96 2.7 liter Timing chain problem

Ok,,,went out to start my truck yesterday morning and it just spun over and wouldn't start.Check the spark at the distributor no fire.So took off the cap,turn motor over,rotor not turning.So I knew it had to be under valve cover.Found this when took it off.WTH,,,what caused this?

 

Looks like the bolt broke and vibrated out . From what I can see in the picture.

Things happen to mechanical parts. The bolt could have been flawed since new and just now failed.

Was the timing chain off lately ??

 

I've had the truck since it had 180,000 miles,it has 230,000 now.I haven't never put one on it.

 

Was your oil good? Looking at all the sludge in there it looks like it could have used oil changes more often, make sure your cams aren't seized in the head or something like that.

 

just forwarding some info


Here at NW TEAM Yota we work on both "interference" and "non-interference engines.

What does this mean?

Interference engines are 4-stroke internal combustion engines. The design of an engines piston and valve paths determine whether it is an “interference” engine or a “non-interference” engine.

If the lowest point at which an engines valves decent is lower than the highest point the engines pistons rise, then the engine would be consider to be an interference engine. While operating under proper conditions the timing of the pistons and valves is such that they are prevented from colliding. If, for any reason, the timing of an interference engine is not correct, then one or more valves may make contact, which will result in extensive engine damage and therefore costly repairs. Toyota 20R, 22R, 22RE, 22RET, 2RZ-RE, 3RZ-FE engines are all chain driven interference engines. The 5VZ-FE and the 3VZE is a belt driven non-interference engine. Therefore the valves can not come in contact with the pistons if the timing is not correct.

you have bigger problems. Sorry.

 

When this happened you heard no strange sounds ??

The fact this happened with the truck parked attempting to start is strange .

weird things happen though .

See what the pistons and open valves are like .

I could see if the bottom end seized at 50 mph or so that breaking the Cam bolt .

 

That's what is so strange to me.I drove it over 100 miles the day before on the interstate.I went out the next day to start it,and it would just wine,meaning the starter was engaging and turning the motor over but it sounded weird.

 

That’s a lot of blow by or oil sludge

 

You guys dont like my sludge engine I see,,lol.I bought it with 180,000,believe it or not,it didn't use much oil and I changed it every 5,000 miles.

 

That’s odd it’s alright not giving crap or anything just wondering prob previous owner problem

 

In any case the engine needs to come apart .

when the engine was cranking the pistons would hit any open valves .

Comes down to maybe just replacing valves maybe pistons only looking will let you know.

At the mileage rebuild this one or find a lower mileage engine or long block.

 

After further inspection this evening while I was turning the balancer under the truck,my friend was watching the timing chain.The big gear that the timing chain goes around is spinning on end of cam.The bolt broke which I showed in pic,and the 2 keys are broke off that why its spinning on cam not turning the gear behind the timing chain sproket.Withit not turning it cant turn the cam with the distributor gear on the end.Do you guys get all that?

 

If the engine is turning and the cam isn't it's almost certain to have bent valves as it is an interference engine, as to why the keys sheared don't know unless a cam is seized in the head.

 

Bases on OP’s most recent post, definitely a seized cam in the head. It happens sometimes on 3RZ’s if debris gets in an oil gallery.

3RZ’s are non-interference contrary to what the internet says. I’ve broken a timing chain on mine/had the timing gear fall off and there was zero damage to any pistons or valves

 

Well this happen on start up in my driveway.So I hope this saved me some serious engine damage.(No high rpms is what I mean).Can I check to see if any of my valves are damaged by doing a compression check on each cylinders with a guage?This is my first Toyota engine I'm trying to diagnose,so sorry for the stupid questions,,,lol.I would think if any valves were bent in a certain cylinder it wouldn't seat and hold compression? Just looking for suggestions for my next step.Thanks for all the help so far.

 

Unfortunately your engine is probably toast. You can start diagnosis by trying to pull the cam journal caps and inspecting the journals. My gut says that you'll find a bunch of galling that caused a seized cam in the head. If the cam is seized, you will need a new head at a minimum and probably an entire new bottom end since there is debris now in all the oil galleries.

 

My truck has 225k and pulled the valve cover at 200k to replace the gasket. My cams and timing chain looked NOTHING like this. You have a very serious sludge problem it looks like due to burnt rings or something of that sort.

 

Take notes young men.I bought the truck with 180,000,the previous owner looks like he didn't care about changing oil.But when I bought it,I have changed oil every 5,000 miles.It just turned 230.Looks like a rebuild is in the near feature.But it didn't leak,used very little oil.And it didn't smoke on start up.

 

I don't think anyone's blaming you it's just obvious that oil changes were neglected at some point in it's life and likely caused or contributed to the failure, not saying it's your fault once the sludge is there it's there and regular oil changes after it's formed won't do much to flush it out.

 

Yeah, I'd say that engine is likely to have bigger problems once you tear into it.

You can somewhat decrease engine sludge by using cleaners like Seafoam or Tranny fluid between oil changes, but this is a little too late.

Gonna be a costly rebuild. I'd suggest looking for another motor at this point.