I thought the secondary tensioner was suppose to take up slack in the chain.




On the A-bank (Passenger side), after I remove the cam indexing tool, the exhaust cam rotates a little (probably due to valve spring pressure) and the secondary chain gets a little slack. It was tight when the cams were locked down.

Shouldn't the tensioner take up this slack? It seems to do so on the B-Bank.

If engine is rotated, the chain will tighten; but, if it is rotated further, more slack is appears. The B-bank (Drivers side) remains tight throughout engine rotation.

1. The cam index tool was locked down tight on cam flats
2. The crank was pegged in the correct hole.
3. All chains were pulled tight, counterclockwise, on driven side.
4. The exhaust cam socket was secured w/ Allen securing bolt, and
5. VVT intake cam socket secured w/ same

Then when I remove cam index tool, the cams move, and the secondary chain becomes loose. Shouldn't the new metal tensioner take up this slack?

I am puzzled by this because I have replaced both the primary and secondary chains and tensioners yet still have some chain rattle on start up. The aforementioned is the only slack I could find in either sets of chains.

gordo[/align]

 

The tensioners are not supposed to back off, that's how they work at keeping the chain tight as it streches and wears. If the tensioners are backing away form the guide when the locks are released, something is not right. double check that they are in fact the correct parts.

 

The tensioner is not backing off from the guide. That is the primary chain system. The tensioner in question is the Secondary on the A-Bank (pass side). It is spring loaded and the piston ends with a plastic slipper thatrides onthe secondary chain.

My question is, are they supposed tohave enough spring tension to keep the secondary chain tight w/o oil pressure? It appears the B-Bank tensioner does.

 

I have replaced timing chains on Ford and GM engines. The tensioners should definitely have enough spring pressure to take the slack out of the chain. The oil pressure supplements the spring pressure in the tensioner.

Since this is such an extensive and critical type of repair, I would just replace the tensioner and not look back.

 

rscultho:Both primarytensioners, and chains are new. That is what is so frustrating.

 

Are you using the new style tensioners with theratcheting mechanism?

 

It turns out the rattle is not in the tensioner assy.

I disconnected the VVT selenoid connector and the rattling ceased immediately. The problem is now isolated to the VVT units.

My theory is the inner ring piston gears, and/or the two helix outer ring gears are worn down. I postulate they partly engage, but then skip a few teeth and re-engage. This skipping of teeth creates the clattering noise.

After the unit heats and the gears expand to mesh better, the skipping is reduced and the noise abates. Behind all this noise, I can hear the click/clack which leads me to believe the selenoids and shuttle valves are activating.

However, there remains the possiblity that the selenoids are rapidly alternating on and off, and causing problems there. I cannot discern whether they are rapidly acuating. I don't think they are, but that needs to be ruled out first. They are the easiest to access and eliminate as a factor.

I am search for a technique to bench test everything.

gordo

 

it is normal.. that when bank one.. cam tool is removed.. the exhaust cam turns a little.. i was puzzled by it when i did tensioners.. with the newest style. the older ones never did it.. they always stayed tight.. once oil pressure is up it goes away..