2006 Torrent -Camshaft Problem ?????

[blueacre]

My daughter has a 2006 Pontiac Torrent with the 3400 V6 engine which I belkieve has Variable Valve Timing (VVT). It lost power while driving earlier this week and then died completely. I tired the following steps
- checked spark - seems OK
- removed hose at throttle body and sprayed starting fluid and cranked it over - did not fire at all
- checked trouble codes - had a P0340 - camshaft sensor circuit failure
- removed the oil fill cap in front valve cover and put a finger on one rocker arm - had someone crank the engine and rocker did not move.
- removed one spark plug and used compression tester - cranked engine and gauge bounced a little but no compression.

Everything indicates the camshaft is not turning. Not familiar with Variable Valve timing - is there a way it can fail and the camshaft not turn ?

Does this model have a dowel in the camshaft sprocket like older engines that possibly sheared off and the sprocket is turning but not the camshaft ?

Appreciate if anyone has any ideas on what might be the problem

thanks
Gary

 

[melsg5]

I could not find anything that indicates the engine is a VVT. Did your daughter mention any noise from the engine prior to it's failure. Sounds to me like the chain/tensioner failed.

 

[blueacre]

Found the problem - 2006 Torrent Camshaft

I pulled the timing cover off the Torrent and when I turn turned the crank the small timing chain sprocket on the crank didn't turn.Pulled the harmonic balancer and could then see that the end of the balancer key on the crank that goes into the timing sprocket had sheared off. Ordered a new one from GM - talked to the mechanic there and he said that they had never seen this problem before.

Putting things back together today - does anyone know if the 3.4 is an iterference engine ( valves and pistons hit each other if valve timing is off) ? If it is can I expect to have bigger problems with bent valves or damaged pistons ??

regards
Gary

PS - re the Variable valve timing comment - I thought I had read someplace that this engine had VVT but wasn't sure.

 

[blueacre]

2006 Torrent Camshaft update

Got the engine together, started but ran very rough. Checked compression on the front 3 cylinders (because they were easy to get at) One cylinder had no compression - figured I had a bent valve. Pulled intake manifolds and front cylinder head - cylinder with no compression had a good size mark on the piston where it hit the valve. One of the other 3 had a small mark and the third was OK.

PRobably will replace with a used engine rather than rebuilding the heads on this one and reassembling - already had issue with timing chain sprocket failure - never know what else may have been damaged when pistons hit valves.

I think it is easier to pull the engine out the top rather than dropping the entire engine /tranny and subframe assembly as most manuals recommend. Has anyone done it this way ?

I know the torque convertor bolts are accessed through the starter opening. I haven't figured out where all the other bolts are located to split the transaxle from the engine - does anyone know location and number ?

thanks
Gary