2000 Mercruiser 3.0L engine noise

[Stingray190LS]

Having lots of trouble with my engine recently... Main reason why I replaced lifters is because of the noise - pls see video. Anyone familiar with this? If so what did you do to resolve?

I'm having trouble adjusting the valves correctly and will try again (this time maybe adjust while running - will this resolve a valve stuck open if adjusted while running and tell the difference since engine will run better?!?)... If you notice, only at 20psi and would the engine shaking be related to that since still not idling properly?

 

[tpenfield]

A bit more background info would be helpful. As I understand it, you replaced the lifters because of the noise and the noise is still there. :noidea:

So, it is not the lifters that is the problem. Have you run a compression test or cylinder leak test?

Definitely a valve noise, but could be more with the valve(s) themselves and not the lifters. . . . unless they are way out of adjustment. Check the actuation of each valve as you rotate the engine by hand.

 

[Stingray190LS]

I am planning on readjusting the valves again and will pay attention more on the "lash" rather than the push rod spin (I was also too worried about making sure at TDC and ended up using the cloth method in the cylinder and waited until blown out - please advise if I can do a better method?). So then at TDC = #1 firing order and then adjust the valves involved... and then how do I know at #4 firing order... spin the crank 360... so does that mean if I'm at TDC on #1 one clockwise spin toward the marker again at 0 = #4? (this is where I mess up the valve adjustment I think...)

Would you rather suggest to conduct a compression and leak test first?

I've read that it is easier to spin the engine by hand if all spark plugs are off...
- if they are all off, can I still check the actuation properly of have to put back each 3 plugs depending on the cylinder im working on?
- where and how would I turn the engine by hand? (I usually bump it by using key in ignition and and it spins clockwise while others mentioned to turn by hand counter clockwise??? which way is correct?)
- where and how can I observe if the valve is stuck open?

How do I know if I have a bad valve? leak down test? I guess my main goal is to adjust valves properly and then leak down or compression test?

 

[Bt Doctur]

sure sounds like a loose rocker arm. remove the valve cover and see if all the tops of the studs are all the same height.
try it this way. starting at the front of the head the valves are E,,I,I,E,E,I,I,E. starting at the front set, rotate the motor until an intake valve (the second rocker arm)opens and closes.You are now on its compression stroke with both valves closed.adjust the pushrods.
go to the next intake valve and do the same thing , and so on until are are adjusted

 

[tpenfield]

4 stroke engines are 2 revolutions of the crankshaft for one complete cycle of the cylinders. So, you very well could have not been at TDC (Compression stroke) for all of the cylinders. Once you find TDC (compression stroke) for #1, then each cylinder is 180 degrees (half turn) of the crankshaft for a 4 cylinder engine (6 cylinders are 120 degrees, 8 cylinders are 90 degrees)

I would get the zero lash set first, to see if your troubles go away with a proper valve adjustment.

 

[harleyman1975]

I'm concerned about his oil pressure. It actually went down when he reved it up. If the lifters cannot be adjusted to make the noise stop I would look at it possibly being a bad bearing.

 

[Stingray190LS]

Wanted to get some clarification... I have seen a video on YouTube for valve adjustment (http://youtu.be/QAlCVA5cCQM) and the cylinder order was shown as 1/2/3/4... 1 on the belt drive side and then 4 towards the flywheel. I'm confused because the spark plug wires order as plugged in goes (1/3/4/2) where #1 is plugged in on #4 cylinder/spark plug. Am I incorrect? And that's only for spark plug wires?

My question is, if TDC is referred to as having it on 0 tab marker and #1 firing order... At 0 tab I should see or line up the needle on #1 spark plug wire... but that's on #4 cylinder? Do I have this all confused?

 

[Bondo]

My question is, if TDC is referred to as having it on 0 tab marker and #1 firing order... At 0 tab I should see or line up the needle on #1 spark plug wire... but that's on #4 cylinder? Do I have this all confused?

Ayuh,..... Welcome Aboard,..... The crankshaft turns twice for each turn of the cam shaft,...

Turn the motor over 1 turn, 'n the rotor will be pointin' to #1,....

The valves are adjusted on each cylinder, when that cylinder is Tdc, Compression stroke,....

 

[M.A.CCruiser]

i know it sounds a little crazy- and it may be a stretch - but start the engine and run your hands along the edge of the exhaust manifold to feel for air puffs. My friends stingray 3.0 was making the same noise last night - blew the exhaust manifold gasket. Sounded like a valve noise because of the proximity to the manifold.

 

[Silvertip]

Do not confuse cylinder number with firing order. Cylinders are numbered 1, 2, 3, 4 from the front of the engine. Firing order refers to the order in which the cylinders fire. They do NOT fire in 1,2,3,4 sequence. They fire in 1,3,4,2 order. Oil pressure is an issue on this engine but get valve adjustment first. A bad oil pressure relief spring may be an issue as well.