Did the marina wreck my engine?

[jimbunyard]

Originally Posted by Joe from ny

Another curious thing i noticed is that the riser exhaust steel band clamp is split and laying in the bilge next to the motor. It is one from the pair closest to the motor. could there have been seawater in there due to a improper winterization which froze and let water get into the cylinder somehow causing hydrolock? The attached photo below is from the internet, and not my actual motor, but it illustrates which clamp (except that it is the other side of the motor).

No. a loose or missing clamp there would let water out of the engine when it was running, but would have no effect on a static engine.

It seems you really need to get someone who has experience and that you trust to look and listen to the engine...

[Joe from ny]

Originally Posted by jimbunyard

No. a loose or missing clamp there would let water out of the engine when it was running, but would have no effect on a static engine...

My thought was that water might have frozen in there in the winter if they didn't put enough of the pink in it. But I don't know if water freezing in there would affect the motor.

[MBWhite]

What you can do yourself is to send off an oil sample for analysis, that can tell you if there is an abnormal amount of bearing metal in the oil which points to a main or rod. As mentioned, a loose flywheel can have a very similar thump.

If the engine was improperly winterized you would probably be seeing water in the oil.

Lastly, if it turns out to be a main it may be possible to just replace the crankshaft leaving the rest of the engine alone. Or even possibly having the crank machined but first thing is to have a different mechanic/yard look at it. If it turned out to be a loose flywheel it could be argued the yard that did the work is responsible and if they did the diagnosis they have a lot of reasons to tell you the problem is something else.

[Joe from ny]

Update - I noticed the yard broke one of the 8 plug wire connectors off the top of the distributor where the plug wire snaps in. Probably when they put the motor back in last year. It is tight there. They probably cracked it and it finally snapped completely off . It was a new Dist cap at the beginning of 2014 season. They also taped the center wire with black tape, not that that is going to stop that thousands of volts from getting through it. This together was probably causing some cross firing in that engine. I had a guy do a compression test, and it looks line one cylinder had a bent valve stem or broken spring. He is removing the stuff this week to get at it and take care of it. I believe that is my problem. He said the motor is fine and strong, besides that. I will post update when the job is done .

[Cadence]

Originally Posted by Joe from ny

Update - I noticed the yard broke one of the 8 plug wire connectors off the top of the distributor where the plug wire snaps in. Probably when they put the motor back in last year. It is tight there. They probably cracked it and it finally snapped completely off . It was a new Dist cap at the beginning of 2014 season. They also taped the center wire with black tape, not that that is going to stop that thousands of volts from getting through it. This together was probably causing some cross firing in that engine. I had a guy do a compression test, and it looks line one cylinder had a bent valve stem or broken spring. He is removing the stuff this week to get at it and take care of it. I believe that is my problem. He said the motor is fine and strong, besides that. I will post update when the job is done .

I believe you have a Chevy four bolt main block? I had one in a truck 300k miles. A good engine but not meant to push something up hill all the time as is the case with a boat. Yep, I've had one there also. Over rev. it a head job for valves. Salt water cooled an accident looking for a place to happen.

JMHO

[sy_gilana]

Did the yard replace the exhaust risers ?

I have worked on a couple of those...

http://gilana.org/44_mallorca2/03summ05/summ05a.htm

[Joe from ny]

Here are the photos of the cracked distributor cap, and the taped wire. But I did happen to put the cracked part back as good as possible before the photo was taken, it had originally been leaning over at about a 45 degree angle. The taped center wire was jammed against another wire boot also before i took the photo. Could the cracked cap have caused the valve issue?

[sy_gilana]

The broken terminal could cause misfiring, but probably not a bent pushrod.
See the photos I posted in a link in my previous post.
These twin motors had a continual problem of water ingestion through the exhaust risers into the exhaust manifold....the few drops of seawater was enough to rust up the valve stem and lock it in place. When the motor was started, the pushrods bent and the clunking sound was heard, and obviously it was not firing on those cylinders that had stuck valves.

The cause of the problem was that the exhaust risers had been changed by a previous mechanic. He used GLM or "after market" parts. The four long bolts that torque the riser down were 1/16" longer than original. Result was that although they were torqued to the correct setting, they had bottomed-out and did not squeeze the gasket enough to seal it.

The symptoms were the same as your engine. Why not check that its not the same cause?

[Joe from ny]

UPDATE: the saga continues. After getting both heads rebuilt, and not fixing the issue, I gave up on the project for awhile at the end of last season. This week I had my shop pull the motor and remove the pan to see what they could find. Unfortunately, they found a spun bearing where the piston rod meets the crank. They disintegrated a bit and fragments are found throughout the engine.

So it looks like the result will be a reman 5.0 going into the boat. They will do the job with a genuine mercruiser rebuilt motor for about $7,000 plus tax. They list the cost of the motor at about $4,500 and the rest is for labor and various crap.

Does this seem reasonable, or would it be better for me to source a reman 5.0 from somewhere else and have them do the swap?


Sent from my iPad using Cruisers Sailing Forum

[Cheechako]

Last I looked rebuilt longblocks from Jaspar engines were about $1600. Lookout. Been a couple years though. Good reputation.

[motion30]

you can get a brand new crate motor directly from Chevrolet for about half of the price you quoted

[Cadence]

You probably won't get any satisfaction. As far as the oil pan, watch they don't have it on a cement flood. I had one drop out from the yard sliding it around that way when doing a head job and taking off the paint. A second thing, unrelated, the tach. may be getting its signal from the points? If the tach. goes bad you can be dead in the water, just disconnect the tach. if you suddenly die.

I might ask if it is a Jasper engine or a factory new. And from your description I would guess a rod bearing not a main, but either way the labor might make a new engine the best choice. And no don't run it that way. Forget destroying the engine, you could has pieces of engine block flying around.

[Cheechako]

Originally Posted by motion30

you can get a brand new crate motor directly from Chevrolet for about half of the price you quoted

Yes I just looked quickly and saw the 5.0 for $2100, new gm crate engine. Not sure about marine. Is the marine engine just a truck engine? That's what I have heard...

[Cadence]

Originally Posted by Cheechako

Yes I just looked quickly and saw the 5.0 for $2100, new gm crate engine. Not sure about marine. Is the marine engine just a truck engine? That's what I have heard...

Same 4 bolt main engine.

[Cheechako]

Originally Posted by Cadence

Same 4 bolt main engine.

Yeah, truck engine has a different cam for more torque on the low end is what I heard. Not sure if the 5.0 is 4 bolt? I think the 350 /5.7 is... When I was looking for a 5.0, the 5.7 was actually cheaper yet because they are so prevalent out there. I guess they are interchangeable...