This is what I posted previously in my head gasket thread

I found a site or so referencing the use of a 320 grit wet/dry sandpaper rather than the White rolec disk. I noticed myself that the Rolec disk left circular marks behind, as I had a second bad head I decided to give sandpaper a shot.

1st up I checked the head 9 thou out in 1 place, sprayed that area with copper gasket seal and let set up.

Sanding process was very straight forward:

• Soaked the head in windex - to capture sandpaper and aluminum dust - this is very fine and the windex stops it for traveling
• 320 grint on a sanding block, a plastic sanding block works is best. I had originally indicated a good straight piece of wood without considering that can be very hard to find.
• 2 passes then dry and re-windex this limits the material getting into engine nooks and crannies
• I used a total of 10 passes

I found no significant change in head depth, but it is not perfect:

• Any left over gasket material has to be removed with a scraper/chemical remover
• You need a long sanding block which can be hard to handle
• you need to be very careful to prevent the windex getting where it should not

The upside is it makes any scratching or other damage very easy to see.

I can not upload images right now,the stall at 90% but will add them later

Any thoughts or comments

 

The steam cleaning tank at the machine shop seems to work out alright

 

1st image is the overall head and the second is a close up of the low area and some of the pre-existing scratches

@robertf thanks for the photos, and yes the machine shop cleaning is always best, but I am not pulling my block so I need to clean that surface in place. With MLS gaskets you want a very clean and smooth surface on both sides.

I figure we can get some input from others make the next guys life easier

 

Using a piece of wood as a sanding block is a huge no-no. Think about how twisted most pieces of lumber are, or how many knots and depressions they have. You need to use a proper flat edge if you are going try and level a head

 

@Llamasayswhat Yea I had not thought about places outside where I am, clean straight lumber is easy here. Thank you for your input

A proper sanding block is best, and to be clear this is about cleaning rather than leveling.

For anyone reading this if you need a head leveled - go to a reputable machine shop the odds of you getting it right by sanding is very slim unless you have huge patience.
It is very slow process, that takes constant checking with a steel straight edge and a good set of feeler gauges to make sure you do not add a wow.

The object of this thread is cleaning the head or block up nothing more

 

Again, sanding with any grit attached to a non-level backer is a bad idea. We're dealing with thousandths of an inch for warpage and high/low spots. You can easily create or exaggerate issues with flatness by doing this.

DIY is great, but this isnt a good one...

 

I found it best to use a flex drive with brass brushed to reduce any metal removal, it does take longer and few brushed but worth the effort , but looking at your photos as a first pass I would check out the dark portion with a magnetic dial gauge, by looking at it its only to confirm your head need a skim to get it back to flat

 

Richard, why have you not sent the heads out to a machine shop to have the valves and valve guides serviced and to have the heads checked for flatness?

 

@frostythor @mln01 thanks for the responses

Hi guys those heads were toast improper torque with TTY bolts had them 5 thou out of true. The max they can be milled is 19, so they became my test bed for cleaning. I need to get my block clean and seemed to be a good idea to test on the old heads.

Ideally the gasket will largely come way when you remove the heads, but I had huge chunks everywhere. To even check your heads for level you need to get them clean, hence this thread. Gasket remover and carb cleaner do a lot of the work but even then you need all the material gone to check.

In the case of the block the same you need all the material gone before installing new gaskets hence this discussion.

The same methods should work on cleaning up the other aluminum mating surfaces we deal with.

 

Berryman chem dip in the gallon can is your friend. bristle brush soak rinse and repeat.