: Head Gasket Repair - Clean Up of Head, Block & Combustion Chambers?



Lawrence
03-01-04, 08:41 PM
I have the heads off for head gasket replacement and am ready for clean up.

Can anyone recommend a method of cleaning that nasty oily carbon from the combustion chamber, both from the head and the pistons? Somehow without getting debris behind and around the valves and rings? I can see that as soon as I start this it is going to be real messy. Is there a prodedure?

One other question to avoid a problem before I get to it. After timeserting the block what happens to the locating pins for the heads? Can you still use the stock ones?

Many Thanks,
Lawrence

BeelzeBob
03-01-04, 08:53 PM
I have the heads off for head gasket replacement and am ready for clean up.

Can anyone recommend a method of cleaning that nasty oily carbon from the combustion chamber, both from the head and the pistons? Somehow without getting debris behind and around the valves and rings? I can see that as soon as I start this it is going to be real messy. Is there a prodedure?

One other question to avoid a problem before I get to it. After timeserting the block what happens to the locating pins for the heads? Can you still use the stock ones?

Many Thanks,
Lawrence
Why bother to clean it off....?? It is just going to come back. Put the motor together and clean it up by doing some WOT operation....LOL

Seriously, I would just use a dull scraper or chiesel to scrape the worst of the carbon off and forget about it. It really is going to come back when you run the engine so what is the point of getting it squeeky clean. Lot of work and potential problems for nothing.... Clean up the gasket surface good and leave the rest alone. The only real problem carbon is that on the flat squish surfaces that mate up to the piston...that is where the buildup will cause the carbon rap noise by hitting the piston. That area will get cleaned when you clean the gasket surface up anyway.

Do NOT use scotchbrite pads or scotchbrite abrasive discs or anything like that to clean up the gasket surface or the pistons or combustion chambers. Scotchbrite is the number one cause of failed engine repairs. Seems like innocent stuff but the nylon fibers contain aluminum oxide particles that end up in the oil no matter how carefull you are and they will eat the engine alive. Keep scotchbrite and things like that as far from the engine as possible. Trust me, you do NOT want to mess with scotcbrite around the engine.

Look at the deck surface ... the four large ports along the outer edges of the block are the oil drain backs...so any trash or debris that falls in there ends up in the oil. Just be carefull with debris... Debris into the water jackets is tolerable to some extent...but not the oil drainbacks.

Get new head dowels at the dealer. You'll end up with vise-grips and a hammer getting them out so they will likely be in no condition to reuse....

BeelzeBob
03-01-04, 08:54 PM
BTW...what did you really find with the head bolts?

Lawrence
03-01-04, 09:01 PM
Sounds good to me! I wasn't much looking forward to cleaning that crap off. No real build-up at all, far less than .010. Just a thin oily coating. I just worry that the stickiness of the oily surface will catch dirt, that will be there at start-up.

So the boring for the timesert will still allow for use of the stock locating pins. Excellent!

Thanks!

Lawrence
03-01-04, 09:09 PM
BTW...what did you really find with the head bolts?

The head bolts almost all let go (at least 8) to some extent upon removal of the rear head. All were good on the front head. Strange.

Most of the rear head bolts threads were also very coked up with thick black stuff. All front ones were clean.

The combustion chamber seals were indeed 100% intact on all cylinders with no indication of combustion chamber leaks, as my my earlier testing indicated. No corrosion of the head gasket.

The only problem was the oil leak at the oil feed in the rear head, from the laxed head bolt. You could see the clean shiny surface on the block between the oil passage and the valley under the intake, about an 1 1/2 or two wide. That area just couldn't handle the oil pressure.

Lawrence
03-01-04, 09:48 PM
Not really relavent but.........I did notice how aggressive the honing marks are. The motor has only 73K on it but it is very apparent how coarse they are. It is easy to see why they use so much oil.

BeelzeBob
03-01-04, 10:06 PM
Not really relavent but.........I did notice how aggressive the honing marks are. The motor has only 73K on it but it is very apparent how coarse they are. It is easy to see why they use so much oil.

It is also why they will run forever like that. Seeing the honing marks clearly after 73K is a good sign....it will look the same way at 200K. The cylinder walls and the rings and pistons really like the extra oil on the walls. Since the honing marks are still there, there is no ridge at the top of the cylinder I'm sure.

You are going to timesert all 20 headbolt holes?? If so, you'll never have to touch the motor again in all likelyhood.

BTW....the plastic chain guides for the timing chains will have grooves worn in them from the side plates on the chains. That is normal. They will not wear any further.....the side plates just mark the guides during the early miles on the engine and then stay that way forever.

Lawrence
03-02-04, 02:10 AM
Seeing the honing marks clearly after 73K is a good sign....
"Clearly" is kind of an understatment. They look like I could dive into them! Must have been your writing I read earlier about the "plateau" honing. Also very apparent.


Since the honing marks are still there, there is no ridge at the top of the cylinder I'm sure..
Right, absolutely zero.


You are going to timesert all 20 headbolt holes?? If so, you'll never have to touch the motor again in all likelyhood..
Yes, I am doing all of them. What a pain getting those locating pins out. Had to split them all the way down the bore.


BTW....the plastic chain guides for the timing chains will have grooves worn in them from the side plates on the chains. That is normal. They will not wear any further.....the side plates just mark the guides during the early miles on the engine and then stay that way forever.
Thanks again for the tip. You can tell I watch that stuff, ey?



bbobynski......please check my newest post about that case half seal and let me know what you think.

Thanks Much!

BeelzeBob
03-02-04, 11:49 AM
Well, yeah, the intent with the engine was to leave an agressive honing pattern on the walls to lube the top rings at 6500 and WOT....it works well but does lead to some oil consumption. Perfectly smooth cylinder wall finishes only work in people's dreams if you want the engine to really live for long periods of time at full throttle.

botboy
03-03-04, 03:16 PM
You get the timesert kit yet?

I also did all 20, the dowels will probably be a bitch to remove. I ended up CAREFULLY grinding the sides with a dremel and then prying them out, careful to not damage the head surface.

I'm curious about something - if anyone knows the answer to this. Will the locktite in the timesert kit survive being boiled down? I want to make absolutely sure that the engine has no leftover aluminum specs when I put it back together. If need be I could probably cap all 20 holes but if I don't have to I don't want to bother...

BTW the alignment dowels will cost you about $22.00. Kinda pricey. Whatever you do, don't buy bottom end parts from cadillac, it will cost you an arm, a leg, and probably a few other appendages too.

BeelzeBob
03-03-04, 03:50 PM
You get the timesert kit yet?


I'm curious about something - if anyone knows the answer to this. Will the locktite in the timesert kit survive being boiled down? I want to make absolutely sure that the engine has no leftover aluminum specs when I put it back together. If need be I could probably cap all 20 holes but if I don't have to I don't want to bother...

.

What do you mean by "boiling down"...?? You aren't thinking of putting the block in a hot tank to clean it are you??? You do NOT want to put an aluminum block in there. I would not suggest doing anything other than soap and water. Blow out the head bolt holes with air and a long piece of tubing to make sure there are no chips in the holes.

Lawrence
03-03-04, 07:03 PM
You get the timesert kit yet?

Received it today. Hallelujah! Thanks.



I also did all 20, the dowels will probably be a bitch to remove. I ended up CAREFULLY grinding the sides with a dremel and then prying them out, careful to not damage the head surface.

I got them out. Your right, they are a bitch. But i did get em out.