Author Topic: Best method for cleaning block surface and pistons (Read 5415 times)

nomad · « **on:** March 02, 2008, 10:47:29 AM »

I'm finally ready to start putting the M42 back together with new head gasket, cam sprockets, chain etc.
Got my cylinder head resurfaced and all looks well.

What's the best way to clean the engine block and piston head surface? I have brass bristle brush wheels for my drill, a plastic abrasive bristle wheel as well. Should I stay away from these? Should I do it by hand?

What sort of chemicals should I get? I was going to get a big bucket and mineral spirits to clean off all the parts with as I reassemble.

FredK · « **Reply #1 on:** March 02, 2008, 11:43:07 AM »

Pistons: Berryman Chem-Dip in a one gallon bucket with a strainer.

http://www.amazon.com/dp/B000J1B0E0?smid=A342F12XA4IW3Q&tag=dealtime-auto-mp-20&linkCode=asn

kowalski · « **Reply #2 on:** March 02, 2008, 11:57:39 AM »

scotch brite.

nomad · « **Reply #3 on:** March 02, 2008, 03:42:12 PM »

Sorry, forgot to clarify. Pistons are in the block, head is off, ready to go on.

So scotchbrite pads? Do it by hand right? Darn, I was hoping for an "easy way out".

Abrax · « **Reply #4 on:** March 02, 2008, 03:45:41 PM »

block surface - You mean outside -> sandblaster with glass particles.

nomad · « **Reply #5 on:** March 02, 2008, 05:32:48 PM »

No, just the head mating surface and the piston heads in the photo.
I had the machinist hot tank the head and it came out ok.
I hit the outside of the engine block with degreaser, let it sit and then washed it off.
It worked good enough that I don't need to revisit it.

I just want to prep the head surface and get the carbon off the piston heads.

Cobra Jet · « **Reply #6 on:** March 03, 2008, 09:07:49 AM »

For what you want to do, w/ the engine in the engine bay, I would definitely use the Scotch Brite pads. I think any other type of abrasive wheel, such as the brass cleaning wheels you had mentioned will be too harsh on the head surface - plus you do not want to take off any material from the head surface... All you want to do is just clean the surfaces, not remove material. I believe you can also purchase Scotch Brite wheels for air tools if you need to remove heavy build up - just be careful as to how long you stay in a certain spot if using air tools.

I would also have a shop vac on hand to remove any/all particles afterwards from the piston holes, water jacket holes, etc... Thoroughly clean the block surfaces & cavities with the shop vac before installing any gaskets, etc...

nomad · « **Reply #7 on:** March 03, 2008, 09:37:55 AM »

that's a great idea about the shop vac. I'll use that. bought a can of mineral spirits so I'll see how that goes. I wish I had air tools but no such luck.

Cobra Jet · « **Reply #8 on:** March 03, 2008, 11:37:59 AM »

If you are looking to just clean off the surfaces of the pistons & top of block where the head will mount, you can use "Brakeleen" or any comparable spray on brake cleaner. The chemicals in those type of products really break down any grime, oils, greases, etc very quickly - plus the chemical itself dries (evaporates) rather quickly. I've used the product for degreasing/cleaning MANY engine parts over the years with no problems.

Oh, one more thing - once you have cleaned everything, then used a vac to thoroughly clean up the debris - shoot down the cylinder walls w/ some WD40 (or even wipe some oil on the walls) to avoid a dry start before planting the head back onto the block.

Best of luck and keep us posted w/ your updates!

DRtothE · « **Reply #9 on:** March 15, 2008, 07:38:37 AM »

Quote from: Cobra Jet;44029

If you are looking to just clean off the surfaces of the pistons & top of block where the head will mount, you can use "Brakeleen" or any comparable spray on brake cleaner. The chemicals in those type of products really break down any grime, oils, greases, etc very quickly - plus the chemical itself dries (evaporates) rather quickly. I've used the product for degreasing/cleaning MANY engine parts over the years with no problems.

Oh, one more thing - once you have cleaned everything, then used a vac to thoroughly clean up the debris - shoot down the cylinder walls w/ some WD40 (or even wipe some oil on the walls) to avoid a dry start before planting the head back onto the block.

Best of luck and keep us posted w/ your updates!

+1 props

colin86325 · « **Reply #10 on:** March 15, 2008, 03:43:57 PM »

I like to use foaming oven cleaner spray. Works great for piston tops.

bmwpower · « **Reply #11 on:** March 15, 2008, 07:03:25 PM »

Don't forget to clean the bolt holes.

Use brakleen and a clean rag (no paper towels) until the rag no longer comes up dirty. You can use a plastic scraper for tough areas and/or a new razor blade for stuck-on gasket. Just be really careful not to slice up the surface.

The block surface does not have to be bright shiney bare metal, just clean.