deadbeatrec

iTrader: (9)

looks like u swolled some valves, which sugests valve srpings or something in the head was broke. the overrev theory sounds very good.

ibanez_926

iTrader: (1)

wow.

jj_008

iTrader: (8)

Nothing some JB weld and quick hone can't fix

Good luck w/ the motor.

CarFanatic

iTrader: (6)

How high can the stock motor rev before you start to have issues??

Stew

iTrader: (11)

Well I dont know how many times to tell you guys the motor has not been 'over'-revved, but hey, keep the opinions coming.

Event-Horizon

iTrader: (1)

There is one thing that is bothering me. I understand that the bottom end let go, but what explains why the valves were hitting EVERY piston? Stew, you should see, if possible at this point, if the engine was still in time. Maybe you jumped a tooth or two on the timing belt?

This is what I have gathered from the pictures:

Cylinder #1: Heat markings on crank: http://www.ctdubs.com/images/motor/m9.jpg , smashed piston more than likely responsible for 90% of the debris in the oil pan, broken connecting rod, heavy carbon deposits on the piston top, very worn piston skirts. Contact with valves, All 4 valves intact.
Cylinder head: http://www.ctdubs.com/images/head1.jpg
Piston: http://www.ctdubs.com/images/cyl1.jpg

Cylinder #2: Broken rod (more than likely caused by debris from piston and conn rod from #1), intact piston, top seems to be in good shape, worn piston skirts, minor contact points with valves. All four valves in cylinder head intact.
Cylinder head: http://www.ctdubs.com/images/head2.jpg
Piston: http://www.ctdubs.com/images/cyl2.jpg

Cylinder #3: Damage to top of piston due to valve strikes of both intake and exhaust. Front and back wear on cylinder walls, one broken exhaust valve.
Cylinder head: http://www.ctdubs.com/images/head3.jpg
Piston: http://www.ctdubs.com/images/cyl3.jpg

Cylinder #4 Heavy damage to Cylinder head and piston top. Valve strikes highly visible, melted material. Front to back wear on cylinder walls, two broken exhaust values.
Cylinder head: http://www.ctdubs.com/images/head4.jpg
Piston: http://www.ctdubs.com/images/cyl4.jpg


So, one half of the engine broke rods, and the other half broke valves. Am I reading this right? It looks like everything that could have gone wrong, went wrong.

It’s looking like cylinder #1 had the conn rod bolt fall off and caused a lot of heat and friction on the crank and bearing until it seized up causing a domino effect of destruction. I would still like to know how the valves hit the pistons though.

C6C6CH3vo

iTrader: (9)

When "overreving" is mentioned, specifically what rpm are you talking about?

Keeping it at rev limiter for a min? Or downshifting with the intent to upshift?

If overreving ultimately did it in, would it be from chronic or one-time instance.

I have zero exp with eng internals but judging from the pictures, it looks like something came loose and was unnoticable (grain size shavings and scratches) then progress until the bitter, bitter end.

Stew

iTrader: (11)

My guess is whatever made enough contact with the balance shaft in the rear to knock it into the block and create a 6" hole caused enough of a momentary force to jump a tooth on the timing belt which would be plenty to knock pistons into valves.

If you notice how pistons 3 and 4 have the most valve damage, it would be fairly obvious that timing was jumped AFTER 1 and 2 broke loose from their connecting rods. Obviously #1 has rotational damage from valves definitely caused from the connecting rod slamming back up into it after it had broken off of the piston, shooting it to the top of the block.

The valves obviously did Not hit until the very end, otherwise the motor would be barely running at all directly after said major valve slap. Once a LOUD knock was noticable the motor did not turn over 3000 RPM, but was held between 2000 RPM and 3000 RPM for 3-4 minutes so I could get off of the George Washington Bridge.

Event-Horizon

iTrader: (1)

Yeah, that makes sense.

C6C6CH3vo

iTrader: (9)

Theres got to be another option, one that can work out better than whats possible with mitsu?

Stew

iTrader: (11)

You mean another option for rebuilding without going through the hastle of jumping through Mitsubishi's hoops, or paying for it all out of my pocket?

nrcooled

iTrader: (4)

Just an FYI - I spun the #1 rod bearing on my '03

Stew

iTrader: (11)

Your numbering scheme might be different than what I have been using for these threads.. I believe the true #1 is closest to the oil pickup, i.e. passanger side most cylinder. I have been calling the driver side most cylinder #1 here, fyi.

Why did your rod bearing spin?

No other comments? Do you submit now that possibly Mitsubishi was at fault in this case?

nrcooled

iTrader: (4)

There were no inferences in what I posted. Just an FYI. And you are correct it was the passenger side #1 that spun.

There are a couple schools of though on what happened to my engine. It's was more then likely attributable to an over-rev condition. I have never missed a shift or gone to second when trying to go to fourth. It may have been due to my raised rev limiter and running the car to 7600RPM at the track....over....and over...and over again. I would also occasionally hit the rev-limiter at 7800RPM at the track.

This coupled with using 10W-30 at the track (even with VERY frequent oil changes) was too light for a tracked car.

Again, these are all guesses on what happened. There was not enough investigation to completely decipher all the evidence to pinpoint a true "smoking gun"

Stew

iTrader: (11)

Agreed, but it is very unlikely that any modifications to the vehicle would cause a connecting rod nut to loosen itself 100% off of the bolt during engine operation assuming proper assembly. A more likely scenerio is improper torque from the assembly line / improper assembly.