Questions re timing belt/seal replacement

Car: 98 OBL 2.5L with 255K miles. My cam seal leak is now bad enough that I have to do something. Dealer quoted me $575 including mandatory timing belt
replacement. Studying the Haynes manual makes me think I can do it for the cost of the seals (timing belt is only about 30K miles old). There are a few bits that are still unclear:
Is it better to raise the front end and work from underneath or work from above?
If I understand it correctly, with cyl. 1 at TDC the cams on the right side will not move when the timing belt is removed, but the cams on the left side will. Is this right? Can I prevent them from moving?
If I'm taking off the timing belt and cam sprocket, how do I keep the cam from moving, or how do I make sure it is in the right position when reassembling?
Do I need any special tools to do this job?
This looks like a job that should take me about a half-day, moving slowly as it's the first time. Is that right? The dealer said they needed a half day to do it.
What am I missing?
Of course while the cover is off I'll check the other seals and the oil pump gasket and replace them as needed.
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If the timing belt has been soaked in oil it should be replaced in my opinion. To answer the remaining questions go to www.endwrench.com for a procedure with pictures. From my experience I suggest you lock ALL the cams as there is too much at stake i.e. bent or nicked valves. This assumes a DOHC engine-right?

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Thanks, Ed. I've read the article and searched the endwrench archive, but there's nothing about how to deal with removing the cam sprocket. Presumably taking off the lock and sprocket will cause the cam to shift unless it's held some other way?
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"Edward Hayes"

I just had a timing belt replaced by a dealer and, ever since then, the engine has a slight knock. [97 Outback Imprezza]
RCM
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Slight knock is hardly a description to help us. Detonation, valve clearance, cam tensioner or engine rod/bearings etc. Tell us more if you wish answers or guesses.

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snipped-for-privacy@here.com says...

If you're just doing the t belt, you can work on it on the ground. If you'll replace the water pump (assuming it's t-belt driven, like a legacy or impreza DOHC), then you'll want it up a bit, probably best on ramps. I'm not sure about working the cam seals.
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CompUser wrote:

What he said.
I pulled the fans and radiator for forward clearance. Having the car up 6-10 inches makes the job easier.
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All good advice. The real experienced Subie techs at our shop do not raise it or remove the radiator. That being said if you want the extra working space remove the radiator, good time for a flush and as said before water pump change. here are my tips. Use a 1/2 inch breaker bar on the crank bolt, place it as close to the drivers side wheel well as you can and bump the starter. Loud bang and the crank bolt is loose. Get the engine to TDC; Subies are real forgiving on the cam drifting when the belt is removed. A good belt will have nice lines for reinstallation. Some use special pliers to pinch and hold the belt to the cam sprockets during installation (picture needle nose vice grips with hoses over the jaws) Remove the tensioner and reset it in a vice. Do all the seals including the crank seal. Are your valve covers leaking? Also not an imposable job but you will need to get at them from the bottom. Getting the belt on can be tricky; some remove a idler pulley and put it back on after the belt is in position
Well, that's all I can think of at this time; got firewood to go cut; good luck
--
Stephen W. Hansen
ASE Certified Master Automobile Technician
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Thank you, Stephen. That's just what I need. I'd just like to re-confirm: Once the motor is at TDC I can remove the belt and the left-side cam sprockets without damaging valves? I have seen the cam lock tool (although I don't have one), but can't use that if I'm removing the sprockets to replace cam seals, right?
An article I read in Endwrench suggested the contrary. It's too cold to commute by motorcycle so I can't risk tying up the car for a week due to bending valves or breaking anything.
I'll look at all the seals. The valve covers are dry. This is definitely an issue with the front seals, and I think only the left-side cam seals are the culprits.
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wrote

Once you remove the belt, one cam useally rotates a bit (right one I think) But just control the speed and only rotate it back, don't go all the way around. Don't overstress on bending the valves, just remember to break the crankshaft loose before any belts removed.
You are right IF this is a dual cam motor, then the tool would have to be removed for the seal change. Also, if one seal is leaking with 255K miles, then the rubber on all the rest are just as dry. many times they can be puled out with a just a hook tool. they are that loose. ALSO sometimes the pullies stick on. use a good rust penatrate if it dosn't come free and be carefull on the cam pullies, they can chip or break if stuck..
--
Stephen W. Hansen
ASE Certified Master Automobile Technician
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Thanks again. This is the twin-cam motor. I will order the parts tomorrow and plan to do the job next weekend.
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BobN wrote:

Don't know what model is being discussed, but the 2002 WRX manual calls for a different approach.

The WRX can collide valves. I'm sure it's somewhat forgiving, but not like some of the other subie engines that won't collide anything no matter where you position things.

WRX manual says to do it in a vertical position. Specifically says to not use a vice. I suspect that applies to all tensioners.
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These are good points. I'll ask the Experienced Techs at work tomorrow on what there opinion is. (These guys do Timing belts and Cylinder head reseals in under 3 hours)
Steve
wrote

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">

Checked with an experienced tech today on his opinions. Subaru Tech training says all dual cams can collide valves, Rex says he knows of this but have never had any problems ever with a bent valve during a timing belt change. The timing marks on a Subaru are set with the pistons 1/2 way down the cyl, no chance of piston contact when doing a subie t-belt by the marks.

Optimally this is the preferred way, but unless you have a special tool for doing this you will end up in the vice and it will work without any side effects.
Steve
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Stephen H wrote:

But you must compress the tensioner VERY slowly and incrementally over several minutes IIRC.
And personally, I would change the tensioner bearing and other rotating/sealing components while I was in there as is typically recommended to be thorough.
Carl
--
to reply, change ( .not) to ( .net)

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On the driver's side of the DOHC engine, the cams are "balancing" on their lobe points and want to release tension and rotate around. When you rotate them back to the alignment marks, you can either turn them a "short way" (maybe 90* or so) or the "long way" (270* or so). The information I've seen warned to NOT rotate them the "long way", to prevent valve damage.

The FSM and Endwrench stuff is pretty picky about compression--only in a vertical plane, slowly, etc. I used a vice to hold the tensioner body and compressed the plunger with a C clamp...easy enough.
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Compressing the tensioner sideways as not recommended and can introduce air. The air may not cause problems until thousands of miles later. Subaru factory is adamant about using only vertical compression and at a max force of ~50 lbs. Foolish to outguess the factory on this critical component with so much at stake. JMO Ed

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BobN wrote:

Hi,
Without getting into the nuts and bolts of the operation (my EA82 engine's a bit different than yours, but all the operations you've mentioned can be done from above on mine--I'm not familiar w/ your engine), let me suggest you do yourself a favor and don't go half-arsed on the parts replacements:
** AUTOMATIC replacement list when I'm getting in that far--
-Cam seals (both sides)
-Oil pump seals (O-rings on rear, conventional seal on front, search archives for "Loc-tite the rear cover" advice_
-Front crankshaft main seal
-Timing belt(s) (even though yours has only 30k miles, removal and replacement has been implicated in early failures, according to my Subie parts guy. He said they learned that the hard way when they used to "retension" belts and no longer do it.)
** Things to inspect carefully and replace if I suspect them AT ALL--
-Timing belt tensioner(s)
-Timing belt idler(s)
** Something many replace just cuz it's a PITA to do w/o doing the above all as one job--
-Water pump
The added cost of these additional bits is minimal compared to the aggravation of having to redo your work.
BTW, on time: allow yourself a full weekend the first time! Yeah, it's only a half day job. Once you know the ins and outs! The learning curve first time out will eat some time... and you don't want to be stressing while you're learning.
Good luck!
Rick
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