[Fortis 621]

I need your expert advice... I'm in the middle of doing a head gasket job and have full access to valves and pistons. There is a slight carbon build up on the piston. What is the best/easiest and most effective way to get rid of the carbon build up? Sending it to a shop is not an option. Is it best to just leave it alone?

Thanks.

Colin

 

[Tubolare Zagato]

Most probably this is the most difficult build up to take of!
I used an engine cleaning agent (i dont remember the brand) along with an old feeler gauge (you could use a thin knife but with a lot care) and a lot lot time!
Good luck, this will not be easy!

 

[slyalfa]

I have found that break cleaner seems to work.
some times it need to sit a while. but if you take your time it will clean up with out scratching anything. I take the valves and pistons and use the buffing wheel on them after they are clean to give that slick shiny look that seems to help keep the stuff from sticking

 

[Geezer]

When removing carbon be careful to not let any carbon get between the piston and the cyl bore. Carbon is abrasive. When done scraping use a vacuum to get as much loose carbon as possible that made it way between the piston and the bore.

 

[Alex]

It's just a thought ... but what about running a thin bead of bathroom silicone sealant around the edge of the pistons to prevent anything going down the sides of the bores? Degrease the area first with e.g. brakecleaner soaked onto a cloth. Once it's set (this might take two or three days) you can start work and you'll be able to remove the bead in one piece. Never tried this but it might work.

Alex.

 

[John M]

I wouldn't touch the top of the pistons for cleaning in a head gasket repair. Too much opportunity to stick a ring. So for me any returns is not worth the risk. Head and valves...another thing entirely. Top of the block good to clean as well. Gunk makes a quart can of solvent with a dip tray. That stuff would work nicely with the head inverted and the solvent poored into the top of the combustion chamber...cams out and valves closed and no leaky valves of course. Then follow with pressure washing after a day soak.

The most important thing to worry about when replacing the head gasket is to insure that the mating surfaces are "new" clean. All gasket material gone. Scuff it fresh with 600 grit wet with oil. Wipe it down. Then use acetone or mineral spirits to wipe it down. Assemble with no finger prints, no drips of anything....sparkling clean.

Best Regards,
John M

 

[Alfar7]

Cleaning piston tops

First plug all oil passages into the block. Cover the engine other than the piston you are cleaning.
Bring piston to TDC.
Pack cotton string aroumd side of piston above top ring. (must stan below top of piston, or you will snag it with wire wheel)
With a wire wheel about 2 inch diameter in an Air Grinder (elec drill is too slow) Polish off top of piston with wheel.
It is best to use shop vac in other hand to collect particles comming off of the wire wheel.
Rj

 

[Tifosi]

The old guy trick:

Don't clean it now, just finish up the head properly. (WAY too much risk of getting a carbon gremlin loose down by a ring which will end up causing a full teardown at some point)

Run the engine up to temperature, bring the revs up a bit, then introduce a small amount of distilled water into the intake.

It'll draw in and vaporize into steam during combustion, which in turn will steam clean the crowns under pressure. (yes, it'll fog steam out the tailpipe)

Repeat a few times, then remove the plugs for a look at the tops of your now clean pistons.

 

[5yearplan]

you can also use trans fluid instead of water. Not too much though

 

[john.harrill]

With the heads off, I wiped the top of the block, tops of my pistons and liners with a rag. Some of the carbon build-up came off the piston tops.

Should I be worried?
I have shop-vac'ed the area......