Fear the worse, loud banging sound comingfrom the engine

[tpenfield]

Re: Fear the worse, loud banging sound comingfrom the engine

Did 'we' get a compression test yet? I am wondering about the oil level and the 600 RPM loss. I would also be checking the valves and pushrods, etc for proper operation. . .

 

[jasonmd13]

Re: Fear the worse, loud banging sound comingfrom the engine

Did 'we' get a compression test yet? I am wondering about the oil level and the 600 RPM loss. I would also be checking the valves and pushrods, etc for proper operation. . .

I'll try to rent a compression tester today. I have never checked a regular motor, only a jet ski. Do I remove all the spark plug wires first then check each plug with the rest of the plugs in?

 

[tpenfield]

Re: Fear the worse, loud banging sound comingfrom the engine

I'll try to rent a compression tester today. I have never checked a regular motor, only a jet ski. Do I remove all the spark plug wires first then check each plug with the rest of the plugs in?

No . . . you can google compression test and get the procedures on the Internet.

 

[emilsr]

Re: Fear the worse, loud banging sound comingfrom the engine

Have you pulled/read any of the spark plugs? What do they look like (grey, black and wet, missing)?

 

[jasonmd13]

Re: Fear the worse, loud banging sound comingfrom the engine

Have you pulled/read any of the spark plugs? What do they look like (grey, black and wet, missing)?

They were extremely black, so I replaced them

 

[emilsr]

Re: Fear the worse, loud banging sound comingfrom the engine

They were extremely black, so I replaced them

All of them? Any worse than the others?

 

[jasonmd13]

Re: Fear the worse, loud banging sound comingfrom the engine

Ok, got the compression tester. All the cylinders had between 112 to 120, but one had 95 the first time, then 60, then 45, all the way to 0. Took the value cover off the side with this cylinder, and this is what I found......

 

[tpenfield]

Re: Fear the worse, loud banging sound comingfrom the engine

Looks broken to me. Hopefully, you can just reset the rocker arm and all will be good :noidea:

How is the push rod???

 

[jasonmd13]

Re: Fear the worse, loud banging sound comingfrom the engine

Looks broken to me. Hopefully, you can just reset the rocker arm and all will be good :noidea:

How is the push rod???

Missing.... The pushrod is gone, and the magnet didn't pick it up. I've got a small camera coming tomorrow, so hopefull we will find it, and it willbe good . It ran good for 2 days on 5 cylinders.

 

[Grub54891]

Re: Fear the worse, loud banging sound comingfrom the engine

Push rod is gone? It must be in the lifter valley,bent out of shape. I have to wonder if it hydrolocked and bent it,sending it south.I thought it sounded like lifter noise in the video.
Grub

 

[tpenfield]

Re: Fear the worse, loud banging sound comingfrom the engine

If the pushrod is gone . . . I wonder what was making the load tapping/banging noise. . . . Maybe it was there for a while . . .

 

[jasonmd13]

Re: Fear the worse, loud banging sound comingfrom the engine

Push rod is gone? It must be in the lifter valley,bent out of shape. I have to wonder if it hydrolocked and bent it,sending it south.I thought it sounded like lifter noise in the video.
Grub

How does a motor hydrolock?
The magnet didn't pick up the push rod, but luckily my brother has a small camera with pliers. Hopefully we will find it and then see what caused it to bend

 

[Volphin]

Re: Fear the worse, loud banging sound comingfrom the engine

That intake manifold has to come off. The pushrod is down in the lifter valley. Looks like the nut came loose on the rocker arm. Hopefully the pushrod didn't damage anything by getting wedged in the cam.

 

[jasonmd13]

Re: Fear the worse, loud banging sound comingfrom the engine

Does anyone know how much to torque the rocker arm nut? I didn't see it in my service manual. Also, found the intake rocker arm has the pushrod pushed through the arm.

 

[Watermann]

Re: Fear the worse, loud banging sound comingfrom the engine

That's because you don't torque that type of rocker down, they have to have the lash manually adjusted. Look for the section on adjusting the rocker arms to get the correct settings. May as well do all of them too while your at it. Also check that stud to make sure the reason the push rod came loose isn't that the stud lifted up from the head.

It's clear in the picture that the rocker arm nut is not down on the stud as it should be, did you loosen it before you took the picture?

 

[Volphin]

Re: Fear the worse, loud banging sound comingfrom the engine

That's because you don't torque that type of rocker down, they have to have the lash manually adjusted. Look for the section on adjusting the rocker arms to get the correct settings. May as well do all of them too while your at it. Also check that stud to make sure the reason the push rod came loose isn't that the stud lifted up from the head.

Yes do check the stud. Some are press fit, others threaded. I suggest adjusting them all when the engine is at idle. But first, use this to get you in the ball park:

To adjust the valves, it is vitally important that the cam lobe for the valve you are adjusting is on it's base circle... the round part of the egg shaped cam lobe, not the pointy end.

INTAKE VALVE ADJUSTMENT: Rotate the engine by hand until the exhaust valve rocker begins to push the spring down on the cylinder your are adjusting. That puts the intake valve cam lobe on it's base circle. Adjust the nut while trying to move the pushrod up and down or twisting it. As soon as you feel a slight drag, and I mean SLIGHT, tighten the intake 1/4-1/2 turn more.

EXHAUST VALVE ADJUSTMENT: Rotate the engine again by hand until the intake valve compresses fully and moves 1/2 way to 2/3 of the way back up. This puts the exhaust valve on it's base circle. Adjust the nut while trying to move the pushrod up and down or twisting it. As soon as you feel a slight drag, and I mean SLIGHT, tighten the intake 1/4-1/2 turn more.

Only do this for the cylinders that are having problems.

Then, start the engine. Loosen the adjusting nut on the valve you want to adjust slowly until you hear it make a TAP TAP TAP noise. Then slowly tighten the nut until the tap sound stops. Now add 1/4 turn tighter. You may notice that it takes a moment for the engine to stabilize when you add 1/4 turn. This is normal. Move to the next valve and repeat until they are all adjusted. Button up the VCs and go boating.

 

[jasonmd13]

Re: Fear the worse, loud banging sound comingfrom the engine

That's because you don't torque that type of rocker down, they have to have the lash manually adjusted. Look for the section on adjusting the rocker arms to get the correct settings. May as well do all of them too while your at it. Also check that stud to make sure the reason the push rod came loose isn't that the stud lifted up from the head.

It's clear in the picture that the rocker arm nut is not down on the stud as it should be, did you loosen it before you took the picture?

No, I didn't loosen it, that picture is as soon as I removedthe valve cover . I found outyest erdaythe intake rocker arm beside it , has the pushrod pushed through the rocker arm.

 

[jasonmd13]

Re: Fear the worse, loud banging sound comingfrom the engine

Yes do check the stud. Some are press fit, others threaded. I suggest adjusting them all when the engine is at idle. But first, use this to get you in the ball park:

To adjust the valves, it is vitally important that the cam lobe for the valve you are adjusting is on it's base circle... the round part of the egg shaped cam lobe, not the pointy end.

INTAKE VALVE ADJUSTMENT: Rotate the engine by hand until the exhaust valve rocker begins to push the spring down on the cylinder your are adjusting. That puts the intake valve cam lobe on it's base circle. Adjust the nut while trying to move the pushrod up and down or twisting it. As soon as you feel a slight drag, and I mean SLIGHT, tighten the intake 1/4-1/2 turn more.

EXHAUST VALVE ADJUSTMENT: Rotate the engine again by hand until the intake valve compresses fully and moves 1/2 way to 2/3 of the way back up. This puts the exhaust valve on it's base circle. Adjust the nut while trying to move the pushrod up and down or twisting it. As soon as you feel a slight drag, and I mean SLIGHT, tighten the intake 1/4-1/2 turn more.

Only do this for the cylinders that are having problems.

Then, start the engine. Loosen the adjusting nut on the valve you want to adjust slowly until you hear it make a TAP TAP TAP noise. Then slowly tighten the nut until the tap sound stops. Now add 1/4 turn tighter. You may notice that it takes a moment for the engine to stabilize when you add 1/4 turn. This is normal. Move to the next valve and repeat until they are all adjusted. Button up the VCs and go boating.

Thanks for that information, it will help a lot. I had to remove the manifold to remove the valve cover, to do these adjustments, I need to pit the manifold back together? Someone said the valves could over heat if I didnt
Thanks again

 

[Volphin]

Re: Fear the worse, loud banging sound comingfrom the engine

Thanks for that information, it will help a lot. I had to remove the manifold to remove the valve cover, to do these adjustments, I need to pit the manifold back together? Someone said the valves could over heat if I didnt
Thanks again

Yes, the exhaust manifold should be fully installed and the boat on water muffs to do the running adjustment. The manual adjustment can be done before you install it.

 

[Silvertip]

Re: Fear the worse, loud banging sound comingfrom the engine

That ticking sounds like it is high on the motor so I too would suspect a broken/warn rocker arm. I've seen push rods that go through the rocker arm, pivot ball areas worn through, push rods with the end worn to point where the oil hole is closed up and keepers that have popped off the valve stem. Do not overlook a broken fuel pump arm spring. Those can break and they sound just like a rod knock. A mechanics stethoscope or a piece of hose can be used to try and pinpoint the area on the motor the noise is most noticeable. Pop a rocker cover and check the valve train.