"What could possibly go wrong?" Let's Play: GM 3100 Head Gasket Job [blind]

[Duke George V]

Not dead yet! Just a little bit "under the weather" as we say!

Thanks Dave. Your encouragement really means a lot to me. While you're in here, what size and type of bit do you recommend to drill out that broken stud? It looks like it's a grade 10.8, which is going to be a bitch.

Not to laugh at your struggles, but that is a very funny pic and line!!!

Again, I aim to please.

[SilentWing]

It should be a grade 5 at best.... even it was a grade 10.9 when it was new the heat cycling has annealed it to the point where it's hardness is probably the same as regular mild steel. Luke went to Harbor Freight and bought a cheap pack of bits and they went right through it on his Supreme.... any of the "titanium coated" ones should go right through. He used a 1/4" bit on his and then ran an M8 x 125 tap through it to get the new one in.... the 1/4" bit just so happened to be the perfect size for that tap.

[turbokinetic]

Thanks Dave. Your encouragement really means a lot to me. While you're in here, what size and type of bit do you recommend to drill out that broken stud? It looks like it's a grade 10.8, which is going to be a bitch.



Again, I aim to please.

No problem! I take for granted that a pile of parts to me is the same thing as a complete engine to most people!

I have a procedure for broken off bolts that will require some pictures. Will post soon. You will need to take the manifold off the engine and clamp it in a vise to do this, so go on and pull the manifold.

[turbokinetic]

Here is how I remove studs from a casting when all other methods have failed. This is a McLaren 3.1 rear manifold. I have to salvage it for another project, so it has have the stud removed.

I blasted the broken stud so you can see exactly what it left. Already heated it up red-hot with torch and did not help.


This is the tool I will use to get the stud out. It's a Dremel rotary tool, with a tungsten carbide tile-cutting bit.



First, drill straight through the stud. A conventional drill bit may be used at this stage.


Now, use Dremel tool to make the hole into a slot. One side of the slot should BARELY cut into the threads.


Use a punch and penetrating oil to "collapse" the slotted stud in on its self.


See the gap opening up at the left side?



Now punch it from the other side. It's loose in the hole now.


Grab it with pliers and unscrew it.


This is the result. There will be a small amount of thread damage in the casting' but nothing near what a full-size drill would do.


Hope this helps!
David

[turbokinetic]

One more thing to look at while it's apart. Inspect your cylinder bores. You want to see crosshatch pattern on all cylinders. If any are smooth and shiney; the engine is nearing overhaul point and will likely use oil. If any of them have "wiping" or "scoring" (vertical, up-and-down marks; maybe some aluminum embedded in te iron cylinder bore) you need to proceed to full overhaul at this point. Wiping or scoring would indicate a piston seized (could have been the cause of the stalling). The result is the piston rings and side of the piston are badly damaged (may not be visible on the top). This will cause the engine to start smoking and burning huge amounts of oil; or worse.

Good cylinder (ignore the annotation about the piston notch):


Scored and wiped cylinders:


Seized piston:


You can see how, the scored cylinder doesn't look like it would be that big of a problem. The problem is, it INDICATES the piston is in the state shown above. The rings are jammed in the grooves by the aluminum shavings and will never seal.

This is caused by overheating the engine so bad that the lubrication oil film between the piston and wall fails.

Not trying to be all gloom and doom. But at this time, you're very close to the point where the pistons can me removed and replaced. Bad to put it all back together THEN find out....

[Duke George V]

The lighting in my garage isn't all that great, so I don't know if there is still any crosshatching in the bores. I do know there is a small amount of pitting in the #6 bore though. Is that going to be an issue?

[babyivan]

The lighting in my garage isn't all that great, so I don't know if there is still any crosshatching in the bores. I do know there is a small amount of pitting in the #6 bore though. Is that going to be an issue?

What was the psi on #6 when you did the compression test? Was that the one with the lower number?



On a side note, as far as lighting, I just bought this for my not so well lit work areas... Gorillatorch Flare 125

Amazing little light! Very bright, 125 lumens. It grips onto anything and has super magnetic feet.

FYI, stay away from the original one, it casts too narrow a beam. The Flare has a different optical lens that casts a much wider beam, perfect for DIYers!

[SilentWing]

Can you get any pictures of the pitting?

[RIPBARNBURNER]

Duke, best of luck moving along with this project. Sucks that the PO fouled your plans with his line of BS, but at least the car now has an owner who cares enough to finally do it right. Will be following along with the thread as you move further along.

[Duke George V]

Can you get any pictures of the pitting?

I'll see what I can do. My camera isn't the best, especially since my kids seem hell-bent on making sure the lens is perpetually smeared with finger prints.

What was the psi on #6 when you did the compression test? Was that the one with the lower number?

No, I believe it was #2 that had 80 psi, #4 had 90, and #6 had 110.

[turbokinetic]

Daniel - if there is pitting on the cylinder, its probably from water standing in the engine. A little pitting won't hurt it. It's only up-and-down scoring that you have to worry about.

Sometimes it's easiest to FEEL for scoring. There can be water marks or varnish deposits on the bores that LOOK like very minor scores, but you can't feel it. That's probably no problem.

Pictures always good, too!

David

[Duke George V]

So how do I unbolt the downpipe from the rear exhaust manifold? I got the left one done, but the right one is in tight quarters. I tried a swivel and five 3" extensions through the wheel well and all I got for my trouble was a split knuckle. I'm too pissed to go take a picture right now. Interference is provided by power steering hard lines and the transmission.

[turbokinetic]

I've always been able to come up from below the car, along the downpipe, with a swivel 15mm socket, and a really long extension. With that it's possible to get the spring nuts off. It is an undercar job (gritty laying on te floor) but it is do-able.

[Duke George V]

I guess I'll give that a shot next time. I'm done for the day. Thanks.

[turbokinetic]

I guess I'll give that a shot next time. I'm done for the day. Thanks.

Better luck tomorrow. No point in getting hurt working on it too long in one day.