Lifter Stuck - Merc 350 5.7 Thunderbolt

[jmicara]

I opened the value cover and found one of the rockers (3rd from the back of the boat) was not moving. I removed the rocker and found the push rod bent. I am assuming that was where the firecracker knocking sound was coming from. So it appeared the lifter was stuck. An old marine mechanic told me to soak it with WD-40 and PB Penetrating lube and then to hit it with a rubber hammer and a block of wood to dislodge it. Well, I hit it and the spring went down but never came back up. I store the boat on the side of my house and was wondering if this is a project I can fix during the winter/early spring time frame. I do not have the ability to lift the engine out and was hoping this can be fixing in place but I do not see any references to stuck lifters and how to fix them.

Any and all help is greatly appreciated!

Joe

 

[jtybt]

Re: Lifter Stuck - Merc 350 5.7 Thunderbolt

No problem.

First, try to lift the lifter out with a small screw driver. There's a wire clip that holds the plunger down. You might be able to raise the lifter by gently lifting with the clip. There may be enuff lifter sticking out to grab with a channel lock. If the lifter is really stuck, you might have to disassemble the lifter.

Disassemble the lifter but be very careful not to loose anything down the block. A small pick-up magnet may help.

First, there's a wire clip that you should be able to easily get to with a needle nose plier because the plunger is down.

There's a cup above the plunger and a flat metal shim like valve above it and a spring under the plunger. After you get the cup and shim valve out, you should be able to wedge the needle nose into the plunger to get it out.

Now you're working with just the lifter body. Hopefully there's enuff lifter body above the block to grab with a plier and work it out. Turning the engine over may push the lifter higher. It may also lower the cam lobe so gently tapping down the lifter will start to loosen it. Try not to do anything to hurt the lifter bore.

 

[Silvertip]

Re: Lifter Stuck - Merc 350 5.7 Thunderbolt

A bent push rod is not an indication of a stuck lifter. If you hit the end of the valve and it stayed down, the valve is stuck not the lifter and that would bend the push rod. The main cause of a bent push rod is improper lifter/valve adjustment followed by over reving which can "float" the lifter causing the piston to hit a valve which can then bend the push rod and/or valve. These are hydraulic lifters and they must be properly adjusted. Adjust them too tight and you bend push rods. Adjust them too loose and you get the clatter. Adjust them really loose and the push rod can pop out of the socket in the rocker arm. And just so you know, you cannot hit the lifter with the intake manifold installed.

 

[jmicara]

Re: Lifter Stuck - Merc 350 5.7 Thunderbolt

Thanks for the replies! It sounds like I may have been given some mis-information about the lifter/spring assembly.

JTYBT - Thanks for the information on how to get the lifter back up.

Silvertip - your last comment concerns me the most right now. "And just so you know, you cannot hit the lifter with the intake manifold installed." Are you saying I damaged it and that is why it is not backing out? Also, if this is just an adjustment issue is that something I can do or does it require a specialized tool?
Finally, the full explanation as to what happened is simply this. I was going 5mph in a canal when I heard this loud firecracker noise. I thought it was misfiring so I just shut that engine down and returned on my other one. I found water in the oil and believe the exhaust manifold may have developed a leak. I still keep in touch with the guy I bought the from 2 years ago and he said the manifolds on that engine were about 3 years old then. So 5 years was probably pushing it. Again, this was going to be an off-season project.

My biggest question is can this be fixed while on the side of my house. I don't want to pay to haul the boat to my house only to find I need to bring it somewhere else to fix it. I just want to make sure that even if I can't do it myself for some reason, that I can call a professional and they will be able to fix it by my house.

Thanks again,

Joe

 

[Silvertip]

Re: Lifter Stuck - Merc 350 5.7 Thunderbolt

You apparently are not familiar with the valve system on an engine so lets get this straight first. The valve lifter is about the size of a small pill bottle and moves up and down as the camshaft rotates. The bottom end of the push rod sits in a cup on top of the lifter. The other end of the push rod sits in a cup on the back side of the rocker arm and the opposite end of the rocker arm moves the valve. So -- you could not possibly have hit the lifter with a block of wood with the engine fully assembled because the lifter is down inside the center of the engine. What you hit was the valve or the rocker arm. The valve has the spring on it which is the only spring you can see with the valve cover off. Got it??

Now then, since you had water in the oil, it likely got there through reversion or a water leak somewhere in the cooling system. What happened is that the cylinder filled with water and as you learned in high school physics (if you paid attention) was that water does not compress so that cylinder may as well have been filled with concrete. Therefore the piston going up in the cylinder could not compress the water and since the valve also could not open something had to give. What gave was the push rod. You are looking at a total engine tear down to see what other damage was done. There may be one or more bent connecting rods, broken pistons, bent valves, rocker arm pivots pulled out of their press fit holes, to name just a few. Keep one hand on your wallet.

 

[boat1010]

Re: Lifter Stuck - Merc 350 5.7 Thunderbolt

Smiling.. Better keep both on the wallet. And as far as a professional coming to your house to fix it... I very much doubt it. Like you said, you do not have any way to get the motor out of the boat. And as Silvertip pointed out, the motor needs to be tore down to see what damage has been done. I'm guessing it could be done in the boat, BUT most prefer to pull them and take them to the shop where they have the tools and can work on them without standing on their heads.

 

[Alpheus]

Re: Lifter Stuck - Merc 350 5.7 Thunderbolt

Read the earlier topic you started. New lifters are 6 bucks, but have your heads checked. You have got a stuck valve...

 

[Yepblaze]

Re: Lifter Stuck - Merc 350 5.7 Thunderbolt

My guess is........
Water probably came in through the exhaust port (for whatever, or whichever reason), rusting the valve stem. The next time you tried to start it, or did start it, it bent the pushrod, clicked, and ran on 7.

Not only did it damage the pushrod, but could, and may have damaged any one of the many other internal component that relies on good clean oil, and not water for lubrication.

So the further you "dig" into it the more sour it may get.

Get an estimate from a pro at a good shop. You may end up paying for the estimate as it usually requires hours of labor. Then hold on as they tell you how much.

And during this time consult with others, (here or elsewhere) to try to get an idea about why, or how this can happen so it is avoided later with the NEW ENGINE

 

[Big Boat Bay Buster]

Re: Lifter Stuck - Merc 350 5.7 Thunderbolt

As long as you don't have water sitting in the cylinders, rusting things up,this can be a DIY job for you.You need to get the intake manifold off and remove the head with the bent valve. Inspect everything including the camshaft lobes. Go to your local book store and get a book on rebuilding a small block chevy---it will tell you what to look for. Get the mercruiser manual.Since everyone is telling you the worst case senario, the best case will be--buy a new valve, lap it in--replace the bent push rod & lifter. Assemble engine with a marine upper end gasket kit and go fishing! Might get it in under $200!!
You can disassemble down to the block before you have to remove the engine.
Find the cause of the problem--watered down oil---water in the engine---weak oil pump etc.
Good luck--report back your findings
Chris

 

[zbnutcase]

Re: Lifter Stuck - Merc 350 5.7 Thunderbolt

Just remember, bent pushrods, stuck lifters, etc are the AFFECT, not the cause of the trouble. 'nutcase