Oh Oh ..... What did I do now?
 

Today was the first chance I've had to get on the water since I got the boat back from the mechanic (valve job).

Sunny, warm and flat seas ..... just a perfect day offshore!
Engine performed flawlessly for about five miles (58mph @ 4600rpm) then throttled back to enjoy the view and get ready to push the stick to the max. Got back on plane and noticed the engine running rough, peaked at about 4000rpm, and when throttling back to listen, I could hear a thumping "knocking" sound from the engine. I thing it was coming from the port side (near the batteries) but can't tell for sure.

I made a video of the engine (listen to the audio) as we came back in. The engine did make it back to port OK but you could feel the roughness, even at idle.

www.desertcom.com/videos/700rpm.WMV
www.desertcom.com/videos/1500rpm.WMV

Any idea of what happened?

Re: Oh Oh ..... What did I do now?
 

sounds like something up top let loose...of left loose by the mechanic....hard to tell though....

Re: Oh Oh ..... What did I do now?
 

Sounds like a really loose rocker arm. Pull the covers and look.

Re: Oh Oh ..... What did I do now?
 

It sounds a lot like an engine I had sounded when one of those self locking nuts backed off from the rocker arm stud. If it is, replace all the nuts. Self locking nuts only have so many times that the self locking works.

Re: Oh Oh ..... What did I do now?
 

or arms..

Re: Oh Oh ..... What did I do now?
 

Hope it's not a spun bearing on the crank.

Re: Oh Oh ..... What did I do now?
 

would a bearing have that chatter??

Re: Oh Oh ..... What did I do now?
 

loose rocker

Re: Oh Oh ..... What did I do now?
 

I would not run it anymore, pull the valve covers, turn it over with a breaker and find the loose rocker, once found make sure the whole deal is good, ftom the valve to the nut, maybe the valve failed but it sure sounds like a major knock from above. Also document the hell out of it or take it directly to the dude and say WTF.

Re: Oh Oh ..... What did I do now?
 

That could certainly be a spun bearing. I had a 454 rebuilt 2yrs ago, the builder put a bearing in backwards = no oil = nearly identical sound after about 30mins.

Good Luck to you, hopefully its something a little less complicated

Re: Oh Oh ..... What did I do now?
 

Sorry to hear about your troubles. It really sucks first time out after motor work.

Pretty windy a few miles south of you. I'm surprised you didn't get any.

Re: Oh Oh ..... What did I do now?
 

Weather was A+ at Marina del Rey.
Sunny at 65* with 1' wind waves (not even) and maybe a 2-3' swell about 15 seconds (seemed like miles) apart. I was actually going to push WOT in the open sea!

FYI
The engine is a 454 Mag MPI with 150 hours
(Only 1 hour since the valve job and tune up)

Oil Pressure stayed at normal!
40+PSI at idle (700rpm) and up to 45-50psi at 1500rpm
limping home.
Was about 60psi when I noticed the problem.

Re: Oh Oh ..... What did I do now?
 

Bring it back . Waranty 100% .

Re: Oh Oh ..... What did I do now?
 

Sounds like valvetrain to me.

Re: Oh Oh ..... What did I do now?
 

Thanks so much for your input everyone.
I do plan to take it back to the mechanic next week.
It is so helpful to at least have a pretty good idea of whats wrong when I take it in.
Not being mechanical, I get BS'd quite often.

BTW
Merry Chismas & Happy New Year to all at OSO

Re: Oh Oh ..... What did I do now?
 

Sound like top end most likely a rocker arm don't think think its lower end you would have lost oil pressure.Could also have a lifter that bleed down.I am hopeing that the one of the keepers did not come out of one of the valves though good luck

Re: Oh Oh ..... What did I do now?
 

Did the mechanic resemble this guy?...... :D

Re: Oh Oh ..... What did I do now?
 

Sounds like you have yourself a diesel.

Re: Oh Oh ..... What did I do now?
 

You probably have a broken lifter or a flat cam lobe because your engine dosen't use lock nuts to adjust thin e rocker arms they are bolted down into position and the machine shop that repaired the heads should have set the valve height and it won't be adjustable once the engine is assembled. I own a boat repair shop in socal and if you have any questions feel free to call Mobile Marine Service ask for Matt at 714 369 7410 and good luck.

Re: Oh Oh ..... What did I do now?
 

Loose Rocker pull the covers.

Re: Oh Oh ..... What did I do now?
 

Don't touch the engine , take it back to your mechanic! He should make it good!

Re: Oh Oh ..... What did I do now?
 

Thanks everyone .....

I plan to call the mechanic on Tuesday morning to help me with this problem and get me back on the water. All of your ideas and comments have been a great help.

Happy Holidays!

Re: Oh Oh ..... What did I do now?
 

That`s funny, right there ! :D

Re: Oh Oh ..... What did I do now?
 

It's even funnier if you know who the picture refers to... :D

Re: Oh Oh ..... What did I do now?
 

My new mechanic (Mario @ SoCal Speed & Marine) should be picking up the wee rocket sometime today to take back to his shop and begin the "restoration" process of my 454. Hopefully, the damage won't be too bad, but regardless, it will be wonderful to get back out on the water.

Frustration YES ... disappointment YES ... regrets NOT A CHANCE!

As my wife reminds me quite often, if it's only money, then give thanks!
Although I fully intend to make quite a "stink" if the problem turns out to be faulty workmanship by the original mechanics, the possibility does exist that the boating gods are simply testing my passion for performance boats.


I'll certainly keep ya'll posted :rolleyes:

Re: Oh Oh ..... What did I do now?
 

Breaking stuff is part of high performance anything. You have the right attitude. Besides, people enjoy hearing stories about the stuff that you've broken. Good luck with it. I want to hear what the diagnosis is.

Re: Oh Oh ..... What did I do now?
 

Sounds like you dropped a valve seat. I just went through the same thing on a 450 hour 502 and it sounded exactly like yours.

http://www.offshoreonly.com/forums/s...d.php?t=143604

Mike

Re: Oh Oh ..... What did I do now?
 

Just to reiterate.....So Cal Speed and Marine is his NEW mechanic. Not the shop responsible for the original work.

Re: Oh Oh ..... What did I do now?
 

I can tell you than I ran mine for only a couple of minutes at idle. I had damage to the piston, the head and the cylinder wall. Good luck and let us know what you find.

I understand that you needed to make it back.

Mike

Re: Oh Oh ..... What did I do now?
 

sounds like valve train

Re: Oh Oh ..... What did I do now?
 

interested in what the out come is

Re: Oh Oh ..... What did I do now?
 

Very well said.

Good Luck

Re: Oh Oh ..... What did I do now?
 

Next time just take a long screw driver and put it on the valve cover, then put the handle up to your ear. You'll be able to pinpoint where the noise is coming from by moving the screw driver around.