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Old 09-26-2010, 08:11 AM
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Radian Radian is offline
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Location: Tucson, AZ
Join Date: Aug 2010
Posts: 814
Mein Auto: '91 535i 5-spd
Originally Posted by robertobaggio20
How were you using the GM top end cleaner? Please give us full exhaustive details.

Sure's a technique I picked up from other mechanics online.

With the cylinder head removed from the engine block, I parked the pistons so that they were all somewhere down into their bores a bit. I then poured enough Top-End Cleaner (TEC) into each cylinder to just cover the tops of the pistons.

Then I just let it sit for about 24 hours. Every 4 hours or so, I'd check up on progress and give the solution a stir with an acid brush. The next day I gave one good last swish with the acid brush to make sure I got the valve relief cut-outs cleaned, then I sucked out all the nasty solution and floating chunks of garbage with a large syringe.

Next I would place the piston at bottom dead center. I then took my syrnige, and squirted fresh motor oil around the perimeter of the piston (not a whole lot, just an even bead enough to get down into the rings). I then slowly brought the piston to top dead center, then back down again. This would deposit the crap-load of junk from the rings, now entrapped in the oil, along the upper surface of the cylinder walls.

You'd be impressed just how much junk can fit in between the piston and the cylinder. So then I'd wipe that off, and repeat the process a couple more times until no more significant deposits were evident, then I moved onto the next cylinder.

This technique involves very little effort in comparison to trying to decarb the pistons with spray cleaner and a rag.

As for the cylinder heads. If found I could literally chisel off the encrusted deposits around the combustion chamber with the corner of an old credit card. Anything left behind was easily dissolved with the wipe of some carb cleaner and a rag. The intake port crud was also wiped out with just a rag soaked in carb cleaner. The deposits were the worst along the lower surfaces of the ports.
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