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Timing Belt, Idlers, and More


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So the story goes like this:

I go on a drive to warm up my car so I can drain the oil easier, and when I start it up it makes a squeaking for around 5 seconds. I figured one of the accessory belts was getting old and just stashed it away in my head as "Replace later". I go on my drive, and not even 2 miles from home the most dreaded event for an interference engine occurs.

 

I'm slowing down, engine braking, up to a stoplight. There's a slight squeak and then the entire car jolts, there's a thud, and the engine stops. I immediately throw it into neutral and try to start it, and it just cranks and cranks. I got it home after pulling the codes and calling up AAA.

 

I finally teared into it today because my schedule cleared up and oh boy. Got the side timing covers off and was surprised to see that the belt was still there, and under tension. The teeth surrounding the crank were completely ripped off and the belt was smooth, but it hadn't actually broken. The #2 Idle pulley's bearing was basically as good as something that's really really bad in it's entirety. It seemed like one of the balls in there had just exploded and sent pencil shavings of metal through the bearing and seizing it up. I'm gonna guess that it was the source of the squeaking on start up, but it was the first time I had ever heard it, and it did not give me much time to get after fixing it before it grenaded. At this point I have a bunch of questions.

 

  1. How does such a failure occur and what steps can I take to avoid it in the future?
  2. What's the likelihood I bent a valve?
  3. Why doesn't the AT model have belt guides like the MT model?
  4. Where can I get those belt guides?
  5. Who makes a good lightened crank pulley for the EJ255? New Ej257 block is near in the future so it would be nice for it to work on both.

 

I guess maybe I learned my lesson? I dunno, I don't think I could have been expected to know that the squealing sound was that serious. Still haven't got around to that oil change :/

 

p.s let me know if I'm an idiot and missing something with the photo upload process. I thought I did what the forum needs but it says I need a security token

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Bummer man, I had to rebuild my '99 DOHC because one of the toothed idler pulleys crapped it's bearings.

 

To upload, reduce the image size about 50% so that the long side is < 2048px.

That will typically fix the upload problem.

 

How does such a failure occur and what steps can I take to avoid it in the future?

- change the belt and pulleys when scheduled by time/miles.

 

What's the likelihood I bent a valve?

- quite high, gonna have to pull it apart to know which and how bad

 

Why doesn't the AT model have belt guides like the MT model?

- I think because the tranny is smoother and can't make the belt jump (ie. can't drop the clutch or similar)

 

Where can I get those belt guides?

- parts.subaru.com

 

Who makes a good lightened crank pulley for the EJ255? New Ej257 block is near in the future so it would be nice for it to work on both.

- Don't recommend a lightened crank pulley. If you want something not OEM, recommend Fluidamper instead.

Edited by Infosecdad
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I agree. No need for a lightened crank pulley. However, make sure your OEM one is still in good shape.

I once dodged bent valves when the bolt of the timing belt tensioner sheared off its bracket :spin:. I was pulling a 2500 lbs trailer at that time.... I still can't believe it to this day. In any case, it is true that the likelihood of bent valves is high. You can use a borescope and do a leakdown test to verify.

 

 

Sorry to hear man. Good luck with the work.

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When was the timing belt and components last replaced (mileage and age, if possible)? What brand are the components? The idler pulleys are more common to fail if not replaced at the same time as the belt.
I bought the car with 142k on it and it had paperwork for the full timing kit done at 113k. The belt itself was a standard Gates belt and unfortunately it looks like the other stuff is off brand (one of the other idlers has "Made in China") and the one that failed looked original. I got a Gates blue belt to replace it with cause that thing is indestructible.

 

 

 

Sent from my Carrier Pigeon using Tapatalk

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Bummer man, I had to rebuild my '99 DOHC because one of the toothed idler pulleys crapped it's bearings.

 

To upload, reduce the image size about 50% so that the long side is < 2048px.

That will typically fix the upload problem.

 

How does such a failure occur and what steps can I take to avoid it in the future?

- change the belt and pulleys when scheduled by time/miles.

 

What's the likelihood I bent a valve?

- quite high, gonna have to pull it apart to know which and how bad

 

Why doesn't the AT model have belt guides like the MT model?

- I think because the tranny is smoother and can't make the belt jump (ie. can't drop the clutch or similar)

 

Where can I get those belt guides?

- parts.subaru.com

 

Who makes a good lightened crank pulley for the EJ255? New Ej257 block is near in the future so it would be nice for it to work on both.

- Don't recommend a lightened crank pulley. If you want something not OEM, recommend Fluidamper instead.

Thanks, that picture thing has been bugging me for a while. I appreciate the information. It seems weird to me that they wouldn't just put those guides on both. Maybe I'm getting a case of Paranoidaboutmycarbreaking-itis, but I think I might get them just to feel a little better.

 

Why is a lightened crank pulley not recommended? It seems like the reduction in weight to spin around would be a good thing. I do understand the whole thing about underdrive pulleys though, but I'm not interested in one of those.

 

Sent from my Carrier Pigeon using Tapatalk

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Once the weather gets better I'm gonna pull the plugs and get my boroscope in there and check things out. I'm prepared to do a rebuild, it was in the cards due to rod knock anyway. Seems I got pretty unlucky with this car so far.

 

Oh well, I like it enough to keep it around and throw money into it (god what a money pit these cars are). Guess I should head over to the CARdiac ICU and start a build thread? Should be a fun build, I plan on doing an EJ257 block and some go fast bits. I don't really know what to do about heads though. I know that STI heads won't play nice with my ECU because it's single AVCS and I haven't seen any way to make it work without going aftermarket ECU. I guess I'm gonna just have my heads rebuild with some +1 valves and call it good. If anyone knows of a good machine shop in the Seattle area that is recommended, let me know. I'm gonna shop around for now.

 

Sent from my Carrier Pigeon using Tapatalk

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Thanks, that picture thing has been bugging me for a while. I appreciate the information. It seems weird to me that they wouldn't just put those guides on both. Maybe I'm getting a case of Paranoidaboutmycarbreaking-itis, but I think I might get them just to feel a little better.

 

Why is a lightened crank pulley not recommended? It seems like the reduction in weight to spin around would be a good thing. I do understand the whole thing about underdrive pulleys though, but I'm not interested in one of those.

 

Sent from my Carrier Pigeon using Tapatalk

 

 

Youtube video by Dominic Acia, a well respected tuner.

Essentially our crankshaft is already super light because of the boxer design.

He's not against lightweight crank pulley, just doesn't use them on Subaru motors.

I like the Fluidampr pulley (several ones on here run one as well), it's around the same weight as stock, but also helps smooth out the engine and keeps components and pressures more stable.

Stock is a fine option as well, and a lot cheaper.

Edited by Infosecdad
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Youtube video by Dominic Acia, a well respected tuner.

Essentially our crankshaft is already super light because of the boxer design.

He's not against lightweight crank pulley, just doesn't use them on Subaru motors.

I like the Fluidampr pulley (several ones on here run one as well), it's around the same weight as stock, but also helps smooth out the engine and keeps components and pressures more stable.

Stock is a fine option as well, and a lot cheaper.

 

You know, this is precisely the video that convinced me to stop using these things!! But I admit I am lazy and I still have them on my cars :spin:

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