4.3 milky oil and water in 5 of 6 cylinders

[CHARGER2]

I have a 1990 4.3. I drained the block last fall and parked it with no further winterizing (I'm a bad person, I know).

Fast forward 8 months to this weekend. I was tearing down the engine to do a vortec cylinder head swap. I removed the old heads to find standing water (and rust) in 5 of the cylinders. I pulled the oil dipstick and found the level was about 2 quarts too high and very milky. There was a white substance on top of two pistons that looked and felt like Crisco. The head gaskets *looked* fine, but I've never seen a bad one so I'm not certain if they were OK.

There was rust on both banks of exhaust valves and on ports of both exhaust manifolds. The intake manifold and intake valves all looked just fine. No rust.

The boat did overheat once, about ~20 engine hours before being winterized. The overheat was noticed when smoke was coming from the engine compartment. It was shut off, cooled, and restarted without issue. Replaced the thermostat and ran the rest of summer without any noticeable performance issues.

My questions:

1: How can water get into BOTH banks of cylinders? Is it possible that water just came in through one spot, then after being still for 8 months of winter, managed to "evaporate" its way to the cylinders? Since the oil was milky and WAY too full, this appears to have happened during regular usage and isn't a result of bad winterizing.

2: How did the block manage not to hydro-lock if I found water inside the cylinders?

3: Could this water be related to the overheat? I've read in places that overheats can kill exhaust flappers and riser gaskets. Is it likely I toasted those on both sides?

4: What is the Crisco stuff on top of the pistons?

5: If I leak down check the block, will that verify if the rusted cylinder walls and oil/compression rings are OK?

At this point, it looks like the first step is to pressure check the exhaust manifolds since they are removed. If those check fine, I would reassemble the heads and intake and pressure check the block. This would check for water leak sources and check if the rusted cylinders still hold compression.

I have had this boat for 6 years with no previous water ingestion issues.

Any thoughts and responses to the questions are greatly appreciated.

Further info for anyone who needs it:

1990 4.3 non balance shaft, alpha one gen one. Mariah 1850XL 18.5' open bow runabout.

Engine serial: 0C768924
Transom serial: 0688349
Drive serial: 0D301183

 

[alldodge]

The motor looks as though it was submerged under water, or someone poured water down the intake. Was the boat left outside with a worn cover?

The gasket between the front 2 cylinders on the first pic is different then the rear. This same gasket issue also shows up in the second pic

Don't know what the stuff is on top the piston, but if its oily then I would say its just oil that has been sitting in water a long time.

 

[CHARGER2]

The boat was stored fully assembled, indoors, with a cover.

The gasket issue you see is between cylinders 1-3, and 4-6. Although it does look a little fishy, it doesn't seem to involve any water jackets or explain water in the other two cylinders.

I think the same about the oily stuff on the piston.

 

[Bt Doctur]

both head gaskets are blown , the crisco stuff is what happens when water sits on top of a aluminum, piston for a long time
You say you winterized it, exactly how? open the drains, probe the holes. etc Not draining the manifolds?

 

[CHARGER2]

Would those blown gaskets cause water leakage? I only see blow-over from piston to piston...

Winterizing- The two block freeze plugs were fully drained and hoses disconnected from bottom of exhaust manifolds and power steering cooler. I really don't think this is freeze damage.

 

[Rick Stephens]

Would those blown gaskets cause water leakage? I only see blow-over from piston to piston...

Winterizing- The two block freeze plugs were fully drained and hoses disconnected from bottom of exhaust manifolds and power steering cooler. I really don't think this is freeze damage.

Sure looks like the manifolds dumped a load of water in on the exhaust valves. I don't know if any other way to get water in those other than down the carb and with the boat indoors, that seems improbable.. You might do an acetone test on the manifolds to be sure.

 

[Bondo]

1: How can water get into BOTH banks of cylinders?

Ayuh,..... Has the motor been run, since the last time the boat was loaded onto it's wagon,..??

Ya mention an overheat,.... Shutters are the 1st thing to get smoked when runnin' the motor with no water flow,...

At the launch, shutters earn their keep,....

 

[Lou C]

Ahh I hate to say it that looks worse than mine, I had 2 blown head gaskets but knew there was a problem in the fall so I was able to blow all the water out of the cyls before draining the block when I winterized it. I sprayed fogging oil like crazy in all the cyls back in October and when I pulled it apart in Feb there was no rust at all in the cyls, or on top of the pistons. I'd say in this case, the overheat might have damaged the riser to manifold gasket, in addition to the head gaskets, which could have allowed a fair amount of water down in the cyls, it seems likely that some came in thru the exhaust manifolds. Take a good look at those head gaskets when you pull them off, I bet that you see a part between the cyls where the fire ring is peeling away from the rest of the gasket. That can let water into a cyl, when the engine is off, sometimes it takes a while but the water will leak down and half fill a cyl. When you started it up to winterize it, was it hard to start? You probably did not need to remove the plugs but if you did I bet they would have shown rust. Before I pulled mine apart, I checked the manifolds with acetone and they were not leaking. My #2 cyl was about half full of salt water and #1 had traces of water in it.

 

[Lou C]

No Title

 

[CHARGER2]

I will pressure/acetone check the manifolds and get eyes on the shutters. The milky high oil level indicates I have been running with water ingestion for a while. Is it possible for 2 quarts of water to seep through the rings into the crankcase from bad manifolds (or flappers)?

The boat was removed from the water last fall and was never started for winterizing. It has not run at all since coming out of the water.

 

[alldodge]

If the manifolds were leaking bad I can see how 2 quarts could make it past the rings, but I would have expected the motor to hydrolock the last time it was running with that much

 

[Bondo]

Ayuh,.... One big swoosh at the launch could account for 2 qts, 'n it had plenty of time to slip past the rings, 'n emulsify with the oil,....

 

[CHARGER2]

No Title

Hi all.

I got started on this last weekend. Turns out BOTH heads were blown in multiple spots and BOTH exhaust elbow gaskets were blown. This must have been from the overheat last summer and explains just about all of the water intrusion questions. I did the acetone check on both exhaust manifolds and they checked fine. I pulled out the exhaust shutters and they look just fine. I actually don't know how an overheat could ruin the shutters... they are solid steel construction and seem pretty bullet proof to me. The only unknowns are if the block is cracked and if the exhaust elbows are leaking. I'm going to assume both are fine for the time being.

I decided to clean up the cylinders with 1000 grit emery paper and hope for the best. Once I get it running, I will run two full oil changes to remove the bulk of the water from the crank case. There is slight roughness on the top 1/2 inch of two cylinders. Hopefully it isn't enough to kill compression or burn all the oil. Hopefully the piston rings will be OK. If it runs poorly or burns tons of oil, I'll run it for the summer and do a full rebuild over the winter.

Still working out some kinks in the vortec upgrade: http://forums.iboats.com/forum/engi...inboards/10368367-4-3-vortec-valvetrain/page2

Will report back when she is all back together and let you all know how she runs.

 

[Rick Stephens]

Exhaust shutters are metal coated with rubber.

 

[GA_Boater]

Exhaust shutters are metal coated with rubber.

Yep. Which means the overheat last summer ate the shutters. The shutters are now ineffective.

Why don't you pressure test the block before hoping for the best? All the money you're spending will be down the drain if the block is cracked.

 

[CHARGER2]

No Title

Yep. Which means the overheat last summer ate the shutters. The shutters are now ineffective.

Why don't you pressure test the block before hoping for the best? All the money you're spending will be down the drain if the block is cracked.

These are the shutters I pulled out. Are they supposed to be coated in rubber? It did occur to me that even when closed water could get past all of the holes. Should I pull these out and put in rubber coated ones?

I have no reason to believe the block is cracked. The block was properly drained and all the crank case water had room to expand over winter. Time allowing I would have checked it, but I don't have as much free time to dig into this as I would like. All the money is already spent so it'd be all down the drain anyhow.

 

[alldodge]

Being a 1990 you would have the flappers shown. The holes that you see use to have a rubber ring around the outer edge of the flapper. I would get some new ones but they will slow the water down, roll the dice with everything else

Using 1000 grit will do nothing so you can skip that one. The roughness near the top of the cylinders is the ring grove. This happens thru time by the rings wearing on the cylinder walls. Assuming your re-using the old rings, so make sure you put the piston in the original bore. Changing them up may cause your rings to break. Using new rings without removing the groove will break the rings.

You need to put a straight edge across the block and head surfaces. The over heating warps things, so use the straight edge and measure the gap with feeler gauges. It its more then 0.001 gap you need machine work

 

[achris]

Have a read of my document on exhaust shutters (in the 'Adults only' section).. water in the cylinders for that long, the rings will be badly rusted and the block will have a corrosion ring. Needs to be bored and oversized pistons fitted.

Chris .

 

[Lou C]

Any updates?
I got mine back together with reman non Vortec heads, Fel Pro marine gaskets ARP head and manifold bolts and a Volvo style center riser style exhaust conversion (this engine used to have the OMC bat wings that are NLA). Ran it on the water hose yesterday started right up and ran well....