Timing belt direction

[bobko]

I just replaced the timing belt on my car over the weekend and, when it was all back together, couldn't remember if I got the belt installed in the correct direction. I know that it's not hard to check the direction and I'll do that. But is it safe to run the car if the belt is on backwards? Assuming the belt is on backwards and I've run the car for 500 miles, can I re-install the same belt in the correct direction and expect it to last? Or do I need a new belt?

The car is running fine, BTW. It's a 1995 Legacy with the 2.2L engine.

Thanks for any answers!

--Bob

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[ciper]

Assuming you have the engine timed correctly there will be no issue with the belt running "backwards"

[bobko]

Originally Posted by ciper

Assuming you have the engine timed correctly there will be no issue with the belt running "backwards"

Just to be clear, the belt is marked with arrows that indicate it is supposed to run in a specific direction, just like tires that are directional. I'm wondering if it will damage the belt if it runs in the opposite direction.

--Bob

[Storm]

No, it won't make any difference. I believe the arrows are there to indicate the running direction for proper positions of the marks on the belts. IE: If it's backwards, the belt marks won't line up with the engine timing marks.

Physically, there is nothing special about the direction the belt runs.

Jay

[bobko]

Ah... thanks. I never noticed that there are timing marks on the belt. I just lined up the crank and camshafts and figured that was it.

--Bob

[Storm]

Originally Posted by bobko

Ah... thanks. I never noticed that there are timing marks on the belt. I just lined up the crank and camshafts and figured that was it.

--Bob

This tells me you reinstalled a used belt. The marks are on new belts to ensure you have the correct number of teeth between each timing mark, which also need to be lined up to the motor marks. If the tooth count is wrong but the pulleys still match the motor, the tensioner will pull the motor out of time and either run bad or not at all. The marks also make the process alot easier. Your car is running now, but it might be a good idea to put a new belt on soon.....Any Subaru motor after 1997 is going to be interference....so you don't wanna end up with bent valves. Food for thought anyway.

Jay

[bobko]

Originally Posted by Storm

This tells me you reinstalled a used belt.

No, it was a brand new belt, from Gates. I did notice that it had arrows on it that indicated the direction of rotation and there were other markings, such as the part number. I just never noticed that there were markings that indicated timing locations.

The belt went on perfectly, once I followed the instructions in the Haynes manual. The car runs normally.

Are you saying that my 1995 Legacy's engine is not an interference engine? That's good to know.

--Bob

[Ioku]

It shouldn't matter what direction you put the belt on if its new, but its a good idea to mark the direction of a used belt if you have to take it off so it goes back on the same way.
And your 1995 ej22 will be a noninterface engine to no worries about bent valves.

[Storm]

Correct.....pre-97 SOHC motors are non-interference. After 97, they became interference design. All EJ25's are interference.

Odd that the Gates belt didn't have hashmarks for the pulley timing marks to line up with. Hmmmm.

The important thing is that your motor is now running fine!

Jay

[ciper]

You should use the timing marks on the cam/cover only as a reference! It is possible to be of by a tooth on all four/two cams if you do it without using the belt marks or counting teeth. If I was you I'd grab a flashlight and a pick and start counting.

[bobko]

Originally Posted by ciper

You should use the timing marks on the cam/cover only as a reference! It is possible to be of by a tooth on all four/two cams if you do it without using the belt marks or counting teeth. If I was you I'd grab a flashlight and a pick and start counting.

Funny that the Haynes manual didn't mention using marks on the belt itself to line things up. It only mentioned lining up the crank and camshafts. My old Subie has just two cams, FWIW.

The car is still running fine and I've put 1,000 miles on it. In fact, it might be my imagination but it seems quieter than it ran before I changed the belt. (I also replaced the two accessory belts, so one of the three might have been making some noise.) However, I will check the timing belt at my next opportunity. It's vacation season for me, so it will be a few weekends before I can get to this car, and I have to do a timing belt in another car (not a Subaru) first.

Thanks for all the help and advice!

--Bob

[ciper]

I think Haynes also had the incorrect torque specification that killed a huge number of Subarus. The torque value was too low and eventually the crank pulley would wobble and destroy the keyway. The car will still run fine but without splitting the case the engine is now junk.

I suggest 110ftlbs if not more.

[Jerry Xu]

In fact, it is so easy to miss a tooth. It was actually easier to install the belt with an extra tooth on the top section. The correct fit is a very tight, precious fit, particularly with a new belt. So if you used no marks, it is recommended that you re-count the teeth to make sure. By now even if you have the marks, they have shifted. But the tooth count is the ultimate and there is no direction as said before.

If you don't want to do a tooth count, you can try lining-up the 3 sprockets in the up position. If they line up perfectly, you already have the right tooth count.

Jerry

[ciper]

For the SOHC engine its 44 passenger and 40.5 on driver IIRC. Here is a document that covers the ej22 install but I didn't see mention of the tooth count http://endwrench.com/images/pdfs/2.2SingleOverWin01.pdf

edit: FOUND IT for the ej22! Page 15 of this document http://endwrench.com/images/pdfs/TBeltEWWin05.pdf says

Note: Here’s a great check — there should be exactly 44 teeth between the mark on
the crank sprocket and the one on the passenger’s side cam pulley, and 40.5 teeth
between the crank mark and the driver’s side cam mark.

For the DOHC engine check page 18 of http://endwrench.com/images/pdfs/2.5Timing.pdf

By far the most accurate method of determining proper belt alignment is to
count the belt teeth. This diagram illustrates the tooth counts for all five timing
marks. Tooth count Z1 is 54.5 teeth. This measures from the crankshaft pulley
timing mark to the right (upper) intake camshaft sprocket timing mark. Tooth
count Z2 is 51 teeth. This measures from the crankshaft pulley timing mark to
the left (upper) intake camshaft sprocket timing mark. Tooth count Z3 is 28 teeth.
This is the number of teeth between the (upper) intake and (lower) exhaust
camshaft sprocket timing marks. The Z3 tooth count is the same for both the left
and right sides of the engine because the same relationship must be maintained
between the upper and lower cams on both sides of the engine.

[bobko]

Originally Posted by Jerry Xu

If you don't want to do a tooth count, you can try lining-up the 3 sprockets in the up position. If they line up perfectly, you already have the right tooth count.

Yeah, I wasn't looking forward to a tooth count, so I wondered if I could just check to see that everything was lined up. That's not too hard in my car, so that's what I will do when there is time.

This is the second time I've replaced the belt in this car and didn't use belt marks previously. It ran fine for 60,000 miles, when I decided it was time to replace it again.

Thanks, ciper, for the tooth count. I wondered about that, too.

--Bob