496 HO Failure

[chris16371]

It's been awhile since I've posted, I've come a long way since then but I could use some advice and remembered the forum was a great resource so here I am.

Sea Ray boat with a 496 HO was towed off the water, owner said it sounded like a bunch of nuts and bolts were bouncing around the motor. I checked the oil, only 1.5 quarts were in the engine. I put proper amount of oil in and started engine, sounded like the customer said. I thought it dropped a valve but now I think something else. I pulled the plugs, all looked lean which I figured they got hot from lack of lubrication in the motor. I did a compression test, good across the board. I removed belt and turned crank and didn't hear or feel anything abnormal. Source of oil leak was a bad seal on the oil filter.
I've only done basic maintenance items on the 496 HO, don't see a lot of them on our lake. I was wondering if anyone had any thoughts, ideas, tips, or tricks before I start tearing things apart. I appreciate it, thanks!

 

[tpenfield]

A fair amount of possibilities if the engine was run low on oil. Connecting rod bearing and crankshaft bearing damage comes to mind.

Just wondering if the owner noticed low oil pressure while running.

You could do a cylinder leak test, just to see if it reveals anything more than the compression test. Also, you could borescope the cylinders to see if you can get a look inside.

 

[Scott06]

Unless you can tell where the nuts and bolts sound is coming from he is looking at a tear down to fully diagnose. Would also think a rod bearing is the culprit or lifter/cam lobe that ran dry

In the end it was run low on oil under load so you can tear into the engine to see what part of it is roached but you are really looking at a new long block. If it was your personal boat vs a customers yeah you could try and piecemeal it, but I wouldn't waste billable hours on it just replace the engine.

Last time I tried to reuse what looked like good heads on a new short block (orig shortblock spun a rod bearing), it later drop a valve roaching the new shortblock... so while the customer wont like it a new or completely reman engine is in their long term best interest.

Who did the oil filter change out? The customer should be checking their oil level regularly as would think it didn't go from full to almost empty in one outing.

 

[chris16371]

Unless you can tell where the nuts and bolts sound is coming from he is looking at a tear down to fully diagnose. Would also think a rod bearing is the culprit or lifter/cam lobe that ran dry

In the end it was run low on oil under load so you can tear into the engine to see what part of it is roached but you are really looking at a new long block. If it was your personal boat vs a customers yeah you could try and piecemeal it, but I wouldn't waste billable hours on it just replace the engine.

Last time I tried to reuse what looked like good heads on a new short block (orig shortblock spun a rod bearing), it later drop a valve roaching the new shortblock... so while the customer wont like it a new or completely reman engine is in their long term best interest.

Who did the oil filter change out? The customer should be checking their oil level regularly as would think it didn't go from full to almost empty in one outing.

My next step was to just start the motor and use a stethoscope to find the location of the failure. I figure at this point it needs torn down or replaced so I might as well listen to it to get a better idea. I checked our records and luckily they hadn't been to our location before so we didn't do the oil change, we are just the only marina that tows so they decided to have us work on it rather than trying to get it to another marina. I asked who did the oil change and the husband said he didn't remember, I'm kinda thinking he did it from the response. I told him they would be responsible for the repairs if he can find the record of who did it. I told him he could try his insurnace as well and at this point might be more cost effective to just replace the motor, he told us to see what rhe failure is and we will go from there.
It wasn't on my work schedule today but I'll be on it tomorrow. Once I have the engine running and find the area the noise is coming from, I'll update the thread. I appreciate the replies!

 

[alldodge]

My next step was to just start the motor and use a stethoscope to find the location of the failure.

Really, Really

 

[Scott Danforth]

Pull the motor and then pull the pan..... You will find a bunch of spun bearings from lack of oil.

Plan on a new rotating assembly

 

[chris16371]

Really, Really
View attachment 387974

I'm sorry if you have an issue with how I do things. I have saved customers thousands of labor dollars by listening to motors, prevented full tear downs. I have yet to damage customers equipment or company pay for a mistake I've made. I haven't had one call back/rework, have a reputation of being the best on the lake (chautauqua lake), and make a hell of a wage so I must be doing something right.
I came here for some input and maybe I could even help someone along the way. If I'm not doing something right or there's another way, kindly correct me and give me a better alternative, everyone then gets along and everyone learns something.
I really appreciate everyone who has given me input on this situation. I'll be back on it today so if anyone is curious I'll have an update later, hopefully with pictures of the failure. Thanks.

 

[alldodge]

Your testing prior tells me its not in the head "compression test" all good.

The top end is good so only thing left is bottom end and it making a lot of noise. Running the motor will do nothing but make anything that might be salvageable less likely. The more it runs the more something else can be damaged beyond repair

 

[Scott06]

I'm sorry if you have an issue with how I do things. I have saved customers thousands of labor dollars by listening to motors, prevented full tear downs. I have yet to damage customers equipment or company pay for a mistake I've made. I haven't had one call back/rework, have a reputation of being the best on the lake (chautauqua lake), and make a hell of a wage so I must be doing something right.
I came here for some input and maybe I could even help someone along the way. If I'm not doing something right or there's another way, kindly correct me and give me a better alternative, everyone then gets along and everyone learns something.
I really appreciate everyone who has given me input on this situation. I'll be back on it today so if anyone is curious I'll have an update later, hopefully with pictures of the failure. Thanks.

Handle the diagnosis as you see fit, just make sure the owner can and does check his oil level before going out.

If the oil wasn't so low I would also think more diagnosis is warranted. I personally wouldn't want put my name behind anything less than a full tear down given the lack of lube. As mentioned above I did that once , heads look fine and it roached a new short block. Dumb in the end.

What size boat is that in must be pretty good size for that lake.

 

[Scott Danforth]

Gen VI and VII BBC's will spit rod bearings for #3&4 if you run them low on oil

 

[muc]

What does the scan tool say for time in guardian?
Here is what I would do If it wasn’t in guardian for much time.
Put the boat back in the water and tie it down good. Run it at 1500 RPMs in gear and use the scanner to drop cylinder’s one at a time. If it’s bearing’s you will hear it better.
Still makes noise? Haul the boat and pull the drive and run it again. I’ve seen too many engines pulled when the noise was in the drive or transom.
The risk of causing more damage is less than the risk of misdiagnosis in my opinion.

 

[dubs283]

Yep

When a boat gets towed in with a nasty running noise the customer has already most likely condemned a major component. You can't really break it any more than it is

Keen thought of pulling the drive, running gear failures as part of the entire package can appear to be engine failures at times

 

[muc]

It would also be a good idea to cut the oil filter open and inspect.