You're probably right, it may keep the axial movement down. I'm not sure of the veracity of what I read, but I did see one website that cited movement of the cam due to thrust plate wear as a potential root cause of the timing chain stretching.

Which kind of makes sense, because timing chains aren't supposed to stretch THAT much. Chrysler has stayed mum on the issue, I'd love to know WHAT exactly causes the stretch, and whether it's been fixed on the new chain or whether it will continue to cause problems.

The cam position sensor has a cardboard/paper dot with a sticky side about the size of a dime. I ordered it from the dealer and picked it up yesterday. Allegedly, according to the dealer tech I spoke with, it has to be applied before the cam sensor is reinstalled, or the cam sensor will not be properly spaced and might be damaged or otherwise read incorrectly. Figured I'd rather not lose a horse for want of a nail, so I bought it for $6.

 

If it restricts axial movement then when it wears the cam may slide forward and could tweak the chain perhaps accelerating wear within the joints of the links. That sounds to me like it makes sense.

I guess I'll pull mine and check it out before I go ordering too many more parts (I would have thrown it in the order if I had known earlier...). If mine isn't visibly worn and I cannot detect any axial play on the cam then I'll probably leave the old one in there.

The spacer dot sounds just like the washers used by porsche with their hall effect sensors, just for setting the sensor gap. If the new and old gears are at all different sizes then I could see it being important. I'll ask my local dealership about it since it is also too late to order that with my other bits. Thanks for the tip. Do you have a parts diagram showing it? I can't find anything from the part number you provided.

Also, do you (or anybody else) happen to have a FSM or other guide for the timing chain replacement? It would be handy to know maximum allowed tolerances and torque specs on some of these things and the chilton manual doesn't really cover it all.

 

Check the kit that you got for the cam gear first, to be sure it doesn't have it. I couldn't find anywhere that gave the thrust plate its own part number. Doesn't mean it doesn't have one, but I know the kit I ordered stated that the plate was included.

I do not have a parts diagram showing the sensor dot. I was skeptical when the parts guy gave me the number after the tech mentioned that I should get one. I googled the part number and couldn't find any pictures, and Factorychryslerparts.com didn't list it, but I called a local dealer and sure enough, they knew it and had one in at 7:30 the following morning.

It didn't even come in an official package; they dropped it into a Mopar loose parts baggie for me so I wouldn't lose it.

Let me know how it goes with yours! I have not ordered the timing parts yet; waiting to get paid next week. I did order a new upper and lower rad hose, inlet pipe, thermostat and gasket, water pump, and radiator cap in anticipation of having that done when I get the timing chain done. It's something I would typically do myself, but I can't see spending $$$ on antifreeze only to have it drained out again when the mechanic does the timing chain job in a month or so.

 

The link you provided gives the thrust plate a part number: 04621623 I checked it against the 3.3L diagram (as you linked a 3.8L) and it seems to check out there as well.

I will not be ordering any more parts until I get around to doing the job which will be some time this summer. First I need to get my auto-x car in order as the first event is May 19, but after that I'll be catching this van up on a few things, air filter, spark plugs and wires, thermostat, timing chain, etc.

Some quick searching seems to indicate that 0.304mm is the maximum allowed camshaft end play, and ~0.24mm is the maximum allowed crankshaft end play. I'll check these both when I pull mine apart to see what is up. If the gears are getting slightly out of alignment I could see it eating up chains pretty quickly. I don't think there is anywhere near enough play there for either the cam or crank gears to contact the front cover, but maybe the misalignment is causing the chain to wear allowing it to slap around.

 

Oh, duh, I didn't scroll down far enough to see that part number. Thanks for pointing that out.

The diagrams on that site are wonky, they use 3.8 and 3.3L diagrams interchangeably but they do provide an "enter-your-vehicle" cross check of the part numbers to show what fits and what doesn't.

Like you, I don't think there's enough room for the gears themselves to hit the timing cover, but I could see one getting out of alignment slightly and stretching the chain over time.

If I get mine done first, I will report what I find.

 

I just wanted to post back and say you were right, I drove down to Montana and picked up the parts on saturday. Much to my surprise when I opened the box I found the camshaft gear box was marked 05137663AA and it did include the thrust plate in the box. This dealership really knows their stuff, and they only charged me $20.52 for it, that's hard to argue with!

Now I just need to find the time to tear into the van and change this thing out. I'll be doing the brakes and sway bar bushings in the coming weeks but with the work I have planned on my autocross car I don't see me getting to the van until at least mid june

 

Cool! I figured you would get the thrust plate too.

Interesting side note, my van is fixed. I misdiagnosed it. It was the water pump. Destroyed itself while my wife was driving it home the other day. It made it home, didn't overheat, lost about a gallon of antifreeze.

I spent Sat. AM on my back in the back alley putting it in, but we've driven it @ 300 miles since then and everything seems great...AND THE SOUND IS GONE!

I also put new hoses, new inlet tube, new thermostat, and a new rad cap and plenty of new MOPAR coolant in while I was in there. It was a job I had been meaning to do so I had everything but the inlet tube already in the basement.

Would still be interested to know how your job goes and am currently thankful and relieved (as is my wallet) that I don't have to do the timing parts for the moment.

 

That isn't encouraging
I have to stock up parts in advance and tackle the whole job together, but at least I don't have to pay labour on any of it so I suppose that makes it a little bit less expensive.

I plan on tackling this over the may long weekend so I get some extra time if it all goes sideways. Can you change the water pump without dropping the passenger side of the engine? If that's the case I will just jump in on the timing chain and do the water pump later if it is still necessary. How long did it take you to change the pump?

 

I have read varying reports on the success of changing out the pump without lowering the engine. Some people said their water pump came right out with no clearance issues whatsoever. Others said they needed a pry bar, and others had to lower the engine.

In my case, I first tried the "pry bar between frame rail and tensioner pulley" to push the engine towards the driver's side and gain clearance to remove the pump. Did not work in my case.

Finally, I removed the top of the air box and the rubber plenum that went to the throttle body (one screw clamp and one sensor harness and it came off) which gave me unfettered breaker-bar access to the three bolts for the engine mount. I sequentially loosened them until I had lowered the engine a centimeter or two and everything worked very well, pump came right out and went right back in.

You cannot change the timing chain without removing the water pump, is my understanding, so you ought to put a new one in either way. If I understand correctly, at the very least the water pump and pulley need to come off to allow the timing chain cover to be removed? Apparently these vehicles are known for water pump issues around 80k miles, so in my case, that's what happened.

A new water pump with a lifetime warranty is @ $35 from Advance Auto Parts. In my case, the new pump I bought had a cast aluminum impeller, while the factory Dodge pump had a plastic rotor. I felt a bit better putting the new pump in.

It took me an even 3 hours. The quoted service time on the water pump is 1.5, but that's on a lift, not lying on my back covered with antifreeze, LOL. I did also replace the thermostat, upper and lower rad hose, and inlet tube, which ate up some more time.

The upper rad hose was almost welded to the thermostat housing because, I assume, of the temps the hose reaches due to its position right over the exhaust crossover pipe. I had to heat the remnants of the rubber hose with a flame and then scrape them off with a knife to get the new hose to fit properly. That took some time.

 

There is a plastic impeller on the stock pump... right.... I think I'll be getting rid of that then and won't be replacing it with another mopar one since it would also come with a plastic impeller. Thanks for pointing that out, I had forgotten, and a lifetime warranty pump is always a good thing to have as we plan on keeping this van for quite some time.

I have invited my dad over to act as a spare set of hands and he isn't free until the may long weekend so I'll try to post back once I have some results but it will be a little while.