Stuck Valve delemma

[frustratedboater]

I just purchased a 85' Mastercraft boat with a chevy 350 engine. It sat over the winter and it appears that some moisture snuck in and sat over my #4 exhaust valve. Long story short, the stubborn valve pushed the rocker pins up (on #4) and I believe I have a valve job ahead of me!! It kind of adds fuel to the fire when my resouces "$" for the boat have dried up for now. After pulling the head off, I kinda rushed through the project, spraying penetrant oil then 40 weight oil in and worked the valve back to an 'operational' mode. I know the guide is scorn by that, and my time is limited, but need your advice.

It has been real long since rebuilding an engine and forgot to seal the intake. That explains why I am experiencing hard starting and very rough idle (if any idle at all). I have some questions, but would welcome any comments...

Q- How long should/could I run the head in this condition?

Q- Should I cash in this season and wait till it's done right?

Appreciate your comments...

~FB~

 

[parrisw]

Re: Stuck Valve delemma

What do you mean by not sealed the intake properly?? Did you use new gaskets?? maybe you have a vacuume leak causing your poor running? The vavle should be ok and shouldn't do anymore damage, as long as it seats ok, it should run fine, I wouldn't think just a little moisture would freeze a valve, you sure something else is not leaking water into there?

 

[frustratedboater]

Re: Stuck Valve delemma

I guess I would need to explain further.. When I said I didn't seal the intake, I mean't I didn't use any sealer, 'silicone' around the intake ports and on the ends. Also, I don't have a valve compressor to clean the valve seat. It was pretty rusty when I found it. I wanted to clean off the face of the seat. I did use new gaskets. Last night I pulled the head off again and made sure I used a thin smear sealer around the intake areas and was real careful this time (I pulled the head, but left the intake manifold in place).

Not sure where the water came from. The spark plug had a thin coating of rust on it and seamed to come from the upper valve area. The valve train was clean, no visable signs of a ripped gasket, and no signs of cracks anywhere. I didn't fog the motor last season, but made sure that I drained the block of water. Real strange....

I'm going to recheck the torque on the head bolts and fire up the engine and hope to see if there's a significant difference.

~FB~

 

[mkast]

Re: Stuck Valve delemma

The only sealant used on an intake manifold gasket is used around the coolant passages and the corners of the front and rear cork/rubber rail gaskets, if used.
According to the Mercruiser Manual, clean both the cylinder head and the intake manifold mating surfaces, install gasket dry.

 

[HT32BSX115]

Re: Stuck Valve delemma

Howdy,

You didn't have moisture "sneak" in over an exhaust valve.

I had a similar problem with my former High Tech OMC 460. Every time I shut it down, water in the risers on both sides would leak thru the riser gaskets into the exhaust ports and into any open exhaust valves that were open. It would sit on top of the ones that were closed.

When I tried to restart it within an hr or less it would hydrolock.

Your problem sounds similar. Unless you have cracked heads there's no where else for the water to get there.

Your problem could be from a leaking riser gasket and/or a cracked riser or exhaust manifold, or possibly a shut-down while still moving "event".


At the least you'll need to replace the riser gaskets (since you have to destroy them to look) and if the sealing surfaces aren't "perfect" and you are unable clean then up or machine them flat, both the risers and probably manifolds should be replaced.


regards,


Rick