Timing belt WTF?

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subytech
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Timing belt WTF?

Post by subytech »

So a friend and I bought this 93 L wagon to fix the oil leaks and the blown head gaskets and sell to a friend. Yesterday we pulled the engine and started to tear it down. When we got the timing belt covers off we found this!

Image

Image

In 5 years as a Suby tech, and the years since doing side jobs for friends and family I've never seen this before? The belt was wearing on the back (block side) ridges of the crank and cam gears. I thought at first that it was because the idlers had no back stop ridges like the newer cars do, but once I thought about it a bit I think I've seen cars run like this before and be fine, anyone seen this before?
92 Legacy Turbo, 5sp MT, Early Large CC 20G heads, Ported custom clocked td04, Cobb catted DP, Injen SS 3" exhaust, Turbosmart MBC @ 10psi, Apexi 20g intake, custom FMIC, Fidanza 11lb flywheel, stock 05 WRX clutch
rallyak
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Re: Timing belt WTF?

Post by rallyak »

Where exactly is it rubbing? Is the adjustable idler square with the belt? In the pic it looks like its not square (tip in on the bottom), I'm sure you've checked that.
Charles

90' White/Gray Outback DD workhorse (670,xxx) miles
92' Onyx Metallic (430,xxx) Wife's DD
68' Barracuda formula S 340 4spd coupe (ongoing project)
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subytech
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Re: Timing belt WTF?

Post by subytech »

On initial inspection all the pulleys seem to be square, but we will double check for sure. It's rubbing on the back (engine block side) of the crank and cam pulleys. If you look close in the first pic you can see they are almost mirror polished on the inner lip.
92 Legacy Turbo, 5sp MT, Early Large CC 20G heads, Ported custom clocked td04, Cobb catted DP, Injen SS 3" exhaust, Turbosmart MBC @ 10psi, Apexi 20g intake, custom FMIC, Fidanza 11lb flywheel, stock 05 WRX clutch
Legacy777
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Re: Timing belt WTF?

Post by Legacy777 »

Wow! I've seen a t-belt shred from a frozen idler gear, but that's pretty crazy.

I'd suspect the belt started wearing or got snagged and once width was reduced enough so cam pullies no longer kept the belt centered, the belt just started walking around.

I'd clean everything up and put on a new belt, then keep an eye on things.
Josh

surrealmirage.com/subaru
1990 Legacy (AWD, 6MT, & EJ22T Swap)
2020 Outback Limted XT

If you need to get a hold of me please email me rather then pm
subytech
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Re: Timing belt WTF?

Post by subytech »

Yea that's what I was leaning towards too
92 Legacy Turbo, 5sp MT, Early Large CC 20G heads, Ported custom clocked td04, Cobb catted DP, Injen SS 3" exhaust, Turbosmart MBC @ 10psi, Apexi 20g intake, custom FMIC, Fidanza 11lb flywheel, stock 05 WRX clutch
robertpaige
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Re: Timing belt WTF?

Post by robertpaige »

That is gnarly looking. Wow.


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subytech
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Re: Timing belt WTF?

Post by subytech »

Update:

We started final reassembly yesterday and I found that the bushing in the timing belt tensioner pulley seemed a bid loose in its bore so we swapped it the crank and the cam pulleys out for ones we had laying around (cam pulleys have rubber almost imbedded in them, I need to blast them clean, crank pulley had worn a weird edge in it so better safe then sorry). I also found that the lower idler pulley on the passengers side of the block had been very badly cross threaded when it was installed last time. We took it apart with impact guns so we didn't notice this the first time, so out comes the helicoil kit! Still would have liked to get some more definitive evidence but I'm fairly confident we've fixed it.
92 Legacy Turbo, 5sp MT, Early Large CC 20G heads, Ported custom clocked td04, Cobb catted DP, Injen SS 3" exhaust, Turbosmart MBC @ 10psi, Apexi 20g intake, custom FMIC, Fidanza 11lb flywheel, stock 05 WRX clutch
Legacy777
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Re: Timing belt WTF?

Post by Legacy777 »

Yeah, it sounds like all those things could have contributed to the timing belt getting off-kiltered a bit.
Josh

surrealmirage.com/subaru
1990 Legacy (AWD, 6MT, & EJ22T Swap)
2020 Outback Limted XT

If you need to get a hold of me please email me rather then pm
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