4.3L Mercruiser Cylinder Head Cleaning....

BAproject · Aug 20, 2010

Hey guys, I am at the point where I have to tear the top end of the engine down...again. Don S. this is the perfect example of "why is there never enough time to do it right the first time..."

Regardless, I don't mind doing this as I have come to the realization that I will not be sea ready this season....

So I need to pull the heads and inspect/clean them. I have read that the push rods need to be removed before taking the head off as to not bend them, and to make sure that all bolts are removed.

I have the manual and will be following it, but is there any advise that the manual does not list for doing this. And, has anyone done this, are the heads impossible to clean...they're expensive to replace and I am hoping to be able to clear them out. any advise would be greatly appreciated. Thanks in advance

zbnutcase · Aug 20, 2010

Re: 4.3L Mercruiser Cylinder Head Cleaning....

What is the issue??????

6meter · Aug 20, 2010

Re: 4.3L Mercruiser Cylinder Head Cleaning....

And you're pulling the heads why? What do you mean by head cleaning? What part of Mass?

JustJason · Aug 20, 2010

Re: 4.3L Mercruiser Cylinder Head Cleaning....

You really don't need to "clean" the heads. You could have deposits on the valves causing them not to close right. But whats the reason for the job?

My only real advice would be to make sure you tag the rockers and pushrods as they come off and mark them so they go back in the exact same location.

BAproject · Aug 20, 2010

Re: 4.3L Mercruiser Cylinder Head Cleaning....

Sorry about that....I am specifically talking about the water pass through areas of the head. When I originally had the intake manifold off the starboard side front passage was noticeably clogged, I though i freed everything but it's almost impossible to really tell.

This is all arising from an overheating problem....in previous posts I have talked about it (sorry for assuming everyone would know hahahah)....has a new t-stat, circ pump, belts, gaskets, risers, impeller, waterflow to the "t-stat housing is great.....water coming off the intake manifold into the t-stat housing is not enough volume, I'm thinking the water passage in the head is still clogged

6meter · Aug 20, 2010

Re: 4.3L Mercruiser Cylinder Head Cleaning....

Take a pressure washer to it. The heads are only like 3-4" thick.

BAproject · Aug 20, 2010

Re: 4.3L Mercruiser Cylinder Head Cleaning....

think I can do that wtihout...

A) Removing the intake manifold (instead shoot thru the t-stat housing opening)
B) having so much pressure that it blows out the gaskets everywhere

I'm liking this idea though

6meter · Aug 20, 2010

Re: 4.3L Mercruiser Cylinder Head Cleaning....

You shouldn't blow any gaskets at all. Don't know about not removing the intake. Take the thermostat housing off and try it. When I worked on cars, I would come across plugged water passages mainly just at the intake to head gasket area. Wasn't very thick, just scraped it out. I'm guessing that after the intake R&R the first time, it's still getting hot now?

BAproject · Aug 20, 2010

Re: 4.3L Mercruiser Cylinder Head Cleaning....

yes it's still getting hot...I will admit the first time I cleaned it I had no idea what I was doing and was probably too cautious!

So you think that high pressure water will free up the passages?

yes it stills gets hot.....well..starboard side runs at perfect temp, port side bank runs way too hot (and yes I am aware one side will always run hotter then the other)....but we are talking 40 degree temperature difference...

what do you think?

JustJason · Aug 20, 2010

Re: 4.3L Mercruiser Cylinder Head Cleaning....

Have you pulled the risers yet and inspected the transfer ports and the water exhaust ports?

BAproject · Aug 20, 2010

Re: 4.3L Mercruiser Cylinder Head Cleaning....

Yes, risers are new and exhaust manifolds have good water flow....it's definitely and obstruction somewhere in the engine/heads....everything else in cooling system is basically new, belts, gaskets, t-stat, impeller, some hoses...also cleared hosse that feed the exhaust manifolds

Todd157k · Aug 20, 2010

Re: 4.3L Mercruiser Cylinder Head Cleaning....

When you pull it apart, and putting it back together, make sure the gasket holes line up and clear all passages. I've been handed gaskets before that we wrong year, wrong model, different bla bla bla... and missing cut-outs or having extra ones in it. Then there's square port, "D" port, and oval port heads... bla bla bla. Bottom line, I've had the wrong gaskets handed to me many-a-times.

BAproject · Aug 20, 2010

Re: 4.3L Mercruiser Cylinder Head Cleaning....

right...when I put the intake back on they were the correct gaskets, all holes that were supposed to be there, were...

and in thinking about it the only way to power wash the channels is with the intake on, otherwise the top of the engine is open and water will get in it, that would be bad

6meter · Aug 20, 2010

Re: 4.3L Mercruiser Cylinder Head Cleaning....

BAproject said:
right...when I put the intake back on they were the correct gaskets, all holes that were supposed to be there, were...

and in thinking about it the only way to power wash the channels is with the intake on, otherwise the top of the engine is open and water will get in it, that would be bad

Not devestating. Just have to change the oil after you're done washing.

6meter · Aug 20, 2010

Re: 4.3L Mercruiser Cylinder Head Cleaning....

Just thinking here, are you running fresh or salt water. Open cooling system I presume?

BAproject · Aug 20, 2010

Re: 4.3L Mercruiser Cylinder Head Cleaning....

open cooling system in salt water

4.3L Mercruiser Cylinder Head Cleaning....

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