Has anyone come up with a decent way to clean the piston heads through the plug hole? I am planning on fabricating a small metal or plastic straw like tube to the end of a wet vac and spraying brake cleaner into the cylinder. Curious if anyone has had luck with this? My engine is old and I'm planning on a rebuild in August. Until then, due to cracked plug tube, just want to clean out some of the carbon and minor junk in #4 and #5 when swapping plugs.

 

Bad idea. You'll bore-wash your cylinder and rings, and your next start-up would be without lubrication until oil is able to get there again.

Don't spray brake-cleaner where it doesn't belong.

Also I don't think a cracked plug-tube will cause gunk to build up inside your cylinder. It's plugged up by the plug, after all.

 

I agree with user 63031 on this one. These cars have enough problem with bore scoring you don't want to exacerbate the problem by washing down the cylinder walls with solvent. Either live with the carbon buildup or have a company like Flat 6 Innovations reconstruct the motor with new pistons and Nikasil bores.

 

Thank you for your feedback and you're probably right. However, to explore a little deeper my question then is why would brake cleaner be a problem for the cylinder? I understand it's a solvent, but so is gasoline. Also, what is "bore-wash"?

 

Bore wash can be used to describe the process of washing all the oil off of the cylinder walls. Yes, gasoline is a solvent and can be a big factor in bore scoring. Fuel injectors get worn/dirty then can leak fuel into combustion chamber on shut down. Again, this will remove the lubrication on the cylinder walls and finds it's way past the rings into your oil, which is not good either. Ask me how I know...

 

Gasoline enters the cylinder in vapour form in very small quantities and burns off directly after injection, so tens of milliseconds after being injected. Spraying brake-cleaner inside your cylinder with the purpose of cleaning will easily be >100x more solvent than the amount of gasoline your engine usually injects for a single stroke.

With severe misfiring in a cold engine or a broken injector, you'd also be at risk of bore-washing your cylinder.