Questions re timing belt/seal replacement

[BobN]

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.

 

[Edward Hayes]

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?

 

[BobN]

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?

 

[RPM1]

"Edward Hayes"

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?

I just had a timing belt replaced by a dealer and, ever since then, the
engine has a
slight knock. [97 Outback Imprezza]

RCM

 

[Edward Hayes]

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.

"Edward Hayes"

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?

I just had a timing belt replaced by a dealer and, ever since then,
the engine has a
slight knock. [97 Outback Imprezza]

RCM

 

[CompUser]

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 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.

 

[Stephen H]

What he said.

I pulled the fans and radiator for forward
clearance. Having the car up 6-10 inches
makes the job easier.

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
ASE Automobile Advanced Engine Performance
ASE Undercar Specialist
Currently working at a Subaru dealership

http://autorepair.about.com/cs/troubleshooting/l/bl_obd_main.htm
http://www.troublecodes.net/technical/
http://www.familycar.com/Alignment.htm

 

[BobN]

Get the engine to TDC; Subies are real forgiving on the cam drifting when
the belt is removed.

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.

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.

 

[Rick Courtright]

Of course while the cover is off I'll check the other seals and the oil pump
gasket and replace them as needed.

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

 

[Jim Stewart]

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.

What he said.

I pulled the fans and radiator for forward
clearance. Having the car up 6-10 inches
makes the job easier.

 

[Stephen H]

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?

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
ASE Automobile Advanced Engine Performance
ASE Undercar Specialist
Currently working at a Subaru Dealership

http://autorepair.about.com/cs/troubleshooting/l/bl_obd_main.htm
http://www.troublecodes.net/technical/
http://www.familycar.com/Alignment.htm

 

[BobN]

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..

Thanks again. This is the twin-cam motor. I will order the parts tomorrow
and plan to do the job next weekend.

 

[Kurt Krueger]

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.

 

[Stephen H]

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

 

[Stephen H]

">

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.

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.

WRX manual says to do it in a vertical position. Specifically says to
not use a vice. I suspect that applies to all tensioners.

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

 

[Carl 1 Lucky Texan]

">


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

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

 

[CompUser]

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.

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.

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.

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.

 

[Edward Hayes]

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