Milkshake OIL 5.7L

[mr300z87]

Yesterday I got a call from my friend that the 5.7L engine in his 89 Sundancer 250 would not start what could it be? Today I went over to the boat and went through the standard checks fuel OK, Spark OK. Symptoms are sluggish to crank and the engine wont fire. So I am thinking clogged jets in carb. Anyway as we were sitting there staring at it hope it would fix its self I pulled the dipstick and found milkshake colored oil and way over full.

Last fall I winterized the boat by draining block and manifold and pulling all needed hosed to make sure there was no water in the engine. Air don't freeze theory. Fast forward to last month and I summerized the boat which included inspection of the manifold to elbow flange and replaced gaskets with Merc parts. Prior to spash day we ran the engine on the hose for a good 20 min to full operating temp no water present in oil. Splash day we ran boat for about solid hour run again no water present in oil. The other day he took the boat out to the local hang out spot Tieces Shoal and after hanging out he noticed hard start condition (sluggish to crank) but got her running for the 30 min cruise home. He says it did not over heat

On Monday we are going to change the oil and do a compression test. After that I am not sure where to from there. Bad head gasket? Manifold flange gasket failure? If Manifold flange wouldn't there be water in the cylinders causing hydro lock? Cracked block what did I miss when I winterized? I have the same Engine in my Invader mine is fine. One last thing to mention I have the my project boat is same model but mine is a 7.4L BB and my exhaust system has 3 inch risers between the manifold and elbows his does not, could water come back up through the exhaust, again water in cylinder not oil pan. BTW both exhaust flappers were intact when we inspected the manifolds. Any advice is always appreciated. I will report back on Monday after compression test. BTW this is his first boat and he is not having to much luck.

 

[tpenfield]

I would imagine you might feel some sort of responsibility, having winterized the engine. Sounds like you did OK though.

If the boat is used in salt water, then a 25 year old engine might be having rust-through issues.

the things that I would do are, as you mentioned,

Compression test,

cylinder leak test,

cooling system pressure test (10-12 psi)

The cooling system pressure test is a bit tricky, as you have to block off the water intake and the exhaust at the elbows. You will also need to fully drain the cooling system, similar to the winterization.. However, it can tell you where water is getting out of the cooling system

I would only do the cooling system pressure test if the other 2 tests are inconclusive. also, keep in mind that cylinders with a fair amount of leak can still have decent compression, so don't just rely on a compression test.

All too often on iBoats, we see folks start tearing down their engine before they have done sufficient testing, which makes the repair process more hit-or-miss.

Let us know how the tests come out.

 

[mr300z87]

Today we went over the my friends boat to do some testing, Started by draining the oil, boy is milkshake thick, we had trouble pumping it out through the dip stick tube with both manual and electric pumps. While the pump was pumping I pulled the all the plugs. Starboard side were dry port side were wet with water. So we then we cranked the motor over to expel all the water and try a comression test. Put my gauge in the # 1 cylinder and it hydro-locked. Removed the gauge and spun the motor over again to expel more water but water kept coming back. Drained the exhaust elbow and manifold and still the water kept coming back, so I am guessing that the exhaust manifold is not the problem. Next thing we did was a compression test on the starboard side The results were not good. 2-60psi 4-90psi 6-60psi 8-120psi so that was were we stopped. I am surprised the engine ran as good as it did with those compression #s. I still dont know for sure how the water is getting in but I am thinking either the block, head or intake manifold it corroded through somewhere as it was not like this on first start up or the first 7 hours of operation this season. The engine has 771 hours of salt water use and was in dry dock for a while before my friend purchased it. Now he needs to figure out what to do, he has quite a bit of money invested, Full bellows job, and new SEI drive before splash this season plus what he paid for the boat last season. I feel horrible for him. Bust Out Another Thousand or this time 4 to 5 thousand. Have a great day.

 

[Scott Danforth]

all is not lost, however it is time to pull the motor.

if money is tight, hit up LKQ for a low mileage truck motor and swap over the marine bits.

is this a moored boat or a trailered boat?

 

[tpenfield]

It still would be worth running a full set of tests, if you can get the water out of the block. The lower end of the engine may be OK and just need new cylinder heads.

Of course salt water use over that amount of time may have taken quite a bit of metal off of the cylinder walls as well.

On the good side . . . 5.7's are not all that expensive a motor to replace. I would go with full closed cooling if your friend ends up going that route.

 

[mr300z87]

The boat is in the water behind his house, the same place I am supposed to keep my boat for the month of July, he has no trailer. At this point we have not even gotten all the oil out of the engine as the milkshake was so thick and it pumped so slow we ran out of time. When I heard this boat run for the first time I thought the motor sounded a little tired, but was not expecting this. With the amount of water coming out of cylinder # 1 the leak, wherever it is, is pretty big. I sent him some links to reman long blocks as well as brand new GM long block. Unfortunate I have my own project boat to work on (which has been on the back burner since its boating season) and do not have time to pull off a full on motor swap right now. Since the boat has no trailer it's not easily movable so I am thinking his best bet is to order a long block, some new exhaust manifold, elbows and maybe and intake (source of the water maybe) and have it installed. He will be back on the water in couple of weeks. Plus a few extra HP from an modern built 350 definitely could not hurt in that heavy boat it was a slug with that tired old one. Its just $$$.

I have not spoken to him yet but his wife said he was feeling depressed. I am going to help him in any way I can.

 

[NHGuy]

Wow that completely blows. I agree that if the motor he gets hasn't had raw cooling do the closed cooling system on the replacement.
If he gets to choose things try for Vortec heads with smallish combustion chambers (64cc), and quench enhancing pistons. Those are the ones with a flat "squish" area away from the valve reliefs and the combustion swirl area included with the valve reliefs. Those better pistons can run 9.3 or 9.5 to 1 compression at full timing advance without detonation. Whereas the standard round dish pistons need to keep down the advance or the compression, either of which leaves unrealized power on the table.

 

[mr300z87]

Thanks for the responses guys. He is going on vacation for 2 weeks so he has some time to decide what he is going to do.

NHguy you are speaking another language up there, I am a mopar guy and could build a 550 horse 440 no problem but these GM vortec/non vortec/no mechanical fuel pump bla bla bla..... drives me crazy. So many incompatibilities between the same engine. I do know that more HP never hurts and the only replacement for cubic inches is more cubic inches!!!!!! :joyous:

I will post an update when he figures out a plan.

Have a great day

 

[mr300z87]

And by the way I posted for the first time in weeks with out an error message :joyous: they are getting there.