motor knocking sound
03-05-2015, 08:20 PM
#16
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why its knocking
If you have already changed your oil to a heavier weight and then you must pull the injector plugs and spark plugs one by one while the vehicle is on and if nothing changes I would take off the valve cover and make sure the bridges for your lifters are not cracked or broke. But if the sound it knock disappears while unplugging injectors or plugs it most likely caused by (Piston slack) and If everything is good it all depends if you recently use any fuel system cleaner or octane booster because if so I also could have sent and bunch of nasty gunk and carbon build up straight to you engine ( most likely why oil is black or darker) soo add some Lucas oil treatment and run a couple of cycles Seafoam . I wouldn't do more then 2 cycyles back to back. And thus will remove the sticky gunk in cylinders and lfters and etc.
03-06-2015, 12:40 AM
#17
Old fart with a wrench
I think you've gone too far already. The rockers seem to have some burnt on oil on their sides, probably from the overheat. You should have started it up with the cover off and observed the valve action. Pressing down on the valve end of each rocker will show if there's a stuck lifter because it will go quiet. From your pics, it seems the springs are good and I can't see any obvious problems with the rockers or studs.
The only thing you can do now is pull the rod caps one at a time and check the condition of the bearings. Be sure to retorque them properly. If there's a problem with them, you'll see it. You can also check the condition of the cylinder walls for scoring. Without aluminum in the oil pan, the pistons are probably okay. Use a good strong light and check the bottom of the pistons for cracks, especially around the pin bosses.
The only thing you can do now is pull the rod caps one at a time and check the condition of the bearings. Be sure to retorque them properly. If there's a problem with them, you'll see it. You can also check the condition of the cylinder walls for scoring. Without aluminum in the oil pan, the pistons are probably okay. Use a good strong light and check the bottom of the pistons for cracks, especially around the pin bosses.
03-06-2015, 01:31 AM
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I think you've gone too far already. The rockers seem to have some burnt on oil on their sides, probably from the overheat. You should have started it up with the cover off and observed the valve action. Pressing down on the valve end of each rocker will show if there's a stuck lifter because it will go quiet. From your pics, it seems the springs are good and I can't see any obvious problems with the rockers or studs.
The only thing you can do now is pull the rod caps one at a time and check the condition of the bearings. Be sure to retorque them properly. If there's a problem with them, you'll see it. You can also check the condition of the cylinder walls for scoring. Without aluminum in the oil pan, the pistons are probably okay. Use a good strong light and check the bottom of the pistons for cracks, especially around the pin bosses.
The only thing you can do now is pull the rod caps one at a time and check the condition of the bearings. Be sure to retorque them properly. If there's a problem with them, you'll see it. You can also check the condition of the cylinder walls for scoring. Without aluminum in the oil pan, the pistons are probably okay. Use a good strong light and check the bottom of the pistons for cracks, especially around the pin bosses.
03-06-2015, 08:20 AM
#19
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I'm with Dave1123 I think you got to ahead of your self from the vid that you have it doesn't sound nowhere close to a bottom end noise. But I'm not there to hear it may be the video throwing me off. Did you start it with the valve cover off? And hold tension on each rocker.
O and another thing check the touque converter bolts.
O and another thing check the touque converter bolts.
03-06-2015, 02:09 PM
#20
Old fart with a wrench
Good catch, Chunky! Loose torque converter bolts will usually quiet when put in drive. While your at it, check for a cracked flex plate.
03-06-2015, 02:52 PM
#21
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I did not turn it on with valve cover off, i did not know at the time it was a possibility. I already checked the TC bolts and they are fine and from what i could see the flexplate is fine also. I really thinking its up top too!
03-08-2015, 01:46 PM
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I think you have found your problem. Some lifters will bleed down but if they don't pump back up that's when you will have a problem. When you were moving that rocker around I couldn't tell if it was pushing on the push rod or not is the slack at the ball end to the rocker like the lifter plunger isn't returning. could you collapse the lifter? Hopefully the cam lobe isn't wiped. You have a few options there you could throw all new lifters in or just the one up to you. It's a flat tappet so your really supposed to replace cam and lifters as a set but I've done it and got away with it. these things aren't running crazy spring pressure like a race motor when you have no choice. See if you can fish that lifter out and check the cam lobe. If it checks out an you choose to put just that lifter in it make sure you put some assembly lube on the face and drop it in. Fire it up make sure it pumps up and bring it up to about 2000rpm for a while to brake that lifter in.
03-08-2015, 02:28 PM
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I was pushing down on the push rod end pretty good. It feels like im plunging lol. All the others did NOT move up or down like that 1 did.
Rockauto has the same exact lifters as autozone for about $35 cheaper! Im going to just replace all of them. Im so glad I found a problem. I say a problem and not The problem because I haven't replaced lifters and turned on the 4.0, but I have high hopes that this is the issue!
Rockauto has the same exact lifters as autozone for about $35 cheaper! Im going to just replace all of them. Im so glad I found a problem. I say a problem and not The problem because I haven't replaced lifters and turned on the 4.0, but I have high hopes that this is the issue!
Last edited by js03wj; 03-08-2015 at 02:30 PM. Reason: edit
03-08-2015, 09:18 PM
#25
Old fart with a wrench
From my experience with drag motors, you can put new lifters on an old cam, but old lifters on a new cam will wipe it out in short order.
One thing to check also is the ball under the stud nut and the rocker for cracks or wear. IDK about the 4.0, but Chevys are known for the studs pulling out of the head because they are only pressed in. On race motors, we usually converted them to screwed-in studs, but that was with high-lift cams and higher spring pressures.
I've never has a 4.0 apart, but you may need to pull the head to change the lifters. If you're going that far, you might as well change the cam and chain.
I'm just guessing, but I'm willing to bet the lifters are toast and the cam is all right. You can check the cam for lift with a dial indicator on the pushrods after you remove the rockers. When you get the lifters out, if the bottoms are worn concave, the cam is badly worn as well.
One thing to check also is the ball under the stud nut and the rocker for cracks or wear. IDK about the 4.0, but Chevys are known for the studs pulling out of the head because they are only pressed in. On race motors, we usually converted them to screwed-in studs, but that was with high-lift cams and higher spring pressures.
I've never has a 4.0 apart, but you may need to pull the head to change the lifters. If you're going that far, you might as well change the cam and chain.
I'm just guessing, but I'm willing to bet the lifters are toast and the cam is all right. You can check the cam for lift with a dial indicator on the pushrods after you remove the rockers. When you get the lifters out, if the bottoms are worn concave, the cam is badly worn as well.
03-09-2015, 05:50 PM
#26
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From my experience with drag motors, you can put new lifters on an old cam, but old lifters on a new cam will wipe it out in short order.
One thing to check also is the ball under the stud nut and the rocker for cracks or wear. IDK about the 4.0, but Chevys are known for the studs pulling out of the head because they are only pressed in. On race motors, we usually converted them to screwed-in studs, but that was with high-lift cams and higher spring pressures.
I've never has a 4.0 apart, but you may need to pull the head to change the lifters. If you're going that far, you might as well change the cam and chain.
I'm just guessing, but I'm willing to bet the lifters are toast and the cam is all right. You can check the cam for lift with a dial indicator on the pushrods after you remove the rockers. When you get the lifters out, if the bottoms are worn concave, the cam is badly worn as well.
One thing to check also is the ball under the stud nut and the rocker for cracks or wear. IDK about the 4.0, but Chevys are known for the studs pulling out of the head because they are only pressed in. On race motors, we usually converted them to screwed-in studs, but that was with high-lift cams and higher spring pressures.
I've never has a 4.0 apart, but you may need to pull the head to change the lifters. If you're going that far, you might as well change the cam and chain.
I'm just guessing, but I'm willing to bet the lifters are toast and the cam is all right. You can check the cam for lift with a dial indicator on the pushrods after you remove the rockers. When you get the lifters out, if the bottoms are worn concave, the cam is badly worn as well.
Ok cool! Will check the rockers when I remove them. Im not really planning on switching the cam out to be honest. Im kinda doing this on a budget since I got the car so cheap so im trying to keep low on spending. Im already replacing almost all gaskets, water pump, hoses, thermostat, timing chain, plus tune-up things. I appreciate all the help! I will keep everyone posted as soon as parts arrive.
03-09-2015, 06:24 PM
#27
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That is a sign of a bad lifter. Oil has to remain in lifter to hold it up. If you are moving it up and down about 3/16 of an inch that is the spring your moving. If motor has been off for quite awhile they will leak down and this would be normal. Start engine with valve cover off and see if it pumps up then shut engine off and try pushing down on lifter again.
03-09-2015, 07:30 PM
#28
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That is a sign of a bad lifter. Oil has to remain in lifter to hold it up. If you are moving it up and down about 3/16 of an inch that is the spring your moving. If motor has been off for quite awhile they will leak down and this would be normal. Start engine with valve cover off and see if it pumps up then shut engine off and try pushing down on lifter again.
Last time motor was running was about 3 weeks ago. not sure if that's long of a time. I did turn the motor over a few times by hand and rocker still showed the same result.
03-09-2015, 09:36 PM
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I would but oil pan is off along with radiator, waterpump etc. Im in the middle of replacing them as well so I prob wont get to it soon. Im waiting on parts. Wouldn't the other lifters bleed down and not just one tho?