Timing belt issues!

So what causes the belt to turn into this?? The guides have the proper clearance and I can't see how they would leave a mark like this on the belt. Thinking its the main guide on the crankshaft, might have been tight, and is the only thing that I can think of that would damage the belt to that degree in under 1k miles.

 

Trying to track down why my freshly built block shit the bed, most likely an exhaust valve on the passenger side, car started making loud valve tapping sounds then stopped starting.

 

Just drained the oil, no debris, so its probably not a bearing, and judging from the sounds it made it was a passenger cylinder head issue.

 

 

 

I would start by removing the guides and looking for mating rub marks.

Those pictures make it very obvious that the crank gear guide was not spaced properly. Did you use the tool?

Like others have said, likely a guide. I've also seen this happen with an intermittently seizing pulley, but your kit was brand new so that doesn't seem likely.

Like others have said, likely a guide. I've also seen this happen with an intermittently seizing pulley, but your kit was brand new so that doesn't seem likely.

 

Now that you say this, why's that tensioner pulley have rust on it? Especially as much as it does, for only having been in use for a thousand miles.

That's a strange sight for <1k miles.

- There are a lot of blue belt deposits on the pulleys.

- There is a lot of rust on the pulleys.

- It does look like at least one of the guides is just too close, but if it was rubbing 100% I would have expected it to have worn more than just turning it black.

I’ve seen those coating come off after some mileage.

I normally use a credit/bendable card as a spacer with no issues between all the guides.

 

 

Sent from my iPhone using Tapatalk

the rust on the tensioner seems like its just surface rust. couldn't tell you why!

 

Theres a tool for the crank guide?

looks like the driver side guide had a loose screw. Im trying to see if my valve issue is timing related or just cylinder head related.

I thought we decided that blue belt was a "no no" years ago...? Just saying.

I thought we decided that blue belt was a "no no" years ago...? Just saying.

 

First I've heard this. Do you happen to know why the blue belt is a no no?

^I remember this too! Not sure why, read here though.

It was because they were sluffing off the backing material onto the pullys.

I just pulled mine after 100K and had none of this happen.

Will I go back in with another blue belt kit. Probably not.

It's a street car.

ugh! blue belt is no bueno because blue stuff comes off leaving gunk everywhere. its a cosmetic thing. original design it stayed on, now not so much.

 

company23 sells a guide kit. the factory manual has guide info too.

 

those guides look really tight. lock tight?

I remember vaguely but not sure of the reason other than blue crap going everywhere.

 

I think i'm done with these belts lol, they cost to damn much, I have like 3 of them laying around all with under 1k miles on them. The marks disappear making it impossible to reuse....,. but motor is designed to go up to 8k rpm, so I wanted the kevlar belt, opinions?

Edited May 12, 2022 by Tehnation

why IS my tensioner rusting? is this some cheap knockoff?

Is it an oem tensioner? I onlu use oem timing components. Too critical parts.

Any coolant leaking anywhere?

I believe it is oem, oem or the aisin one.

 

No leaking coolant, well not from leaks but I was playing with the coolant temp sensor, but I don't think the coolant could have gotten past the cover.

 

Its the AISIN BTF-500

 

Thats according to orders I made, but it says ntn on the actual tensioner... tbh I have like 2 or 3 tensioners so who knows at this point lol.

Edited May 12, 2022 by Tehnation

Judging by the surface rust on other components in that picture, it may just be where you live. Those things dont rust like that here in the PacNW. One nice thing about the blue, is that it's suuuuper obvious the guides are too tight. I don't think you need a kevlar belt to rev that high. Isn't there a JDM motor that revs pretty high? OE is likely good enough, but definitely stay away from gates in general.

Yeah it's not just the tensioner rust that has me going wtf, but the rust on other timing components and belt guard as well. Is your center timing cover missing the gaskets?

https://parts.subaru.com/a/Subaru_2005_Legacy-25L-TURBO-5MT-4WD-GT-Limited-Sedan/_54102_6030209/TIMING-BELT-COVER/B13-022-02.html

Got all the rubber gaskets.

I had a timing belt tensioner fail on me 10 years ago. I got lucky. No bent valves..

 

Did you check our valve clearance since you believe there is a valve related issue?

Going to check the lashes as soon as I can find my feeler gauge. Been looking for 1 of them all day, i got a bunch laying around somewhere.

 

I'm hoping the head is fine and the piston took the beating, its forged and softer so hopefully it took the brunt of the damage.

So I pulled the headers and intake to take a look inside the heads, and I see this crap in the passenger head hot side (where I heard bad noises ). Some kind of debris at the bottom where valve seals. Could just be crap from the exhaust manifold and turning engine upside down a couple times made it fall in there.... who knows!?!

 

 

Gotta pull the passenger head!

 

Would bad belt guide tolerances cause timing to jump?

Edited May 15, 2022 by Tehnation

I don't think it should. That's the tensioners job.....right?

 

Sent from my SM-G996U using Tapatalk