Exhaust cam shaft question

[alia176]

Real Time help: Exhaust cam shaft question

When removing the Exhaust camshaft from the cylinder head, the FSM states
" Secure the exhaust camshaft sub-gear to the main gear with a service bolt:..."
page EG-25, Paragraph 35.A (see first picture for more details).

If you don't do this step, will the sub gear rotate under spring tension and end up being out of alignment with the main gear teeth? Perhaps this is what the sub-gear did as I removed it and didn't see it spring rotate? I inserted this service bolt (after the fact) and I'm still seeing the slight misalignment of the two sets of teeth. There's no other way to insert the service bolt through both gears! Will the two gears realign themselves when the intake gear is mated with them? See the second picture of what I'm referring to.

Why is the sub-gear under spring tension and why is there a sub-gear to begin with?

Thanks.

 

[landtank]

the two gears are under spring tension to eliminate backlash. On the equipment I service we have a predetermined amount of rotation to load that spring. I didn't see that in the FSM for our truck.

With the service bolt in place there should be load on that spring and the teeth should line up. The bolt should pass through both gears.

All I can say is to rotate that spring until you meet those two requirements and put the service bolt in. Hopefully somebody else has better info for you.

 

[DTAYLOR]

sounds like a job for Robbie (powderpig) or possibly CDan can find this out from a tech at his service dept.

 

[Tools R Us]

As Rick said, the spring loaded gear is to eliminate backlash noise, without it the exhaust cam gear would click when rotating off the lobes at low RPM.

 

[alia176]

Backlash reduction makes sense.

Question I have is will the two gears align themselves once I reinstall the Exhaust and the Intake camshaft? As you can see from the 2nd picture, they're not aligned right now!

 

[landtank]

Backlash reduction makes sense.

Question I have is will the two gears align themselves once I reinstall the Exhaust and the Intake camshaft? As you can see from the 2nd picture, they're not aligned right now!

They will be aligned once you rotate the gears and place that bolt in them on your BENCH.


take an end shot of the gears so we can see the holes. I would think that the threaded hole for the bolt is close to the opposing hole in the other gear and that would be how much you need to rotate it.

 

[Cass007]

Bumping this back from the grave after 13+ years ... doing my HG today and got lazy and chose not to consult my step by step notes and I removed the intake cam before setting the set screw for the exhaust cam.

Can anyone confirm which way the outer (front thinner) part of the cam should rotate (clockwise or counter when facing it) to line back up with the set screw hole? Mine looks like it jumped one tooth counter clockwise, but I really have no idea. Hard lesson being learned

Also, can I do this while still in the truck? None of the cam covers have been loosened or removed yet on the exhaust side.

 

[ppc]

The movement is spring loaded. Without the bolt it should only rotate clockwise and needs to rotate approximately one tooth. I believe this is documented in the installation section of the FSM.

 

[IdahoDoug]

Just looking at your bottom picture indicates the front piece in operation is trying to move counter clockwise (viewed from the front of the car at front of hood) with springing action. You can see that by the wear pattern where the subgear is pushing anti-clockwise on the intake cam gear (from spring). And the main gear portion has wear on the opposite face. So my guess is you'd correct it by rotating the sub gear clockwise against the spring to have spring tension, insert the bolt (yes you can do it in the head like you have it) and hold the spring under tension. I'll check my FSM in a bit to see if I can discern further or others may chime in.

 

[Cass007]

I see it now on page EG-46. Will have to see how hard it is to rotate the sub-gear (front) while holding the cam with a wrench on the hex part.

 

[xcmountain]

Good evening, long story short I am in a similar boat or at least I was. I tore the motor down to replace the cam seals because I hate leaks (I should have left well enough alone) and I did it last winter on the wife's Sequoia so no problem (hahaha). I got it torn down and 1 side finished using the FSM. Started the other side tired and well.. skipped some steps. I ended up with a DS intake cam that wouldn't seat correctly, after tightening the cam holders it was still an issue. Removed the cam only to place it on my bench and it broke (oh damn). Shopped around and found a used set. Yes 2UZ Yes VVTI. Went to put them in the last few days and it's making a ticking knocking sound, much like mentioned above. Not recalling if I set the back last I tore the DS down again, and behold the backlash wasn't set. I pulled the exhaust cam rectified the alignment and placed the service bolt in. Reinstalled the exhaust cam and SOB if it's not making the same noise, it might be a little quieter but I wouldn't bet on it. It is reminiscent of rod knock. I can hear the normal valve train noise underneath this sound. It increases revolutions with the motor rpm's, wasn't there with the old cam, etc.

Does anyone care to take a guess as to what the heck that noise is?