The Correct way to change your TIMING BELT!

papaindigo · **Posted:** Sat Jan 03, 2015 2:13 pm

Go to http://colorado4wheel.com/manuals/Jeep/KJ/ where you can download Jeep service manuals that cover the Jeep with the 2.5LVM CRD. There may be some auxiliary/external parts differences between the installation of this engine in a Jeep as opposed to a Voyager just as there will be differences in placement of some external components between left and right hand drive vehicles. However, those differences do not matter to your situation as the basic engine and its timing are the same between vehicles.

That said based on the assumption that the 2.5 and 2.8 VM CRD engines are essentially the same with respect to "timing"
1. given the condition of the timing belt I think its a certainty that the vehicle stopped and won't restart because when the timing belt teeth went the engine timing went and in all probability you have one or more destroyed rocker/lifter assemblies.
2. given #1 you are going to have to pull the cam gears (you will need a cam holding tool to do this and the reinstall as the cam pins along won't stand the torque associated with removal/reinstall of the cam gears) and pull the valve cover in which the cams are installed to get to the rocker/lifter assemblies to replace them (you really should replace them all not just broken ones)

Once you deal with the lifter problem you will need to retime the engine and reinstall the timing belt, etc.
1. scroll "up" in this discussion for the dimple on the crank that hints at flywheel position and geordi's comment on how to find TDC (you will need a new crush washer and "O" ring to reinstall the #1 injector and I suspect the 6mm long shaft allen key trick (see 05 FSM) for finding the flywheel hole will work (you can tap around the hole to make sure you are in the right spot)
2. once the crank is in the proper position you can rotate the cams into the proper position and pin them
3. from there follow timing belt install instructions.

geordi · **Posted:** Sat Jan 03, 2015 2:15 pm

VMdiesel wrote:

Hi!

Thanks, flman! I see there are some minor differences between the Jeep and the Voyager engine layout. The Voyager has no Viscous heater and the power seering pump is mounted on the other side of the crankshaft pulley, just below the AC compressor. Perhaps this is more due to my 2.5 CRD as opposed to your 2.8.

I was hoping that there was no slip but apparently there is. Hope is the last thing to leave man, so I'm still hoping the valves are OK and with a massive load of luck even the rockers. Would it be possible to assess the rocker condition by just turning the cam sprockets while the crankshaft is in the 90 degree position? Shouldn't there be some resistance when the rockers are actuated by the cam and the valves are pushed down? If one (or more) rockers are busted, there should be no resistance when the cam rotates past that position.

/Fredrik

If this is like the design of the 2.8, then the rockers are the designed failure point for any timing mishap. The pistons would impact the valves, and shove them up against the head... And if the rockers didn't break easily, then massive valve damage would be the result.

Plenty of CRD owners have had this happen, and the only thing they needed was a set of rockers in addition to replacing the timing belt kit. You should be in the same boat, you may as well save the energy of "testing" and just pull the cam pulleys and remove the valve cover to expose the rockers. I'd wager that a significant number of them are snapped in half.

Unlike much on the Jeep CRD, this particular system does seem well designed and actually functions as it is supposed to.

ArmyChief · **Posted:** Sun Jan 04, 2015 12:20 am

geordi wrote:

Unlike much on the Jeep CRD, this particular system does seem well designed and actually functions as it is supposed to.

LOl...

VMdiesel · **Joined:** Fri Jan 02, 2015 8:55 am **Posts:** 4

papaindigo wrote:

Go to http://colorado4wheel.com/manuals/Jeep/KJ/ where you can download Jeep service manuals that cover the Jeep with the 2.5LVM CRD.

Wow! Now I don't have to guess anymore :ALONE:

Rotating the cams reveals that all exhaust rockers are busted and probably two of the intake ones, at least judging from the resistance felt and valve noises (click when closing) I hear. The intake cam only resists twice every rotation (should be four I assume) and the exhaust one gives me virtually no resistance at all. Replacing all rockers seems like a good idea... Don't wait around here for anything to happen here anytime soon as I seem to remember that I have a job to attend to after the holidays (seems distant after the cambelt ordeal).

To all that replied: a great thank you for all your assistence. I'll definitely report back in time with the results!

/Fredrik

VMdiesel · **Joined:** Fri Jan 02, 2015 8:55 am **Posts:** 4

Ok, so now I've removed the inner timing belt cover. I had absolutely zero clearence between the water pump sprocket and the cover as I slid it out, but I guess that's the way it's designed. Also, the AC coolant lines were somewhat in the way.

Now the big question for today: The shop that diagnosed the problem for me initially said that there was no fule to the injectors. I tried to rotate the high pressure injection pump and at first I felt some resistance. After a few turns the resistance sort of released gradually and I could turn it almost as easily as the spanner sprocket or the idler pulleys. Is there any way to tell if the injection pump is broken by just rotating it and feel the resistance, or do I have to run some other test on it? Maybe it was only the built up pressure that caused some resistance and when I turned the pump, then the pressure was released gradually.

Since it resisted initially, could there be some problem with it that lead to the timing belt losing its "teeth"? (Of course it COULD, but how likely is it?) Anyone with experience in this?

I also consider replacing the water pump to make sure I don't have to do this all over again just because that component fails. It's a bit tight with the water pump located between the engine and the passenger compartment, so there's not much space left.

/Fredrik

flman · **Posted:** Sat Jan 17, 2015 9:30 am

VMdiesel wrote:

Hi!

Thanks, flman! I see there are some minor differences between the Jeep and the Voyager engine layout. The Voyager has no Viscous heater and the power seering pump is mounted on the other side of the crankshaft pulley, just below the AC compressor. Perhaps this is more due to my 2.5 CRD as opposed to your 2.8.

I was hoping that there was no slip but apparently there is. Hope is the last thing to leave man, so I'm still hoping the valves are OK and with a massive load of luck even the rockers. Would it be possible to assess the rocker condition by just turning the cam sprockets while the crankshaft is in the 90 degree position? Shouldn't there be some resistance when the rockers are actuated by the cam and the valves are pushed down? If one (or more) rockers are busted, there should be no resistance when the cam rotates past that position.

/Fredrik

If you only have one broken rocker, there would be less resistance in comparison, both in the same cylinder would equal no resistance.

geordi · **Posted:** Sat Jan 17, 2015 5:49 pm

You only need to replace the front half of the water pump, the 5 bolts that parallel the center shaft of the pulley connect the front half to the back half of the water pump. There is a thin o-ring in there, be certain that it is removed from the old one and that the new one is clean and in place.

The back half of the water pump is just a metal housing and connections - If it isn't leaking, I wouldn't mess with it.

To see whether your fuel pump is working, you could loosen one of the injector lines and then use a drill and socket to spin the fuel pump (clockwise) and see if the injector line spits.

kjjet · **Posted:** Tue Jan 27, 2015 9:48 pm

Still fighting all those VM - CRD engine problems? Its like ground hog day. Same thing OVER AND OVER :banghead:

Good luck
KJJET

JAFO · **Joined:** Thu Aug 13, 2015 10:35 am **Posts:** 54

weeks101 wrote:

Brianawd wrote:

they should have used a keyway on cams and cam gears.

Not to split hairs, but the camshafts have a keyway. It's the the cam gears that don't.

Anyway, this blew my darn mind when I saw it. That and the torque values for the cam sprockets are only 80 ft. lbs.

Sometimes I have nightmares about it.

If I were someone with a CNC machine I would start making a cam gear kit with woodruff key slots and timing marks as a direct bolt on replacement (Hint to anyone with machining capabilities) :BANANA:

lacabrera · **Posted:** Fri Sep 11, 2015 2:44 pm

JAFO wrote:

weeks101 wrote:

Brianawd wrote:

they should have used a keyway on cams and cam gears.

Not to split hairs, but the camshafts have a keyway. It's the the cam gears that don't.

Anyway, this blew my darn mind when I saw it. That and the torque values for the cam sprockets are only 80 ft. lbs.

Sometimes I have nightmares about it.

If I were someone with a CNC machine I would start making a cam gear kit with woodruff key slots and timing marks as a direct bolt on replacement (Hint to anyone with machining capabilities) :BANANA:

On my last cam belt change I decided to cut key ways to the 2 sprockets and made keys. Its not difficult to do, the hardest part is cutting the slot in the correct place in the sprocket.

thermorex · **Posted:** Sat Sep 12, 2015 12:49 am

Why would you guys care about woodruff keys? If you lock the cams in position and use the proper tools, you really don't need any key. Plus, with a key you're limited to the position of the cam sprockets relative to cam key and not to the timing belt, with no option to move the sprockets slightly to perfectly align sprocket teeth with belt teeth..

lacabrera · **Posted:** Sat Sep 12, 2015 3:16 pm

thermorex wrote:

Why would you guys care about woodruff keys? If you lock the cams in position and use the proper tools, you really don't need any key. Plus, with a key you're limited to the position of the cam sprockets relative to cam key and not to the timing belt, with no option to move the sprockets slightly to perfectly align sprocket teeth with belt teeth..

Thermorex its nice to sleep easy at night? This is the only twin cam engine I have worked on that relies on the torque to hold the sprockets in place. I wonder how many cam belts have failed due to movement of the cam sprockets and we say well the cam belt failed? rather than the sprockets moved and caused the valves to hit the piston causing the cam belt to snap.

geordi · **Posted:** Sat Sep 12, 2015 4:40 pm

Over 50 of mine are out there and currently... Not one has keys behind those pulleys, and not one has failed or subsequently had a problem with the rockers. The VW TDI has no key behind the cam pulley either, and many many tens of thousands more of those engines are driving around right now without issue. Far more out there than the CRD.

This is not one of the problem areas that needs to be redesigned.

thermorex · **Posted:** Sat Sep 12, 2015 10:07 pm

lacabrera wrote:

thermorex wrote:

Why would you guys care about woodruff keys? If you lock the cams in position and use the proper tools, you really don't need any key. Plus, with a key you're limited to the position of the cam sprockets relative to cam key and not to the timing belt, with no option to move the sprockets slightly to perfectly align sprocket teeth with belt teeth..

Thermorex its nice to sleep easy at night? This is the only twin cam engine I have worked on that relies on the torque to hold the sprockets in place. I wonder how many cam belts have failed due to movement of the cam sprockets and we say well the cam belt failed? rather than the sprockets moved and caused the valves to hit the piston causing the cam belt to snap.

Totally agree with sleeping good and easy, but usually woodruff keys are placed where is a need to time the sprocket with the axle it gets connected to (like the cp3 pump). Since the crd cams have the ability to be locked, independently of sprockets and do not rely on sprocket marks, I one do not see a need to have any woodruff key on them. But, if you want to avoid using the cam keys, I agree, a woodruff key is useful. The only issue is that you can't fine tune the sprocket position to fit precisely the timing belt, which is the reason I believe vm motori didn't use them. It may work with sohc engines, but not so well with dohc engines with timing belt.

I also agree with Geordi. But I appreciate you explaining your point of view

.

lacabrera · **Posted:** Sun Sep 13, 2015 9:20 am

geordi wrote:

Over 50 of mine are out there and currently... Not one has keys behind those pulleys, and not one has failed or subsequently had a problem with the rockers. The VW TDI has no key behind the cam pulley either, and many many tens of thousands more of those engines are driving around right now without issue. Far more out there than the CRD.

This is not one of the problem areas that needs to be redesigned.

The VW tdi overhead cam engine do have locked cam sprockets? On the earlier ALH/1Z/AHU engine the camshaft has a tapered camshaft and sprocket that clamps the sprocket much tighter (a sprocket puller is required to remove it). Even on these models there have been a number that have failed and slipped causing engine damage. But yes I do agree that they are unlikely to slip on the VM, But like I said its one item I do not have to worry about.

lacabrera · **Posted:** Sun Sep 13, 2015 2:01 pm

thermorex wrote:

lacabrera wrote:

thermorex wrote:

Why would you guys care about woodruff keys? If you lock the cams in position and use the proper tools, you really don't need any key. Plus, with a key you're limited to the position of the cam sprockets relative to cam key and not to the timing belt, with no option to move the sprockets slightly to perfectly align sprocket teeth with belt teeth..

Thermorex its nice to sleep easy at night? This is the only twin cam engine I have worked on that relies on the torque to hold the sprockets in place. I wonder how many cam belts have failed due to movement of the cam sprockets and we say well the cam belt failed? rather than the sprockets moved and caused the valves to hit the piston causing the cam belt to snap.

Totally agree with sleeping good and easy, but usually woodruff keys are placed where is a need to time the sprocket with the axle it gets connected to (like the cp3 pump). Since the crd cams have the ability to be locked, independently of sprockets and do not rely on sprocket marks, I one do not see a need to have any woodruff key on them. But, if you want to avoid using the cam keys, I agree, a woodruff key is useful. The only issue is that you can't fine tune the sprocket position to fit precisely the timing belt, which is the reason I believe vm motori didn't use them. It may work with sohc engines, but not so well with dohc engines with timing belt.

I also agree with Geordi. But I appreciate you explaining your point of view

.

VW and other manufactures use a 2 piece cam sprocket. Fist part bolted and keyed to the camshafts 2nd part, 3 or 4 bolted to the 1st with slots to allow for timing adjustment. But I guess that's deference between German and Italian engineering?

The Correct way to change your TIMING BELT!

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