Blown Mitsu MLS Head gasket

[fivestardsm]

Well after tearing the motor down today hopeing to find just a couple of melted pistons, I find out that I need to kick the machinest, and myself in the NUTZ. If you look at the pictures, you can see where the gasket lifted because of the dip in the cylinder wall that I did not notice until now.

Here is the Original Post of the repair I did on the #1 cylinder because of the D-Bag that cleaned the block surface with a grinder. Well it turns out that he also dipped the #4 and it should have been welded before it was decked aswell. I didnt look close enough after I got the block back from the shop.

Sadly, this wasnt the only issue that lead to the demise of the motor though. The fuel pump that I bought also had issues and was malfunctioning which created fuel cut, and detonation because it ended up leaning out. Mix that all together with enormous boost creep/spike, and you have the #2 cylinder going dead because the spark plug detonated along with the valve burning. #4 Spark plug was toasted also. you can see the reminace of it on the cylinder wall just below the gouge in the edge of the cylinder.

Well long story short, I threw a chunk of cash out the window.

 

[Brianawd]

Looks more like you popped a ring land and burned a valve. /ubbthreads/images/graemlins/dunno.gif

 

[prove_it]

At least they were stock valves now you have an excuse to upgrade!
Sucks though. I feel your pain. I think we all do.

 

Quoting Brianawd:
Looks more like you popped a ring land and burned a valve. /ubbthreads/images/graemlins/dunno.gif



Yeah that dip in the block looks like an after the fact thing. They are going to make sure that is flat before it comes back to you.

 

[fivestardsm]

It wasnt an after fact. It's so shallow that you could barley see it it just looks deeper since the block surface is dirty. You can see the grinder marks in it that go the opposite way of the machine surface marks.

 

Why didn't you lift when you heard the detonation??? You had to stay into it for quite along time for that to happen. Did you get caught in the heat of battle or something?

 

[fivestardsm]

I lifted right after I felt it. There was no battle going on, I was just going around the perverbial block (4 miles) when it happened. I had turned the corner and rolled on out of 3rd with WOT and "POP" it started missing instantly. I am actually thinking that the valve might have been cracked prior to the build Its hard to say.

I just pulled the head off from another motor which came out of that 90 talon that I was selling on here a few weeks back, and it actually is a .5 (.02) over fresh rebuild. It so fresh actually, that it never even got carbon build up on the tops of the cylinders. It turns out that it was like so many others of the motors that I have found, a bad time job. Some one had just put it together and timed it wrong. The car only had 146k on it when it was parked because of the timing jump.

So next thing is to get a hold of the shop I had the other block machined at, and see what he will do for me. I'll try to talk him into getting me some work done at a huge discount. Either that, or never go back. I think I can still salvage the original block if I break the welder out again and have the deck o-ringed. And if the guy that took a grinder to the block wasnt dead, I would drive down to Kentucky and kick him in the nutz.. (R.I.P.)


The thing about it is, the owner of the shop dosent do all the machining, but he does the milling. If I would not have wanted the block done that weekend, the actuall machinest would have finished the block and I would not have these problems. Damn my impatience.

 

The valve wasn't cracked, Thats what happens when you burn a valve. It basiclly torches a hole through your valve. If you look at your valve you won't see any cracks, you will notice it looks like someone cut it with a torch.

 

You really need someone to tune that thing that knows what they are doing, or the same thing is going to happen again.

 

[Brianawd]

Quote:
The valve wasn't cracked, Thats what happens when you burn a valve. It basiclly torches a hole through your valve. If you look at your valve you won't see any cracks, you will notice it looks like someone cut it with a torch.



QFT

Quote:


You really need someone to tune that thing that knows what they are doing, or the same thing is going to happen again.

QFT


I also think you need to pull the #4 piston out to make sure the rings and ring land is still one one piece. Because looking at the pic makes me think you popped a ring land.

 

^^^^+1000^^^^ You should go through your entire engine again, I bet that burnt valve and the block issue isn't your only problem.

 

[fivestardsm]

Quoting BOOSTIN HARD:
The valve wasn't cracked, Thats what happens when you burn a valve. It basiclly torches a hole through your valve. If you look at your valve you won't see any cracks, you will notice it looks like someone cut it with a torch.

Why didn't you lift when you heard the detonation??? You had to stay into it for quite along time for that to happen. Did you get caught in the heat of battle or something?






Thanks for your input guys. /ubbthreads/images/graemlins/wink.gif

I have seen hundreds of burnt valves in the last 20 years, they are not that hard to identify, and yes this valve did burn out, I am just trying to say that the burn most likely had to start from a point and there might have been a crack in the valve prior to it going in the head. The reason I am thinking that is because several of the valves came from a head that was severly warped. Basically I am just speculating. I just figure it was my luck because out of the 20+ heads that are sitting on the shelves, I would get lucky enough to pick the one that had an issue.

As for the tune on the engine, although it wasn't dialed in perfectly, the failure of the fuel pump and the blown head gasket due to the damage on the cylinder edge, are leading the way to the entire failure.

The motor on the other hand will be dissasembled, and gone through to see what parts will be able to be salvaged. I still belive that the ring-lands are going to be torched, which was my first assumption before I even tore the head off. Will I use it though? That depends on how much money I want to spend, and how anal I am going to be. I have 5 other blocks sitting in the garage right now that all could be the donor for the next build, I just havent decided which way I want to go. I also have a fully built motor with the Eagle/Wiseco combination in it, but I bought it for #27's build.

Decisions, decisions.



Quoting BOOSTIN HARD:

Why didn't you lift when you heard the detonation??? You had to stay into it for quite along time for that to happen. Did you get caught in the heat of battle or something?



Also, you asked why I didnt lift, and I forgot to mention that after it happened, I said screw it and drove two miles home and parked it. I knew there was going to be a full rebuild coming anyway.

 

[Brianawd]

Sorry to say but in the last 10 years I have been playing and working on 4g motors I have never ever once seen one with a cracked valve. And I have seen some really fucked up heads.

 

[fivestardsm]

My camera dosent take the best pictures up close, but if you zoom in on these, you can see it well enough.
On the last picture, you can see that the valve had started to burn. I would say that the head hadnt been run very long with this valve, or it would indeed look like the one in my head.