Hello, I have an 02 WRX STi with an ej257 conversion which I just had serviced on Friday. The mechanic told me the Harmonic Balancer is vibrating and suggested contacting the place that did the coversion. Is it likely to be the Harmonic Balance that's at fault or is it more likely something else that's connected to it? Would I need to look for parts for an 02 STi or for an ej257? I can't exactly take the car to the place that did the conversion if they ended up needing to check it either, I live in Albany and it was the Japanese Wholesalers in Perth that did it. I'm sort of lost as to where to look to in terms of getting this fixed which I want to do asap considering the mechanic said it could wreck the motor if anything happens. Any help would be greatly appreciated.

What harmonic balancer?

No such thing.. the only thing close is the crank pulley, and I've never heard of one of those going out of balance.. they're a solid steel pulley.

To find the source of a vibration, check:
Engine mounts
Flywheel/clutch
Big end bearings

The weighted crank pulley

Ok, must be the crank pulley they meant then. How do I check the engine mounts, flywheel/clutch (clutch they said was fine) and the big end bearings? Are they reasonably easy to check or will I have to get someone to check them for me?

you can check the crank pully by starting the car and looking at it, if it looks like its turning out of ballance then you have a problem.You can check the mounts visually from underneith look for things like cracking and splitting. you have to remove the sump to check big end bearings.

I have seen 3 wrxs with shagged crank pullies,when they are out of balance you can see it and feel it when driving

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Marti


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Ok, i'll have a look at the crank pully tomorrow and i'll check the mounts when as soon as i have a bit of spare time and can get the car on a level surface to jack it up. As to checking the big end bearings, I might have to get my friend to help me with that one, just quickly looked it up and I think I'd rather someone with a bit more experience remove the sump. If the crank pully is turning out of balance then what should i do?

Sorry Joe but OEM the front crank pulley is a 2 piece pulley with rubber between the inner & outers, so yes the stock pulley is a harmonic balancer as such. It's designed to reduce vehicle NVH at low rpms.

I've got a solid under drive crank pulley on my current motor but the crank, flywheel & solid crank pulley were dynamically balance as an Assembly when my motor was built.

O.P. A simple solution would be to purchase an under drive pulley set to suit your 257 (Ebay or where ever), the installation is very simple - just be sure the pulleys come with the drive belts.

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Ok cool, that sounds easy. Just confirming but this is what you're reffering too? Under-drive pulley set (2 pulleys and belts included) | eBay

It's pretty common on all EJ series engines. The EJ25 and EJ20 series balancers are all interchangeable. The crank key is often damaged as well. You need to get another (new or good used) harmonic balancer (or underdrive pulley as mentioned) and a brand new woodruff key from Subaru. Get someone in the know to install it and check the crankshaft for damage. The cam belt and drive gear usually need to be removed to get the key out, depends on how fucked up the old one is.

Alright thanks for the info, i'll get someone to help me out with checking the camshaft, woodruff key, etc.