I have read on other threads that some will 'polish' the exposed top of block and 'polish' the top of the pistons when they are doing a head swap.

This is done to clean the surface and get the carbon off. Most I have seen just use a plastic putty knife to gently scrape off carbon, old gasket material, etc.

What I am wondering, some use a socuring pad on a orbital pad and it leaves swirl marks all over the piston heads and block deck surface.

Do you think this is a bad thing?

 

Yes, I would do a very careful plastic putty knife job, and finish with some scotch brite by hand to take off the very small particles.
It takes a little time to do it safely, but it's worth it.
I certainly would NOT use any hand-held machine to do it.
Since the block is aluminum, and very soft, you need to be careful.

Also, before you put the heads on and bolts back in, take paper towels and roll them up into long strips, almost like pipe cleaners, or something straw-sized, and stick them down into the head bolt holes to remove as much of the coolant as possible that may have fallen in there when you removed the heads initially.
It also takes time to get all the moisture out of those bolt holes, but it is a great way to make sure you have all the clearance you need for the new bolts.

Just my way of doing it, I'm sure others may chime in.

 

Do you use the scotch brite on the piston heads as well? I would imagine (me dummy) this would be done while piston is at TDC

Also, do you cover or plug the water jackets to avoid debris falling in, or is this not a concern....

 

I have never cleaned the pistons, but that's just me.
If they were really caked up, then I could see it.
Just make sure you clean the cylinder thoroughly, maybe vacuum each one after it's done.
I'd also put a piece of tape over each bolt hole and coolant hole if you fear debris falling in there.
Couldn't hurt, might just take longer.

 

Here is a pic from another thread on the forum.

At first it looked a little harsh. But I can see alot of effort went into cleaning the block and pistons. Anyone think this might damage something or is this the desired prep?

 

IMO if you plan to tear down the motor regularly then Ok to clean/scrub pistons...if not you may be giving crud an easier foothold to cake onto your pistons. This is of course if they are only lightly soiled, if they have considerable build up already then I would make an effort to clean them up.

As for the deck surface, this you do want to clean up as good as possible but I too would be cautious of using power tools on it.

 

A shop vac helps a lot in the clean up. Never use a metal scrapper on aluminum. NEVER!

I used a device from NAPA in my electric drill sold specifically to clean the block and heads of gasket material. It was a green disc about 2 inches in diameter and had about 100 abrasive finger that were about 1/2 inch long. Like a scrub brush with large abrasive bristles about 1/8" in diameter. Did a fantastic job in cleaning everything up. Don't remember the name.

I ran a shop vac along with the drill to catch as much stuff as possible. I cleaned the piston tops with lacquer thinner and paper towel. Let the thinner soaked towel sit on top of the piston over night covered with plastic to keep it from evaporating.

 

 

Scraping the top of the block with a plastic putty knife or similar tool, and, if needed, giving it a once-over with Scotchbrite is fine. Any more than that and you'll want to take some special precautions.

I've found that a piece of 1/4 inch Plexiglass with one edge cut at a 45 degree angle makes an excellent scraper. Soft enough not to scratch the alumnum but stiff and sharp enough to scrape well.

I would avoid anything like sandpaper or the sandpaper flapper wheels - it can shed abrasive particles into your cylinders which can get imbedded into the cylinder walls and scratch the rings.

Scotchbrite doesn't shed much, and wetting it with a little kerosine will help control the debris that it takes off. Masking tape is good for cleaning up any remaining bits once the kerosine has dried.

Leaving some light swirl marks on top of the block is fine. I wouldn't mess with the pistons unless they're really dirty, in which case they really should be removed and cleaned.

Ditto if you really want to polish the pistons; but if you're going to do that might as well have them ceramic coated.

I find a gun-cleaning kit works well for cleaning out the threaded holes. Use a slotted holder and a patch with a little kerosine on it, sort of screw it into the threaded hole then pull or screw it out, depending on how tight it is. Then dry patch the same way.

You can also blow air (or use one of the canned-air computer duster things) into the hole to get stuff out, but wear safety glasses when doing so!

 

i just spray the pistons with brake/parts cleaner...
let it sit a minute then wipe it up.....
always clean the sides of the pistons with a air gun to make sure you dont leave any particles on the rings....
i use scotch brite pads on the engine but i know what im doing...
please use some common sense just a little is needed to remove the gasket material//

hope that helps...
udriveslow

 

i also usually clean and polish the valves and combustion chambers while the heads are off, even new ones can use a good once over.

 

So, in your opinion, is the attached photo what you want to end up with or is it too excessive. (note:the swirl marks on the top of the piston)

 

 

Ed,

It is important to clean the pistons well, just make sure you take the necessary precautions to preclude debris from entering the lifter galley.

The block surface needs to be cleaned as well - just do not use anything that will in any way gouge the surface. I recommend solvent to remove any surface grime and flat, extra fine scotchbrite pads to "polish" the surface.

When done, don't forget to clean and blow out the head bolt holes.

Take care,

Charlie

 

Charlie,how's the shop doing!?

George

 

I could "officially" open anytime. The dyno is being delivered Monday, so give it a week after that.

Stop over and take a look at what I've put together so far... 26536 Ruether #606

Charlie

 

I'll stop by on Tuesday!!

 

Thanks for your help Charlie, it is much appreciated.

Ed