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Timing Belt removal cam calibration to marks


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This is a 98 2.5L DOHC.

I have the timing belt ready in position and ready to remove, engine on the stand. The marks are all lined up. Of the 5 mark positions, most line up pretty dead nuts except for 1 sets of double marks that don't line up quite exact on the left side cams. They are a degree or two off from lining up with each other however they are , close but not exact. Whoever changed the belt before (I think I only had it changed once before at the dealer) ran a single white line over the double marks as a reference to line then up. I will count the teeth before I take it off to be safe. I made paint marks on each pulley, cam and crank sprocket in relation to the belt. Since the last mechanic did the job with the engine in the car, I figure it is possible a cam got slightly out of position.

The question is how do you know each cam is perfectly lined up. I don't want to assume the last guy did the job right or he didn't have a cam slightly move on him then he reinstalled the belt . The cam to cover alignment marks have to be a good general reference indicator that things are lined up in relation to the TB. It doesn't necessarily seem to me that it is an definite indication that each cam is adjusted in the perfect position. Seems that checking each cam lobe individually in relation to each corresponding lifter while rotating the crankshaft may be the way to verify this. I also thought of checking compression on each cylinder before removing the belt to verify this, but not sure if that is the best way either.

 

I decided to get the service tool to lock the cams in place before removing the belt to be safe. Has anyone done this without the cam lock service tool? The dealer says to grab the pulley by the hand and use an impact wrench. They only use the locking cam tool when changing the belt in the car because they can't get an impact in there due to clearance. Seems to me that a cam can easily slip which can be taking a gamble.

Any thoughts?

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keep in mind this isn't like reading a ruler. you can't be "a little bit off" if it's installed properly - the design of the teeth mean it's either right or wrong. it's not like you can be a "little bit off" in the sense that it's not lined up right. if you line the marks up properly, you're fine.

 

install it using the marks, personally i ignore any hand made or added marks. the marks on the engine are exact, use those. they work %100 of the time, or should assuming nothing is abnormal about the whole deal.

 

i do them all by hand, i certainly don't have the "special tool", it's not needed. frankly the first DOHC i did was easy and i didn't have a problem at all getting them all lined up. i have done tons of other Subaru's though so that helps, but still the DOHC wasn't really any more difficult, just some extra parts to line up.

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I use Dayco belts and on the DOHC's they look like they don't quite line up. I thought it was me. The first few I kept removing and redoing the belt (which meant recompressing the tensioner, etc).

 

I didn't realize the Suby belts lined up better until I had a Suby tech do a 2.5 DOHC TB job for a friend of mine. He had never used a Dayco and had the same alignment issues that I have every time. Since he's used to only OEM parts he hadn't seen this. He called me to see if I had this happen to me since he knows I've done a lot of them with the Dayco belts.

 

So if you're paranoid at all I'd spend the money on the dealer belt. IIR the marks on the cam pulleys on the drivers side where they point to each other is where they didn't exactly match. I have a pic on my laptop somewhere but I doubt that I can find it easily.

 

I've still never used a Suby belt of any kind.

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The problem here is that two of the pulleys that are supposed to align with the double marks are not quite aligned. All the other marks are aligned though. That's why I was wondering if when I remove the belt I should try to realign them to the exact match or align them to the slightly off position they are not in. An Endwrench article says they might not align perfectly, but also states they all need to be aligned perfectly, which they are currently not.

 

Also, is it easier to loosen all the pulley bolts prior to removing the belt or is hand strength good enough to hold after removing the 1st pulley and TB while loosening the pulleys and sprockets?

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I use Dayco belts and on the DOHC's they look like they don't quite line up. I thought it was me. The first few I kept removing and redoing the belt (which meant recompressing the tensioner, etc).

 

I didn't realize the Suby belts lined up better until I had a Suby tech do a 2.5 DOHC TB job for a friend of mine. He had never used a Dayco and had the same alignment issues that I have every time. Since he's used to only OEM parts he hadn't seen this. He called me to see if I had this happen to me since he knows I've done a lot of them with the Dayco belts.

 

So if you're paranoid at all I'd spend the money on the dealer belt. IIR the marks on the cam pulleys on the drivers side where they point to each other is where they didn't exactly match. I have a pic on my laptop somewhere but I doubt that I can find it easily.

 

I've still never used a Suby belt of any kind.

 

Great, thanks for the info, the double marks are the ones I was referring to.

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i've always removed the cam bolts with the timing belt in place, it's been enough to hold. get the marks lined up before trying to remove the bolts, if the cams happen to slip for some reason, it should only slip a bit and it's not in a position to cause interference i don't believe. i don't think you'll have "interference" even if it did slip a tooth when all the marks are lined up.

 

since you have the engine out and this is your first time, just remove the valve covers and use the flat spot on the cams and hold that with a wrench to remove the cam bolts. go ahead and replace the valve covers, now is a good time anyway with the engine out.

 

i wouldn't worry about the belts not lining up, i've seen this before even in 80's vehicles. it's annoying, but it happens. there is always one "position" that is closest, that will be the correct one.

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How was it running before? It is always possible the existing belt is a tooth off somewhere along the line.

 

Well, that is why I posted to being with. The Endwrench artile on the 2.5's show state some of the marks can be off in relation to the ref mark on the cover due to production stamping, however the article also emphasises that the you need to be accurate and there is no such thing as close.

 

I believe after reading DaveB's post that I will find that if I try to fine tune or re-align the double marks, that they won't work. In relation to the center-center positioning of each tooth on the belt, I am taking about a few degrees off on the positioning of the double mark alignment of cams. Sounds like that can be normal.

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i've always removed the cam bolts with the timing belt in place, it's been enough to hold. get the marks lined up before trying to remove the bolts, if the cams happen to slip for some reason, it should only slip a bit and it's not in a position to cause interference i don't believe. i don't think you'll have "interference" even if it did slip a tooth when all the marks are lined up.

 

since you have the engine out and this is your first time, just remove the valve covers and use the flat spot on the cams and hold that with a wrench to remove the cam bolts. go ahead and replace the valve covers, now is a good time anyway with the engine out.

 

i wouldn't worry about the belts not lining up, i've seen this before even in 80's vehicles. it's annoying, but it happens. there is always one "position" that is closest, that will be the correct one.

 

One more comment here, I am the orig owner and the engine after 11 years and 108k miles seems to run as good as when I bought it. I am questioning this from what I read in the Endwrench article which states if the cams or timing belt is off a bit, the car will still run, but may not be optimized for proper burn. The fuel effic. will not be optimized and that is really what I am concerned with, to make sure it is dead nuts accurate.

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I counted and verified all the belt tooth positions, and made extra paint marks on the belt, cover and sprocket pulleys. Then loosened all the pulley bolts and cam sprocket bolts, with the belt still installed, no problem. I removed the lower belt idler and when the tension came off the LT-in and LT-EX cam sprocket pulleys, they sprung back so apparently I should have used the cam lock tool after all. The LT-In & LT EX cam sprockets came right off with no effort, but the RT-IN & RT EX cam sprockets are frozen in place on the shaft. Has anyone had any luck removing frozen cam sprocket pulleys such as these without a pulley puller?

 

With the cam sprockets all back in position, it seems that it only takes a slight shock or vibration for the (loaded) sprockets to move again. Is it safe to unbolt the cam bolts and remove them in this position?

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I counted and verified all the belt tooth positions, and made extra paint marks on the belt, cover and sprocket pulleys. Then loosened all the pulley bolts and cam sprocket bolts, with the belt still installed, no problem. I removed the lower belt idler and when the tension came off the LT-in and LT-EX cam sprocket pulleys, they sprung back so apparently I should have used the cam lock tool after all. The LT-In & LT EX cam sprockets came right off with no effort, but the RT-IN & RT EX cam sprockets are frozen in place on the shaft. Has anyone had any luck removing frozen cam sprocket pulleys such as these without a pulley puller?

 

With the cam sprockets all back in position, it seems that it only takes a slight shock or vibration for the (loaded) sprockets to move again. Is it safe to unbolt the cam bolts and remove them in this position?

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  • 1 month later...

Ok, I've been reading this old thread (and many others online) and I hope one of you guys is still around to answer my question because this is the most informative thread I've found....

 

I have a 2000 Outback, 2.5L SOHC.

 

Q1) with the belt off, how do I make sure the cams and crank are aligned properly? I understand about the tick marks...I'm more concerned with which way to I turn things to get them right. The RH cam is aligned, the crank is aligned ("square" mark on sprocket matches with the tick mark on the gear attached to the back of the sprocket, which is aligned with the mark on the oil pump) but the LH cam tick mark is about 40 degrees past alignment. I dunno whether to turn it counter clockwise or clockwise to align it.

 

 

Q2) the document referenced earlier in the thread (TBeltEWWin05.pdf) mentions that there should be 44 teeth between the RH Cam and the crank and 40.5 between the crank and the LF cam. The yellow lines on the belt I purchased, which exactly matches the old one, does not have this spacing. It is spaced 47 & 44. I don't know how to handle that, or if something is just way wrong. Both belts are exact...223 teeth each. The new belt is a gen subaru part, so I don't understand why it's different. Does the teeth count really matter as long as everything is aligned to the proper ticks?

 

 

thanks....

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thanks, that makes me feel better.

 

Seeing as how the new belt was identical to the old one, I put it on despite my questions and the lines on the new belt matched the tick marks exactly. Spun it by hand a few times and I don't hear anything hitting, so I think I did a fine job...I'll find out tomorrow when I start it up I guess.

 

Interesting that you pointed me to that post...that guys situation is identical to mine...the bearings on my toothed idler blew out (luckily I was just sitting in my driveway), but it remained somewhat in place and the belt didn't pop off.

 

I wonder what it is with the toothed idler; mere coincidence or a symptom of a larger problem.

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fired up perfectly...though I was scared for a little while there before I remembered to reattach the ignition coil!

 

Bubu has a nice quiet hum now; but the emergency brakes being engaged for 4 months was apparently not a good thing. Time to go fix that...

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