Bad engine tap

[Temporary Sanity]

Took a 2 hour ride this weekend port engine dropped 500 rpms once readjusted throttles and everthing seemed fine.
spent 5 mins at 1,000 rpms thu no wake zone and then slowed to idle to dock and the port engine started tapping very loud. Check the oil, full and clean. Engine runs smooth

Any common issues with the valve train on 2001 7.4 mpi horizons? I have 225 hrs on them.

Compression checks are next and pull valve cover.......I hope it's not major issue.

 

[Redhook98]

Tapping? Or knocking? Big difference as far as $$$ goes.....

 

[Thomas Molin]

Took a 2 hour ride this weekend port engine dropped 500 rpms once readjusted throttles and everthing seemed fine.
spent 5 mins at 1,000 rpms thu no wake zone and then slowed to idle to dock and the port engine started tapping very loud. Check the oil, full and clean. Engine runs smooth

Any common issues with the valve train on 2001 7.4 mpi horizons? I have 225 hrs on them.

Compression checks are next and pull valve cover.......I hope it's not major issue.

Sorry I don´t know the technical english words, but I had the same issue abut a year ago. In my case it turned out to be one of the "6 inch pins" that holds the lifter under the valve cover that had been bent and turned loose. I was very lucky that the pin still was there.

My suggestion is that you idle the engine and try to find out which side the tapping comes from. It´s a few hours work to take the valve cover off since you have to dismount the exhaust manifolds to get to the lower bolts of the cover.

 

[Temporary Sanity]

Engine tap.......compression test done today-good, valve covers pulled-no signs of failed parts. Shop is trying to find what cylinder is tapping tomorrow. Could be a bad lifter or cam shaft? Does any one know if this engine has roller lifters? Exhaust elbows not leaking, oil is clean.

 

[johngus]

sure it is not an exhaust leak at the head to manifold?

 

[fc3]

it has roller lifters. Use a mechanics stethoscope to determine if the noise is the top or the bottom end. Odds are, you have a collapsed lifter.

 

[northern]

If the lifter is hydrolic putting a quart of ATF in the engine oils some times will clean things up in a car and clean the lifter. No idea if boat lifters are solid or hydrolic.
In my opinion best to have a mechanic look at it rather than try a remidy that some times work.