Toyota Repair: Run x Timing chain, oil pressure sending unit, cam timing

Question
QUESTION: Hi there.

All 8 my outlet valves recently bent. The timing chain is not broken. The cam-timing was 100% when I opened the tappet-cover.

I haven't changed the oil for some time now. Could this have an impact on the valves bending?

I've replaced the outlet valves now, but I still would like to know what the cause of this might have been, as I ded not overref the car when it suddenly just died on me.

Pleaseeee help!

Kind regards

ANSWER: Is it a DOHC?  If so, the the chain on the outlet cam could have jumped a tooth or two.  This could have caused all the outlet valves to open at the wrong time.  Check your chain markings to ensure the crankshaft and camshafts are aligned.

---------- FOLLOW-UP ----------

QUESTION: Its got the VVTi system in. Is there a diagram on the web somewhere where I can check how to look for the chain markings?

ANSWER: HAYNES may make a manual for your vehicle.  Their illustrations are very clear and informative.
Usually the timing chain will have little dents in the links which will line up will similar dots on the crankshaft and camshaft.  Slowly rotate the crank until its timing mark lines up.  At that point, check the camshaft to see if the dots line up.  If they don't then remove the chain and line them up.
Replace any tensionors and guides while you're at it; you're there already!

---------- FOLLOW-UP ----------

QUESTION: Hi. We've replaced the outlet valves, and when we tried to get the camtiming in, we discovered that the dell keeping the camgear onto the outlet camshaft have broken off, resulting in the bending of the valves. Do you have any idea why this could have happened? Also, my oil light is coming on/off sporadically. Any suggestions as to why? Do I have to replace the oil pump?

Rgds

Answer
See if you have sufficient oil level.  I know this sounds simple but it has happened before.
Check your oil pressure sending unit and the wiring.  You could have a bad sending unit or bad wiring connection.
Changing the oil pump is an involved process so try the simpler stuff first before you do this.  Also, check your pickup tube in the oil pan to make sure it is fitted up properly and not leaking.

When you say "dell" what is that?  I've never heard that term before (other than the farmer in the dell...).  

Hope this helps.
Vince