Several days ago, I posted about my screw-up during my cam install. Here's a little background of what happened... After realizing that I didn't have the dot-to-dot quite right (before I started the car), I tore everything apart to the timing cover, rotated the crank for the cam spocket dot to come down, disconnected the timing chain, and rotated the crank to get the crank sprocket dot facing up. After hearing a big thud, I realized I screwed up bigtime...I forgot to pull the pushrods...!

I then pulled both the heads, with the following results:

Several of the intake valves on the driver's side were bent, and left tiny gouges on the pistons where they contacted. When I tried to pull the passenger-side plugs, #8 was too tight to get out. I couldn't turn it at all. I know I hand-threaded that sucker in there, and even used a rubber tube to get it in the rest of the way. Just like with the rest of the plugs, I only used my socket to snug it up. I also used anti-seize.

After pulling the passenger side head, I saw why the plug wouldn't come out... The #8 exhaust valve was snapped completely off. and ruined the spot on the head where the #8 plug sticks out. The pistons look about the same as on the driver-side (just tiny gouges from the valve contact.)

The cylinder walls look fine, and the pistons only have slight marks on them from the valve contact.

Since I have the heads off, and the passenger-side head is messed up pretty bad by #8, I'm going to break down and buy a new set of ported heads while I'm at it. After doing a lot of reading, it looks like I'll order a set of Patriot Stage II heads from TSP.

To clean up the pistons, I have a few questions:

1. What can I use to remove the carbon build-up from the pistons?

2. Should I sand the ridges formed by the valve contact smooth?

3. After cleaning/sanding, what should I use to prep the pistons/cylinder walls before putting on the new heads (assembly lube/oil)?

Thanks in advance...it's been a long sleepless week!

 

If the ridges are not too deep, you may try polishing them out with a dremel tool or similar. However, you don't want that grit to find it's way down beside the piston. Also, don't remove too much material. YOu just want to smooth and blend the notches, not grind gouges to remove them. It is also very likely that you can run them as is (but I'd like to see them to say that for sure). Just my thoughts....

Anyone else?

 

I would use a sharp chisel and a small hammer to take the ridges off the piston crowns; that way you don't have to get abrasive dust in the engine. If the ridges have sharp edges and you leave them there, they could cause hot spots that could result in knocking. Carb cleaner and a razor scrapper should take off the carbon deposits.

 

I've used a stiff gasket scraper to scrape the nicks off pistons before, they are quite soft. I wouldn't worry too much about the carbon deposits, just smooth the piston nicks out. You can use some spray lubricant like WD40 in the cylinder walls, it'll burn right off when you start it. A film of it is plenty. If it were sitting for a while before starting it, some of that thick GM engine assembly lube works great and clings to anything you put it on. One thing to remember when cleaning everything is to remove all the coolant from the head bolt holes before reassembly.

 

I would leave it alone. The last thing you need is screww up one of you crank bearings by pounding onn it. Also, you don't want to get any shaving in between the ring and the cylinder wall.

 

If you scrap or grind or whatever, you might try getting a friend to hold a vaccum cleaner nozzle in there to suck up the stuff as it comes loose.

Good Luck

 

Ive done this WAY too many times :-/

So heres the tried and true procedure:

Take a peice of emory paper and some motor oil. Put a tissue at the bottom of the cyl (in the downhill corner). Wet the emory paper with motor oil and start rubbing. The edges should soften out very quickly. Im not sure why, but the material is very soft and emory paper is more than enough. Use the issue to clean the oil/material off.

Hammer and chisel? Are you insane? A dremel would be far too much far too quick for me and spray metal everywhere.

Sorry to hear about the results. Ive been there and its no fun.

Chris

 

...agree with Viseral

make sure you do this with the piston out of the hole.. e.g. at the top....

before you move the crank to the next piston, spray ALL open bores with silicone and clean with a new paper towel...

when ALL bores are clean, move the crank so the next piston comes to the top and repeat the procedure....

do not get gunk between your bore walls and pistons...

 

Oh yeh; one other consideration...

...since your factory head is no longer acceptible as a core for the head swap, consider purchasing Lingefelter ported LS6 ASA heads at $980 per with NO core charge required,....

These are sold by our sponsor SDPC. Before you buy them, however, see if they will work with the cam you intend to use....the heads are milled .055

 

Thanks for all the help everbody!

I'll be sure to take really good care when smoothing out the pistons...

BTW, after doing a little digging I ended up calling Trevor at Texas Speed and Performance. I ended up ordering a set of Stage II 5.3L heads.

Maybe there was some good in this fiasco after all!

 

Im glad to hear you are back on track. I think everyone covered prepping the pistons pretty well. I would still clean off the carbon though. I had a lot of gunk on the surface of my pistons and I was able to shave it off with a razor blade and then an emory cloth to clean it up.

My only other comment is, I didnt realize valves were that brittle. You were only turning the engine over by hand, right? Either you are VERY strong, or valves are very brittle. I could understand a valve breaking by the starter cranking the enigne over, but not turning it by hand.

Oh well, good luck with everything!

 

Bring the piston up to top dead center before working on the smacks. Apply some vasoline or grease to the cylinder walls, just in case to catch any errant metal or carbon pieces. Lower the piston down after you are done and wipe clean.

FWIW, carbon pieces can score cylinder walls. Be just as careful as with the piston metal when removing it. Because of this, you might want to try using acetone to cut the carbon down. It may take a bit more elbow grease to get everything off, but it will be safer. Hope this helps!

 

On other point:
since you have a lot of carbon build up, while you have the heads off, connsider installing an LS6 valley cover....you probably need an oil catch can too...these dudes prevent oil from getting sucked into the engine...

 

Forget that, take the easy way out.
Forged pistons, and rods. But just the pistons will do.