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    Guest Message by DevFuse
     

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    E7 300 Valve Lash Help



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    9 replies to this topic

    #1 OFFLINE   Funky

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    Posted 15 November 2010 - 07:07 PM

    Hey, first post. My names rob. I've been an auto mechanic for a few years now but don't have too much experience workin on diesels, let alone bigger trucks. I've run into an issue setting valve lash on a 92 mack cab over with the e7300. I don't have alot of know how on mechanic lash adjusters and how to set them properly. The vibration dampener has timing marks as well as cylinder markings on it. I've been turning the motor til it ligns up with the marks, then setting the intake valve for that cylinder, then moving it to the next one and setting that and so on and so forth in firing order sequence. But it seems like on the next go around for the exhaust valves sometimes their too tight, sometimes they open up quite a bit. I'm just not sure what i'm doing wrong. If anyone could walk me through setting valve lash i'd be much appreciative. Also, how can you tell if a motor has dynatard. I don't see a sylenoid attached to the rocker arm rail, or anything else for that matter. Thanks in advance

    Rob...

    #2 OFFLINE   rhasler

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    Posted 15 November 2010 - 10:38 PM

    Hey, first post. My names rob. I've been an auto mechanic for a few years now but don't have too much experience workin on diesels, let alone bigger trucks. I've run into an issue setting valve lash on a 92 mack cab over with the e7300. I don't have alot of know how on mechanic lash adjusters and how to set them properly. The vibration dampener has timing marks as well as cylinder markings on it. I've been turning the motor til it ligns up with the marks, then setting the intake valve for that cylinder, then moving it to the next one and setting that and so on and so forth in firing order sequence. But it seems like on the next go around for the exhaust valves sometimes their too tight, sometimes they open up quite a bit. I'm just not sure what i'm doing wrong. If anyone could walk me through setting valve lash i'd be much appreciative. Also, how can you tell if a motor has dynatard. I don't see a sylenoid attached to the rocker arm rail, or anything else for that matter. Thanks in advance

    Rob...

    The intake and exhaust valves on the same cylinder are adjusted at the same time. When VS pointer and mark 1-6 on the dampner is lined up and number one cylinder is due for adjustment (pushrods will be lower in their bores than the pushrods in number 6) you will adjust both valves on cylinder number 1. A dynatard will have a solenoid in the rocker shaft towards the center pair of rocker arms. The electrical connections should come from the right side of the engine just above the exhaust manifold. The lash adjusters on the Dynatard exhaust rockers have a larger jam nut than the non-Dynatard rockers.
    "Mebbe I'm too ugly and stupid to give up!"

    #3 OFFLINE   Funky

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    Posted 15 November 2010 - 10:57 PM

    That's what i thought. No dynatard on this motor. Another thing though. What does the bolt in the center of the number 1 rocker arm mount do. The one that pins the shaft. Does that affect valve lash. and how do you adjust that if it does. Thank you for the help so far.

    #4 OFFLINE   rhasler

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    Posted 15 November 2010 - 11:00 PM

    That's what i thought. No dynatard on this motor. Another thing though. What does the bolt in the center of the number 1 rocker arm mount do. The one that pins the shaft. Does that affect valve lash. and how do you adjust that if it does. Thank you for the help so far.

    Should just be locking the rocker shaft to the front mounting bracket.
    "Mebbe I'm too ugly and stupid to give up!"

    #5 OFFLINE   Funky

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    Posted 26 November 2010 - 11:19 AM

    This truck is winning. I set the lash by starting on tc on the damper for cylinder 1. Then move down the line 5,3,6,2,4. After replacing the starter and a battery cable out finally started and easily at that. The motor knocks real bad. I pulled the valve cover and it just seems screwy.. some of the valves seem to open way to far when not on that stroke to adjust but theyre perfect when I rotate to adjust them. Also when it started giving it throttle didn't do anything, no change in rpms. Am I lookin at a bigger issue here?

    #6 OFFLINE   MACKS

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    Posted 26 November 2010 - 12:13 PM

    When you say you started out with no one on tdc make sure it's on the compression stroke.

    #7 OFFLINE   rhasler

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    Posted 26 November 2010 - 12:27 PM

    The valves are actually adjusted at 30 degrees after TDC. Unless this is an early E7 engine, you should have valve set markings on the flywheel. There should be a cover on the bottom of the flywheel housing held on with 6 small bolts. Remove the cover and you should be able to find the marks on the flywheel for adjusting the valves. If there are no marks on the flywheel you will need to make sure that the pointer at the front of the engine isn't bent before using it to adjust the valves.
    What kind of noise/knock are you hearing? Is the knock the reason you started adjusting the valves to begin with?
    "Mebbe I'm too ugly and stupid to give up!"

    #8 OFFLINE   Funky

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    Posted 26 November 2010 - 01:01 PM

    There aren't any markings on the flywheel. At least not any that line up with the damper markings. I took the rails off when I had the head off too replace a head gasket. The pointer doesn't appear to be bent. To make sure I was on compression I used a little sliding ruler to see which push rods were lower.
    could part of the problem be air still in one or more of the fuel lines?

    #9 OFFLINE   Funky

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    Posted 29 November 2010 - 06:10 AM

    Would installing the wrong fire rings for one Head make it run like this?

    #10 OFFLINE   Funky

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    Posted 06 December 2010 - 12:38 PM

    I found my problem.. I had 2 push tubes installed incorrectly. One bent real bad the other one was fine though. Installed a new tube, adjusted the lash, same way I did before and it fired right up and ran mint..

    Thanks for all the input!




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