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2005 Deville
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I recently bought a 2005 deville with 145,000 miles on it. It has been taken excellent care of all service records and receipts in glove compartment, never even late on an oil change, It broke down on the original owner and someone told him that the motor was going to have to be replaced so he got rid of it. I bought it for 800 hoping it did not need a motor he just had new tires put on that costed more than i gave for the whole car. I thought as good as he took care of it that it couldnt be the motor. I was hoping for a sensor but no such luck. so i started into the motor and when i took off the right side cam cover the timing chain was slack on top the left side was tight. When i got the front cover off there was lots of pieces of the plastic guides in the bottom. now wnen i rotate the motor to align the marks on crank and intermediate gears to 12 and 6 o clock the cam gears on the left side are both at 12 o clock but the right side is not. they are around 7 and 5 o clock. with chain off should i move them manually to where the should be and put new guides and tensioner on or what?????

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Yup, the cams need to be repositioned before putting on the new pieces.

Depending on how much wear there was you may need to replace all 3 tensioners since there is metal on metal once the hard nylon feet wear out. On the passive guides you probably only need fresh nylon guides.

Replace any chain that had contact with metal on it’s tensioner foot.
Good idea to replace the intermediate gear as well, so as to get a fresh bearing in there.

Inspect all the toothed pulleys for excessive wear on the teeth and replace any suspect ones.

It should be noted that the Northstar is an interference engine, meaning that the valves open into the cylinders far enough to potentially collide with the piston top if they lose proper timing. Should this happen while operating it will bend valves and damage pistons.

With the engine sitting static, and a cam out of time, when rotating the crank to locate the marks, be wary of any extra resistance to the turning force. That may indicate a piston touching a valve.

Sounds like you already have it set to TDC so hopefully you don’t have this problem.
However, with one set of cams facing the exact opposite direction from where they are supposed to be, I’m afraid of the potential for damage.

When turning the cams to the correct position be very cautious if you get any resistance beyond that caused by opening valves against spring pressure.
Something I would do is to rotate the engine CCW away from TDC 45 degrees crankshaft and then put the cams in position and then rotate the engine CW back to TDC. This will give clearance for the valves when turning the cams.

To check for bent valves you need to inspect all the valves to see if they fully seat or are being held ‘up’ by the head being bent. This can be done by using a small machinist rule to check the height between the spring seat and spring retainer/valve stem top. The cams will have to be turned to relax certain valves due to the fact that at least one set of valves will be held open by the cam lobe. Set the engine back 45 degrees as explained above. Then you can rotate the cams as needed.

All the valve heights should be the same, or very close. I’m talking thousandths here. If any valve has a shorter measurement then it could be a bent valve head keeping it from closing all the way. If you find any that measure low, further investigation would be required.

A compression test is the ‘no disassembly required’ way to check this, but obviously the timing chains would all have to be installed for this to work.
There are other test methods available, but no need to describe them now.
For now, lets assume they pass the measurement test.

Assemble and time the chains as per the FSM. It’s not hard but doing it in the car could make it more ‘fun’ than with the engine out.

By the way, since you said both covers are off, I hope you used the correct puller to get the water pump drive pulley off the left intake cam. ANY hammering or prying will damage the front bearing thrust face.

Another caution:
Some of the broken pieces could have ended up in the bottom of the oil pan. These will find their way into the oil pickup screen. Hopefully it will not be enough to restrict oil flow, but it is possible. There is no easy solution for this. Just have to take your chances.

Keep in mind that you are working on an aged engine and after you fix the timing chains, there could be other things wrong. I’m not saying don’t fix it. I’m saying that once you fix it and get it running other things might show up, so prepare your mind for this.

So now have at it, and let us know how its going.


-Administrator- 2002.5 F55 STS 2014 FWD Explorer
66,321 Posts
Timing setup for the 2000 - 2005 Northstar non-VVT engines.

It's an interference engine, so if the cams have jumped time there's a very distinct possibility of damaged valves and heads.

You can lock the cams from turning by inserting a slip of printer paper under the front bearing cap, tighten into place. Do your chain setup, remove the papers and torque the caps correctly - use a tad of break-in lube in the dry bearing caps.

Don't pull the pins on the new tensioners until everything is in place and lined up.

Remember that the correct harmonic balancer torque procedure is absolutely necessary - do it wrong and you have no oil pressure.

You will NEED the GM/Helm service manuals to do this job correctly - too many special procedures and hoops to jump through.

The last picture is a cutaway of your roller cam follower setup. Click to enlarge, use the side < > to scroll.

Timing_Chain_Installation.jpg Timing chain and tensioner exploded.gif Timing chains and marks gif.gif Timing intermediate chain sprocket.gif timing marks - crank.gif oil pump removal.gif 2000+ roller valve actuator.jpg
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