Head Gasket Job

[quadracer37]

So, first head is cleaned up and de-greased. Looks to be in very good condition and is laser beam straight from all angles. I'm thinking about just lapping the valves by hand and replacing the oil seals, polishing the surfaces and bolting'er back up. I'll clean the other head up in the morning and make sure it's in the same good condition. If so, I may skip the machine shop and valve grind.

On a slightly disturbing note, I never did find an obvious blown cylinder ring on either gasket. I've had the same in previous HG jobs. Was just hoping for the obvious defect. Must have still been a small leak past the ring.

I recommend you take them to the machine shop either way to get them decked. A valve job isn't 100% necessary but 9 times out of 10 they will take a few thousandths off the surface to get them perfectly flat.
When we do head gasket jobs at my shop we also always have them pressure tested just to be safe as well. Especially since you didn't physically find any spots on the gaskets that were the culprit it is an even better idea to have them pressure checked.
Any basic engine machine shop should be able to handle this work for 175-250$ roughly.

 

[Belldiver]

I was thinking about skipping the machine shop until I broke an extractor out in that damn glow plug. So they gotta go in anyways.

I'll have them pressure tested for sure. They are absolutely laser beam straight in every direction. I have a certified straight edge and I can't slip an 0.0015" feeler gauge under anywhere at any angle.

 

[jlawles2]

You may mind that even though the heads are flat, some of the valve guides may need to be replaced.

That is the only thing they found wrong with mine. And they only took a small amount off to clean up the heads.

 

[Belldiver]

Back to the broken glow plug...

So, I dropped the heads off at a local machine shop this morning. They're going to pressure test and do a leak down test on the valves and then we'll decide to do a valve grind or not. Also going to shave a couple thousands just to true them up.

I broke a damn extractor off inside the glow plug stub. Machinist says he probably cant drill the extractor out without messing up the head and it'd probably be a good idea to just leave it in and run with 7 glow plugs. I'm not completely opposed to this but have a couple questions for you guys. I don't have any personal experience with this machine shop. I called around to a couple and went with the guy that sounded halfway intelligent...cross you fingers...

1. Would it be that hard to drill out an extractor?
2. Unless outside temp is below zero, will running with 7 glow plugs cause any real problems?
3. Is it going to throw a check engine light all the time? And if so, what can I do about that?
4. Last, I got about a half turn on that glow plug before it snapped off. Think that will make it leak?

Thanks for any input.

Jim

 

[quadracer37]

Back to the broken glow plug...

So, I dropped the heads off at a local machine shop this morning. They're going to pressure test and do a leak down test on the valves and then we'll decide to do a valve grind or not. Also going to shave a couple thousands just to true them up.

I broke a damn extractor off inside the glow plug stub. Machinist says he probably cant drill the extractor out without messing up the head and it'd probably be a good idea to just leave it in and run with 7 glow plugs. I'm not completely opposed to this but have a couple questions for you guys. I don't have any personal experience with this machine shop. I called around to a couple and went with the guy that sounded halfway intelligent...cross you fingers...

1. Would it be that hard to drill out an extractor?
2. Unless outside temp is below zero, will running with 7 glow plugs cause any real problems?
3. Is it going to throw a check engine light all the time? And if so, what can I do about that?
4. Last, I got about a half turn on that glow plug before it snapped off. Think that will make it leak?

Thanks for any input.

Jim

my machine shop does it, carbide drill bit.
compression on that cylinder would be lower if you ran without a glow plug.

 

[SmokeShow]

why would the compression be lower? Sounds like the lower end of the glow plug is still in and as long as it's all sealed up, why would the compression go lower?

 

[quadracer37]

why would the compression be lower? Sounds like the lower end of the glow plug is still in and as long as it's all sealed up, why would the compression go lower?

I didn't know the tip was still in it, sometimes when they break the tips come out with the nut and just the threads are left in the head.
if that's the case then now you risk the chance of the tip falling in the motor...

 

[Belldiver]

The tip is still in. Machinist said he'd have to cut that off when he shaves the head.

 

[Belldiver]

Can I tig weld the extractor into the old gp threads?

 

[quadracer37]

Can I tig weld the extractor into the old gp threads?

I doubt you'll have any luck doing that. find a machine shop that's willing to remove it. I've seen it done many times.

 

[Belldiver]

I'll call a couple more shops.

 

[ripmf666]

Have it removed no way I would leave it in.

 

[Belldiver]

Called around town this morning and a couple other machine shops backed away. I got one of the industrial machine shops to take that head and give it a try. Turns out the owner/machinist of the company that I brought the head to drives an '07 Duramax too. Good omen...

He didn't promise anything, but going to give it a try. Couple more questions though...

1. How does the glow plug seal into the head? They have straight threads. Does it seal at the bottom of the stem below the threads? I don't see any type of crush washer.

2. If we end up destroying the G.P. threads getting this bastard out, what are my options? Can we oversize and re-thread the hole? Plug it off? Weld it closed?

3. Check engine light. How would I disable the error code that I'm sure this will throw? This truck is stock tuned.

4. Three of the other Glow Plugs had one thread of aluminum stuck in them. Any big concern? Or just chase the treads with a tap and install the new G.P.'s with some neverseize.

Thanks in advance,

Jim

 

[Dallas S]

I don't see any reason why you couldn't helicoil that glowplug hole.

 

[Gmclbz]

It is definitely salvageable, just need to find the right machine shop...

 

[Fingers]

Worst case, you have to drill it out and helicoil the threads. Good part is the helicoiled hole will not bind up on the glowplug.

Sent on the run from my Cell Phone

 

[juddski88]

Copper anti seize... the glows seal below the threads, yes. And worst case is a NAP insert, which is bigger than the helicoil. Anything beyond that and you're going to be replacing the head.

 

[Belldiver]

Would the threads "seal" in a helicoil? They are straight, not tapered threads. And there's no crush ring to speak of.
I guess it just bottoms out in the hole against the aluminum with the tip of the glow plug in the combustion chamber.
I should find out how they did in a day or two.

 

[juddski88]

we've used helicoils several times, the threads work perfectly. Like I stated before, the sealing area is below the threads, the threads just hold that sealing area tight

 

[Belldiver]

OK, good news. Machine shop #2 got the old glow plug out without destroying the threads. They look good enough to go back into and I've run a tap through all of them.

Got the heads back from the Cylinder head shop #1 and all in good shape. Pressure tested good. Machinist shaved off 0.004" to get them cleaned up.

I have the block deck clean and checked and looks good and straight. A couple spots I can slip a 0.002" feeler just barely but nothing larger.

I checked max piston protrusion and the max I can find anywhere is 0.014". The Haynes manual recommends Grade C gaskets (which I have) for piston protrusion between 0.0128" to 0.0148".

Question: Do I have to account for the 0.004" that we shaved off the heads for valve clearance? 0.014" + 0.004" = 0.018"?

We did not grind the valves on this one to recess them any further. Leak down test held tight so I went with it.

How Close do those valves come to the pistons on these engines? Should I do a clay test?

Thanks in advance.

Jim