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YASVT (Yet Another Sixteen Valve Turbo) - now 16V Whiteblock (LS)

My best guess would be that your tune is either horribly wrong or the sealing surfaces aren't in good condition if you are seeing repeat failures, assuming that the rod bolts were being torqued correctly and that you have the correct washers under the heads of the bolts so they aren't sinking into the cylinder head.
 
My best guess would be that your tune is either horribly wrong or the sealing surfaces aren't in good condition if you are seeing repeat failures, assuming that the rod bolts were being torqued correctly and that you have the correct washers under the heads of the bolts so they aren't sinking into the cylinder head.

I've been running the same head on a different block/this block for quite a while.

it's been a mixed bag of results. At some points I have detonated the engine to death (tin ear, sigh) with not a single issue from the head gasket.

I have had two Cometic failures so far, but interspersed with a bunch of miles of very hard use without any HG issues at all. To be honest, I really haven't beat on it all that hard this last time (since it went back together after the wrist pin break). No 20 - 22 - 24 psi pulls of awesomeness. It's just been ~ 16 psi. And most of the time I've just been leaving the boost control switched off and driving it on 9 psi.

I'm figuring I just did something a bit off on the head torquing. I'll get it all shiny, check the head, check the block, bolt it back together.

ARP nuts are using ARP washers, no distortion of the head where they sit. They're not the smaller washers that someone used that crushed the head down and crimped it onto the studs.
 
It just sort of looks like the head has been very slightly wiggling around, and thus rubbing those raised crimped rings around the combustion chambers. The black coating of the cometic is worn off, and on all 4 cylinders there are sections where the crimped area has cracked, or worn, and there is a split along the crimp.

This is the precise reason that Volvo uses a graphite head gasket on this car from the factory. The aluminum head expands and contracts faster than the iron block, so there's a little bit of rubbing going on between the block and head. Graphite is a dry lubricant, so it lets them slide a bit without causing problems. With the MLS gasket, that rubbing rips the gasket apart, as you're seeing happen on yours.

My car has the original 30 year old gasket because the gasket is a little bit slippery. So many cars need an HG every 100k miles because they wear out, due to dissimilar block and head materials.
 
My car has the original 30 year old gasket because the gasket is a little bit slippery. So many cars need an HG every 100k miles because they wear out, due to dissimilar block and head materials.

How much power is your car making?
 
Mine probably somewhere between 350 and 400 when it's feeling frisky. I've only ever had it dynoed at just over 300, but that was a long while ago and it's gotten a lot more stuff done to it since then, and it feels significantly faster. I have no idea how long a stock style head gasket would last in this situation.

The MLS is supposed to let the head and block slide around as well, that's what they use on some slightly more modern alu head and steel blocked cars from the factory.
 
Re the gaskets, a lone wolf in the far north of NZ does his own breed of MLS gaskets, and don't think the style above when you read that. It has metal skins, but a composite core. The reason I went looking at all and found this is that my ute cylinder pressure pushed my firing rings back and out of the way. No signs of detonation and running home brewed rocket fuel and a conservative tune. Just stretched the paper thin metal and started blowing BIG bubbles into the cooling system. Not good enough. Both the style above and the style of this random kiwi guy have an advantage: the steel behind the firing ring or equivalent goes further back and isn't able to just be pushed out of the way. IE, it's physically stronger in a lateral direction.

But I came in here to say thanks for these two photos:

IMG_2001.JPG


IMG_2008.JPG






I just went out with them on my phone and looked in my RHD 240 bay, and my booster stops about where that bulge starts just to the left of where the air con pipes come through. IE, I can fit a 16V head in there without any drama at all! Even the inlet should be OK with no brake booster on the other side, maybe. Or close to it. So thanks! That put a smile on my face. :-)
 
Just read this from start to finish.....wow! Great work, and even greater perseverance.

All this head gasket talk is interesting, didn't yoshifab make 400whp on his 16v, wasn't that on a stock HG? My research into the topic (albiet limited) seems to suggest that while MLS head gaskets , when executed perfectly have greater power holding capabilities, standard gaskets are a LOT easier to get right, and sometimes (read: almost all the time with the power levels on TB) that's far more important.
 
At ~300 crank hp out of my setup with say 12psi or so, I'd definitely run a factory Mazda gasket, but on 18psi / ~400 crank hp, it's just not enough. So yes, at lower power levels, modern OEM sort of levels, for sure, graphite all the way. On the other hand, my itsy bitsy turbo Suzuki uses MLS stock and makes a whopping 100hp from 1 litre. Note 18psi from a smaller turbo with smaller plumbing such as exhaust manifold, intake manifold, TB, IC pipes, IC itself, downpipe, exhaust, etc, would be roughly 300hp or so and only deserve a stock gasket. (all of my stuff is 3" and hand flowed inside)

And yes, Josh did. I queried him on the right headgasket to use for when I build my 16v engines and he said "just go stock" to which I replied "surely not, blasphemy" etc. For my 240 I'll be using a TD05HR16G and running a stock headgasket. For my 740 I'll be running a bigger turbo and bigger better everything, but I might try it to start with, anyway. We'll see.

Your research is right, BTW. You need to get the block and head both flat and smooth to within some ridiculously low RA number. The back yard techniques seen in some other threads recently are not acceptable.
 
Agree with Ben, how is the flatness and surface roughness of the block/head. And tune.

Other thing i think could cause big cooling issues is lowering the mounting position of the expansion tank. Mount it low enough in relation to the engine and certain high points in the cylinder head won't get the continous presence of coolant. Maybe when the engine is at a certain rpm they get spash cooling, or more, but to me it would be a gamble i do not want to take. Maybe it lacks cooling when engine is shut down?
EDIT: the above about the coolant, maybe i am mixing things up between threads, cos i cannot find this in your thread now.

A few years ago i had a discussion with an Elring engineer for aftermarket/motorsport. I am curious what he would think of this failure.
 
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I've had this thing apart and back together a lot. I think I've probably gone through 5 headgaskets at this point, and I've only had weird failures like this on 2 of them. So the odds are... pretty good?

Anyhow, I cleaned up the head and block last night, put a little copper spray on the HG (so far I've gone back and forth on that, sometimes some Hylomar, sometimes some copper spray, never have done it totally dry though).

Right before I set the head down I thought I'd run in a couple of the short head studs to act as a guide for the head, so it goes down onto the block/HG straight and you don't have to scoot it around. Put the first in, screwed it in. Then, I wasn't paying enough attention (my kid was out reciting an endless spiel of Portal 2 facts/quotes) and when I went to put in the second stud, instead of the head bolt hole I put it in the oil drain. And it fell inside. All the way inside. Clink, clink, rattle, clatter. Hit the oil pan.

Oh, boy, that was a stream of obscenities. 1 half second of inattention, now I'm going to have to pull the motor out and fetch that damn thing out of the oil pan. I pondered briefly just leaving it down there, and using a stock head bolt. Nah.... not going to do that.

Then, just for S&G's, I decided to try a little fishing. I got one of those long flexible claw tools ( https://www.amazon.com/Flex-Cable-4-Finger-Retriever-Pro-Tools/dp/B006ZEOXJY ) and stuck a powerful little hard drive (neodynium?) magnet on it. I tried the hole I'd dropped the stud down, nothing down there. Tried the hole next to it. Nothing. Tried the next one down and... was that a piece of loose metal? It was! But not a good grip. I gently pulled it up and as I did, I started to feel the magnet sliding over threads, click click click. Very gently, kept pulling up. I could feel when the magnet finally done sliding up the length and around to the end. And then I had to pull it up out of about 8 or 9 inches of block. Which isn't smooth internally, every few inches it would catch, and I had to gently twist and wiggle, thinking the stud was going to drop of at any moment. Until, finally, the stud appeared at the top of the hole and I grabbed it.

I have no idea what the odds were on that working. It's a tiny hole, barely bigger than the stud itself. And there are only a few of them, and the flexible grabber can really only reach straight down from them, so the odds of the stud being right under one were low.

That was a HUGE relief, don't have to pull the motor, I can just proceed with putting the head back on.

I set it on, torqued to 30 ft lbs, torqued to 60 ft lbs, let it sit for the night. This evening I'll go up to 100 ft lbs in 2 increments. Last time I did 90 ft lbs, and suspect that just wasn't enough.
 
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