timing engine
#1
05-12-2015, 10:05 AM
timing engine
hello folks.
i am a new member and unsure of proper procedures so i'll throw this out there and i'm sure i'll be told what to do or where to go.i have a 2003 l300 that needed a new water pump.no big deal there,but while doing an errand,a helper decided to examine the timing belt and of course messed everything up.i'm trying to replace timing belt but engine is now out of time.crank has been turned and so has cam gears so i have to start from scratch.when i turn crank after a turn or so it hits metal,which i presume is a valve.so do i turn cam gears to get them out of the way first?i thought that if cam gears were on marks they were timed,but can they be 180 out?help with how to procede please.
i am a new member and unsure of proper procedures so i'll throw this out there and i'm sure i'll be told what to do or where to go.i have a 2003 l300 that needed a new water pump.no big deal there,but while doing an errand,a helper decided to examine the timing belt and of course messed everything up.i'm trying to replace timing belt but engine is now out of time.crank has been turned and so has cam gears so i have to start from scratch.when i turn crank after a turn or so it hits metal,which i presume is a valve.so do i turn cam gears to get them out of the way first?i thought that if cam gears were on marks they were timed,but can they be 180 out?help with how to procede please.
#5
05-12-2015, 03:22 PM
actually,i should have known better than to leave the vehicle without the instruction not to touch anything until i got back.it does have the mileage and should be changed-it will now-but there are failsafes to stop timing from changing.i did gm parts depts. for close to thirty years.thats alot of tech watching.i do all my own work but sometimes come across something i haven't done.from what i've seen on this thread i'm sure someone will steer me in the right direction.
#6
05-12-2015, 08:30 PM
found this on the net -- not quite what you are looking for , but hope it helps
_________________
Changed L300 timing belt, water pump, and main accessory belt myself this weekend! (mine is a 2001, and it just hit 100K miles). And yes, it ran perfectly afterwards. After finding out that the dealer wanted over $1100 to do these 3 things, I decided to do it myself. I had read some helpful posts on this forum, and have the Haynes manual also. It cost about $250 for the parts, so you save a bundle. Also, I didn’t use the specialty tool(s) – I think these are designed as a “mistake proofing” method to make it easier and faster for mechanics who do this job on a routine basis, but if you’re VERY careful, and check your work (and you’re pretty good with your hands) you can do it. But….I wouldn’t recommend this job for someone who isn’t mechanically inclined. I used vice grips to lock the camshaft wheels (someone else had posted some pics of this, and it worked perfectly, just don’t clamp them too hard, you don’t want to stress or bend the camshaft’s toothed wheel).
The water pump and main accessory belt are pretty easy, but you do have to be really careful changing out the timing belt, mainly in 2 key areas:
1) Make sure that before you remove the belt, that you get the crankshaft rotated so that you have cylinder #1 at TDC – you do this by slowly turning it until the timing marks on the camshaft wheels are lined up with the timing marks on the cover. Be careful to mark which of the 2 timing marks is on each camshaft wheel, since there are 2 (there are good illustrations of this in the Haynes manual). Note – I didn’t remove the plugs like they recommended, because I wanted to keep compression in the cylinders, which keeps the crankshaft locked in place really well. It makes a little harder to turn the crank, but you should get the TDC alignment done before you remove the crankshaft belt pulley, so you can use the pulley to turn the crankshaft.
2) There are 3 idlers/tensioners that the belt runs over, an upper, lower, and main. If you understand how they work and are adjusted, it makes the change out a lot easier – I couldn’t find any explanations of this anywhere, so thought I’d put it out here so it might help someone else. All of them pivot around an eccentric “cam” type mount, so rotating the tensioner changes the amount of tension, mainly on the section of the belt where that tensioner is located. Before loosening any of them, I made a mark with a permanent marker on each one, and then made a sketch on a paper to show the exact orientation of each one – i.e., upper tensioner mark at 2 o’clock, lower at 10 o’clock. You don’t have to worry about the main tensioner, since it has a small cam with built in alignment marks, and should be set at 3-4mm, as indicated in the Haynes book. You adjust it by turning the center portion with an Allen key, and then tighten the bolt to lock it.
I noticed that as I released tension on the belt over the front cylinders (3&4), the #3 camwheel actually moved about a half tooth (even with the vice grips installed), so be sure to observe the belt carefully as you remove it, so you can compensate when you put it back.
So, the key thing as you re-install the belt is to make sure that the belt is fairly tight between each pulley or toothed sprocket, when the upper and lower tensioners are set at their original position when you took them off. Then you finish setting the overall tension with the main tensioner, which has the built in alignment mark. Double check everything just to be sure. Hope this helps someone out there, and good luck!
_________________
Changed L300 timing belt, water pump, and main accessory belt myself this weekend! (mine is a 2001, and it just hit 100K miles). And yes, it ran perfectly afterwards. After finding out that the dealer wanted over $1100 to do these 3 things, I decided to do it myself. I had read some helpful posts on this forum, and have the Haynes manual also. It cost about $250 for the parts, so you save a bundle. Also, I didn’t use the specialty tool(s) – I think these are designed as a “mistake proofing” method to make it easier and faster for mechanics who do this job on a routine basis, but if you’re VERY careful, and check your work (and you’re pretty good with your hands) you can do it. But….I wouldn’t recommend this job for someone who isn’t mechanically inclined. I used vice grips to lock the camshaft wheels (someone else had posted some pics of this, and it worked perfectly, just don’t clamp them too hard, you don’t want to stress or bend the camshaft’s toothed wheel).
The water pump and main accessory belt are pretty easy, but you do have to be really careful changing out the timing belt, mainly in 2 key areas:
1) Make sure that before you remove the belt, that you get the crankshaft rotated so that you have cylinder #1 at TDC – you do this by slowly turning it until the timing marks on the camshaft wheels are lined up with the timing marks on the cover. Be careful to mark which of the 2 timing marks is on each camshaft wheel, since there are 2 (there are good illustrations of this in the Haynes manual). Note – I didn’t remove the plugs like they recommended, because I wanted to keep compression in the cylinders, which keeps the crankshaft locked in place really well. It makes a little harder to turn the crank, but you should get the TDC alignment done before you remove the crankshaft belt pulley, so you can use the pulley to turn the crankshaft.
2) There are 3 idlers/tensioners that the belt runs over, an upper, lower, and main. If you understand how they work and are adjusted, it makes the change out a lot easier – I couldn’t find any explanations of this anywhere, so thought I’d put it out here so it might help someone else. All of them pivot around an eccentric “cam” type mount, so rotating the tensioner changes the amount of tension, mainly on the section of the belt where that tensioner is located. Before loosening any of them, I made a mark with a permanent marker on each one, and then made a sketch on a paper to show the exact orientation of each one – i.e., upper tensioner mark at 2 o’clock, lower at 10 o’clock. You don’t have to worry about the main tensioner, since it has a small cam with built in alignment marks, and should be set at 3-4mm, as indicated in the Haynes book. You adjust it by turning the center portion with an Allen key, and then tighten the bolt to lock it.
I noticed that as I released tension on the belt over the front cylinders (3&4), the #3 camwheel actually moved about a half tooth (even with the vice grips installed), so be sure to observe the belt carefully as you remove it, so you can compensate when you put it back.
So, the key thing as you re-install the belt is to make sure that the belt is fairly tight between each pulley or toothed sprocket, when the upper and lower tensioners are set at their original position when you took them off. Then you finish setting the overall tension with the main tensioner, which has the built in alignment mark. Double check everything just to be sure. Hope this helps someone out there, and good luck!
#7
05-13-2015, 01:44 PM
thanks derf,that is what i was going to do before the ****** messed it up.now timing has moved and i need to pick it up from there. i know where the timing marks are,i hac actually marked with marker where the gears were and all that.now crank has been turned and so has the cam gears.if i turn the cam gears,the valves will move.how do i know when the valves are in the correct position?can they be 180 out?once i get that straightened out then i can put the crank in tdc.does this sound right?
#8
05-13-2015, 05:29 PM
Don't worry about the crank. As long as you have the timing mark on it in the right spot and the #1 piston is at TDC, you'll be fine. It's those damn camshafts you need to be concerned with. Place them where the marks are supposed to be and see if the rockers all move. If so, then all the valves should be closed. If some are tight, rotate it 180 degrees and then check it. Once you've got play in all of the rockers on BOTH cams and the marks are lined up, you should be good to go. I'm not an ASE mechanic, and I've only done one DOHC in my 43 years of fooling with cars. But, the same principal applies to all cars. As long as all the valves are closed and all timing marks are where they're supposed to be, theoretically, you should be good. Try that, and then rotate the engine a couple of times by hand and see what you have. If that doesn't work, then I don't have any ideas.
#9
05-13-2015, 10:22 PM
If you go to the general help tab and then go to the online Saturn manuals. There is a complete factory section on replacing the timing belt. It describes how to get everything back in time without bending any valves.
#10
05-13-2015, 10:26 PM
I just purchased my lw300 so I have not got to the belt yet, I plan to purchase the tool kit on fleabay for about $80.00 delivered. When I go in it will get seals and a water pump. Let us know please.
Andy
Andy
