Blown Motor @ 11psi

[igdrasil]

Why would a piston hit the valve like that.

Im begining to think that the turbo did not caused the failure...but the intake cam.
Intake cam broke, left the valves open, piston 1 hits them end kept open, turbo fills up the chamber, detonation, it eventually kills the piston 1 due to stress.

I dont know..

Turf....most likely, if you broke rod 4, rod 1 may go too.

 

[igdrasil]

Do you think that the piston slammed into the valve and snapped the components you see damaged in the cams and so forth? Is the valve damged or bent at all? That was my only thought as to how some of the damage could have occured.

I think they are bent...

 

[TurfBurn]

Why would a piston hit the valve like that.

Im begining to think that the turbo did not caused the failure...but the intake cam.
Intake cam broke, left the valves open, piston 1 hits them end kept open, turbo fills up the chamber, detonation, it eventually kills the piston 1 due to stress.

I dont know..

Turf....most likely, if you broke rod 4, rod 1 may go too.

We'll see how my pistons look once I get them out. I'm half waiting to find them al pristine and happy and just the rod being FUBAR.

But anyway... my thought behind your engine that may be a possible sequence (and it's just my random conjecturing) is that you got the detonation or whatever condition that blew your piston/snapped your rod which then smacked into a valve since it wasn't connected anymore. With that valve getting hit it bent it and wedged it enough that the camshaft took quite a beating when it tried to move it (or was trying to move it opposite of the cylinder's forces on it).

Thoughts? I'm just making s*** up LOL.

 

[igdrasil]

Nah...Both piston 1 and 2 are broken!!!! They broke because of the rod snap. There was NO piston ring damage, and no detonation sign at all ON the piston. No melting no ring seat broken. The rod bent and as a consecuence, broke the piston fron the under side.
I saw the rest of the piston lying in the crank...the crown is still sitting there on the cylinder..which has a nice hole to...thats the cylinder that got the worst damage.

Pistons 2 and 3 looks healthy, but rods are bent too.

I tried to pull it up (piston 1) but I couldnt.

That piston (1) you see is only the crown...how I know? Because I pushed it by hand and rotated it (which means that is sitting alone without the rod)

 

[TurfBurn]

Ok.. shoot my theories or something . That is one seriously damaged engine though.... yikes.

 

[Kooldino]

Why would a piston hit the valve like that.

Im begining to think that the turbo did not caused the failure...but the intake cam.
Intake cam broke, left the valves open, piston 1 hits them end kept open, turbo fills up the chamber, detonation, it eventually kills the piston 1 due to stress.

I dont know..

Turf....most likely, if you broke rod 4, rod 1 may go too.

WTF...someone else I know who is N/A blew a motor because of valve contact. Aren't these things non interference???

 

[viVid]

I understood them to be non-interference, at least with stock cams.

WTF...someone else I know who is N/A blew a motor because of valve contact. Aren't these things non interference???

 

[igdrasil]

Yeah the are non interference. But in my case, The rod broken in the piston, now that the piston is loose, the rod will continuosly hitting the piston, making it rotate and push it up to the head HIGHER and BANG!...HIT THE VALVE with an edge of the piston that does not fits the valve.
Check the pic, it shows WHERE the valve touched the piston

 

[LinuxRacr]

Exactly! A rod breaks, they are no longer non-interfering motors!

 

[Brian MP5T]

Why would a piston hit the valve like that.

Im begining to think that the turbo did not caused the failure...but the intake cam.
Intake cam broke, left the valves open, piston 1 hits them end kept open, turbo fills up the chamber, detonation, it eventually kills the piston 1 due to stress.

I dont know..

Turf....most likely, if you broke rod 4, rod 1 may go too.

I'm leaning towards your CAM theory too. The ticking thing is what makes me think that. Sorry to hear of the boom, but you did have a good kill there for a couple of runs!

 

[MPNick]

Why would a piston hit the valve like that.

Im begining to think that the turbo did not caused the failure...but the intake cam.
Intake cam broke, left the valves open, piston 1 hits them end kept open, turbo fills up the chamber, detonation, it eventually kills the piston 1 due to stress.

I dont know..

Turf....most likely, if you broke rod 4, rod 1 may go too.

Cylinder pressure killed your engine. We are very lucky in one way. We have a great head gasket. We are very unlucky in one way. We have a great head gasket.

Because of our stock OEM MLS head gasket, we do not blow head gaskets everyday. Because we do not blow head gaskets all that load goes down to the next weakest point. That is the rod. They can only take so much load pushing down on them. They will sooner or later start to bend. They can only last so long if they are bent. Two thing can take place. They will keep bending untill the bottom of the piston hits the countershaft of the crank. Then the pistons will break under the pin bores. If this takes place on the downstroke the head is saved. If this takes place on the up stroke you will hit the head.

Do not kid yourself you have been detonating. You may be adding alot of fuel and running real cold plugs but it will not help. You need to find out why you are detonating. When you run more boost the air temp can go up real fast. What size is your intercooler? Can it handle the boost you are trying to run? If you are pumping in alot of hot air you can add all of the fuel you want but it will not stop detonation. At the point of running a good afr more fuel will hurt you. I am not just talking with loss of power. I mean it can cause pre-ignition and fuel wash. Same with the plugs. You only need a heat range that does not glaze over or burn the plugs. Colder then that may also cause damage and loss of power. If you find you detonate at a level of boost all of the time even after tuning, you need more octane. In the 2.3 world it we need to go to a higher octane over 18-20 psi, we use 100 octane. It does not matter how much fuel we throw at it or how much timing we remove. It will still detonate and then we kiss the head gasket good byeday.

Whay is your setup? Stock pistons are what 9.1 to1. How big is your intercooler? Can it flow well and keep the air temp down at 11psi? 9.1 to1 and 11psi needs a real good intercooler. I know race cars go up to 10 to 1 now on turbo engines, but they have good intercoolers and they run C16 fuel. How about your header? Does it glow at all at higher boost levels?

I know your engine is down for good right now. But before you spend anymore money you need to you look at your set up from top to bottom. You need to make sure that all of your parts can handle all of your goals. All I am trying to point out is turbo engines love to detonate, colder plugs, spark retard, very rich afrs will only take you so far. After this you need to see why is it detonating.

Thanks again

Later...........Nick

 

[speedhawaii]

ouch

 

[igdrasil]

New motor is in....

My clutch is slippin...some oil reached the clutch when it blew...cleaned it but i think is wasnt that good of a clean

I added some pics on the first post but here are some more:

1st pic - new motor with aditional injectors installed
2nd pic - view from the crank...bent and bloken rod. Actually it bent and twisted!!!!
3rd pic - closer view of the rod.

 

[Brian MP5T]

Nice!

 

[smp3000]

Wow!!! God I'm scared now lol. I'm boosting 9psi- but may go down to 7 in this heat! I hear no detonation and the car feels good with AF's in the 11's, but who knows what is really happening. Yes I'm on stock internals and yes that scares me. Plan on getting some oliver rods and CP pistons very soon. Goal is to have 300 to the ground by the end of the year.... and yes we're talking new turbo as well

 

[StreetUnit]

The Subaru and Mitsu guys see more and more Mazdas passing them each day.

 

[TurfBurn]

When I was a Mitsu Lancer guy.... the general word was that you couldn't cross 8 psi without risking your motor on the stock block.... so we have it good! LOL...

 

[Shane-O]

I'm gonna turn down my boost as well, I'm running 10lbs, I better take it easy after reading all these "blew my motor today" stories! How much do you think it cost's in average to bebuild a motor, yourself as one cost, and a mechanic shop as another cost?

 

[TurfBurn]

forged or not... and with head work or not?
My engine with headwork and forged doing it myself with a new block etc... is going to run me about 3600 bucks... if I had it done by someone it would run around 4300 I think.

Without forged... probably knocks off about 600 and no head works knocks off about another 1000... so.. you should in theory be able to do a new stock engine yourself for like 2000 I'd estimate. Those are just general numbers based off what I'm going through and doing right now... and assuming no turbo and/or valve train damage or so forth.

 

[igdrasil]

Well. A nearly new motor was about $800 and $200 for the install....DONE