Aluminum Cylinder Head Prep?

[5CYL300SD]

Now that I have the head off my 3.5 OM603, I need to prep the surfaces for the new gasket. Block is easy using razor blade and shaving cream to prevent debris in holes.

I’ve been using the same tactic for the cylinder head. I used Goof Off, razor blade and brake clean.

I’ve done roughly two and a half cylinder areas. I’m thinking this isn’t clean enough. Am I being too picky, or should I go to the other coast and look for a machine shop?

[Usaguy]

For aluminum use only Plastic razor blades (steel can create grooves in aluminum). Then with 180 grit on a sanding block you clean it all up.

Or just take it to the machine shop. They may even "clean it up" to a proper Ra surface roughness. Although then you will have to take out the prechambers. Or pay them to do it

[Sugar Bear]

If they are stains in the metal it is fine, if it is raised and you can feel it isn't ok.

The Ra (roughness average) matters. If the surface is too smooth like a mirror the gasket will leak. Discuss with the machinist if going that route.

Good luck!!!

[tjts1]

Check for flatness and reinstall it. Having a diesel head resurfaced should be avoided. It also required pulling the prechambers which is a PITA.

[Diesel911]

This could be a repeat as I did not read the other posts.

I have used this for many years: CRC Gasket Remover. No. 05021, Item 1003638
Of course other companies make a similar product. It will also remove paint so be careful of that.

After spraying and letting it soak in you can use plastic, hard wood, dull steel (like butter knife dull) and brass or stainless steel hand wire brushes used by hand to get it off.

[Diesel911]

Note before re-surfacing a Cylinder head with pre-chambers that protrude you need to measure the protrusion/the amount sticking out for reference. It will help you pic which thickness of seal ring you might need.

When they are installed you also need to measure the pre-chamber protrusion to be sure it does not stick out too far.

[JohnLeCar]

Originally Posted by Diesel911

This could be a repeat as I did not read the other posts.
.

?????

[Diesel911]

Originally Posted by JohnLeCar

?????

I was in a hurry to post so did not read what others had said previously.

If I posted new info fine if I posted info someone else said it is because I did not read the other posts. Seems clear to me.

[5CYL300SD]

Thank all!

Deep discoloration is actually corrosion.

Since I got it pretty smooth with the razor blade and goof off (really nasty stuff!), I’m just going to clean up the block deck, and slap it on with a new gasket. Guess I’ll update after it's running.

Original gasket was intact upon removal. I had to lift the head due to a destroyed chain tensioner rail.

[BillGrissom]

If the prechambers don't protrude past the surface (hard to tell in photos), I wouldn't be afraid to sand it with 400 grit. Search for they youtube by OldSkoolFunk. You need a thick piece of glass to spray-adhesive the sandpaper to. I would jam paper in the oil passages first, to pull out debris with the paper. Chemicals which might help are "fireplace window soot remover" and phosphoric acid. The later removes oxides and slightly etches bare aluminum (good for painting). You can buy it for concrete etching at Home Depot, or is in some of the rust-remover sprays.

[5CYL300SD]

Originally Posted by BillGrissom

If the prechambers don't protrude past the surface (hard to tell in photos), I wouldn't be afraid to sand it with 400 grit. Search for they youtube by OldSkoolFunk. You need a thick piece of glass to spray-adhesive the sandpaper to. I would jam paper in the oil passages first, to pull out debris with the paper. Chemicals which might help are "fireplace window soot remover" and phosphoric acid. The later removes oxides and slightly etches bare aluminum (good for painting). You can buy it for concrete etching at Home Depot, or is in some of the rust-remover sprays.

I would do that, but the prechambers protrude quite a bit. I don’t have the tools or experience to pull them either...

[dieselbenz1]

Was the head checked for flatness?