Mercruiser Head removal

[Squab]

OK I am looking to replace my head gasket and have already removed the valve covers and the Intake manifold along with the risers and exhaust manifolds. My question is, do I have to remove all the rocker arms or can I just simply unbolt the head and pull it all off in one piece.

 

[Bondo]

Re: Mercruiser Head removal

Ayuh,... Is this the same cracked block motor you're workin' on,..??
I forget, is it a 3.0l,..??

 

[Squab]

Re: Mercruiser Head removal

No No its a 1989 4.3 v-6 Merc.

 

[ussoldier_1984]

Re: Mercruiser Head removal

you dont have to pull the rockers or anything just unbolt it but the pushrods will fall when you lift the head so what I usually do is losen each rocker a bit untill you can move the rocker off the pushrod then slide the pushrods out mark them to where they went so you can put them back where they came out of.

 

[Squab]

Re: Mercruiser Head removal

If I loosen each rocker bolt then how do I know how tight to make them when i re install? Is there a specific torque they should be at?

 

[Bt Doctur]

Re: Mercruiser Head removal

Depends, some adjust ,some are just torqued

 

[ussoldier_1984]

Re: Mercruiser Head removal

You will have to adjust the rockers one at a time. start with #1 at tdc both valves should be closed and you should tighten the rocker untill it has a very tiny amount of wiggle then go to #3 same thing tdc and tighten both rockers untill a very little wiggle room. go through every rocker doing the same thing. then after everything is tightened up and the motor is ready to be started. You need to adjust the rockers after the hydrolic lifters have been pumped up. with the valve covers off engine running (very messy job) go through and loosen one rocker untill it ticks then tighten it just enough for the tick to go away do this for each rocker If its hydrolic rockers that is anyway

 

[Squab]

Re: Mercruiser Head removal

Do I even have to remove the rockers? Cant I just unbolt the head and remove?

 

[ussoldier_1984]

Re: Mercruiser Head removal

you dont have to unbolt the rockers completly just enough to slide the rocker off the pushrod to get the push rod out. if you dont they will just fall everywhere and you will not know what cylinder or if its exhaust or intake pushrod. I have always been told its important to put the pushrod back to the same rocker for wear but thats up to you if you just want them to fall everywhere. its also a good idea to take each pushrod and roll it across a flat surface like glass table to make sure you dont have any bent pushrods while you have the head off

 

[ussoldier_1984]

Re: Mercruiser Head removal

its really not hard to adjust the rockers

 

[TilliamWe]

Re: Mercruiser Head removal

Do I even have to remove the rockers? Cant I just unbolt the head and remove?

Sure, if you want to drop all 12 pushrods per side. And then you are going to have to somehow line up all 12 pushrods as you place the head down over them at re-install? Sounds like a nightmare to me. But hey, you do what you want, okay?
Adjusting valves is as described above, and it's even simpler when you actually start to do it. I use the technique of "tighten the rocker arm until you can not turn the pushrod with your thumb and index finger. Then back it off just a touch". After that, adjust them by ear. Loosen til they rattle, then tighten slowly til they stop. It's also not real messy. I packed rags all around the head of my 5.7 when I adjusted my valves, and not one drop of oil spilled on them.

 

[Don S]

Re: Mercruiser Head removal

Here is a link to the OEM service manual for your engine. I would strongly suggest you follow the procedures in the manual instead of using a bunch of short cuts that are going to cause you problems. Section 3 covers the engine itself.
http://www.4shared.com/document/1FdjddET/Service_Manual_07.html

 

[Squab]

Re: Mercruiser Head removal

Hey don, I live in Jersey and is still cold and wet. the engine is still in the boat and I am going to do the work in there. If I take off the intake manifold and heads, is there a chance things can get rusted if there is a tarp on the boat and there is a engine cover. I know direct water will not hit it it but there will be some condensate. What do I do?

 

[ussoldier_1984]

Re: Mercruiser Head removal

I would coat it in oil or transmission fluid it will prevent moisture to directly contact the metal