Well, I have a distinctive ticking noise (lifter type noise)coming from the right side of my starboard engine. The engine is a 502 mag with 350 hours. As soon as I noticed/heard the ticking I shut the engine down and brought the boat back and trailered it. My questions are:

1- What do you think I need to have done/what could be wrong (top end job or just valves/lifters looked at)?

I was planning on refreshing the engines this winter.

2- What would the worst case scenario be and how much am I looking at to get it fixed (max dollar amount)?

Thanx

Rgrgoog

No way to know until you get into it. Could be collapsed lifter, bent pushrod, broken valvespring, etc. Sometimes it is just a piece of dirt or varnish that gets into a lifter and makes it stick. Only way to know for sure is to pull the valve cover.

Best case scenario would be what I described, which could be as little as a bottle of oil supplement followed by an oil change if you are extremely lucky. Expect a valve job to run $500 - $1500, depending on what needs to be done and how much of the work you do yourself. Worst case scenario would be a broken or tuliped valve, which could do major damage. This would be a total rebuild, which could easily head north of $5000. I have seen bearings pounded from detonation spreading out and catching a crank throw and making a ticking sound similar to a lifter noise, but that was a supercharged application.

Best bet is to pull valve cover and isolate the noise, followed by leakdown test. Get going - the season is upon us.

Just saw that you have superchargers. Prepare for that worst case scenario, especially if the exhaust valves are not inconel. Hope I'm wrong!

If the engine still has the original cam and valve train it has a flat tappet cam and non-adjustable lifters. Look for a roccker arm that is loose when the cam is on it's base circle. You might have lost a cam lobe, could be collapsed lifter, could be alot of things. Definately check it out before it does more damage.

Do you have headers? Have you made sure it's not an exhaust leak? Call me crazy but I've seen people mistake a valvetrain noice for an exhaust leak.

If the noise is coming from the left or right side it may not be a lifter. Most lifter taps you can hear in the center. Get a long screwdriver or something metal and stick it to the valve cover and the other end on your ear. Move it around until you locate the sound.

Great suggestion. People do mistake exhaust leaks for lifter noise.

Interesting on the exhaust leak. I have the original cast iron manifolds. The sound was definietely coming from the right side of the starboard engine. Only thing that lead me to something like a valve or lifter was that I had some slight exhaust smoke (just a tiny bit) coming from the far right exhaust. The ticking does speed up with the rpms. I shut it down as soon as I noticed it so hopefully not much damage has been done and this will be a small fix vs. a large project.

I only run 3-5 lbs of boost on the superchargers so I hope it is not the tuliped valve situation.

The engine was running fine, I opened up the engine cover and noticed the tapping. That is when I basically shut it down.

Turned out my knocking/ticking was a bad exhaust manifold gasket.

Nice, you got lucky !! could have been a lot wor$e.

I'm surprised to hear you have "stock cast exhaust manifolds" with blowers.