What's that knock

[2kvert]

Hoping to shed some light before I start tearing into my 97 rinker 4.3.
i noticed a ticking noise while cruising back to the ramp last night opened the engine cover and yep. Definitely a bad noise. Seems to be higher up and not a knock { fingers crossed)
Valvetrain? Lifter , pushrod?
Anyone care to weigh in before I start wrenching?

 

[Bt Doctur]

seeing those batwings you could have stuck a valve and bent a pushrod. pull the valve covers to inspect

 

[2kvert]

Batwings?
and can I pull the valve cover without removing the exhaust manifold?

 

[Bondo]

Batwings?
and can I pull the valve cover without removing the exhaust manifold?

Ayuh,..... Those exhaust manifolds are known as batwings, 'n are also known to leak, internally due to core-shift in the manufacturing process,.....

The only safe fix, is replace 'em with the 2-pc versions,....

 

[2kvert]

Got the stethoscope out, doesn't really sound live the valve train but too high for a rod.
im suspecting the balance shaft.
Time to start pulling her apart I guess

 

[achris]

:lol::lol::lol::lol::lol::lol:

If the engine hasn't lost any power... It's a rust hole on the under side of the exhaust manifold. Had a V6 of the same age do EXACTLY the same a couple of years ago....

Yeah, sounds like a valve/lifter... It's not...

Chris..........

 

[2kvert]

:lol::lol::lol::lol::lol::lol:

If the engine hasn't lost any power... It's a rust hole on the under side of the exhaust manifold. Had a V6 of the same age do EXACTLY the same a couple of years ago....

Yeah, sounds like a valve/lifter... It's not...

Chris..........

I would like this to be the case, and it does make sense. Would I be able to Geelong the hole, or the bliwby while it's running? Yes I know it would be hot pretty quickly

 

[2kvert]

Pulled the valve cover, rockers and pushrods seem good.
it never lost power, infact it was running great.
Gonna look for the exhaust leak idea tomorrow

 

[achris]

.... Would I be able to Geelong the hole, or the bliwby while it's running? Yes I know it would be hot pretty quickly

Never heard those terms used... :noidea: Please elucidate...

Chris.........

 

[2kvert]

Sorry gotta stop using voice to text.
would I be able to see or feel the rusted out hole or is it internal? Not sure how marine exhaust manifolds are made

 

[achris]

Sorry gotta stop using voice to text.

yeah...

would I be able to see or feel the rusted out hole or is it internal? Not sure how marine exhaust manifolds are made

It's in the exhaust passage, right where it bolts to the head. Yes, you'll see it (if you can get low enough down), and if you put your hand down near the hole while it's running, you feel the hot exhaust gas pulses....

Chris......

 

[QBhoy]

If not the above (likely is)...are all the plugs right ?

 

[2kvert]

Well Damnit, felt all around the exhaust manifold, while running NO LEAKS,
Putbthe stethescope to it again, the noise is strongest at the back of the block and the bell housing. Suspecting a rod again although it doesn't seem like a deep enough tone. But I'm not sure what else it could be.
HAPPY INDEPENDENCE DAY. I'll be watching from the shore

 

[Scott Danforth]

pull the drive

run the motor

if the problem is gone, it may be the drive, u-joints or the couplling

if the problem is still there, then its engine related

if you havent been pulling the drive every year, inspecting the u-joints, checking the alignment and greasing the coupling splines....shame on you

and get rid of the bat wings

 

[H20Rat]

pull the drive

run the motor

Also pull the belt off to eliminate any accessory causing the noise. I've seen noises transmit through engines in strange ways, so eliminate every variable! Highly doubt it would be here, but... never know.

 

[San_Diego_SeaRay]

I was at my boatyard two days ago and asked the mechanic to help diagnose a "rumbling" sound. It was a video on my phone so he had a hard time diagnosing, but he mentioned that a common suspect for noises towards the back of the engine are the exhaust flappers. Not sure how other mechanics on this site feel about that but you might want to eliminate that as a suspect as well.

As Scott Danforth pointed out, if you pull the drive and run the engine you eliminate quite a few suspects right there. I have a Bravo so I would have to find an alternative way to supply water w/o a drive attached. Not sure of your situation.

 

[2kvert]

Both great ideas, thank you guys. I've had the lower unit off to do the impeller, never had the drive off in the 5 years I've owned it.
I'll start there before pulling the engine apart.

 

[2kvert]

I was at my boatyard two days ago and asked the mechanic to help diagnose a "rumbling" sound. It was a video on my phone so he had a hard time diagnosing, but he mentioned that a common suspect for noises towards the back of the engine are the exhaust flappers. Not sure how other mechanics on this site feel about that but you might want to eliminate that as a suspect as well.

As Scott Danforth pointed out, if you pull the drive and run the engine you eliminate quite a few suspects right there. I have a Bravo so I would have to find an alternative way to supply water w/o a drive attached. Not sure of your situation.

Good point what do I do about water? I guess a minute of running shouldn't be too big of a concern?

 

[Bondo]

Ayuh,..... Either jam the water hose into the water port in the gimbel housing, or plumb it into the in-comin' line at the t-stat,.....

With no water, the exhaust gases burn up the rubber parts in the exhaust system,.....

 

[2kvert]

Lower unit out, haven't started the engine yet.
is this too much play?