Head Gasket questions

[captainofiron]

SO Im getting ready to pull apart the engine to see what is ticking (im thinking its the lifter)

And I was considering replacing the head gaskets while I am there (from many threads I have seen and read)

Would it be beneficial to get the head planed or anything?

Can I just stick new gaskets in there without doing anything to the head?

Keep in mind my car has about 155K on the clock.

Im a little hesitant as this is my first time messing with aluminum heads

[1badz]

Have the heads machined at a machine shop for the sake of proper sealing when you throw in the new gaskets. There is an accepted tolerance for warpage which can be tested with a true straight edge and a feeler gauge (I cannot remember the actual accepted values off the top of my head). In my opinion it is not worth going through that trouble and still having the chance of the heads not being in the best condition possible for proper sealing. Just spend the little money it costs to have them machined flat and be done with it. I have heard of people using copper-coating on the gaskets when a surface is un-known and shaky. It is supposed to fill in any imperfections.

[95ImpySS]

Have the heads machined at a machine shop for the sake of proper sealing when you throw in the new gaskets. There is an accepted tolerance for warpage which can be tested with a true straight edge and a feeler gauge (I cannot remember the actual accepted values off the top of my head). In my opinion it is not worth going through that trouble and still having the chance of the heads not being in the best condition possible for proper sealing. Just spend the little money it costs to have them machined flat and be done with it. I have heard of people using copper-coating on the gaskets when a surface is un-known and shaky. It is supposed to fill in any imperfections.

Copying exactly what I was going to say. lol

[1badz]

lol remember, I was present when both ideas were taken into consideration :P good times

[captainofiron]

Just a question, but what is the point of getting the heads as flat as possible, if the block is not decked, also the coefficient of thermal expansion between iron and aluminum means that the aluminum will grow much more, meaning warpage anyways...

So whats the point?

[95ImpySS]

The point is to get it as close to perfect as possible. Since the aluminum will expand and contract at a different rate than the iron block. There is a much greater chance that the heads will be warped more than the blocks deck surface. Its cheap insurance IMO. Here in Miami its only $25-$30 per head to get it checked out and resurfaced.

[captainofiron]

right now my compression is well within the allowable range, which makes me think any warpage of the head will be negligible.

I still think planing the head and not decking the block would be of little gain, but thats just why I was hoping for an explanation on your point of view

[1badz]

It is not a gain you are after, it is the extra security. A head gasket will be much happier sealing up to a flat surface that a slightly warped one. Like Brad said above, the iron block expands at a much smaller rate than the aluminum heads, almost to where it would be negligible.