2005 Matrix exhaust cam pin sheared

[1redtex]

Hello everyone. Has anyone experienced this? 2005 base model Matrix 185k miles has new timing chain tensioner,oil level stays full does not burn any oil,and been running fine no CEL's etc.I was accelerating on the on ramp around 6k rpm then engine died.I think this is what happened but not sure why yet.It looks like the exhaust cam thrust collar was galding to the front bearing cap ,the knock pin sheared between the exhaust cam and cam gear,cam gear bolt appears stretched nearly sheared,cam timing slipped enough to quit running and timing chain tensioner ratched to next groove (chain way too tight).The only thing funny is that I just bought a 2000 Celica for a father son project with the exact same problem.If this is really rare how did I get two of them?

[fishexpo101]

To happen once is quite unusual, these engines are not known for that issue. But to happen two have two cars with the same problem - couldn't even begin to calculate the odds of that happening.

For the Matrix - What oil weight are you using? What oil are you running, what oil filter? How often do you take it up to 6K RPM or beyond? From the description, sounds like it was oil starvation that killed it. To find the exact cause, you'll have to tear down the engine. My suspicion is dead oil pump or clogged oil pickup screen. Could also be a shredded timing chain guide or FUBAR timing chain tensioner. Leaking timing chain tensioners are a pretty common issue on almost all the Toyota cars with VVTi on them, usually manifests when you get close to 100K miles or so. There are also oil drain tubes inside the valvecover that direct oil over the cam and timing chain, might be worthwhile with the valvecover off to check to see if those tubes are clear.

[1redtex]

only had the car for three months, has 187k miles.automatic transmission,the oil level was still exactly full after about 1000k miles on 5w30 valvoline high mileage oil and toyota oil filter,had new timing chain tensioner,and the first time rpm went that high.i have removed the head all cam bearing caps look good ,the intake cam good,cylinder walls still have pretty good hash markings,i checked the thrust clearance of the still good intake cam and its barely at the minimum clearance spec at barely over .001.and fianlly the front cam bearing cap on exhaust cam side where the galding took place the bearing cap is not concentric any more and binds cam.looking for another head now.think i would like to see a little more thrust clearance though.seeing this max cleareance is .0039.

[fishexpo101]

That is pretty bizarre. Did a spec of dirt get jammed into the bearing cap - causing it to heat up and gall from metal on metal contact - possibly when shoving in the new timing chain tensioner (mine was covered will all sorts of junk, had to hose down the area with some solvent before I removed and replaced my tensioner)?

187K miles is a decent amount of mileage, but way before I'd expect to see something like this in a 1ZZ-FE engine.