No problem removing the cam bolts.


Now waiting on new VVT gears. It’ll be next weekend at best to get going again.

 

After having thoroughly looked over all the old timing parts, I’m not convinced that there was anything wrong with any of the chains, guides, and tensioners. I needed to see what was going on inside the phaser, and I think I further confirmed the real problem.

 

P-Bod, Wow, thanks for the detailed and easy to follow step by step. I think it's quite out of my league but still fascinating to see how these repairs are done. If you ever saw my tool shelf (that's correct, a shelf, not a tool box, you would immediately understand. Looking forward to seeing you troubleshoot and resolve this issue.

 

That is really interesting and an awesome find. So the question is are the parts actually within spec and can you fasten them so the locking pin works correctly? I find it odd that the parts could actually wear in a way that would cause this issue.

 

I've been pondering the same thing. I'm not so sure it's wear, but manufactured tolerance possibly being too big. 50,000 - 100,000 miles of heat cycles causing the housing to slip ever so slightly to the point of not locking?

Can you loosen the 3 bolts, rotate the motor by hand to tease the phaser housing over, then re-tighten the bolts? Maybe this could be done with only removing the valve cover and not the front cover. The small hole in the phaser cap lines up with the small hole in the fat lobe when the phaser is supposed to be locked.

I'm not going to try it, but it could save a ton in parts. The phasers are $500-900 each!

Also, to the idea that the noise is of no concern, I tend to agree. If you look at that lobe that hits the stops, there is essentially no damage at all. Each side of that lobe also looks like it has a hardened piece of steel for greater durability. I can see a little polishing of the contact surfaces, but that's it. The greater concern would be whether or not the violent stop-to-stop startups can cause a chain to jump time. That would show up pretty quickly on a scan tool.

I've also wondered how many secondary tensioners have been changed for startup rattle and have not fixed the problem. The secondary tensioners are not the ratchet type, only the primaries are. The secondary tensioners don't provide much force without oil pressure. As noted, my RH secondary chain was loose, but it did tighten as I rotated the motor. On the RH side, the secondary spring is underneath, and the LH side spring is on top. I didn't realize that at first.

 

Well, I'll have to add this which may help in your thought experiment:

When I first noticed the rattle at startup, I'd just finished running the engine pretty low on oil. Ugh...I hadn't owned it very long and was unaware that it was "consuming" oil. In quotes because there were no leaks that I could detect, no smell of burnt oil....nada. Anyhow...maybe running with a low oil condition contributes to this issue with the timing gear...

 

The more I thought about it, there is no way the lobes and gear could be off center from each other. I put them on the cam shaft for a better demonstration.

 

Okay, I get it. So the assembly can not really "shift" because the chain gear is centered at the came shaft with tight tolerance and the tri-point lobes thing is also dead centered on the cam via the bolt. So your only variable is the oil chamber ring, which does in fact have play or out of roundness, etc. An no, the terms I used are not actual of course. lol

So can you in fact set it to lock and tighten the three bolts down to set it into a new position? Or how about just milling off the stopper a few thousandths? Also, why does this look like a locating pin location to me?

 

Your terms are making sense to me! Any real engineers here are probably laughing at all the terms I’m using too.

I think you could probably reset it, but I suspect it will ultimately work its way back to failure unless you somehow take up the slack. Milling a layer off of that lobe probably would fix it for good. I’m hoping my new phasers will be revised something just like that.

The hole goes all the way through. It may be for a locating pin during assembly, but doesn’t seem to have a purpose in the running motor.

 

I would be curious if a location pin could be sized and inserted to see what happens then to the functionality. I dug through all the shop stuff I have, unsurprisingly since this unit is sold as a part on its own there is no internal blow-ups. I did learn that the older styles are adjustable for wear but this design is not. Also it was not clear, but at least one person did say they can be replaced without removing the front timing cover. Not sure how hard that would be and maybe it was even for another engine. Frankly I think with this type of work a full front end tear down is best. May as well check the guides, etc. Also I am curious how much slop/play/etc the new ones will have if any. There is so much play in the oil chamber ring it just seems odd, although maybe you don't want to crack open a new one. Eitherway, very helpful thread with photos and info. Really appreciate the effort you are putting into this. It is not exactly a common issue but comes up enough. It will certainly help me and I plan to push my motor to over 300k miles. Hitting 200k now.