Mercruiser 350 v8 5.7 klanking noise

[staticlush]

I Have Been hearing a knocking sound on my port side of my I/O.
Its a baja force 220 with a 300 tempest v8 5.7.
At first i suspected it to be the roller rockers but I have adjusted them twice. I read that it could be a blown gasket or leak so i looked at my plugs and there is no water all though cylinder #7 was a little black on the plug. I had a blown gasket last year that i replaced. could this be my rocker arms?

 

[Bondo]

Re: Mercruiser 350 v8 5.7 klanking noise

Ayuh,.... Welcome Aboard,.... Never heard of lifters Klankin',... usually it's just a tickin',....

Have ya used an ole broomstick to isolate the noise,..??

 

[staticlush]

Re: Mercruiser 350 v8 5.7 klanking noise

Thanks for replying Bond-o! I have uploaded a video of my problem. I used a broomstick and cant hear the sound as well when i poke around where the sound is coming, I hear it better just listening to the top of the rockers maybe I'm doing it wrong. I also unplugged the the spark plugs from the two cylinders the noise is under and it didn't stop. If you watch the intake rocker on 7 (exhaust) it seems to be coming down right as you hear the sound.

VID 20130618 172520 112 - YouTube


Video link 2:
VID 20130618 172520 112 - YouTube

 

[alldodge]

Re: Mercruiser 350 v8 5.7 klanking noise

I Have Been hearing a knocking sound on my port side of my I/O.
Its a baja force 220 with a 300 tempest v8 5.7.
At first i suspected it to be the roller rockers but I have adjusted them twice. I read that it could be a blown gasket or leak so i looked at my plugs and there is no water all though cylinder #7 was a little black on the plug. I had a blown gasket last year that i replaced. could this be my rocker arms?

You said it was a knock, if it was a clapsing lift it would be more of a tap. Sounds don't work out very well in type but if it is a true knock, then that would lead me to a rod bearing as the most likely culprit.

You say no water thru #7 what about number 8?

 

[alldodge]

Re: Mercruiser 350 v8 5.7 klanking noise

Should have waited on the comment until after the VID. That sounds like a tap more than a knock. Sounds like a collapsed lifter. I would loosen them one at a time until the sound increases and bring them back down to original position or sound goes away or engine runs worst. If engine runs worst without sound being reduced you found the lifter

 

[staticlush]

Re: Mercruiser 350 v8 5.7 klanking noise

Should have waited on the comment until after the VID. That sounds like a tap more than a knock. Sounds like a collapsed lifter. I would loosen them one at a time until the sound increases and bring them back down to original position or sound goes away or engine runs worst. If engine runs worst without sound being reduced you found the lifter

If a lifter is collapses wont I be able to pres down on the rocker and it will go down? I believe i found the lifter i tightened the rocker and the sound went away momentarely engine ran worst but then the sound came back. would this happen?.

 

[staticlush]

Re: Mercruiser 350 v8 5.7 klanking noise

Ayuh,.... Welcome Aboard,.... Never heard of lifters Klankin',... usually it's just a tickin',....

Have ya used an ole broomstick to isolate the noise,..??

Thanks for replying Bond-o! I have uploaded a video of my problem. I used a broomstick and cant hear the sound as well when i poke around where the sound is coming, I hear it better just listening to the top of the rockers maybe I'm doing it wrong. I also unplugged the the spark plugs from the two cylinders the noise is under and it didn't stop. If you watch the intake rocker on 7 (exhaust) it seems to be coming down right as you hear the sound.

VID 20130618 172520 112 - YouTube


Video link 2:
VID 20130618 172520 112 - YouTube

 

[alldodge]

Re: Mercruiser 350 v8 5.7 klanking noise

If a lifter is collapses wont I be able to pres down on the rocker and it will go down? I believe i found the lifter i tightened the rocker and the sound went away momentarely engine ran worst but then the sound came back. would this happen?.

The lifters are small hydraulic cylinders, the oil pressure keeps them filled and solid. The preload is ajusted by bringing the valve to no-load position (closed), turn the stud with your finger until you feel resistance then add a 1/2 turn in. While running if you can back off the stud until the engine acts up then turn it back in until in runs correctly and add an additional 1/2 turn. Now if you turn in the stud it sounds good, tapping stopsand then it starts tapping again, your lift is calapsing and needs replaced. If you keep turning the lifter slow enough it will totally calaps the lifter and the tapping will return. In the old days racers only used solid lifiters and all valves tapped, but you have one failing.

 

[staticlush]

Re: Mercruiser 350 v8 5.7 klanking noise

The lifters are small hydraulic cylinders, the oil pressure keeps them filled and solid. The preload is ajusted by bringing the valve to no-load position (closed), turn the stud with your finger until you feel resistance then add a 1/2 turn in. While running if you can back off the stud until the engine acts up then turn it back in until in runs correctly and add an additional 1/2 turn. Now if you turn in the stud it sounds good, tapping stopsand then it starts tapping again, your lift is calapsing and needs replaced. If you keep turning the lifter slow enough it will totally calaps the lifter and the tapping will return. In the old days racers only used solid lifiters and all valves tapped, but you have one failing.

Ok Im pretty sure its a failing lifter once it heated up it went away. Also i re adjusted all rockers. but now i have another concern. attached is a video of another noise! This one concerns me much more.

VID 20130619 174507 001 - YouTube

 

[alldodge]

Re: Mercruiser 350 v8 5.7 klanking noise

I heard some noise but while not great not that bad. Not real sure what I'm hearing.

First how many hours is on the engine?

 

[staticlush]

Re: Mercruiser 350 v8 5.7 klanking noise

I heard some noise but while not great not that bad. Not real sure what I'm hearing.

First how many hours is on the engine?

578 hours. I do know from the repairs i have done that the impeller went out oil pressure got to high and the head gasket blew. i have replaced these things along with all new gaskets.

 

[alldodge]

Re: Mercruiser 350 v8 5.7 klanking noise

578 is quite a few hours and its starting to sound like your coming up on rebuild time. Many have achieved many more hours but they were "set your watch on time maintenance" engines. Do you have any very accurate numbers for oil pressure and compression?

 

[staticlush]

Re: Mercruiser 350 v8 5.7 klanking noise

578 is quite a few hours and its starting to sound like your coming up on rebuild time. Many have achieved many more hours but they were "set your watch on time maintenance" engines. Do you have any very accurate numbers for oil pressure and compression?

My compression's were all around 150 - 170 my oil pressure gets to 70 at 3000 rpms

 

[alldodge]

Re: Mercruiser 350 v8 5.7 klanking noise

Wish mine was putting out 70 @ 3000 rpm, mine makes it to 50 and I have 250 hours. Looks like your in pretty good shape if your numbers are accurate

 

[Don S]

Re: Mercruiser 350 v8 5.7 klanking noise

With the engine running, just but your finger on each rocker arm one at a time just above the push rod. You will be able to tell the sound difference which one it is. Then slowly tighten down the noisy rocker arm and see if the sound goes away.
Report back what you find.