Timing belt tensioner...good or bad???

[buschiniowa]

I've rebuilt my 2.5 twin cam boxer and replaced the timing belt and one bad idler. I believe that my tensioner also needs to be replaced, but wanted to get a second opinion from Y'all. Here's the situation.

 

The cam sprockets for cylinders 1 & 3 are aligned to the timing marks properly.

 

I've counted the timing belt teeth from the intake to the crank, and from the crank to the timing mark on the (intake) cam sprocket for cylinders 2 & 4.

 

However, the timing marks on the intake and exhaust sprockets for cylinders 2 & 4 are a little "behind". It's hard to explain but basically it appears that the 2 & 4 cylinder bank is off by a tooth or two, but by counting the teeth, it's not. However, if the tensioner was putting more tension on the belt, it would result in turning the cams in the correct direction to make the timing marks line up. So, with all that said, I'm 95% sure that I need a new tensioner. The only thing that gives me pause is that this tensioner is pretty strong yet. I put a small nail in it to hold it closed and it's strong enough to bend the nail as soon as I release it from the vise.

 

I'm going to post picts on photobucket here in a few minutes. Check back.

 

Thanks for reading!

[idosubaru]

the new style tensioners fail fairly often. unless it's a really crappy car i replace them as a rule, a used new-style tensioner that's got 100,000+ miles on it and 10 years old is not worthy of another reliable 100,000 miles, i've seen too many fail to count on them. i either replace or install an older style tensioner that generally don't fail - but even they are getting aged and not really worth it either.

 

i would replace it anyway. the ebay timing belt kits have all new pulleys and tensioner for a good price, that's what i usually use.

 

if you're still amped to mess with it:

is it an aftermarket or Subaru belt?

are all the cam sprockets positively installed on the right cams?

rotate the engine a few times by hand - any settling, any difference?

 

the marks on the pulleys are what matters. if you're having issues i would ignore teeth counting myself. install the belt, release tensioner and rotate engine a few times by hand. do the marks still line up?

[1997reduxe]

It's just my opinion, but if one idler was bad, then I would have immediately replaced all of them, and water pump etc.

I just got a great deal off of ebay for $200, where I got a Continental pro timing belt kit with all idlers and new tensioner, (I'm assuming all are oem or better as that's how the Conti parts are; I even called Continental and spoke to one of their engineers, he seemed really shocked that a customer would even find his name, let alone call), and he told me the wp was Aisin, which it was when I got it.

The way I look at it is that since you have all those parts off of the front of the engine, take the time and money to do it right, as then you can prevent the future need to take apart, to for example have to go back in and replace a cheapo water pump, AND have to take the chance on some yahoo doing it if you are out in the boonies, etc.

When I was looking around for my tb kit I talked to one parts dealer who said one time he had a pulley seize on him, and it actually pulled out of the entire block, ruining the engine due to the big hole in it.

The thing I've found about suby oem parts is they are so well engineered they last an awful long time, even when they're a long way toward failure. Just don't take advantage of it (I tell myself)

'97

[buschiniowa]

Replaced the timing belt with a OEM subaru belt. I only replaced the one pulley because the bearing was rough and loud. All others smooth, quiet, and tight.

 

Gary, I turn the motor over and the timing marks on cylinders 2 & 4 always end up just a bit late. I've posted pictures on photobucket. I'm now 99% confident that I'm I need to replace the tensioner. It's always nice to get a second, third, or 20th opinion before spending money!

 

Posted pictures at:

 

http://s1094.photobucket.com/profile/jbusch4alliniowa

 

Thanks

[1997reduxe]

yeah, but like i was saying, the interval to replace belts is like 80 or 100k, right? so the question isn't if they're good now, it's whether you'll feel comfortable with them 2 or 3 years from now.

that;s all

'97

[WoodsWagon]

When doing a belt job, replace the timing belt tensioner, the water pump and the 3 other idler pulley's.

 

The newer arm with a vertical piston tensioners fail the most often, followed by the cogged tooth idler pulley next to the water pump, and then the water pump itself.

 

If the pump fails, it usually siezes so the engine overheats but doesn't jump time. If the cogged tooth idler goes, then the engine will often jump time and the idler grinds into the side of the oil pump. If it's an interferance engine, jumping more than a tooth or two on the cams will cause valves to hit pistons and bend.

 

theimportexperts on ebay seem to be a good source of good timing belt, tensioner and idler sets.

[1997reduxe]

yeah...i got a kit from the import experts on ebay before, but as i said you gotta ask who makes the water pump, and back then i believe john here told me that you should ask them for the german belt they sell, which meant the Continental (Conti-tech) belt. It is strange because I thought I got the better Conti belt of course with my recent Conti kit, and then it said "Made in Mexico" on it. One of the things I learned in researching the Conti belts is I believe the best ones nowadays are HSN or "highly saturated nitrile". I believe now they are looking to make belts to last 200000 miles plus...

http://www.conti-online.com/generator/www/com/en/continental/pressportal/themes/press_releases/1_topics/fairs_events/salon_geneva_2005/ct_salon_geneva_en.html