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Sigh...valve adjustment screwed my engine up, runs rough

This is a discussion on Sigh...valve adjustment screwed my engine up, runs rough within the Technical / Maintenance forums, part of the General Discussion category; I have a 1995 GMC K1500 with a 350 that ran ok a few hours ago. It was running alright ...

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    1986 ATC250R FTW Nick_R_23's Avatar
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    Sigh...valve adjustment screwed my engine up, runs rough


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    I have a 1995 GMC K1500 with a 350 that ran ok a few hours ago. It was running alright but idle was a bit rough, so I changed out the plugs, wires, cap and rotor, which helped a lot. It still ran a bit rough afterward, so I figured with 200k miles it probably was well past due for a valve adjustment. I adjusted it per the manual (remove lash by tightening nut while rotating pushrods, then one full turn). This made it run like absolute crap, so I backed it off and tried again with the engine running, and tried 1 turn again, 1/2 turn, 1/4 turn, and 1/8 turn. 1/8 turn makes it run the best, but it's still not as good as before. Tried playing around with the timing which helped a little, and also replaced a bad EGR valve with didn't change anything. I have no engine codes. I've been trying to get this piece of **** to run right for nearly 10 hours straight and I'm about to just say **** it and set it on fire. Anyone have any suggestions? I've exhausted all my ideas.
    1988 Chevy Silverado 5.9L Cummins : 1968 Ford Mustang Pro-Touring

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    Re: Sigh...valve adjustment screwed my engine up, runs rough

    did you do it with the engine off? only part of the cylinder rockers, then rotate the motor and do the other half? I can't remember the exact order.
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    Re: Sigh...valve adjustment screwed my engine up, runs rough

    Do it again with the engine running. Slowly. Back them off and reset one at a time. Slowly. As soon as you hear the clatter stop, add 1/4 turn. If you do it with the engine running, you don't need to concern yourself so much about the firing order and EOIC.

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    1986 ATC250R FTW Nick_R_23's Avatar
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    Re: Sigh...valve adjustment screwed my engine up, runs rough

    Tried it both with engine off and engine running. Made no real difference that I could tell.
    1988 Chevy Silverado 5.9L Cummins : 1968 Ford Mustang Pro-Touring

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    Re: Sigh...valve adjustment screwed my engine up, runs rough

    Sounds like you need to start with the basics, do a compression check first.
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    Re: Sigh...valve adjustment screwed my engine up, runs rough

    OK here is what I have learned in the 20+ years of turning wrenches.

    DO NOT SET THE VALVES WITH THE ENGINE RUNNING!!

    THere is no way to know it they are all set the same. Assuming you have a healthy cam, all valves should be set the same and they need to be set on the flats of the cam not the lobes. With the intake on it is hard to tell which lifters are on the flats and which ones are just starting to come up on the lift of the lobe.


    1. Remove valve covers.
    2. Loosen all rockers so that they are not putting pressure on any part of the valve train
    3. Pull #1 to TDC
    4. Tighten rocker nuts until the point of zero lash. DO NOT assume zero lash by rolling the pushrod. Too many factors can cause the pushrod to still rotate freely beyond the point of zero lash. Lift the pushrod up and down instead until just at the point where there is no more play in the pushrod. This will assure zero lash with out any preload.
    5. For most lifters including stock 3/4 of a turn rotation of the rocker nut will set the proper preload of the lifter. Do steps 4 and 5 for both the intake and exhaust valves.
    6. Rotate the engine to the next cylinder TDC. CSB firing order is 1-8-4-3-6-5-7-2.
    7. Repeat steps 4-6 for each cylinder.
    8. Reassemble engine and test.

    This should get you back to how the factory set the engine and it will allow the engine to run as good as possible with the mileage you have. If it still runs rough or not as good as it did before you messed with it you may have damaged the valve train. You can flatten a cam pretty quick with poorly adjusted valves.

    Massey
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    1986 ATC250R FTW Nick_R_23's Avatar
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    Re: Sigh...valve adjustment screwed my engine up, runs rough

    I'm starting to lean towards failing lifters. I'm still getting a tick from one no matter how it's set, and a few of them make the engine run great for a few seconds after adjustment until they bleed off, then it's back to having a miss. I think I might just have to pull the intake and find out.
    1988 Chevy Silverado 5.9L Cummins : 1968 Ford Mustang Pro-Touring

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    Re: Sigh...valve adjustment screwed my engine up, runs rough

    are you still trying to adjust them when the engine is running?

    Massey

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    1998 Silverado 1500 5.7L
    1999 Camaro RS
    2000 Camaro Z28

    Is there life after death? F**K with my truck and you will find out!

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    Re: Sigh...valve adjustment screwed my engine up, runs rough

    Honestly IMO adjusting the valves while its running is the best way , I mean if the valve train is working right then its simple to do just back off untill it ticks then tighten till tick is gone then turn 1/2-1 turn then move to next rocker. Hydraulic lifters are easy and even if some of them are not adjusted exactly the same you have a little room for error unlike solid lifters. every engine I built and broke in I always set the valves before hand then after engine is broken in I re adjust them and some times the engine does run different . IMO if your still getting a tick after adjusting the valves while its running I would start to look at the lifters to see if they are not pumping up

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    1986 ATC250R FTW Nick_R_23's Avatar
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    Re: Sigh...valve adjustment screwed my engine up, runs rough

    I've tried both ways, with and without it running. It seems to do best right at zero lash.

    I'm going to pull the intake later this week and check out the lifters. Hopefully they are just full of crap inside as the engine is a bit dirty inside itself. I've had good luck doing this before.
    Last edited by Nick_R_23; 02-14-2012 at 12:09 AM.
    1988 Chevy Silverado 5.9L Cummins : 1968 Ford Mustang Pro-Touring

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    Re: Sigh...valve adjustment screwed my engine up, runs rough

    thats what I would do , hey how long have you had the truck and how long has it been running like this?

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    Re: Sigh...valve adjustment screwed my engine up, runs rough

    Just picked it up 2 weeks ago for a beater daily driver. It ran ok except the idle was a slight bit rough and it would hesitate slightly on acceleration. It had all original ignition parts, so I replaced them with all new stuff, and it made a big difference. Still had a little bit of a low end miss and I could hear a valve ticking around 1500-2000 rpm, so I figured it needed a valve adjustment. But now I think the lifters just aren't pumping up correctly.
    1988 Chevy Silverado 5.9L Cummins : 1968 Ford Mustang Pro-Touring

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    Re: Sigh...valve adjustment screwed my engine up, runs rough

    ya I would start with the lifters and go from there , the only thing else that would make a tick is a exhaust leak but you would hear that at idle .

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    1986 ATC250R FTW Nick_R_23's Avatar
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    Re: Sigh...valve adjustment screwed my engine up, runs rough

    Well, I pulled the intake last night and took a look at the lifters. They all seemed OK, all looked like they were pumped up fine. I tried pulling a few of them out of their bores, they move freely but stick once they become flush at the top of the bore, which makes me think they may be mushroomed and the cam may be junk. I tried checking the condition of the lobes through the oiling holes, but I couldn't see much. I think I'm just going to pull the engine and reseal it, and at the same time check out all the bearings, timing chain, cam, lifters, valves, and clean everything out.
    1988 Chevy Silverado 5.9L Cummins : 1968 Ford Mustang Pro-Touring

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    Re: Sigh...valve adjustment screwed my engine up, runs rough

    ya the cam could have a wiped lobe and thats why that valve would not adjust properly. IMO I think I would just do what you are thinking about doing , ya its more work but at least when its ripped down you can have a good look at everything and start out fresh. Then at least you know what you have when you put it back in

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    1986 ATC250R FTW Nick_R_23's Avatar
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    Re: Sigh...valve adjustment screwed my engine up, runs rough

    I'm going to try and get a good deal made on a Vortec roller cam setup, since I'll likely be replacing everything cam related anyway. It still has 65+ psi oil pressure when warm, so I figure the bottom end is probably still solid.
    1988 Chevy Silverado 5.9L Cummins : 1968 Ford Mustang Pro-Touring

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    Re: Sigh...valve adjustment screwed my engine up, runs rough

    The lifters not wanting to get out of the bore is pretty normal. There is a small layer of buildup on the bottom of the lifter that is a couple thousandths thick which makes them not want to pull up and out of the bores easily. Use some type of soft faced pliers to pull them up. If you twist as you pull it will help cut the buildup off faster. It is really hard to mushroom a lifter, they will usually shatter first. Now flattening a cam lobe is possible and now that the intake is off it is easy to tell. Get a dial mike with a magnetic base and measure the lift. All the lobes for the intake and all the exhaust should have the same lift. If so then you should be good and readjust as I have described earlier. It is much easier with the intake off.

    Massey

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    1998 Silverado 1500 5.7L
    1999 Camaro RS
    2000 Camaro Z28

    Is there life after death? F**K with my truck and you will find out!

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    1986 ATC250R FTW Nick_R_23's Avatar
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    Re: Sigh...valve adjustment screwed my engine up, runs rough

    I couldn't even get these ones to lift up past being level with the bore surface, I have no way to grab them. Best I can do is catch the inner ridge with a pick, but that doesn't do much. Either way, I'm at the point now where it's half torn apart, I just want to spend an hour and yank it out and check everything over.
    1988 Chevy Silverado 5.9L Cummins : 1968 Ford Mustang Pro-Touring

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    Re: Sigh...valve adjustment screwed my engine up, runs rough

    Yup that sounds about right. I have also gotten them out by using a pair of needle nose pliers and pulling them open on the inside lip of the lifter and lifting up. This is much harder than squeezing but it does work as well.

    Massey

    Click below for pics

    1998 Silverado 1500 5.7L
    1999 Camaro RS
    2000 Camaro Z28

    Is there life after death? F**K with my truck and you will find out!

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    1986 ATC250R FTW Nick_R_23's Avatar
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    Re: Sigh...valve adjustment screwed my engine up, runs rough

    Hmm, this is an interesting development. I tore the engine apart getting it ready to pull, and decided to yank the cam real quick. Its looks fine, no bad lobes. The wear pattern is a little close to the edge for my liking, but all the lifters seems to have been pumping up and spinning. I could only get to the first 4 lifters, but each one has an ever-so-slight dish. The pushrods aren't bent and none of the valve springs feel weak, nor do any valves seem to be sticking. I'm not really sure what to think now...
    1988 Chevy Silverado 5.9L Cummins : 1968 Ford Mustang Pro-Touring

 

 
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