04-2009 at 09:09 AM.

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    Veteran 0rion's Avatar
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    any chance you swapped your coil harness' around and have them hooked up backwards? Check those coil pack harness'.

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    Member stephen02ws6's Avatar
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    Quote Originally Posted by 0rion View Post
    any chance you swapped your coil harness' around and have them hooked up backwards? Check those coil pack harness'.
    maybe. i did take the coils off to paint the brakets. how can you tell if they are backwards?

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    Veteran 0rion's Avatar
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    on my 98 they're labeled. Not sure on the 02's though. It sounds like a possible coil order issue if you're sure you have it dot to dot.

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    Member stephen02ws6's Avatar
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    Quote Originally Posted by 0rion View Post
    on my 98 they're labeled. Not sure on the 02's though. It sounds like a possible coil order issue if you're sure you have it dot to dot.
    ya triple checked the cam before tightening. i will swith the brackets and see if that works. if not i am going to end up readjusting the rockers.

  13. #13
    Member stephen02ws6's Avatar
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    is there any way it is the tune?

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    Senior Member rajiv1998's Avatar
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    Quote Originally Posted by stephen02ws6 View Post
    what do you guys think? think it could be the valves staying open?
    Pushrods to big??

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    Member stephen02ws6's Avatar
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    Quote Originally Posted by rajiv1998 View Post
    Pushrods to big??
    no i used the shorter ones that came with the rockers. i talked to crane and they told me to use the shorter ones.

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    Senior Member mrr23's Avatar
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    first thought was not using the 7.250 pushrods that are needed with the crane rockers. next thought, and most common, is improper adjusting of the rockers as they are adjustable. sounds like you have them too tight and have hung the valves open.

    follow these instructions on how to properly install and adjust the crane rockers.
    http://vincihighperformance.com/LS1%...TRUCTIONS.HTML

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    Member stephen02ws6's Avatar
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    Quote Originally Posted by mrr23 View Post
    first thought was not using the 7.250 pushrods that are needed with the crane rockers. next thought, and most common, is improper adjusting of the rockers as they are adjustable. sounds like you have them too tight and have hung the valves open.

    follow these instructions on how to properly install and adjust the crane rockers.
    http://vincihighperformance.com/LS1%...TRUCTIONS.HTML
    i used those instuctions. i think i just tightened them too tight for zero lash. went to finger tight, not to were they werent clicking. is that what im supposed to do?

  18. #18
    Senior Member mrr23's Avatar
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    do not do the finger tight method. the lifter plungers are very easy to push down. this is why they suggest lifting the rocker on the pushrod side to see when there is zero lash.

  19. #19
    Member stephen02ws6's Avatar
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    ok it sounds like i over tightened them then. i will try to adjust them tomorrow.

  20. #20
    Senior Member mrr23's Avatar
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    95% of the time when people use the crane rockers and it won't run, it's been because of the improper finding of zero lash. i've had these rockers on both of my cars.

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