I changed out original 276K motor with used 76K . Outback is 5 spd manual. Did all wear point replacement and of gaskets / 5 Star HG. Car had been running great. Normal MPG 28 or so. No symptoms displayed before breakdown.   Sold to my friend and has now come back to me for the repair.    I did not use a genuine Subaru timing belt so that is in the back of my head.  Compression is about 50% ~ 110psi. No spark with induction timing light.  Car sounds different than I remember when turning over also.  Oil is clean. So any other suggestions before I start disassembly?  Any experience with premature timing belt failures?  This was my 5th Subaru timing belt and easiest since I had the motor out. So could the belt have slipped one tooth and reduced the compression?  Why no spark with an induction timing light?  Any advice appreciated.

yeah, pull the covers and check timing - maybe just slipped if no bad noises.

 

bad tensioner, bad idler, cracked cam pulley.....anything thing that confuses the cam/crank sensor 'pulse timing' and the ECU will kill starting I think

Did you put the timing belt guide over the crank sprocket on the new engine? If the car rolls backward in gear it can slip the belt without that guide....

 

GD

Yes, GD. That keeper is in place, case you get bumped from the rear normally.  Well now I can make my post more interesting.  This was catastrophic failure.  Belt broke cleanly in one place, showing its fibers.  Only had one other timing belt even fail on me - 86 Honda Accord but it just slipped a tooth.   I checked all of the pulleys and do not see any sign of freeze-up.  All of it was replaced with the TB replacement 14K miles ago, Cam gears do not feel frozen and move with normal resistance.  I am also aware of the interference fit design so this cannot be good.  I am however curious enough to consider putting one of my used timing belts back on and do a compression test.  If magically if it comes out to 220 psi per cylinder - unlikely???? - .  At minimum it would allow me to ensure the engine rotates around freely before pulling the heads.   Ever seen anything like this?  This car was running great until this happened.  This is highly disturbing. If the engine rotates smoothly with TB belt in place, what could possibly cause this kind of failure?  I have been reading the discussion about parts - about them not being equal - I admittedly was on a budget when I did this engine work last year. I do not think I will be so cavalier when buying key engine parts again. 

 

Never thought this could happen at 14 K miles.  Further detail on the compression test.  My friend had Outback towed to Pep Boys at first.  They did compression test and reported 50% compression and gave 4 readings.  I verified their test and got zero at #1 piston. I went no further then pulled engine covers and found the broken belt.  Very suspicious they were able to get compression readings on all 4 cylinders with a broken timing belt.

Edited June 6, 20178 yr by hzimmerman1111

It will have many bent intake valves. This is easy to tell by simply rotating the cam sprockets. There will be obvious massive play and knocking noises as the valve lash is very large due to bent intakes.

 

Can also pop the valve covers off and see the loose rockers....

 

It doesn't take towing it anywhere or compression tests. The tests are simple and visual.

 

GD

Edited June 6, 20178 yr by GeneralDisorder

 I did not use a genuine Subaru timing belt so that is in the back of my head.  

 

Doesn't have to be original, but should be grade A quality brand name.

 

I personally only use Mitsuboshi or Bando.  Continental also seem to be good but I've seen some where the alignment stripes where not right on the proper part of the tooth.

 

But definitely stay away from any cheap belts.  Especially if it comes with a whole kit from China or Philippines or whatever.

Changed out TB with a Mitsuboshi brand and replaced all rollers (except water pump which I hope I do not regret later). Started up OK and runs strong.  Now getting a P0171 code.  BTW those curious, the valve clearances were crazy large and when I got the heads off and sure enough, #4 was the worst but all intake valves exhibited bending so bad and obvious gaping open about 2 mm where they couldn't possibly seal. 

 

If I can find and solve the PO171 fault [sYSTEM DETECTS LEAN FUEL MIXTURE - BANK 1 ]  this one is behind me. Moral:  PAY ATTENTION TO TIMING BELTS!!! BREAKING ONE CREATES A LOT OF REPAIR WORK on the interference engines.  Further, if you have a TB like the one above with those picture markings (and wish I could find the manufacturer), do not use it! 

The P0171 is simply a vacuum leak. It's causing the MAF reading to be low and the closed loop O2 sensor readings are causing it to add a bunch of fuel to compensate unmetered air getting into the engine. You can watch fuel trim to see this - it will be high positive at idle, and will come down closer to zero as you rev the engine. Some hose is disconnected or loose most likely. 

 

GD

Edited June 27, 20178 yr by GeneralDisorder

Right GeneralDisorder on your diagnosis!, Found that lower edge of the air box collar to throttle body was curled under, making a straw-like passage for the air to pass through and hence the entrance of unmetered air causing the P0171.  I reinstalled it more carefully.   Have about 130 miles on it now and no codes.  Thanks all for their posting input during this Outback repair.

Guys, so how often should this fiber belt be replaced?  My H-6 '03 has 151,000 and has never been touched. 

 

Running until it finally lets loose does not strike me as a very good idea. 

H6's don't have a timing belt.

 

GD

Guys, so how often should this fiber belt be replaced?  My H-6 '03 has 151,000 and has never been touched. 

 

Running until it finally lets loose does not strike me as a very good idea. 

 

What he said - that engine doesn't have a timing belt, it has a timing chain which doesn't require replacement.  

To answer your question "this" engine in this thread requires timing belt replacement every 105k,105months

Guys, so how often should this fiber belt be replaced?  My H-6 '03 has 151,000 and has never been touched.  

Guys, so how often should this fiber belt be replaced?  My H-6 '03 has 151,000 and has never been touched.  

 

 

Guys, so how often should this fiber belt be replaced?  My H-6 '03 has 151,000 and has never been touched.