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Chaning timing belt this week.... Question about locking cam sprockets

3K views 31 replies 12 participants last post by  CaptainMorgan 
#1 ·
Has anyone locked the cam sprockets when replacing the 2nd gen 3.5L timing belt?

I found a method in the following post...

NOT ALLOWED TO POST URLs YET SO I WILL QUOTE THE POST....

You can get the puller at your local AdvanceAuto or what not on rental.....its specifically has the set-up for the Chrysler 2.7,3.2,3.5 with out having to pull the radiator...this will simplify things. Just have to pull the fans...top radiator hose and 1 trans line on top.
Save time and rent it. Her is a pic.



BEFORE you remove the belt or tensioner turn the crank till you line the pointers on the crank together and the line on the cam gears line up between the dots on the covers..lock them as follows

Just lock the cams in place before you remove the belt..here is a poor mans version.....Remove the cover bolt behind the cam gear... use a longer bolt and a piece of tubing/pipe or an old piston pin like i did. you can adjust it up snug against the gear and then tighten it down...simple.....( I saw this from TFC on a search before I did my first one..what a little trick)









Install the belt counterclockwise ..crank to right side cam gear under waterpump to left cam gear and under tensioner pulley. (as looking from front of vehicle)

You can get a quality timing kit from Gates...TCK295. Includes the Pulley assembly with the belt.

The factory belts were made by Gates.

I have done 2 of these in the last few months..one on a 2000 LHS and just yesterday for my 2000 R/T.

It will take you the afternoon or better your first time.
Its pretty simple....

You need the puller....

few metric sockets...7,8,10,13,15,18 mm

standard screw driver

bucket to catch anti-freeze

vise or press pre-set the hydr tensioner..and a small allenwrench to use for a pin.

...seems it can be done without special tools. I'm willing to buy an extra tool if there is one to accomplish the same goal, but if it can be done without an extra tool .... even better.

I'm just not understanding exactly what he used to lock the cams, even with pictures and descriptions. Did he take out the bolts behind the cam sprockets, the thread them back in slightly with a piston pin over them?

If anyone has any advice for locking my cam sprockets when I do this job, I'd appreciate it. As much advice as anyone wants to give is greatly appreciated!! :)
 
#2 ·
He took out one bolt behind each cam sprocket in the locations pictured. He then used LONGER bolts(sourced from a hardware store?) with a piston pin as a "spacer" to hold the sprocket in place. I believe you could use an old socket or buy some pipe/fittings from a hardware store in place of the piston pins. After you're done pull the long bolts out and replace with the original ones.
 
#3 ·
You aren't going to want them locked. You'll need to advance/retard the sprockets as you put it back together.
 
#4 ·
That's the method I use, minus the piston pin and needing to buy a longer bolt. You can use on of the bolts that you remove from the serpentine belt tensioner if I recall correctly. A lot of people don't even bother to lock the cams, it just makes it easier. I only lock one cam (passenger), I'm not sure if they do in that method or not, I don't feel like reading the whole thing.
 
#5 ·
I didn't lock my camshaft sprockets either. I didn't see the need as long as you don't loosen the camshaft sprocket bolts (which you don't need to do).

On a related note, I found that the pitch of the timing belt teeth equaled the range of the guide marks on the block (i.e. the marks that the corresponding mark on the sprocket falls between when the engine is TDC). So I found that there was only one belt position where the two camshaft sprockets marks both fell between the marks on the engine block.
 
#6 · (Edited)
I have never locked the sprockets. Easier to time that way. You will need to move one or the other just slightly to get it timed. Only time you need to lock them is if you are removing the sprockets, which then I would strongly recommend the special tool, which keeps them lined up perfectly for removal/installation of the sprocket. Even when i did that, I removed the locks before installing the belt.
 
#7 ·
Others (Ross) posted in the past that you can use a lug nut in place of the socket/piston pin/whatever.

The *most* important thing if you use that is to be sure not to forget to remove it before cranking the engine over. :)
 
#8 ·
My plan was to lock the cams in place while the old belt was still on. Are you ALL suggesting this isnt a good idea? I was going to rotate the OLD belt until the CRANK sprocket was at TDC, then lock the cam sprockets in place. In my mind, this was ensuring I got the belt on EXACTLY how the old one was.

Why wouldn't that make things easier?
 
#9 ·
it is easier to install the new belt without the locks because one of the cams will have to be moved slightly to allow for the tooth of the belt to go over the sprocket and then be pulled tight to put everything in time. if you try to install the belt with both cams locked then you will likely have the timing be one tooth off once you install the tensioner and pull the belt tight.
 
#10 ·
I see.

Then can someone please explain what the BENEFIT of locking them is?

I'm confident I can do it either way. I've done lots of brake jobs, tie rod ends, axles shafts, hundreds of oil changes, fuel filters, belts, alternators, starters, etc. in my life. Never done a timing belt by myself, but I have helped with one on a Honda Civic. I have been the "second guy" on 20+ engine swaps in all my years.
 
#14 ·
Oh.


Well thanks guys. I thought the purpose of locking the cams was so you could get the belt back on exactly how the old one was in place. But evidently , from what everyone is saying, it's very easy to just use the timing marks and do it that way

I'm looking forward to doing this on Thursday or Friday when my gates belt/pump/pulley arrive from Rock Auto.
 
#16 ·
It is pretty straightforward to line them up. LIne up the DS cam as close to dead center between the dots as you can...for the PS cam if you can, bias the mark more toward the right (inboard side), when you release the tensioner, it should pull it in pretty close to dead center.

Also, to keep things in place while threading the new belt on, after I got the belt on the crank sprocket, I stuffed a rag between the timing case and the belt to hold it in place. Same thing after I got it on the DS cam. With the rags holding it in place, it makes it easy to finish threading it around the WP and the PS cam and tensioner pulley. Just remember to pull the rags out.....
 
#17 ·
I have done it both ways. 2 with using the TFC cam locks (long bolt through sockets) and 1 without. I will now do them without locking the cams although I would not go as far as saying it is harmless!! My finger begs to differ. Got caught between the belt and pulley during a "snap roll"!~ OUCH!

I also will use the method of installing the hydraulic tensioner by leaving it extended and alternating tightening each bolt slowly as the tension applies pressure on the Idler bracket. IIRC this method required advancing the drivers side cam 1 tooth to the right. And it is then drawn back as the tensioner is installed.
 
#18 ·
SO the cam sprockets snap back violently enough to hurt you if your fingers are near them? If thats the case I might want to lock them..... LOL.... I thought you had to pull on the belt to keep tension on it when installing it around each pulley..... will this tension cause them to snap back?
 
#20 ·
I thought you had to pull on the belt to keep tension on it when installing it around each pulley..... will this tension cause them to snap back?
If the cam sprockets are in the right position as you begin the install the belt, you really should not have a problem. The teeth & grooves on the belt & sprockets sort of keep everything in place as you move along. If you use the rag to keep it in place on the crank sprocket when you start, that will keep the teeth & grooves meshed, and the belt won't slip. Then you keep tension on it as you thread it around the DS cam sprocket. The belt doesn't stretch, so as long as you keep tension on it, you just need to adjust the cam sprocket slightly till the teeth and grooves mesh with the timing mark between the dots (as close to center as you can get it). Once you position the belt properly on the DS cam, place another rag there to hold it. Then the teeth/grooves will hold everything in place while you continue to thread it under the WP and around the PS cam sprocket. Keep up the tension and slightly adjust the cam sprocket like before (on this side, if you can, keep the timing mark between the dots, but biased slightly toward the right). Then go around the tensioner pulley and you should be all set. When you replace the tensioner plunger, it will take up the remaining slack, and it should rotate the PS cam sprocket just enough to center between the dots (this will also snug it up against the WP pulley).
 
#19 ·
Here's my $0.02:

The cams will stay in position (properly aligned between the dots), in general. I've changed my TB twice, never had a cam flip around on me, but yes, there is a good bit of tension on them.

Only if you end up turning them beyond the alignment marks should you have to worry about it breaking loose on you. But the only time you'd be doing that would be to possibly make an adjustment to the TB fitment, in which case I definitely recommend using a breaker-bar and appropriate socket. Keep a firm grip and you'll be fine. Your leverage on the breaker bar will easily overcome the tension of the valve springs.

My first TB/WP swap was scary as all get-out, had never done any kind of work on an engine like that. I ended up one tooth off on the belt, didn't really notice until a day or two later and it ran rough at idle. Had to tear it all back apart and re-install the belt. Lesson learned - do NOT skip the step where you rotate the crank around a few times to verify that all the dots line up properly after a full rotation.
 
#21 ·
Just keep your hands/fingers on the outside of the belt and there are no worries. My snapped over on me when I was trying to get the right side advanced enough to allow it to come back in the dots after the tensioner was installed.

There is a nice video on youtube done by Grayslater (Cory) that will show you all the ropes.

 
#23 ·
for the purpose of "bumping" the camshaft to help the sprockets line up with the ribs in the belt, I would suggest using a wrench rather than a socket (especially on the drivers side). If you bump the drivers side over too far with a ratchet and socket then it will quickly spring over to the neutral position where as if you use a wrench then you will have more control over it.
 
#24 · (Edited)
That's why Mr. Big Stuff said to use a breaker bar (vs. a ratchet). :) But you bring up a good point and the point is worth emphasizing, So - yeah - either a box or open end wrench *or* socket with breaker bar.

 
#25 ·
When I am doing this job, is there anything (besides the water pump, tensioner pulley, and belt) I should change just vecause I will have easy access? Will I have easy access to the thermostat? If so , I think I'll put a new OEM one in. My car runs at perfect temp, but at 140,000 miles the thermostat could go anytime.

I got the car with 136,000 and only recently got in touch with the original owner to find out if the timing belt had been changed. I found out <1k miles ago it had NOT been done. Needless to say I'm doing it ASAP.
 
#26 ·
Well, your instincts are good. With the radiator fans out, and draining the coolant to change the WP, now is as good of a time as ever to do the thermostat. It's a pain to get to, but some have had success by pulling the alternator (or at least swinging it upwards) and attacking from up top, rather than below.
 
#28 ·
I definitely prefer going at it from above. Easier access once you have the alternator out of the way. Make sure you install the new t-stat the correct way (coil into the block). Be aware that there is a small lenght of heater hose (maybe 8-12") from the t-stat housing to the heater return tube. Makes it a bit of a PITA to get the new t-stat in.
 
#31 ·
Below is what it looks like reaching the thermostat with the alternator removed. Work on it from above.

Another tip: Remove the oil filter to give you more room to work in down there.

In the photo, I'm showing off my factory hose clamp removal tool - I can't tell you how much easier it makes working with those clamps! AUtozone and NAPA have some decent ones - around $25 IIRC.
 

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#32 ·
Lots of great advice here. These guys have it covered.

I did a huge project with my TB/WP change a couple years ago. I swapped to a police alternator, ASP crank underdrive pulley, Alternator OD pulley, and new belts. I didn't do my Tstat because mine isn't all that old, I changed it a few years back and it's got plenty of life left. I wish I had known about the method of removing the alt to get in there from the top, working in a driveway from the bottom sucks.
 
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