Cam Timing and Timing Belts
For a stock cam that has just been R&Red: With the engine at TDC, the small mark on the crank sprocket and intermediate shaft sprocket for the cam timing belt should be pointing at each other (also along the C/L of the center of these pulleys). Then the cam sprocket has two little arrows (triangles) opposite each other that point at the center of two holes in the sprocket. You should line up these arrows with the junction of the #1 cam tower cap and the head (you will be able to see this clearly through those holes). Then install the belt without moving any of these. Start at the crank and work to the intermediate shaft, then to the cam. There should not be any obvious slack in the belt as you do this. Finally get the belt past the tensioner, tension the belt. If you do not have the tensioner tool, then the belt is properly tensioned when you cannot rotate the belt more than 90 degrees or 1/4 turn midway between the cam and intermediate sprockets. You should turn the engine over a couple of revolutions and recheck every thing.
One more method of setting the timing belt tension is that there should be approx. 5/16" of deflection from center possible midway between the cam sprocket and the crankshaft sprocket, about where the head meets the block. Also, 90 degrees twist should just be possible midway between the cam sprocket and the intermediate sprocket. I pulled this from the Haynes book.
An easy way to check your cam timing without having to look at the engine sprockets, is to turn your engine to TDC using the flywheel mark, and look at your cam sprocket. Make sure the little arrows are lined up on the cam bearing seam. I use a mirror to get a straight look at it, since your head won't fit in there :)
This will ensure cam-crankshaft alignment, and the intermediate shaft alignment is not quite as critical and and be a tooth or two off since it only times the distributor, which of course can itself be rotated when you tune-up your car.
Replacing the 3.0 V6 timing belt
Note: There is a longer description of how to do this, including lots of pictures and notes on special tools and other maintenance to do at the same time - click here to read it.
- To start off , jack up and support the vehicle , remove the right front tire and the drive belt splash shield . Also drain the coolant .
- Remove the drive belts and the serpentine belt tensioner .
- Remove the upper radiator hose .
- Remove the A/C compressor attaching bolts .
- Remove the A/C belt idler pulley and the tensioner bracket .
- Remove the 2-15mm bolts that hold the power steering pump to the front mounting plate and the 2-15mm bolts holding the bracket from the rear of the P/S pump to the engine block .
- Remove the 22mm bolt from the crankshaft pulley and slip the pulley off .
- Remove the A/C compressor bracket .
- Remove the 2-15mm bolts holding the front motor mount to the frame and use a block of wood on a jack and lift the engine from under the oil pan.
- Remove the front mounting plate and mount from the engine .
- Remove the 3 piece timing belt cover .
- Set the engine to TDC (top dead center) and line up the timing marks on the crankshaft pulley and both cam pulleys .
- Remove the timing belt tensioner and the belt .
- Remove the single 12mm bolt on top of the water pump and loosen the two others , pry the bracket up to gain water pump clearance .
- Remove the 5-12mm bolts holding the water pump in place and pry out the water pump .
- Replace the "O" ring on the water pump cross over tube and replace the water pump .
NOTE: I suggest using a factory original water pump because it will come complete .
NOTE: After replacing the timing belt , turn the engine over a few times by hand and recheck the tension and timing mark alignment .
Roger Lister wrote about Caravan timing belt replacement:
The job isn't terribly difficult if you don't mind getting dirty and beware you will skin some knuckles. The hardest part of this job is getting the motor mounting plate off the front of the block. You have to take off your AC compressor and bracket, remove the bolts for the power steering pump (don't forget the nut on the back). Naturally the AC and serpentine belts must come off. Support the motor with a jack before trying to remove the motor plate. After the plate is off, remove the timing belt covers, with a 1/2" drive breaker bar slowly rotate the crank so that the timing marks on the crank (mark on oil pump) left cam (mark on alternator bracket) and right cam (mark on housing) all line up. Loosen the timing belt tensioner, pull off the old belt.
You might take this time to clean the area at the crank sprocket of any dirt and debris that may have collected there. Also take a moment to check the crank seal (pull the crank sprocket should come off by hand) to see if it is passing oil. If you suspect it, change it while you are there. Not hard, but you will cuss some. And save some grief later.
Now, putting on the new belt (oh boy, here we go!). Put the belt around the right sprocket (front cam), down to the crank sprocket (you put it back on didn't you?), try to keep tension on it while you putt tension on the top and put on the left (rear sprocket). Don't forget to loop the belt under the water pump pulley (yes, that is the water pump) and in front of the tensioner. This may take a few tries, it did me. Do not worry about getting tension on the left side where the tensioner is, until everything lines up and is tight.
Then apply tension to the left side and tighten the tensioner.
Now at this point I put the crank pulley back on and tightened the nut. Reconnected the couple of vacuum lines and wires that I took off to make getting the plate off easier. Made sure that the motor was securely supported, and started the motor and let it run off the battery for a few minutes. I shut it off, rotated the crank with the bar so all the marks lined up, and I was happy.
One small note in my case.My rear cam is a hair before the mark and the front cam is a bit after. Not a whole tooth mind you, but a bit. I want to find a set of adjustable cam sprockets like the racerboys use on their Honduhs. Then my timing will be spot on and I can make adjustments to play as well, for fine tuning.
If everything stayed lined up, make sure the tensioner bolt is tight, and start buttoning it all back up. You shouldn't have any left over parts (hey where'd this come from?). After you have it all back together, start it up and listen for any thing that may make odd sounds. It should be quiet.
Pat yourself on the back, grab all the neighbors and tell them what you accomplished, make your wife come outside so she see the thing running ( you know she doubts everything I say I can do) and help yourself to a cold one, you deserve it. Congratulations.
What I did was a bit more involved, but I don't throw any more oil on the ground now. One thing about Chiltons. They oversimplify everything. There are more than 11 steps to changing the belt. There isn't anything terribly tough, just time consuming. You could do this job in a day. I took three with all I had to do. But then there was more than I expected too.
Water pump replacement (Roger Lister)
If you suspect that your water pump is going to die on you sometime soon, go ahead and replace it [when you change your timing belt].
A word of caution (This is what happened to me). When I replaced mine 2 years ago, I bought an aftermarket one through NAPA. Almost all aftermarket pumps come as only the front half of the pump. You need to take the back half from the old pump. If you buy the pump at your local dealer, be prepared to spend about $145 US. NAPA was only $45US. When I removed the water pump, it had a handful of bolts on the front, and one countersunk Phillips head screw on the back. I couldn't remove the damn screw. I used my impact hammer, I heated it with my propane torch and even soaked the area in various penetrants. Finally, I needed the balk half so I broke the front half at the screw to get it apart. The screw got really munged up so I figured when all the parts places opened, I could replace that one screw.
Long story short, I couldn't find the screw. I did though, find an Allen headed bolt of the same thread pitch and diameter (metric) and chucked the bolt in my drill and used a file to cut the bottom of the head to a bevel to fit the countersunk hole. I put in this bolt after I had the rest of the pump gasketed and sealed (added extra permatex in the area of the modified screw) and then ground down the head of that screw/bolt. There is enough of an indentation to use an Allen wrench in it, but I didn't try since I was putting together to stay not take apart on a constant basis.
If I need to replace it ever again, I hope I can get it out. I lived in San Diego at the time and STILL couldn't find that one damn screw.
Since you will have all of the timing belt stuff off anyway, now would be a VERY good time to change your front oil seals on the cams and the crank. IF you don't leak now, it won't leak ever if you change them now. The seals harden with age. My crank seal was so hard at the crank that it fell apart when I was removing it. Until they seat, they may leak a bit, but then be fine. I replaced all that and the oil pump gasket this past weekend and was VERY upset to see fresh oil on the ground at work the next day. I wiped the area at the oil pan (under the crank seal/oil pump) and it has remained clear since then.
The job isn't terribly difficult. If you have a manual of any sort, you are ahead of me when I did mine, since I didn't have anything. I don't recommend that path. Just pay attention to what came from where and you are in good shape.
Cordell Loken added:
My local mechanic friend and I have a suggestion for you to make it easier. He told me I did NOT have to take off the intake manifold, and here is how we did it.
After loosening the water pump, loosen the four bolts [plus take out the two additional brace bolts] on the alternator mounting bracket. This allows enough room to get that strap-iron brace off the top of the water pump. One of the three bolts can not come all the way out, but that's ok.
In order to make it easy to put the other two bolts back in, I ground off about 1/8" from one of them. If the manufacturer had put a slot in the top end of that strap-iron, it would have been easy to remove -- in fact, the two holes which don't attach to the water pump could be slotted. I work in a machine shop, so that's why I came up with that slot idea.
Ed Treijs wrote:
If your cam is off by one tooth, your engine will barely run, or at least be very unhappy.
If you are convinced it's cam timing rather than ignition timing (or you can't adjust the distributor far enough to get the specified advance), well, you can retime the cam without pulling the bottom of the engine apart. Loosen the tensioner, and carefully pop the belt over by one tooth on the cam sprocket. Keep tension on the lower part of the belt! You can mark the sprocket/belt to make sure you only change by one tooth.
If engine runs fine, done.
But Butch wrote:
I can, without a doubt vouch that this part is untrue. My first run ever at Lebanon netted me only 17.00 sec/84 mph runs. My cam was one tooth advanced. I fixed it andwhen I started the car, it ran fine, but didn't make real power until 2500 rpm. Ididn't tighten up the tensioner enough and the cam jumped back one tooth! At present, with the cam timing perfect, I'm running, on street tires andreal crappy launches, 16.00/87.5 mph. Bottom line, the car will run OK one tooth off either way but low end power is sacrificed one way and top end is sacrificed the other way.
Neil Emiro wrote:
Get your timing light, if it has an advacne dial, set it to 12M-0, if not set the timing to 0M-0, then shine the light into the little hole in the side of the timing belt cover. You should see a hole in the cam sprocket in there, if it's in the middle of the hole, cam timing is OK, if it's towards the front, it's advanced, towards the back, it's retarded a tooth.
1987 Daytona 2.2 timing belts:
"Chrysler Tech" wrote:
The timing belt is adjusted by a counter weight tool. Just the weight of the tool is all the tension you need. I check with a tool rental or parts store to see if you can rent one. There is very little tension on the belt, to much and it makes noise and to little and belt will jump. So if you can, find the tool.
Most people who do this job the first time aren't aware of how little tension is required for the timing belt. If you're not using the special tool, rotate the tensioner pulley counter-clockwise just enough to remove the slack from the belt, and then about three degrees more. Remember that cogged belts run much looser than V-belts. You only need to tension it enough to prevent it from flapping around while running. It's important not to over-tighten the belt if you want to avoid premature failure.
Beiseker Bob wrote:
KD tools makes the tensioner tool under part number 3282, or OTC also supplies this tool as a 7695. Either and or both should be available at various auto parts chains for about twenty something bucks USD...or of course, you could contact your local Snap On distributor (little plug here...*grin*) and they carry both of these, or should!!