Changing the timing belt, big oof.

Hey all, so I recently picked up my 1st gen and was getting excited to report some progress I've made, however I'm now suffering to my own incompetence.

After sifting through the (many) great posts on here and youtube related to changing the timing belt, I began my endeavor. And really, everything was going smoothly.

And then, my luck began to unwind... I was trying to figure out why my timing marks on the cams and crank weren't quite lining up. When i hit TDC on the cams, the crank was a bit BTDC (if i had to guess, maybe 25 degrees). it wasn't until i hit the "T" with the cams, that the crank was hitting its TDC mark. I sort of naively thought that maybe i just needed to rotate the crank several more times. During this time, i started to feel some pressure as i tried to rotate, but i pushed past it. It still didn't line up, so i tried again. Again i felt some pressure....i again pushed past it. Yup, stupid.

Suddenly, I looked down and noticed half of my timing belt is shredded. I stopped. I Wondered if I somehow missed that but not sure how I could have. Of course, then it hit me...something must have fallen down into the crank pulley. There was nothing visible from above when i shone a light down behind the cover, but once I took the crank pulley off and the lower timing cover completely off there it was, a gummed up plastic piece that looked like it might be a mount for one of the sensors was jammed on the driver side of the crank gear looking like some well used big league chew.

SO now, i sit pondering the what if's. I certainly won't continue turning the crank like i was since I now can't be sure i didn't jump time, but what should I do? I'm thinking of carefully backing the cams to TDC while also being mindful of the position of the crank, being extra careful not to force anything back. Then, can i remove the old timing belt, move the crank to where it needs to be, and finish my timing belt job? I do plan to do a compression when it's all said and done. I'm really hoping i didn't bend a valve.

 

set the crank shaft so that the mark on the crank pulley points to the bolt on the driver side idler. when in this position all of the pistons are down far enough to avoid the valves so you can freely spin the cams

if you need photos i can try and get one tomorrow of what i mean

 

Hot damn that's a quick reply! I believe i know what you're referring to but for sure a pic couldn't hurt. Should i attempt to do this with the current belt still on? I assume the answer is no, but thought i should clarify.

 

Chances of hurting things is low. Just go nice n slow.

 

Nice rhyme bro.

 

This may help with timing marks: https://www.toyoheadquarters.com/threads/toyota-2uz-fe-timing-belt-marks-4-7l.335/

Thanks to @BubbaW for the link

 

Thank you! That definitely helps clarify some things. I'll likely be picking up on it tomorrow and report back.

My biggest worry is that I've jumped time by an unknown number of teeth when I had the plastic piece jammed in there, but I'll go super slow. I'll remove the spark plugs too.

My plan of attack is to get either the crank to the mark empty_lord (and, it would appear shiftys link) describes, or the cams to the "T" mark, whichever I can get lined up first. I'll then remove the old belt, and carefully align either the crank or cams to their marks. Next, put the belt on and make sure the new belt lines up with the marks on the cams and crank.

 

Once you get everything lined up as expected, and the belt installed, you should be able to turn the engine over freely with no resistance. If you turn things over and feel resistance at any point, that's when I'd be worried (and wouldn't continue turning, I'd back off to where it was free, remove belt, and seek advice).

 

So I hear it's possible, but has anyone on here actually bent a valve while changing the timing belt?

 

So thank you @empty_lord & @shifty` for the help. Helped me a ton. I'm still finishing up putting everything back together but I got it all aligned. Since i was unsure whether i had jumped time with my incompetence, i did the following:

The cams were actually closest to their marks, at the "T", so i very carefully rotated them to that mark. I then took the belt off.
I rotated the crank very carefully, and got it close to aligned with the pulley bolt empty_lord described. From there, i put the new belt on and lined up all the belt markings with the correct marks on the cams & crank. after putting the new belt on, i put the crank pulley & cover that shows the timing marks back on, and rotated several times. each time the cams and crank hit their marks right on the nose. success!

One thing I'll mention is taking the spark plugs out, while maybe overkill, gave me a better feel for things in the process.

 

I see you got there and took actions necessary, but just to reply....

I'm not aware of it happening, as in, I've never seen anyone admit to it. I think usually if things don't line up, or a cam jumps, people come here and post up. THAT is something we've seen a number of times.

However, I can't help but believe it would take ample enough force to bend that I'd hope anyone manually turning things over without the belt intact would stop and think, "oh damn, something doesn't feel quite right here" and stop what they're doing. If not, I mean, that sucks

You were smart to pull the plugs to reduce resistance if you weren't confident in what you were feeling. Good thinking on your part!

 

Final update on the matter, we're all good! Did a bunch of "while I'm in here" things, so I did the seals, fan pulley, thermostat, radiator and hoses, and spark plugs.

I'm moving on to the steering rack & front suspension. Thanks guys!