Spun Bearings in block?

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khai_tuan_nguyen

Senior Member
What is the cause of spinning a bearing in the block?
How do you know if you have done it, while you are driving?
If I disassemble my block will I be able to tell if my bearings are spun?
How much do the bearings cost to replace?

Khai
 
the cause for spinning a bearing is when the crank touches the bearing because usually there is a thin film of oil keeping it from touching and if it does touch it will probly spin it. you will know you have done it because you might lose some oil pressure and probly here some knocking in the motor you could probly tell if you just took the oil pan off but you might have to dissasemble it more. and the price...couldnt tell you but if only the bearings are bad it shouldnt be too much but make sure noting else got messed up.
 
What else could get messed up?
Anyone know how much to replace the bearings?
Knocking noise? Like rattling or pinging? Any other symptoms?

Khai
 
Depending on how bad things are it could damage your piston rod, piston, and block. As far as the cost to replace the bearings probably like $5 for each set of 2 (top and bottom) if it is just the bearings, much more if there is other damage. Symptoms you will hear a noticeable knock that will get louder as rpm increases if its bad enough you will notice a loss of power. If you have a listening device you can put it next to your oil pan to get an idea if the sound is coming from that area of your motor or like crx b16b said you can pull off the oil pan and look from there.
 
Originally posted by spydy43@Sep 10 2004, 04:52 PM
Depending on how bad things are it could damage your piston rod, piston, and block. As far as the cost to replace the bearings probably like $5 for each set of 2 (top and bottom) if it is just the bearings, much more if there is other damage. Symptoms you will hear a noticeable knock that will get louder as rpm increases if its bad enough you will notice a loss of power. If you have a listening device you can put it next to your oil pan to get an idea if the sound is coming from that area of your motor or like crx b16b said you can pull off the oil pan and look from there.
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I hear a ratlling (does not sound like knocking, pinging) it sounds like a rattle. This only happens at lower rpms like 3-4 and only if i accelerate fast (like full throttle) When i accelerate slowly i can not hear it and also when it gets to the higher rpms i can not hear it even if i accelerate fast.

KHai
 
The knocking sound I experienced when I spun a rod was loud and constant, regardless of whether I was revving the motor or not. I was out in the middle of nowhere when it happened, so I had to drive 5-10 miles before I could shut her off. I didn't rev it above 3000 rpm, because it sounded like it was going to blow up. Luckily it spun the outside, and so the crank was not scratched up. If the load on the bearing surface (from the cumbustion/power stroke and inertia) exceeds the oil pressure on the bearing surface, you are going to start wearing the bearings. mine were paper thin when I pulled them out.
 
You can have a mild knock that's only discernable at certain rpms.

The best way to check is when the engine is cold quickly *blip* the throttle so the rpms go up to about 2500 and as they descend listen for an accentuated *rattle or knock*. If you suspect this, with the engine idling, go to your spark plug wires and pull them off out one at a time if the noise goes away after pulling a spark plug wire then you know which cylinder is guilty.

If none of this applies to you then you probably don't have a bad bearing.

But if you do have a bad bearing, there is a possability that you can just replace the bearing without having to regrind/replace the journal. But of course you have to check the tolerances on the journal. If the journal needs to be lathed or replaced, you have a rebuild on your hands. If the journal is fine, you can (in certain cases) get away with just replacing the bearings.

An interesting thing that happened to me was my h22 started getting this 'cold engine knock'. I determined that the no.1 cylinder was guilty and dropped the oil pan. As I was preparing to remove the cap from the no.1 rod, one of the bolts literally fell out... checked the tolerances and everything was fine. So I just locktited the bolt and reinstalled it with stock torque specs.

What happened was the company I get my engines from check the bearings prior to selling the engines and someone didn't torque that bolt sufficiently! :blink:

Anyways, the point is don't always assume the worst, check everything out for yourself. It takes about 2 hours for the layman to drop an oil pan so if you're really worried get in there and check it out.

Other problems could be:

1) Exhaust rattle

2) maybe even your ignition timing is too advanced and you're getting detonation (since you said you hear it when you get hard on the throttle right?)
 
Awsome Info for a Rod knock.

That is my EXACT problem. Only thing is that my cars Warm right now, and as you say "best to check when its cold"

So slapping new bearings in there is the cure?
 
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