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2G Slight knock at idle (Solved)

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VivaLaOC

Proven Member
121
25
Mar 16, 2021
La Grande, Oregon
The other day when I was driving I came to a stop after driving on the freeway and was in neutral and ebrake was on and I started to hear a knock like sound almost like a belt smacking somewhere I thought the timing belt was loose but I checked on it and got it to TDC and it was tight and timing marks were perfect. I'm still hearing the knock though and I noticed oil pressure was somewhat low but my oil pressure wiring isn't the best either so it could be that too. I'm gonna do an oil change tomorrow and see what its looking like, I just really hope I didn't spin a bearing, but I also don't run anything over stock boost and as far as I know everything internally engine wise is stock. The only things I've done is master and slave cylinder, aftermarket boost guage and an MBC but its set at stock boost I got them and installed those two things I have a FPR and 255lph fuel pump that aren't installed.
 
Glad you got it solved. Good call on not starting again. I personally haven't experienced this one so gives me something to think about going forward to watch out for. About how often do the harmonic balancers go bad on our engines?
But I've heard of a LOT of 2ga's with 420a's that almost always separate my brothers 96 2ga did the same thing but with much less miles. His only had about 150-160k miles and it had been replaced before as well
 
Glad you got it solved. Good call on not starting again. I personally haven't experienced this one so gives me something to think about going forward to watch out for. About how often do the harmonic balancers go bad on our engines?
Idk the life expectancy. When I inspected mine, I didn’t see any cracks or signs of wear. Going to go with fluidampr next year so I will never have to worry about it.
 
It isn't just miles it's the life it had and age. I've had 2 fail on 2 different cars. One of them only had about 75k on it but it was 15 years old. Neither gave me any warning. Bang, pop and I was on the side of the road.
 
About how often do the harmonic balancers go bad on our engines?
I've worked on 6-7 4g-series engines over more than 20 years most all of 'em when I bought the car. I've seen one bad harmonic balancer and it was really a pulley failure. I've heard of another that was the same. I believe the causes of those two failures was a lose crank bolt that came out causing a failure of the pulley/balancer hub. In both cases the thing eventually took flight through the front of the engine, taking out the cover, various belts, a water pump ... I don't remember it all. Both engines did survive though -- the driver I knew said it was a horrific sound and he got it stopped immediately.

Came close to another one on my dd -- a 4g93 engine. When I changed the oil pump a couple months ago the crank bolt was not tight at all -- the little electric impact wrench just spun it out.

The rubber between the two halves of the harmonic balancer part is a rare enough failure that I haven't seen it yet, though I'm sure it happens more often on 4g63's than on the more sedately driven 4g64 and 4g93 that I've spent the most time on.
 
I've worked on 6-7 4g-series engines over more than 20 years most all of 'em when I bought the car. I've seen one bad harmonic balancer and it was really a pulley failure. I've heard of another that was the same. I believe the causes of those two failures was a lose crank bolt that came out causing a failure of the pulley/balancer hub. In both cases the thing eventually took flight through the front of the engine, taking out the cover, various belts, a water pump ... I don't remember it all. Both engines did survive though -- the driver I knew said it was a horrific sound and he got it stopped immediately.

Came close to another one on my dd -- a 4g93 engine. When I changed the oil pump a couple months ago the crank bolt was not tight at all -- the little electric impact wrench just spun it out.

The rubber between the two halves of the harmonic balancer part is a rare enough failure that I haven't seen it yet, though I'm sure it happens more often on 4g63's than on the more sedately driven 4g64 and 4g93 that I've spent the most time on.
Very educating thank you for the super thorough explanation. Im currently running the unorthodox racing crank pulley right now that was put on in the early 2000's, i think they revised it and came out with a second design which was like half the weight. Im considering going to an OEM balancer due to finding information that an aftermarket crank pulley can cause premature bearing ware because it is not a balancer but a simple pulley . Not sure how accurate that is but its definitely something i need to look into.
 
A good friend of mine lost a head due to a bad balancer that chucked the rubber into the belt. Honestly with these cars being 20-30 years old, rubber parts are failing, and either a new OE balancer ought to be sourced, or a quality aftermarket- IMO that means Fluidampr or ATI.

That said, if your budget doesn't allow, a cheap aluminum pulley that doesn't dampen might not be great for the motor, but it won't murder your valves by eating a timing belt either ;)
 
A good friend of mine lost a head due to a bad balancer that chucked the rubber into the belt. Honestly with these cars being 20-30 years old, rubber parts are failing, and either a new OE balancer ought to be sourced, or a quality aftermarket- IMO that means Fluidampr or ATI.

That said, if your budget doesn't allow, a cheap aluminum pulley that doesn't dampen might not be great for the motor, but it won't murder your valves by eating a timing belt either ;)
A good friend of mine lost a head due to a bad balancer that chucked the rubber into the belt. Honestly with these cars being 20-30 years old, rubber parts are failing, and either a new OE balancer ought to be sourced, or a quality aftermarket- IMO that means Fluidampr or ATI.

That said, if your budget doesn't allow, a cheap aluminum pulley that doesn't dampen might not be great for the motor, but it won't murder your valves by eating a timing belt either ;)
Very very true, yeah I already have an OEM one on the way it'll be here on Monday thankfully and not the 5th of Nov like it had originally estimated :D
 
I've been gone from home all day but the balancer did show up 2 days earlier than expected (thank goodness) but it looks great! Its not used or damaged at all here's the photo/video of it out of the package
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Houston we have a problem.

I just now was able to actually look at my balancer that got here yesterday in person and I'm extremely upset. This is how it came and looked from out of the box.

Chipped and the rubber seal is actually REALLY bad.

I should've known getting my part early wasn't luck, it was because it was a POS part.

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Houston we have a problem.

I just now was able to actually look at my balancer that got here yesterday in person and I'm extremely upset. This is how it came and looked from out of the box.

Chipped and the rubber seal is actually REALLY bad.

I should've known getting my part early wasn't luck, it was because it was a POS part.

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Where did you buy it from?
 
I THINK oem has numbers in white and a blue dot on the pulley
They refunded me and let me keep the part too so that's cool at least, but I did put it on the car and started it and it sounds strange. Almost like a belt is rubbing on something but from what I saw there wasn't one rubbing at all, but the sound is effected with rpm and also if you turn on the headlights. Not exactly sure what's going on.
 
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