Replaced the chain guides on my 2001 3.4 996. I did the project because i found brown pieces in my oil sump and the cam deviations were bank 1 -.4 and bank 2 -.78.

i found the guides were all in pretty good shape. Replaced them anyway and reassembled. Started the car yesterday and after ir ran for a few minutes the i checked. Bank 1 -.08 and bank 2 -.6.

i did not change the chains. Was that a mistake?

might it be that i need to run this a few more times and keep checking?


Bank 2 underway

Bank 1

Bank 1

Bank 1

Bank 1

 

How many miles did you have on the car before rebuild? With my minimal experience those guides actually look great for the age!

 

They do look good. I believe the engine had 75k on it.

This engine was installed when the original 103k engine failed. I have no history on this engine.

made me really wonder why the bank 2 deviation was so bad. One of the lower guides was a little worse than the one shown, but not very much. The chunks in the sump seem to have come from the end of a lower chain guide.

 

Even your original numbers were very good. Both less then 1. Your bank 2 numbers r not bad even after the repair. Bank 2 always seems to be a little further off 0 then bank 1 all the time. U didnt get a big change because the old pads were still good. There is really no target for cam deciation just a range because there r a ton of variables and the car runs 100% when in that range.

 

wait, it is 0.08 degree on bank one and 0.6 degree on bank two .. ?
If so, that is close to no deviation.

 

Is there a way to tell if you have issues other than having stuff in the sump? My car has 112 k and runs perfect but I have found a very small piece of the guide last oil change

 

Yes get a scanner that can see the cam deviations. Over +- 6 is when u should get it done.

 

OP I am confused, you said bank 2 deviation was bad but your original post said it was -.78 or less than one degree out.

You do understand that is just about perfect?

 

My bad… one decimal off.. bank 1 is 0.8. Bank 2 is 6.0. Before the work they were 4.0 and 7.8. So bank 1 improved by 3.2 and Bank 2 only improved by 1.8.

drove it today. Ran great but it seems the brand new temp sensor i installed is not working. It has a new low temp tstat but the gauge goes up to 100 when you turn the key but does not move.

And there is an oil leak i think on the bank 2 scavenger pump. Put new orings in but its coming steadily.

any ideas on the difference in the change? The pads showed a little less wear on bank 2. Not making sense, is it?

 

OK that clarification helps.

Double check scavenge pump orientation. And check that the AOS breather hose directly above Bank 2 scavenge pump is attached.

What tool did you use to lock the cams when setting timing? I ordered a generic chinese kit from Ebay, the locking tool was horribly misaligned and was easily 6 degrees off.

 

It could be just worn chains. Did u replace the short chains? The long chains can not be swapped and they can wear. U can cheat the cam gear and get the deviations closer to 0. U have to pull the tensioner, pull the scavange pump, loosen the 4 bolts on the cam gear and rotate it slightly. U may have to do this several times to "cheat" it to an acceptable number.

I do not remember which direction to rotate or how much. @Porschetech3 was gonna help me do this but i blew up the motor.

Also i was only able to get 2-3* of change when i did the pads and chains. Less on bank 2

 

I got 8 degrees improvement bank 1 and 5 degrees bank 2. New small chains and small pads. I did have to reject that EBay timing tool tho.

 

Used the cheap ebay tool. Felt it was probably not too accurate. The oval part was not machined right and would not fit in the hole at the end of the cam. I was careful to make sure the notch was facing the right was and was at 90 degrees.

no new chains. With 65k on the motor and being cheap i decided not to invest the $300 in new short chains. Regret that now.

oil leak might be the aos hose, but it seemed dry and in good shape before i reassembled things and it is dry above the scavenger pump, or looks that way. Have to pull the air cleaner and inspect more.

as it seems i probably have to take off the scavenger pump to stop this leak, anyone know which way to rotate the gear to decrease this angle? Do i have to lock in the cams? Not sure how to do that with engine in.

Thinking about it, there are a lot of things to take apart…

 

Yes u absolutely have to lock the cam so nothing moves but the cam gear. They make a small cam lock that bolts onto the front of bank 1. The bank 2 is easier to get to the scavange pump when in the car. Bank 1 scavange pump requires the engine to be pulled to the rear so it clears the fire wall.

 

Found the oil leak. The ring at the scavenger pump was not set properly and was crushed. I had saved the old one and got it in ok. ran it up and it seems to hold.

Anyone know which way to rotate the drive gear to reduce the deviation?

Thanks.