Questions on cleaning cylinder heads

[CrazyAndy]

Okay, just got an AAZ cylinder head in the mail last week.  Thanks Catlin!     Now that I've got it bare minus knocking out the precups, my mind turns to cleaning it.  I will be using a MLS gasket so I know head surface smoothness is critical.  What is the best method for cleaning; hot-tanking, steam cleaning, or something as simple as WD40 and a light brillo pad for the mating surface?  Let me know what you guys do if/when you cleaned your cylinder heads.

NOTE:  Tried the search function; didn't really find anything, much less pictures.

[ORCoaster]

I think it was CRSMP5 That described a glass plate and 600 or smoother grit sandpaper method in that crazy exchange about using the soda bottle for a hone. 

[CRSMP5]

nope not me... not that add/ocd/anal... i use scotch brite pads on die grinder... but yea a flat piece of something solid would work good.. use oil to clean as you do it.. but be carefull.. oil may let you do too good a job.. keeps the paper lubed and clean so possible to go too far..

[theman53]

That was ARB.

IIRC the surface for the MLS gasket was fairly rough so it bit in. I cannot remember right now, but the machinist did something different for mine since I used an MLS.

To clean as in take the oil and nasty off you can use many things. Stay away from simple green and stuff that eats aluminum. Diesel works well.

[745 turbogreasel]

6 RA finish for MLS. it's pretty smooth

[CrazyAndy]

I like theman's idea of using diesel to clean the buildup off; I keep forgetting diesel is a great cleaner as well as a fuel.  I'd also combine that w/ CRS's brillo-pad-on-a-die-grinder idea.  How do you attach the pad to the grinder?  I've got a dremel so I can use that.

[CRSMP5]

scotchbrite not brillo... they make pads with a screw on fixture that screws into a piece for a diegrinder... its not a "rigged" thing.. the adapter shaft is to thick for a dremal... go visit a body shop type of suply store..

[theman53]

I sell those things CRSMP5 is talking...it is 3M Roloc discs in scotch brite. Many different versions, most popular are the A coarse, A medium, and A fine, Brown, Maroon, and Blue/green respectively.   Many people call them cookies.

On the finish for the MLS...I was wrong guessing above, as shown in the post after mine, I knew it was something different, but it was super smooth, not rough to seat the MLS gasket.

[CrazyAndy]

Oh, you mean those brown discs w/ screws on the back?   We have those at work; no problem then!    Red should be fine?  If no then I can get the blue-green ones no problem.

So what about ports after I'm done opening them up?  Fine-grain sandpaper flap wheel on a dremel/die grinder?

[CRSMP5]

fine... if it was a non metal one you could use/have not as smooth a finish... 1 deep scratch metal does not seal... so unless your 100% on your capabilities.. and take your time... you can ruin a good head.. so there is the warning..

after you paint your engine block.. before you clean the head.. how i do this.. i use the new pad to remove the paint from things like waterpump mounting bosses, sealing surface, headgasket surfaces, mount ears and such... this wears the roughness of the pad out and makes it no so agressive..

why i speak of mounting bosses and such.. the thickness of paint on them will allow things to come loose even after being torqued to spec..  you want bare metal to bare metal.. you can leave the unused ones painted..

[CrazyAndy]

fine... if it was a non metal one you could use/have not as smooth a finish... 1 deep scratch metal does not seal... so unless your 100% on your capabilities.. and take your time... you can ruin a good head.. so there is the warning..

after you paint your engine block.. before you clean the head.. how i do this.. i use the new pad to remove the paint from things like waterpump mounting bosses, sealing surface, headgasket surfaces, mount ears and such... this wears the roughness of the pad out and makes it no so agressive..

why i speak of mounting bosses and such.. the thickness of paint on them will allow things to come loose even after being torqued to spec..  you want bare metal to bare metal.. you can leave the unused ones painted..

Thanks for the tip on wearing down the pad; got some Rust Bullet paint and metal etch spray in the mail 3 days ago; guess I'll just paint over that stuff to have enough over-paint to prepare the disc.

Figured that much about paint between mounting parts; acts as a movable buffer that come come loose or work out from between the parts over time, causing partial or even total loss of original torque force.  Seen  one guy around these forums snap a bolt head off his injection pump bracket where it went to the block; not saying that's because of bad torquing, but don't want that to happen to me!

Now, I'm just going to focus my efforts on the removal of hard carbon in the main cylinder areas, nothing beyond a brake cleaner spray and wipe down beyond those places.  Still no aim in port finish though; I'll figure it out.

Thanks for the recommendations. 

[theman53]

Port finish can be smooth as glass. There is no need to have the air mix with the fuel in the ports like a gasser. If the shape is correct so there isn't tumble then it will go in best with a smooth finish usually.

The 3m fine blue/ green pad is capable of a 3 or 4 rms finish on stainless steel with the proper person on the tool.

[CrazyAndy]

So I tried cleaning my cylinder head mating surface using the method that CRSMP5 described, except I wore the disc down cleaning my manifold gasket sealing areas instead.  What I found was not very comforting, not because of the method used but because of what I found under the crud.

Pics hopefully show it; sorry for the piss poor shots but my camera's range function no longer works.




Kinda hard to see, but there's some pitting around the water jackets.  Looks like I'll have to get this head resurfaced after all. Nuts, but the cleaning method wasn't too bad, so consolation prize. 

Time to go knock out my precups. . . .

[CRSMP5]

dont remove precups... bad idea IMO..

the one jacket on end/edge of head.. i do not know if that pit can be removed...

also fyi.. got turbo rebuilder that does great work 75 miles from me... vs shipping to canada..

[theman53]

On the precup removal...

My machinist now says that if they come right out he will not take them out. He thinks if they are in there good, don't piss with them. I tend to agree. He doesn't fly cut his heads he abrades them down, so no worries about protruding cups etc as the arguement has been.