eyeball kid

So, head is off (header studs still attached)--thanks to everyone for advice. The car was running rich before I parked it in July. Piston #1 and 4 have noticeable carbon layers--like I can chip it off with a fingernail. I assume I had a vacuum leak which caused this.

This rebuild includes wb and boost gauges--to better monitor things, a rebuilt and upgraded turbo (Evergreen in Fla.), 3bar fpr, mbc, Vitesse chip, vacuum line replacements, ISV replaced, rebuilt TB, SFR upgraded IC, new coolant pipes, resealed AOS, LR steam vent, and some other stuff.

My questions: Is there a best way to remove the build-up? Can I move the pistons from TDC with timing belt removed (but balance shaft belt still attached), and should I consider a gasket other than the Widefire? I'm assuming I do not need to replace head studs, but I'd like that confirmed.

Am I missing something important?

Does it make sense that pistons 1 and 4 are built up while 2 and 3 are pretty clean?

Thanks

Dan

Jeremy Himsel

Or..... you could leave it as is and use some seafoam a couple of times once you get it running. I typically use it on a motor prior to teardown whenever possible. I run it through my corvette about every 20K.

eyeball kid

Interesting. Wait you own a corvette and that's your avatar?

Cory9584

soak it in carb cleaner and wipe it down. Then blow it out good with compressed air especially around the rings

Chris White

You can use a brass brush to scrub the tops of the pistons along with shots brake cleaner. Make sure the piston rings do not get crap in them.

The carbon deposits are usually from worn valve guides/seals.

Tedro951

+1 on the brake cleaner, but use a fan to keep air moving....I get a cough every time I go through a few cans of it. It wont hurt to rotate the crank with the TB off. The balance shafts will stay in "time" with the crank. Just be sure to set it to TDC before attempting to bolt the head down (with the cam mark lined up).

jerome951

I found brake cleaner didn't do much on mine. Seafoam and carb cleaner seemed to work a little better. Let them soak for a while to dissolve the crap. It was ~40 degrees in my garage when I did this so maybe a little heat might help.

Tedro951

I think its the brush that does most of the work. I really haven't found anything that works magic on carbon, except steam.

Chris White

OK, I should mention that if you are doing this with the engine still in place there are some more steps that you should take when cleaning the pistons – I use some very heavy grease to seal up the gap at the edges of the pistons – this will help to prevent junk from getting down into the ring. Once carp gets into the rigs it will not come out – and it will really hurt piston ring sealing. The rings have to seal against the walls AND the ring lands on the pistons. If you get a little junk under the rings they will not seal well…ever. Blowing the stuff off with compressed air can only make that worse.

My favorite cleaner is 3M brake cleaner….use ventilation or say bye bye to some brain cells!

Once done it’s a good idea to spray some cleaner down the oil drain hole with the pan plug removed. Then run a quart or two of oil down through the head once you have it bolted back on – also with the oil pan plug removed. That will flush out any crap that got down the oil returns and the antifreeze that also got into the pan when you pulled the head.

Jeremy Himsel

LOL, you should see my Porsche avatar on the Corvette forums.

JDS968

Sooo...install water injection?

Makes sense, but how do you get THAT out of the gap when you're finished?

Go on...

eyeball kid

Ok. Grease up and brush away with the brain melting 3m good stuff. I assume the grease, once cleaned up, just lubes the bores on start-up. Thanks for all the advice.

cruise98

I am with Jeremy on this one. Leave the carbon on the pistons alone, grease the perimeter of the pistons and stuff the holes in the block with towels while you clean the gasket surfaces only, reassemble and run some fuel injector cleaner through it. You are getting the head fixed I hope. New guides, seals etc.?