Clacking/tapping noise due to blown head gasket

[2500HD]

Agree that the head has to come off, One possibility for the backfiring sound is the compression and firing could cause a backfire through the intake of the other cylinder. Why it would be under load only is beyond me. Send it off and they can tell you if the head is good or not. I would suggest doing your injectors while your there. When i did my head this spring i took a peek at my injectors and i couldn't believe it ran at all. I looked up the vortec specs and it turns out i could use the same one's out of a 95 camaro an reman's where only 29 bucks each. The other thing to do while your there is new rockers and rods, and don't reuse your head bolts buy new ones.

[CJD]

2500 just reminded me...with a stuck valve you will frequently NOT getting intake popping at idle. But, under load the mixture goes richer, and there's more volume of mixture in the cylinders, so that can trigger the intake front firing. That could explain what's going on. I guess a bad gasket could cause the same...but that would still be extremely rare compared to stuck...or burned...valves.

[pridekit]

Don't mean to hijack the thread, but 2500 are those the same injectors for the 2006? Do you have a part number?


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[roosm]

pridekit
Don't mean to hijack the thread, but 2500 are those the same injectors for the 2006? Do you have a part number?

Don't worry about that. Valid question as well! =)

CJD
2500 just reminded me...with a stuck valve you will frequently NOT getting intake popping at idle. But, under load the mixture goes richer, and there's more volume of mixture in the cylinders, so that can trigger the intake front firing. That could explain what's going on. I guess a bad gasket could cause the same...but that would still be extremely rare compared to stuck...or burned...valves.

There are lots of thoughts spinning around my head right now....
1) Head gasket shouldn't cause 0 compression.
2) It is very unlikely that we see 2 stuck intake valves at the same time.
3) It is uncertain if head-gasket would cause the noise, but a burnt valve will.

What do you say to this theory. The engine blew a head gasket, this caused rough running, but no noise or anything. My girlfriend reports she felt something "strange" with the boat when we left the dock, but it was probably a month since she last drove it / sat in it so she were a bit uncertain. I didn't feel it, though I was rather busy getting in to my wetsuit.

So we started with "just" a blown headgasket. Could this somehow cause the burnt valve, suddenly causing the noise?
If so, could it cause it in both cylinders at a time?



We will soon be able to stop speculating as I will post loads of pictures of tore down engine tomorrow night (well for you around lunch on saturday). If everything goes to plan.

My plan is:
Flush engine (without running it) with freshwater to get rid of any salt.
Empty engine of water.
Disconnect battery, any cables going to intake manifold ( injectors ) and remove hoses form thermostat.
Remove manifolds and risers.
Remove valve covers.

Remove Distributor??? I am uncertain on this one...

Remove Intake manifold.
Remove Cylinder heads.

Take pictures through out the process and especially when I am done for the day.
Post said pictures here and wait for your input. Then I can do any further investigation on sunday and probably order parts on monday/tuesday (I happen to be in luck as my brother will probably visit the US in 2 weeks and will then be able to bring back the parts for me so I save a ton on shipping. Prices here are unreal. The fel-pro gasket set that summit offers for 129 incl shipping is north of 400 dollars here.).

So any holes in my plan?

Thanks again guys for your input!

Mike

[2500HD]

Don't mean to hijack the thread, but 2500 are those the same injectors for the 2006? Do you have a part number?


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If i remember correct i got the part# off one of the injectors. The intake and mpi system appear to just be gm parts. nothin special about it.

[CJD]

Yes, the distributor goes through the intake, so it does have to come off too.

Once you remove the head we will be able to tell exactly what's going on...

Where are you located?

[roosm]

I am located on the west coast of Sweden, Europe.

So I finally pulled the heads today. Went smoother than expected.

When I separated the riser from the manifold on the port side (where my problem is) I saw evidence of water in the exhaust. Guess this has been going down to the cylinders. Might be the reason for my blown head gasket?

Once I pulled the head on the port side it was obvious the gasket was blown and the cross-firing between the cylinders has been burning though the head. I heard this was a possibility and it is obvious in my case. I will never get a gasket to seal that and it is too much to be able to machine it off. The head is scrap...

What is more troubling though is what I saw in cylinder 8. Here I see what looks like a hairline crack almost halfway around the cylinder.
Still no signs of water in the oil and compression was 210 on that cylinder.

What would crack the block. Freeze-damage, right? Maybe overheating.

I did not have any evidence of overheating when the gasket blew. In fact I only know I have had an overheat-problem once and that was 2009 or 2010 when the oil-cooler-filter got full of seaweed and was clogged.
I also know that back then 2009 and 2010 1) I didn't know the correct procedure back then and didn't empty the block of water before filling it with anti-freeze/water mix, but rather just flushed it with anti-freeze-mix which might have left the block with water in it in some remote locations without much or any anti-freeze. 2) we had a really cold winter either 2009 or 2010.

If what we are seeing is in fact a crack could this have happened 5 years ago I didn't notice?

Is the block done? Just get a new block and heads and move on?

Thanks for all your help!

Mike

IMG_1489.JPGIMG_1501.jpgIMG_1506.JPGIMG_1504.JPGSPPX8315.jpg

[CJD]

Hey Mike,

Freeze damage can affect odd places in blocks. It usually cracks the outer wall, around block drains, but could very well have caused your #8 crack.

Machine shops in the states could easily fix that block with a liner. They bore the cylinder and then install a sleeve liner to bring it back to stock size. The last time I had it done it was $80 per sleeve. Sometimes that is cost effective, and others it's just as cheap to find a used block to start with for a rebuild.

I guess that's the bad news...the motor will have to come out and completely apart to repair the crack. This will turn into a full rebuild. If I were in your position, I'd consider the following options, and research to see which is the cheapest...
1). Sleeve your current block, hone and install new rings.
2). Look for a decent used engine.
3). Look for a new or rebuilt engine.

The heads don't look terribly bad, but they should get skimmed(decked), and have a valve job done while they're off. Unless you find a complete replacement engine, you will need the following parts in the rebuild...

1). Gasket and seal kit.
2). Main and rod bearings.
3) timing chain set.
4) ring set.

After an inspection, the crank may need machining, you may need oversize pistons if the cylinders need boring oversize, and you may need new valves and guides.

If you need an intermediary to help with shipping, and maybe save some duty charges, I'd be glad to help in any way I can. In the states you could pick up a rebuilt small block engine anywhere, but I imagine it's much harder in Sweden.

[roosm]

Hey!

Real nice offer about the shipping. Thanks!
We'll see what happens and I think I have intermediaries all ready...

I seem to have some good news. I am fairly certain that what I first though was a crack is in fact not a crack, but rather an edge created by salt-water lying in the cylinder for some period of time.
I you look at the image lower right part you see signs of corrosion, this surface is rough, well, maybe not so much to the touch but at least to the eye...
This goes over into what looks like a crack and comes all the way around the cylinder. In the part of the cylinder that faces the sky "the roof" as the cylinder is angled, this line looks completely perpendicular to the direction of the piston. I think the line is created by the piston sitting at this level. Then on the part facing the earth, "the floor", we have some corrosion and a small edge. This is so slight I can't feel it with my finger, though it catches my nail if I pull my nail over it. Just barely.. but still..

The cylinder head has a scorched "channel" between cylinder 4 and 6 which will make it impossible to ever seal it again. I think it is something like 0.05 - 0.1 inch deep. So, deep!
That will not be possible to remove by resurfacing as it would take too much of the head off. So at least I need a new head. The other head looks decent.

So, good news, no crack. Still bad news as I have 1 ruined cylinder head and some corrosion damage in (at least) one cylinder.
My best bet is that this corrosion-damage is old, not from this season, and maybe several years old. I think that if the head gasket wouldn't have blown (which I am still uncertain of why it did) I might never have known about this.
Could the gasket have blown due to a leak between riser and manifold? And then the blow-by scorched the head?

So as I see I have 4 choices.
1) Buy a new cylinder head and a gasket-set and install this. Live with the corroded cylinder wall and hope the engine survives a few more years (at least).
2) Drill and re-sleeve the cylinder(s) that are corroded. No one knows how much that would cost but I guess it is expensive. (i.e. rebuild).
3) Find a new or rebuilt engine.
4) Look for a decent used engine.

I am leaning towards going with 1 and then when time comes go with 3...
The reasoning is basically that with a saltwater / raw water cooled engine the water-channels in the intake manifold as well as maybe the heads and block it self will not live for ever. It is already a 13 years old engine and even if I rebuild it might not last me more than 5 more years.
A new/rebuilt engine would hopefully last at least 10, but then this engine is junk and in the mean time I might get a few years out of it without much work, just replacing one head and the gaskets.

Input on this?

I share with you the horrors of what saltwater does to an intake manifold... =)

[CJD]

If you are sure it is not a crack, don't worry about the slight corrosion in the cylinder. It will eventually fill in with carbon and not cause any problem at all. I bet the compression check on that cylinder was fine before the head came off.

.1" in the head is, indeed, too deep to fix. It had to run for a very long time with a hole in the gasket!

How is the block between the 4 and 6 cylinders?