Timing Belt Woes

So I'm helping the neighbor's grandson with a timing belt and not doing a good job of it. He's got an '01 4Runner (5vz obviously). His timing belt snapped while driving last Monday.

We completed the job and it was stumbling and rumbling bad. Multiple cylinder misfires. Tore it back apart and here's where the timing marks fell when we got it to TDC:

 

We adjusted the belt and here's where we're at now:

 

Do you think it was 1/2 tooth off on the crank on the first attempt? And does it appear in time now? Motor is still sitting with the timing belt on, nothing else bolted on, because I want to ensure we've got it right before assembling it again. Don't want to need a 3rd attempt

 

Bump

 

That coolant dripping pooling up does not look very pinkish
Original coolant was still in there never changed?

 

That was actually blood lol. Knicked my knuckle on a water pump stud and sliced it

 

HFS!!

 

Looks correct to me from what I can see, how was it running prior to the belt breaking?

 

I'm told it was running fine (but it does have 330k miles and some teansmission issues). He was doing about 35 mph when it broke. He heard a loud thunk and the engine immediately cutoff. We're planning to put it the rest of the way back together tonight after work and see if we're correct this time around

 

If it still runs poorly I'd check compression, there's always the possibility of bent valves when a timing belt breaks even though the 5VZ is generally considered a non-interferrence engine.

 

Looks good to me.

 

Clean as much of the loctite out of the inside of the crankshaft as you can before you reinstall.

 

That happened on my '91 prelude. (interference engine)
Bent half the valves when the timing belt broke.

 

Yeah those positions on the cams and crank should be fine. That’s what mine looked like when I did the job a couple months back. I’d agree to look at compression. Hopefully you can feel resistance when turning the crank by hand but definitely gotta use something to actually measure it.

 

I have a compression tester, so we can definitely check that easy enough. I was kinda thinking that in my head when we first started it up after installing the belt (the 1st time), and it was stumbling that bad. This kids in a tough position, so I didn't want to worry him further. We'll slap it back together tonight and try to fire it up, if it's rough again, then we'll check compression at that point

 

Bent valve is my guess

 

For this kid's sake I hope you're wrong, but it did make a weird valvetrain noise briefly while we had it running after the first timing belt installation attempt, so it's a very real possibility.

Sounded excessively clattery in the top end (above and beyond the typical valvetrain clatter the 5vz normally makes)

 

So we got it back together tonight, and it fired up on literally the first crank and idled perfectly for about 3-5 minutes. Then it started bogging down and sounded like this:

https://youtu.be/02NlTAKIogQ?si=3B3WilWbR6XUCN2m


And then we ran a compression test and got these results:


Does this all align with the bent valve hypothesis?

 

Also I did whip out the ole' $12.99 Amazon borescope and snapped these photos inside of:

Cylinder 3:




Cylinder 4:

 

The compression could have been that way before (330,000 miles). I'd be reluctant to condemn the valves just yet. Maybe it's something unrelated like the intake elbow decided to split open right then and there or something else forehead-slapping.