Water in cylinders

[forbes210]

Hi All. Recently I've had issues with my mercruiser 5.7 motor on my maxum 2500 that I couldn't troubleshoot. It was stalling multiple times but then would run fine. Recently also it started running rough, so I decided to pull out spark plugs. Starboard side was fine but when I removed first plug on port side I noticed water and then water coming out after removing rest of the spark plugs. I quickly removed exhaust manifold on that side and it looked like water was coming from cylinder #1. What's weird is that when the exhaust valve on cylinder one was closed water would accumulate above the valve in the head and not in the cylinder. What could cause that? If I'm correct blown head gasket would send the water right into cylinder. The only thing that came to mind was rusted or cracked head somewhere around the exhaust port on cylinder 1. If that's the case do you think I should just replace the heads? Is there better way to test it to make sure that the block of the engine is fine? On the other hand I got 910 hours on that motor and could go with new long block. Besides this issue engine runs great with plenty of power. Also I could replace heads myself with boat in the water where engine swap would be bit much for me to handle. New engine from the shop would cost me way more money and with heads replacement I wouldn't lose rest of the season. Late summer/fall is a prime time for me as far of boating adventures.

[mmwjr]

I would first perform a compression rest and leak down test on all cylinders. It does sound the Head is cracked so you’re at least looking at that. I suspect the block is ok and should last to 1500-2000 hours but then again common to see them go at 1000 hours. I would look at the cost of new heads and install verses a long block.

[forbes210]

Thanks Mike! I did compression test today. With all the spark plugs removed on starboard side I was getting around 180 on all cylinders but on port side 210/220. It was most likely caused by the fact that as soon as I've noticed water on I sprayed bunch of dw40 inside the cylinders to flush out water and prevent corrosion. I'm gonna tear up the motor and see how exactly things look on the inside. Can I install vortec heads instead of regular? I believe I'll have to change the intake manifold to vortec as well. Might be not the best idea but I figured to explore that option.

[mmwjr]

With those compression numbers if there is a crack it's not in the combustion area of the head. What year is the engine? Thinking it's already a Vortec. 8 bolts on the intake manifold. Just be sure to match the same combustion chamber size on the replacement heads. Do you plan to have the head magufluxed to inspect or cracks?

[forbes210]

It's 2002 2bbl 5.7 rated 250hp. I will check bolts on intake manifold tomorrow.I think I'll be able to start tear down tomorrow. I had a significant amount of water coming in so I should be able to see it after disassembly. I can get complete mercruiser heads from local supplier. He found them based in my engine number so it should be perfect fit. I'm assuming to replace both of them? Should I be looking into doing anything to the heads before installation?

[jparsons121]

Don't overlook the manifold/risers as a potential source of the water, particularly since its above the valves. If they are more than a few years old, I'd replace them if you were doing the heads, just so you don't ruin any new parts if the manifolds are leaking.

[jrsick]

For sure check your manifolds and risers for leaks before you get into engine teardown. There are videos for this and it's a quick and easy test. You have the manifolds and risers off anyway so not much extra work. Can you post of picture of the manifold?

[mmwjr]

Originally Posted by forbes210

It's 2002 2bbl 5.7 rated 250hp. I will check bolts on intake manifold tomorrow.I think I'll be able to start tear down tomorrow. I had a significant amount of water coming in so I should be able to see it after disassembly. I can get complete mercruiser heads from local supplier. He found them based in my engine number so it should be perfect fit. I'm assuming to replace both of them? Should I be looking into doing anything to the heads before installation?

You could just replace the one head but with 910 Hours the other needs a valve job anyhow. Once the heads are off check the block deck for flatness with a know flat metal bar. I'm assuming your replacing the exhaust components as well.

[mmwjr]

Originally Posted by jparsons121

Don't overlook the manifold/risers as a potential source of the water, particularly since its above the valves. If they are more than a few years old, I'd replace them if you were doing the heads, just so you don't ruin any new parts if the manifolds are leaking.

He has the exhaust off and water is still collecting around the exhaust valve so while the exhaust may be bad he has a head issue.

[jparsons121]

Originally Posted by mmwjr

He has the exhaust off and water is still collecting around the exhaust valve so while the exhaust may be bad he has a head issue.

Ah. Missed that piece of data. Thanks!

[forbes210]

I'll definitely test exhaust manifolds and risers but it didn't look like source of problem. The only way to take them off on my boat is in one piece so I can test them but I did remove them before beginning of this season to inspect. They looked decent so I cleaned as much as I could and put them back. If I'll have a time maybe I'll get a new exhaust now but I'm desperate to get the boat functional again. The worst case scenario I can do that after season is over. In NY we don't have much of it left

Mike, I just verified that my intake manifold is mounted with 8 bolts.

Today I was able to remove all the components on the way to the intake manifold and heads. I should be able to have aheads removed by the end of tomorrow.

[mmwjr]

Any progress?

[forbes210]

Sorry for late response. Crazy busy with work.

So after taking the heads off I was able to confirm that port head was cracked. When I flipped it upside down and plugged water supply with rags I slowly filled water jackets and sure enough water showed up in exhaust port on cyl #1. On top of that intake valve on cyl #2 was sticking but no signs of water there. I had my heads reconditioned about 5 years ago by the shop. Short block looked healthy so I purchased brand new heads from mercruiser and begun installation. It was first time for me to strip the engine apart to that point but everything worked out great and after hours of "boating yoga" in my engine compartment I was able to fire her up again. She idles and starts better then ever. Super happy. At this point I probably added another 20 hours to it.

[forbes210]

https://youtu.be/LmLPVHxforI

[mmwjr]

Wow a big city slicker who can turn bolts.

Glad you got her up and running, now enjoy the last few weeks of the season.

[BrianC72]

Born in the Bronx, lived in Queens worked in Manhattan..for 40 odd years, and have been spinning wrenches soon after standing upright. 10 years in Norcal, I just finished a 4.3 swap, by myself, with a forklift (never used one before).

Still a handy wrench, for a city boy. Best part, I'm GC, compliance, contracts, office guy for a small High Voltage Power Line company. Lineman who build the power grid but mostly can't change their oil were blown away that I did the engine swap and it actually ran.

Great news about the new heads. These engines look like a lot, but they are pretty simple once you dig into them. Just nuts, bolts and stiff backs from engine bay yoga.

[mmwjr]

Originally Posted by BrianC72

Born in the Bronx, lived in Queens worked in Manhattan..for 40 odd years, and have been spinning wrenches soon after standing upright. 10 years in Norcal, I just finished a 4.3 swap, by myself, with a forklift (never used one before).

Still a handy wrench, for a city boy. Best part, I'm GC, compliance, contracts, office guy for a small High Voltage Power Line company. Lineman who build the power grid but mostly can't change their oil were blown away that I did the engine swap and it actually ran.

Great news about the new heads. These engines look like a lot, but they are pretty simple once you dig into them. Just nuts, bolts and stiff backs from engine bay yoga.

To be honest I grew up in the city as well and was turning bolts since my first car. The basic engine has not changed since the overhead valve design can out decades ago just exterior bolt ons.

A name like Forbes sounds like a Wall Street guy so I was just jabbing him.

[jrsick]

Did you re-use the old rockers, pushrods, and lifters?
What comes with new heads? I assume the heads, valves, and valve springs?
Good work, engine sounds great.

[forbes210]

Mike, nothing like that. My nickname is totally coincidental and other then the fact that very often I work for "big shots" from wall street I got nothing to do with stock trading.

Thank you all for good advice and support.

As a kid I always played and dissembled household gadgets and tools and had fun with internal motors etc. Now same as most of us I got never ending project which floats Other then that theres serious deficit of decent mechanics in my area. Most of them would scrap my existing motor and go for a swap which might require less finesse which also with their speed would kill rest of my season. I had a strong desire to make run for Block Island but with Dorian near by winds and seas look bit unpredictable.

Jrsick, heads came completely assembled with valves, springs etc. I was able to reuse rockers, pushrods and lifters. Heads were reasonably priced but all the bolts, gaskets, cleaners and sealants almost doubled the cost of parts.