Water in Cylinders, switch to tall risers?

[dacarter]

I let my 2003 5.7 GXi sit for about 4 months and after I started it recently, I had a knocking sound. It sounded like a stuck valve to me, so I did a compression test and found compression on #5 was low (90psi). I also see some rust on the threads of a few of the spark plugs, including #5, and all the plugs were very black and dirty. When I pulled the valve cover off, I did find two rockers very lose on the same cylinder, but it wasn't #5, it was #7 which had the highest compression (160), which makes no sense to me.

I will play around with trying to get the valves unstuck by tapping on the rockers, and of course I may have a stuck ring or two as well, so will look into a leak down test.

My risers are original and I resealed them 2 seasons ago since they looked like they had a few years left in them, so not sure if the water is coming from a riser gasket leak, or from stopping the boat too fast. Is it an option for me to go to the tall risers just to be safer? I think I have room in the engine compartment, but of course the piece going down to the Y will have to be longer.

I also remember seeing some posts here a couple of years ago about stainless exhaust/risers but can't find much info on them now.

 

[alldodge]

I let my 2003 5.7 GXi sit for about 4 months and after I started it recently, I had a knocking sound. It sounded like a stuck valve to me, so I did a compression test and found compression on #5 was low (90psi). I also see some rust on the threads of a few of the spark plugs, including #5, and all the plugs were very black and dirty. When I pulled the valve cover off, I did find two rockers very lose on the same cylinder, but it wasn't #5, it was #7 which had the highest compression (160), which makes no sense to me.

I will play around with trying to get the valves unstuck by tapping on the rockers, and of course I may have a stuck ring or two as well, so will look into a leak down test.

My risers are original and I resealed them 2 seasons ago since they looked like they had a few years left in them, so not sure if the water is coming from a riser gasket leak, or from stopping the boat too fast. Is it an option for me to go to the tall risers just to be safer? I think I have room in the engine compartment, but of course the piece going down to the Y will have to be longer.

I also remember seeing some posts here a couple of years ago about stainless exhaust/risers but can't find much info on them now.

Extra height can almost never hurt except in high end performance. So going with extra height can in most cases be added insurance. That said if you stopped to fast and go some water but you were able to run back to the dock without issue, then in my opinion you did no damage. With the water showing up in all those places I would check you manifolds and elbows first.

So far as stainless exhaust, that is a 2K to 4K dollar question. You can add some EMI thunder with stainless elbows for less than 2K.
http://eddiemarine.com/emi-thunder-...-system-sb-chevy-with-ss-silent-choice-risers

These are 1700 but if you need other things to accommodate (fuel filter, Power steering brackets) then the price can increase

 

[Dave-R]

In the few cases I have run across. Water got in the cylinders from turning the engine off with the boat moving fast. Once at Lake Powell, a friend left his boat beached in the sand for the night. There were a lot of high waves slapping the transom that night. Next morning, the engine was hydro locked. Pulled the plugs, and blew her out and she fired right up. I boat in fresh water and the manifolds last quite a long time. Pull them off and take a good look at them. Make sure you have a good clean straight surface when using your new gaskets. I would not get taller risers, the factory set-up should work ok. I fill my manifolds up with acetone, and check for leaks. A new set of manifolds is a lot cheaper than an engine. Dave-R

 

[Bondo]

I let my 2003 5.7 GXi sit for about 4 months and after I started it recently, I had a knocking sound. It sounded like a stuck valve to me, so I did a compression test and found compression on #5 was low (90psi). I also see some rust on the threads of a few of the spark plugs, including #5, and all the plugs were very black and dirty. When I pulled the valve cover off, I did find two rockers very lose on the same cylinder, but it wasn't #5, it was #7 which had the highest compression (160), which makes no sense to me.

I will play around with trying to get the valves unstuck by tapping on the rockers, and of course I may have a stuck ring or two as well, so will look into a leak down test.

My risers are original and I resealed them 2 seasons ago since they looked like they had a few years left in them, so not sure if the water is coming from a riser gasket leak, or from stopping the boat too fast. Is it an option for me to go to the tall risers just to be safer? I think I have room in the engine compartment, but of course the piece going down to the Y will have to be longer.

I also remember seeing some posts here a couple of years ago about stainless exhaust/risers but can't find much info on them now.

Ayuh,.... It sounds like ya mighta had a year, 'n 1/2 left, rather than a few, on yer manifolds,...

I'd start there anyways,....

I know I've seen ssteel risers for Mercruisers, both cast, 'n custom, mostly custom,....

Donno 'bout Volvo,....

'n yer hull hasn't needed riser blocks up til now, can't see what changed,....

 

[dypcdiver]

This might interest you, http://www.hitekmarine.com.au/volvo.htm They have a USA agent too.

 

[dacarter]

Thanks for all the tips/advice. I turned the engine over with one of the valve covers off and could see the #7 exhaust valve not going down. I suspect it was stuck in the fully closed position which gave good compression. I tapped on it some and got it to go down some but it doesn't spring back up. Obviously I can't turn over the engine now since the piston might hit it. Might try soaking in PB Blaster and/or WD40, but if it won't free up, looks like I'll be pulling the heads.

What I don't understand is both rockers on #7 were very lose. If the push rod goes up, and the valve doesn't go down, something has to give. The push rod looks straight to me, so I don't understand what really happened in this situation. The rocker nut looks to be in the same position as the other rockers, so not sure why the are so lose.

 

[poconojoe]

What about the exhaust shutters? Are they letting water in?

 

[dacarter]

I thought the shutters were on older engines. Mine is an '03.

 

[jerryjerry05]

You said there was rust on the plug threads and then you said they were all black??
Pics?
Any rust on the plugs?
Any rust in the intake/ exhaust passages?
Salt water?
If it's been in fresh the manifolds could be bad but 10-11 years isn't that old. Remove and check the outlet.Pics.?

 

[dacarter]

Didn't see any rust on the electrode area, just black flaky stuff. The plugs are not that old, so not sure why they were so black. The boat is used in fresh and salt water and has a closed cooling system, but I know that doesn't help on the risers. Plenty of rust and flaking metal in the exhaust passages. This boat came from Puget Sound originally, then the owner moved to Austin, TX and used it in fresh water for a few years. I bought it a couple of years ago and live in Houston and trailer it to lakes and to the coast and take it offshore and in the bays. I'll try to get some pics up tomorrow.

 

[jerryjerry05]

Usually if the riser/ manifold is leaking into the cylinder the plugs would have rust on the end.
The black residue is carbon from a too rich situation.

 

[dacarter]

No Title

Here are some pics of the plugs, manifold and riser, also the head with the #7 exhaust valve down and not springing back.

I'm going to order the stock manifold and riser tomorrow. Next step will be to pull the manifold and see what I can see by looking in the exhaust port. Expecting to have to pull the the head, and may play around with freeing up the valve and cleaning it up myself depending on what I find. Of course I might as well pull both heads and replace the head gaskets while I'm in there. My one concern is that I may have a stuck ring on #5 with 90psi compression, and after all this work, I won't have the knocking but I still may not have good compression in that cylinder. Thinking it makes sense to see if it frees up after some running instead of doing a full rebuild.

 

[dacarter]

Here's what the risers looked like when I cleaned them up and reinstalled them about 2 years ago.

 

[Lou C]

The sealing surfaces look bad on both the riser and manifold,
but this last pic where you cleaned it up looked good. Based on that, it seems like the gasket between the riser and manifold failed to seal letting in water. If you pull off the manifold on the side with the stuck valve I think you'll see rusty exhaust valve stems.

 

[dacarter]

When I resealed the risers a couple of years ago, I talked to a local long time VP shop, 30-40 years experience, and he recommended an aftermarket, non-metal gasket with airplane sealant?(black RTV type sealant) He said he had had the best luck with these gaskets/sealer. He was very convincing, but I'm thinking now it was a mistake to listen to his advice.

I ordered the manifolds and risers today, and will probably pull one of the heads tomorrow. I'll probably put it together and run it and see if I can get good compression to come back on #5, but if not, rebuilding a SBC doesn't look too bad based on the Youtube video I watched today.

 

[jerryjerry05]

The inside of the riser/ manifold should be black.
That color shows water intrusion.
I like Marvel Mystery Oil for freeing rings.
It's saved many a motor.
Now your gonna hear from some others that MMO is a waste of $ (everyone has an opinion)

If the valves have stuck?? Get the heads off and rebuilt.

 

[dacarter]

No Title

I got the heads off this evening and there's lots of rust in a couple of the exhaust ports and the stuck valve is badly rusted. I'll take them to a machine shop tomorrow for clean up. The head gaskets looked pretty good. This boat has about 780 hours on it over 12 years.

I answered the question I posted above.... When a valve is stuck closed and the rocker is trying to open it, something has to give. What gives is the rocker stud gets pull up and out of the head. I had 2 very lose rockers, both on #7 with the stuck valve and both of the rocker studs are higher then all the others. The push rods all look straight and I don't see any other damage.

There's also a lot of carbon build up on the throttle valve for some reason, maybe normal?

Since I have closed cooling, I assume I can use a standard head gasket. I'm wondering if the intake and thermostat housing gaskets is a standard part as well.

 

[jerryjerry05]

Yes you can use a regular gasket but IF for some reason the system fails and you get sea water in there your gonna be replacing again.
It's not that much more expensive to buy the right one.
The intake and thermo housing gasket is generic.
No the carbon buildup isn't normal. Get the manual and set up the system right.
While your at it maybe check the other side??

 

[dacarter]

I have both sides off, just didn't post pics of the other side. The other side looks pretty good,with just some light rust to clean up. Obviously both side had the riser gasket failure.

I just found a machine shop not far from me that said if I bring the heads in in the next 2 hours, they will have them done by 5! Didn't expect to find that quick of a turnaround. I'm trying to get the boat going by next Friday to make a once a year event down the coast in Rockport. This is why I'm looking to find gaskets retail. My new manifolds and risers should be delivered today, so there's hope!

On the carbon, I have the links to the manual on this site, and will take a look. Maybe related to the black plugs? I guess I thought there wasn't a lot adjustments on these computer controlled engines.

 

[dacarter]

No Title

I got an amazing 6 hour turnaround on the heads! Two valves and one valve seal were replaced. The two rocker studs that were pulled out by the stuck valves were pressed back into place. 3 angle grind on the valves and an acid bath for everything, $300 total. The exhaust manifolds and risers arrived and I have a Fel-Pro PermaTorque Extreme Duty head gasket on order with Autozone that should be in tomorrow. This is all going much faster than expected. I've got a full weekend of cleaning a scraping, and should be putting stuff back together by Sunday.