1G 6 bolt: bent connecting rod

[Mr Peepers]

Tearing down my engine after my car started on fire a while back from a cracked/split fuel line. The engine made no strange noises before the fire, and stopped running as soon as flames came out from between the hood and windshield

I bought the car about a month before it started on fire. I was only running ~15psi through it since I was still looking for a logger. The previous owner said they ran 20+ psi on the 14b for a pull or two before the IC piping blew off, which I didn't like the sound off, but there was no other sign of damage.

P.S. This isn't the car in my profile even though it was also a 91 AWD. Mods were 550's, 2g MAS, Dejon super SMIC, all hard IC piping, 3" turboback, , 2g exhaust mani, boost gauge, AFC (not being used) etc.

I have another engine I'll be using anyway, but what could have caused this? Especially without any signs of it. Everything else was in alright shape for a 120k mile motor. I thought 6 bolt rods rarely bent This was the 3rd piston away from the cam gear side of the engine.

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[Dream On]

My net is too slow to show the pic, but maybe they took it too high in rpm.

 

[SlowSpyder]

ouch..... im in the same boat. My car is currently down for a rebuild right now but ill show you the carnage that happened. This is a 7-bolt 4g64 that was turboed.

 

[Mr Peepers]

Wow, I consider myself lucky. That was the next step If I didn't notice it

 

[BlackWhiteBeast]

That's some major catastrophic damage. That 7 bolt 4G64 block looks majorly blashed out ! I hope you get that fixed soon, thats a bummer man.

 

[Mr Peepers]

Fire damage too if anyone was curious. The bent rod is not related.

 

[diambo4life]

I feel pain just looking at it.

 

[pooker]

Oh my, sorry about the bad luck.

 

[tqmx1]

The way that rod looks my guess is a injector stuck open and partly hydralic locked the cylinder so the next start it tweeked the rod.

I came close to having a twin of yours (the fuel inlet Oring shrunk) filled the top of the intake with gas!

Rather be luckey than good!!

 

[Mr Peepers]

Heard about an injector getting stuck open, blowing a hole in the side of the block from hydraulicking, then the fuel igniting WTF The car burned to the ground

Could have been worse, the block is still good

 

[2gAWDTalon]

stock 6 bolt rods will also bend around or above 550 whp... maybe the guy that had it before you did not tell the truth about what he used that motor for.

 

[Mr Peepers]

I've also heard the rods are good for around 550whp, but that's with a good tune. Wouldn't 20+ psi pulls knocking with a 14b cause just as much if not more damage? I know the seller and I even have all the receipts from the time he got the car, and the owner before that is the owner of www.plymouthlaser.com seen in this link: http://www.plymouthlaser.com/awd.htm

 

[snox135]

Wow, I consider myself lucky. That was the next step If I didn't notice it

Wow is right. How are you keeping a postive attitude. I would rather have a rod through my block than my car burnt. At least your ok.

 

[Mr Peepers]

Wow is right. How are you keeping a postive attitude. I would rather have a rod through my block than my car burnt. At least your ok.

It happened at the beginning of this year. My friend and I were in the car when it happened, and as we were staring at it with all the fire trucks and cops around, we just started laughing. It was very surreal. The next morning it hit me and really took a toll after that. But now, I see it as a chance to put everything back together just how I want it and make the car my own. The damage ends at the firewall, and all I need body wise is a new hood, fender, and windshield. I'll be using my red 91 as a parts car for everything under the hood and wiring. I could write a novel about this, and I've been contemplating starting a thread about my progress. No injuries at all to me and my friend, more importantly my friend. Thanks for the concern

 

[DirtyBirdRacing]

I've also heard the rods are good for around 550whp, but that's with a good tune. Wouldn't 20+ psi pulls knocking with a 14b cause just as much if not more damage?

Knocking is a sign of detonation. As far as I know, detonation will cause broken ring lands and stuff like that. Not bend a a rod like that, but hey i'm not saying its impossible. But i'm glad you and your buddy are ok. Also, it sucks that that happened to your car, but at least you still have your car in "ok" condition. The buddies I have that have had this happened to them had to sit on the side of the road and watch it burn to the ground before anyone came to put it out.

Bill


P.S. I did some research and found this posted by Defiant:
"Detonation" is the spontaneous exploding of the fuel/air mixture, and will occur with force enough to bend rods, crack pistons, snap head studs and fracture water jackets. So yeah I guess it could of caused your bent rod.

 

[BUCK]

I bent a Rod exactly like that with a bad ECU that flooded Combustion Chamber (& block) with Gas - With new ECU it still ran great & I didn't know until I wrung a Timing Belt & pulled Head - damn that was a nice black 1G...

 

[Mr Peepers]

I bent a Rod exactly like that with a bad ECU that flooded Combustion Chamber (& block) with Gas - With new ECU it still ran great & I didn't know until I wrung a Timing Belt & pulled Head - damn that was a nice black 1G...

Yes! Very possible. That reminded me, when they took the car to the track they said it ran a really bad time. Reason? Bad ecu and it was cutting out and running horribly on the top end. New ecu and problem solved.

Thanks, nice 1g's are getting harder to find

 

[dsm-onster]

Just another post showing that 6-bolts arn't invincible. Cylinder pressures can be high enough during detonation to do this. This is just a testamony to stock iron rings and the 4g63 crank and bearings.

It doesn't take 500 hp THEN knock to bend a rod. 550 hp can bend a rod w/ no detonation. Detonation causes a terribly high spike in cylinder pressures; much more than in a 550 hp blast from normal combustion.

 

[Meh987]

I've seen a rod bent like that in a Nissan Titan. The guy driving it went into some DEEP water and hydrolocked the motor. Only bent one rod, but it bent it enough to hit the block every revolution!

 

[Mr Peepers]

I got a little more info on what the car was doing when the ECU was bad. It would randomly dump enough fuel to kill the engine at idle, and he said something about the TPS reading 17% but he wasn't very clear about it.