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Boober909 08-30-2010 11:13 AM

Timing belt help
hey guys so i decided to replace my timing belt/water pump this weekend and so i went to start it back up after and it was really rough idle at about 1450 rpm. i used a gates timing belt with all the timing marks on it and thought i had everything lined up correctly, the only thing i can think of is that the crank rotates twice for every one rotation of the cams, is it possible i went one rotation out with it? any help would be great

wagonracer 08-30-2010 12:13 PM

It's possible you're off, the DOHCs are a little tricky, because the intake (drivers side) cam wants to turn on you. What I always do is get all the marks (including the belt) lined up and then turn it over with a wrench a full 360 at least twice, and check that all four cams and crank marks keep lining up with the lines on the covers and each other again (the lines on the belt won't line up after the first turn) before I start the engine.

With what you're describing, I'd take the covers etc. back off, and check the marks by turning to TDC again. If it's off you'll just have to reinstall the T belt.

Boober909 08-30-2010 12:34 PM

okay i'll try that again. ugh so much work i have so many cuts on my hands lol. yeah so many times i'd have it almost there and the bottom drivers side would spin on me. on the top i used a piece of wood to hold it with a c clamp and it worked okay. so is even one tooth off enough to cause problems?

RcrsWetDream 08-30-2010 02:19 PM

1 Attachment(s)
[quote=Boober909;249639]so is even one tooth off enough to cause problems?[/quote]


man show 08-30-2010 04:24 PM

Did you happen to use any good online write-ups for this job or is it pretty easy to figure out? I've never done it, but it's a job I'm considering tackling in another 40k miles or so.

RcrsWetDream 08-30-2010 04:57 PM

1 Attachment(s)
[url=]Impreza Manuals |[/url]

First link, all you need to ever work on your car ever.


The section you'll use for timing is H4DOTC Engine- Mechanical

Boober909 08-30-2010 04:58 PM

i took it apart all myself but used some guides for the timing belt alignment part. this one is good : [url=]Timing Belt and Water Pump Replacement - ClubWRX Forum - Subaru Impreza WRX and STi Community and Forums[/url]
but ugh i can't get it i had it all lined up perfectly lines on the marks on the pulleys, spun it a few times and each one is three teeth off the line on the belt. i dunno what to do now :S i looked up the belt to make sure it's right and it's the same number as online gates t328rb.... the belt is routed correctly i looked at pictures, i dunno what to do. :s

Boober909 08-30-2010 05:01 PM

do you guys think if the crankshaft is rotated one rotation past the rest that could be my problem as it rotates twice for every one rotation of the cams? when i'm turning the belt with the crank belt it goes harder and easier, this is just the pistons reaching TDC correct?

Boober909 08-30-2010 06:08 PM

i went and took it off and put it back on again, (by the way anyone doing this it is alot easier to use the bottom left tensioner for slack tand run the belt from the crank clockwise than by starting top left and workign counter-clockwise)

but anyways, the belt lines still won't match up, no matter how many times i spin the whole belt. all the cams will be right at TDC along with the crankshaft. what do you guys think? should i leave the cover off and throw the belts and stuff back on and try to start it and see what happens?

wagonracer 08-30-2010 09:44 PM

Don't worry about the lines on the belt. They will only line up once, when you first put the belt on. Once the engine is turned, those lines will never match up again. Make sure that all your timing marks on the cams, the notches on the back cover, and the crank all end up at TDC every time you turn it through a full cycle (two turns of the crank). Once you confirm that you're good to run it.

Boober909 08-31-2010 01:13 AM

okay. i'll try putting it back together tomorrow. i mis-understood your earlier post that the lines on the belt won't line up after one rotation, but will after two rotations. duuh. my bad.

wagonracer 08-31-2010 05:17 AM

The how-to on ClubWRX is good with one exception. You should definitely replace the hydraulic tensioner when you replace the belt. They can and will fail, and the results are catastrophic. If you have to re-do the job re-compressing is fine, but a vise or vertical press is the way to go if you have one. I've used a floor jack and the weight of the car in a pinch too :o A little C-clamp would be a bi-atch.

If your belt is due for replacement, so is the tensioner. Trying to save that $100 (or whatever they cost these days) could cost you big-time in the long run.

Side note: I can't believe they did that DIY thread with such a dirty engine. It's well worth the few minutes it takes to clean up under the hood before tackling repair projects :p

RcrsWetDream 08-31-2010 09:39 AM

1 Attachment(s)
Yeah, the belt will be off after the first turn of the crank. The marks on the cam gears and crank need to match up still.

Chase 08-31-2010 10:14 AM

[quote=RcrsWetDream;249656][url=]Impreza Manuals |[/url]

First link, all you need to ever work on your car ever.


Agreed, I did a full rebuild using that;)

Boober909 08-31-2010 01:02 PM

ugh so it is back together and still runs like shit. it will sit at like 1000 rpm or so and if i rev it it doesn't sound good. what are the chances i bent the valves?

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