Laser = toast?

[Underdog]

So the last few days the laser has been having some issues. Was making full boost but not accelerating. Hesitating a lot. Wasn't able to tear into it and try and figure out the problem. Went to pick roommate up from airport. Halfway home it starts making a loud clanking sound. Park it, pop the hood. Turbo is glowing red hot which has never happened before and I wasn't even driving the car hard. Temperature gauge was normal right in the middle. It sounds like it's resonating off the exhaust manifold heatshield too in the vid clip:
http://www.youtube.com/watch?v=http://www.youtube.com/watch?v=NMl6tgfZaOM

Spun bearing?

[DROOPY209]

Can you build boost? It does sound kind of funny. I've never blown up a 4g63t engine(knock on wood) but I'm positive somebody else in here has, or has atleast heard one dying.

Sounds to me like a valve floated and is hitting the piston, or rod knock.

[Underdog]

Yeah it still builds boost.

[EuroEclipse]

i can't see the video from here. but if you say that it's building boost and not going anywhere and it sounds like metal slapping something else, you've thrown a bearing. check your head components too.

[my3awds]

My old gst did that when it threw a balance shaft rod. First, do a simple compression test. Then, drain your oil and check the consistancy. That will narrow alot down. If the compression is in check and your oil is silver, I'm better its the rear shaft bearing. If it is the balance shaft, you may be able to get away with just doing the bshaft removal mod. I did it to the old gst and got away with a few more thousand miles before pulling it out to do a 6bolt swap.

Manny

[Underdog]

Looked at it some more today. I believe the turbo is blown. Sound definately sounds like it's coming right from the turbo. Gets louder when you accelerate and sometimes completely goes away for a split second right when you let off the gas whether in gear or revving in neutral. Also the turbo is heating up fucking quick, 15 minute drive not driving it hard is enough to make the exhaust housing glow bright red. It's fucking hot right now but once it cools down I'm going to pull the intake pipe off and see if I can tell any damage from that side. Talked to a friend at school that had his turbo blow in his 2g when he used to be in to DSMs and he said his did the same thing.

[Underdog]

Scratch the idea about the turbo I don't think that's it. Turbo has very minimal side to side shaft play, same as it did when I bought the car, and no in and out shaft play at all. Spins perfectly without any noise or anything.

At this point I don't really know what else to do. What else CAN I do to narrow down the problem? If it's a thrown bearing is there really any way to know for sure before the motor is pulled apart? I disabled fuel and just cranked the motor over and just cranking it over you can hear it too although obviously not as loud.

My compression tester was left up in Washington so I can't compression test it. I don't even have a decent place to work on the car as the apartment parking lot is less than ideal.

[Underdog]

Ok well looks like I spun a bearing. With the engine running i removed and replaced the spark plug wires one after another. When I removed the spark plug wire for the number one cylinder the knocking almost completely went away. Hooray, now I need to find a place where I can take my car to be able to work on it. I'm not going to rebuild it I don't have time for that I think I'm going to just put in another long block. Anyone have a 7 bolt long block for sale?

[DROOPY209]

I'm not going to rebuild it I don't have time for that I think I'm going to just put in another long block. Anyone have a 7 bolt long block for sale?

A 7 bolt? WTF?

Now is your time to take advantage of this issue, upgrade and get a 6 bolt.

[my3awds]

Compression gauges are $20 at Autozone and if you can't afford one, I'm sure someone here can bring one to the meet for you to borrow. I'll see if I can find mine. If your compression checks out, then go for the oil and drain it. See if the oil has silver in it or shards come out. It's the only way I know of to take a first glimpse at what your motor is doing before tearing it apart; short of leakdown test and dropping the oil pan.

Manny

[my3awds]

Also, Jonathan has a bare 6bolt he is selling I believe (outside of M&S).

[Underdog]

Hey manny, did you find your compression tester by any chance?

[BenGSX]

kinda sounds like a crazy exhaust leak popping against the heat sheild.

And a spun bearing makes more noise when you let OFF the gas than when you get on it..

[Underdog]

Really.....hmmmmm Because it's definately a LOT louder when you get on it than when you let off, it almost goes away when you let off.

Shit.....I wonder if it's just a loose spark plug.....

[BenGSX]

Yeh Spun bearings usually dont knock when your ON the gas accelerating.. (from plenty of spun bearing experience..)

Dont know about balance shaft bearings going out..

Sounds more like somekinda leak than a knock..

Its too regular..

Look again

(Sounds very similiar to my car right now.. My exhaust manifold cracked.. bad.. havnt looked at it yet.. but it sounds just like that..)

[Underdog]

OK i checked the plugs, wasn't a loose plug. With an exhaust leak that bad would it cause the hesitation problems that I'm encountering? Another thing I should mention is it seems like the engine is under more load, it's building up more boost at less throttle because it feels like there's some sort of resistance that's putting the engine under more of a load if that makes any sense.

[BenGSX]

DIagnose it for gods sake mang!.. Get out a long screwdriver and do it old school.. Listen to it..

[Underdog]

I'm working on it, I'll finally get a chance to this weekend. Going to school all morning, sleeping during the afternoon, working at night, and sleeping when I get back from work until school during the week doesn't leave me time to mess with my car, I'm just trying to get some ideas beforehand.

[BenGSX]

well take that heat shield off and look for cracks..

[Underdog]

That's the plan. Going to check the mechanical timing as well and pick up a compression tester in order to check compression as well.

[OldDirtyNoSeven]

OK i checked the plugs, wasn't a loose plug. With an exhaust leak that bad would it cause the hesitation problems that I'm encountering? Another thing I should mention is it seems like the engine is under more load, it's building up more boost at less throttle because it feels like there's some sort of resistance that's putting the engine under more of a load if that makes any sense.


Thats because the rod is trying to WELD itself to the crank, if you hear any noise other than a little normal valve train noise your 7 bolt is toast. the bearing surface area on 7 bolts is HALF that of 6 bolt, that is one of the biggest reasons to NEVER build a 7 bolt, their performance is limited to to that one engineering screw up at Mitsu.

if you don't want to go the entire 6 bolt swap route, at LEAST build a 6 bolt lower end and put your 2g top end on it.

unless you get a good 7 bolt engine for almost nothing its not worth it.

[Underdog]

It's not a 2g 7 bolt. The car is a 92. But I realize the 1g 7 bolts are still nowhere near as good as a 6 bolt. I'm going to work on the car more today to try and figure out for sure what the problem is so I can decide what the next step will be.

[OldDirtyNoSeven]

The 1g 7 bolts still have the small bearing journal, they just don't have the lame ass oil squirters.

[BenGSX]

Yah NM. i listened to it again on real speakers instead of on my laptop and i listened to the whole thing.. Sounds gnarly..

[Underdog]

Wasn't a spun bearing, here's what the shop found:

http://img242.imageshack.us/img242/6750/pistonuq7.jpg

On top of all this, the 2600 is TOAST. I bought it used with supposedly 500 miles on it and I put maybe 12,000 miles on it since then, but it has barely any friction material left and the pressure plate and flywheel were heatchecked very badly. Either something was defective with the clutch or I was lied to and the clutch had way more than 500 miles on it. I didn't know as much about clutches back when I bought it that I do now so I don't recall if the clutch looked very worn when I bought it. Live and learn I guess. Just ordered a new 2600.