How to Clean a Head Gasket Surface
 

How to Clean a Head Gasket Surface

There are many ways to clean a head gasket surface.
This is just one way, and it is the method I prefer.

I do not like the use of “rol-locs” for cleaning a head gasket surface, for block or head.
Cast iron or aluminum.

This is for COMPOSITE Head gaskets, Not MLS

MLS Head gasket surfaces need more prep.

A rol-loc can an will “wave” a gasket surface when used improperly. In most cases it is.

So do not use this!!
https://www.miataturbo.net/attachmen...ine=1334161503

What I prefer to use is a hard back body board with 80-100 grit sand paper.
https://www.miataturbo.net/attachmen...ine=1334161503

https://www.miataturbo.net/attachmen...ine=1334161503

The reason to do it this way is….
1) more coverage area
2) will not “wave” the gasket surface
3) will show low spots in the gasket surface

Use moderate pressure when going over the gasket surface.
https://www.miataturbo.net/attachmen...ine=1334161503

and go at different angles, using long steady strokes
https://www.miataturbo.net/attachmen...ine=1334161503

and

https://www.miataturbo.net/attachmen...ine=1334161503


You want to go over it enough to just “shine” the surface and remove all the old traces of the head gasket but not remove the metal of the block or head.


You should end up with something like this.
https://www.miataturbo.net/attachmen...ine=1334161503

Now the surface is prepped so the head can be checked for warp and other imperfections.


Notice the dark marks above the exhaust valves and around the water ports, this shows the low areas and fire rings.

This head needs to be surfaced so to hold a head gasket properly.

How much more is required for MLS gaskets? Just repeating with some finer sandpaper? This is assuming the head is in better shape than the one pictured, of course.

For a MLS, the head needs to shine.

This method will work with a MLS, depending on the finish that was there before.
Works just fine with a composite gasket.

This is mainly for geting the surface clean for inspection