spun rod=seized engine?

[mike b26]

My 2g engine started making a noise that I believe to be rod knock (loud knock at around 3000 rpm and when lifting off the throttle). It lasted for about two days then I pulled up to a stop sign and the engine shut off and appears to be seized. Here are questions:
1) Would a spun rod bearing cause a total seizure of the engine?
2) If that is indeed the case, what is the least expensive option? Rebuild the engine? Find a new engine? Sell the car as-is?

What would you do?

 

[andymoraitis]

If the bearing seizes up, it can freeze the crank. You really won't know what your options are until you remove the oil pan and drop the crank, pistons and rods. I would strongly recommend that you have a machine shop look everything over and let you know if the block is usable. If the block is cracked or damaged, you may need a new one. If not, you'll need to have them make a determination as to the state of the rotating assembly (pistons, rods, crank, etc).

Having a professional look at is mandatory. Good luck and let us know what you find out.

Andy

 

[mjarrell20]

The cheapest option would be to have it rebuilt, the only thing with a spun bearing is you're gonna want to have the block bored out to make sure the cylinder walls are smooth. When I spun my #2 rod bearing I had the motor rebuilt, sent the block to a machine shop and bored out to .20 over, and did a few upgrades while I had it torn down. All in all you should be able to have it rebuilt for around $1,300. Now I don't know if a spun bearing could cause the motor to seize, I didn't drive on my after it happened.

 

[420Aturbopwr]

since you gotz the awd model i would keep it and find a nice 6 bolt motor for it. Once those 7 bolts break once they tend to do it again and again, and again......like my friend's motor, he got it rebuilt it twice by professionals and it still spun a bearing. He finally got a JDM 6 bolt and has had no problems since. And to answer your first question, when my friend spun a bearing the only damage was to the bottem end, you're head should still be good.

 

[Blackmitzu]

If you motor is seized and you still have the stock 7 bolt motor, i would swap it out for a 6 bolt. You can find a jdm 6 bolt for around $1200. Thats the best idea, cause if you do decide to sell it further down the road, it would be much more desirable to a dsm nut. If your motor was knocking only at 3000 rpms sounds like it might have been another problem. Usually rod knock is heard at any rpm, but increases as rpms increase. I have seen a motor lock up from a rod bearing though. Good luck man.

 

[mike b26]

Wow, that was fast!
The engine was at idle when it stopped and I haven't done anything other than try to rock it in gear so I'm guessing that the block is okay. As I read through the forum I see a lot of mentions of spun rod bearings. Is this is a common problem with the 7-bolt? This engine always had low oil pressure since I bought it (with 14,000 miles on it). Is that also common?

Blackmitzu,
Any idea what the noise was caused by if it wasn't a rod bearing?

 

[eldiabloz13]

Now a seized bearing could cause a crank to seize. I think it may have seized when you were driving and thats when the noise started to come it. Then as you slowed down the bearing started to grip and finally slowed the crank enough to stop it. Think of it like this......you have a bicycle tire off the ground and you crank that tire as hard as you can by the peddle. Then you stop peddling and try to grab the tire to stop it. Since it was spinning so fast you cant completely get it but you still slowed it down. Now you do that again but at half the speed you did before. You go to grab it and your hand force stops it. Now say your hand is the bearing and the tire is the crank. Now if you slid your hand along the tire to slow it down also there comes a noise. My guess is that what happened is exactly that. I also agree with the statement of the 7 bolt. It breaks once it will do that ever after. It will never happen to a 7 bolt or it will happen as long as it run there no in between.

 

[Defiant]

It could have been a balance shaft bearing, and the seizure was due to the shaft locking up, shearing off cam belt teeth, and ramming pistons into valves.

You need an accurate diagnosis, not guesses.

 

[cottonballs43]

Hey I have a 98 gst that sounds like the same thing, did you ever figure out what caused your car to stop? I had the same problem where it was making that noise starting around 3,000 rpm and getting louder the higher the rpms, I thought it was just a lifter going bad but then as I was driving it sounded like somthing shot out of the engine and the engine started smoking, its completely seized up now. I haven't gotten a chance to look at it yet.. but I think its going to need a new motor.

here's a video of the noise it was making before it died.
http://s142.photobucket.com/albums/r83/cottonballs43/?action=view&current=MOV00089.flv

p.s. it leaked no oil at all

 

[nightspeed87]

my new built 6 bolt engine at 80miles started knocking, and increased with rpm so i knew it was rod/ crank/ bearing related. I stopped driving it once I hear it, i hope the block wasnt damage. Im getting mines fixed next week, and doing it right with new bottom end.
I had the 6bolt fully rebuilt new everything until i got to the crank which I ran out of money and had the old crank used and cut/ machined out... May have been my problem, also during those 80 miles of driving it the stock oil pressure gauge wasnt workin and sometimes it would work occasionally but only read somewhat low oil pressure when it did work and it made me nervous ( since i dont have balance shafts shouldve had a lot of pressure ) so then i opened the oil cap and there was oil in the head so figured the gauge was just acting crazy and that i needed a new oil pressure sending unit and was about to hook up a manual gauge the same day it started knocking and acting crazy.... I tell ya this dsm is nothing but a money pit of headaches... Im just going to get it done right this time and for the last time...