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  1. #1

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    Argh crap. Knocking from the engine after re-assembly. FIXED (?)

    One fun night after another, it just doesn't end!

    So I put in new LIM gaskets and when I started putting stuff back together I broke a rocker arm bolt when I accidentally overtightened it. (http://www.w-body.com/forum/index.php?topic=70015.0) Long story short, I managed to wiggle out the broken bolt from the head and replaced the rocker arm with a brand new one I got from the dealer.

    Well, I finally put everything together and the car started up instantly. But now there's a knocking sound from the engine!!

    So I have no problem tearing everything apart but how do I know what is knocking? I am blaming a loose rocker arm - or a misaligned pushrod, I mean, what else can it be? But, how do I find out exactly? Can I remove the valve covers and run the engine to see what is happening in there? Do you think the replaced rocker arm could be the culprit?

    Thanks!!

    PS. Oh yeah and I got the Check Engine light on too... 
    1999 Lumina LS, 3.1L V6 SFI<br />1995 Firebird Formula, 5.7L V8 FOR SALE<br />2001 Firebird Formula, 5.7L V8

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    Re: Argh crap. Knocking from the engine after re-assembly.

    ouch. that is not fun at all. does the noise sound more like upper or lower. I would have to say maybe the roller rockers are adjusted a little too tight
    rockfangd

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    Re: Argh crap. Knocking from the engine after re-assembly.

    i say find out what code its throwing

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    Re: Argh crap. Knocking from the engine after re-assembly.

    Get a long screwdriver, and place the tip of it on various locations around the engine. Hold your ear to the end of the handle while doing this, and you should be able to hear where the noise is the loudest. Go looking for troubles in that area.

    Good luck!
    - Jeff W.

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    Re: Argh crap. Knocking from the engine after re-assembly.

    Well, the knock is very clean sounding, rhythmic and not random, and it speeds up and slows down with revving the engine up/down.

    The only thing I can place the blame on is the rocker arm that I broke and replaced. I just wonder what could have gone wrong there? Is there any chance that it was not identically matched? I mean, it looked identical to the stock ones and it was a GM part. I dipped it in oil before I installed it and I torqued it to whatever I was supposed to (this time around) - 168 in-lb. It had no problem going in and staying in, so it didn't seem like I stripped the inside thread. And, besides, when I removed the broken stud it just unscrewed easily and it wouldn't have had the thread been broken.

    So, again, in order to see the valves, can I open just the valve cover and watch the rockers in operation or no? Or do I need to tear everything apart again?

    Thanks!!
    1999 Lumina LS, 3.1L V6 SFI<br />1995 Firebird Formula, 5.7L V8 FOR SALE<br />2001 Firebird Formula, 5.7L V8

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    Re: Argh crap. Knocking from the engine after re-assembly.

    I think you can remove the rocker covers on the 3.1 and still have everything assembled enough to to run, but I'm not sure. What I do know is that if you try to run the engine with the covers off, you will send oil flying EVERYWHERE!

    I know that you used to be able to get little guide plates that would keep the oil in when you had the covers off and the engine was running, but that was back when you had to properly adjust valve lash. I don't know if you can get any that are suitable for the 3.1.

    My guess though is that if your knocking is very audible (and possibly caused a code to be set), you will be able to see it plainly when you pull the covers.
    - Jeff W.

    1992 Grand Prix SE 3.4TDC 4T60e, 59,000. Proudly driving daily!
    1987 Fiero GT 5 Speed project car
    2005 Chevy Equinox LT (Wifey's Ride)

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    Re: Argh crap. Knocking from the engine after re-assembly.

    You changed the LIM gaskets... Was the oil all milkshakey??? You may have a bottem end giving up the ghost from washed bearings.
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    Re: Argh crap. Knocking from the engine after re-assembly.

    Quote Originally Posted by 1LoudCutty
    You changed the LIM gaskets... Was the oil all milkshakey??? You may have a bottem end giving up the ghost from washed bearings.
    No, actually the oil was clean because none of the coolant got into the oil. I noticed green puddles on the driveway and I was losing about a quart of coolant a week, so I got scared and decided to change the gaskets but no coolant got inside. However, I guess I wasn't careful enough when I took the manifold off and some coolant did actually spill inside since when I did the oil change after I put everything together about half a glass of coolant ran out before the oil...
    1999 Lumina LS, 3.1L V6 SFI<br />1995 Firebird Formula, 5.7L V8 FOR SALE<br />2001 Firebird Formula, 5.7L V8

  9. #9

    Re: Argh crap. Knocking from the engine after re-assembly.

    Pushrods are all installed correctly?
    Yeah, it's still on the road. 218K+ (WTF)



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    Re: Argh crap. Knocking from the engine after re-assembly.

    Quote Originally Posted by Brian P
    Pushrods are all installed correctly?
    Will find out tomorrow I guess. (Friday night somehow my girlfriend takes precedence ) For now I'm just hoping I don't have to tear it all apart again. It was my first time doing it and it took me about 6 hours to go one way and about 6 to go back up, not counting the time to get the broken bolt out, but now I think it should take me no more than 2 to open it all up again. I just hated having to drain the power steering, coolant and the fuel lines.

    Oh yeah, and if I do have to tear into it again, is there anything you'd advise me to replace while half the engine is apart?
    1999 Lumina LS, 3.1L V6 SFI<br />1995 Firebird Formula, 5.7L V8 FOR SALE<br />2001 Firebird Formula, 5.7L V8

  11. #11

    Re: Argh crap. Knocking from the engine after re-assembly.

    It's pretty common for lifters to stick afer doing the LIMG's. And damn do they make a racket.

    Also...........make sure no bolts made it down an intake passage or something...........I saw that happen once (my tech was lucky that *I* had a spare set of LG8 heads sitting in my garage that I got for free and hadn't gotten around to selling for a profit).
    1999 Dodge Neon R/T: Is MINE now.........WTF?? Maybe I DO have a working car for autoxing after all!<br /><br />1997 Honda Prelude SH: Still going tap-tap, and still being abused......8000rpm is good for it, I SWEAR.<br /><br />1993 Nissan Sentra SE-R: The parts and organ donor has appeared but has yet to be used.<br /><br />1992 Nissan NX2000: Rusting quietly while I try to figure out if a Bluebird long-block is really worth it.<br /><br />1991 Pontiac Grand Prix: Currently in 4th gear due to a shift-cable malfunction, but I&#39;m so lazy it may NEVER get resurected AGAIN.

  12. #12
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    Re: Argh crap. Knocking from the engine after re-assembly.

    Quote Originally Posted by BIGBULS
    It's pretty common for lifters to stick afer doing the LIMG's. And damn do they make a racket.

    Also...........make sure no bolts made it down an intake passage or something...........I saw that happen once (my tech was lucky that *I* had a spare set of LG8 heads sitting in my garage that I got for free and hadn't gotten around to selling for a profit).
    yup, and even more so if GMs TSB on proper torqueing isnt followed. I think it was release 2 years ago. So if you have torque specs older than that, they are more than likely incorrect.
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    Re: Argh crap. Knocking from the engine after re-assembly.

    Quote Originally Posted by spiderw31
    I think you can remove the rocker covers on the 3.1 and still have everything assembled enough to to run, but I'm not sure. What I do know is that if you try to run the engine with the covers off, you will send oil flying EVERYWHERE!

    I know that you used to be able to get little guide plates that would keep the oil in when you had the covers off and the engine was running, but that was back when you had to properly adjust valve lash. I don't know if you can get any that are suitable for the 3.1.

    My guess though is that if your knocking is very audible (and possibly caused a code to be set), you will be able to see it plainly when you pull the covers.
    x2
    You won't like it if you run your motor with no covers, but you may laugh about it someday if you do. Though it won't be that day. I wonder if you can get those deflectors. They do sort of work. My advice is try the screwdriver technique (you'll be surprised how effective it is if you've never tried it), locate the general area, pull covers and see what you see there. If you do pull the covers and run it, be sure to get some video!

  14. #14

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    Re: Argh crap. Knocking from the engine after re-assembly.

    OK, well guess what. I just ran my motor without the back cover. Not a single drop of oil went anywhere, it stayed right where it was.

    And before I did that I did the screwdriver trick. The screwdriver told me the knocking came from the back cover because when I listened to the front cover the knock was muddy and not as pronounced. Then I opened the back cover and took a good long look at all the rockers, touched every single one, made sure it wasn't loose, made sure it had a push rod underneath it, and so on. Then I decided to be brave and put everything together leaving the cover off and started the engine. Again, there was no oil splattered anywhere... But also I didn't have any idea what was knocking. All the rockers were going up and down just dandy. WHAT AM I LOOKING FOR??

    I did the screwdriver trick again and set the tip of the screwdriver on the plenum. The knocking was very pronounced there. Then I set it again on the front cover and the knocking was muddled... Right now I have no idea what to look for and I'm going to take off the front cover, maybe I'll see something there... Maybe someone can chime in?

    If anyone thinks he can tell by the sound of the knocking I can take a cell phone video and post it if it'll help.

    Thanks !!!

    Quote Originally Posted by redcar_96
    Quote Originally Posted by spiderw31
    I think you can remove the rocker covers on the 3.1 and still have everything assembled enough to to run, but I'm not sure. What I do know is that if you try to run the engine with the covers off, you will send oil flying EVERYWHERE!

    I know that you used to be able to get little guide plates that would keep the oil in when you had the covers off and the engine was running, but that was back when you had to properly adjust valve lash. I don't know if you can get any that are suitable for the 3.1.

    My guess though is that if your knocking is very audible (and possibly caused a code to be set), you will be able to see it plainly when you pull the covers.
    x2
    You won't like it if you run your motor with no covers, but you may laugh about it someday if you do. Though it won't be that day. I wonder if you can get those deflectors. They do sort of work. My advice is try the screwdriver technique (you'll be surprised how effective it is if you've never tried it), locate the general area, pull covers and see what you see there. If you do pull the covers and run it, be sure to get some video!
    1999 Lumina LS, 3.1L V6 SFI<br />1995 Firebird Formula, 5.7L V8 FOR SALE<br />2001 Firebird Formula, 5.7L V8

  15. #15

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    Re: Argh crap. Knocking from the engine after re-assembly.

    No oil at all? I dunno, but that just doesn't sound good to me. So the knocking is strongest from the plenum area? Collapsed or stuck lifter perhaps? If for whatever reason there wasn't enough oil to pump the lifters up (and I say that only because you saw no oil under the valve cover), that sure would make a nasty racket.
    - Jeff W.

    1992 Grand Prix SE 3.4TDC 4T60e, 59,000. Proudly driving daily!
    1987 Fiero GT 5 Speed project car
    2005 Chevy Equinox LT (Wifey's Ride)

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