Timing Belt Slack Explained [Merged 6-7] loose cam sag sagging sprockets gears

[defbear]

I was just wondering if its normal for the timing belt to have some slack after its been sitting over night. I have been checking it for the past few days. When the car has just been shut off and for a few hours after its nice and tight with virtually no play. But in the morning when I check it there is some, not alot, but some play. More than just after its been driven. The timing belt and tensioner were replaced about 2000 miles ago. Anyone have any ideas?

 

[mark95turbo]

How did you install the new belt? You should have started at the exhaust cam, lined the marks up, put it over the intake cam, clipped those down, then fed it loosely around the idler pulley, pulled it tight and wrapped it around the oil pump sprocket, then tightly around the crank sprocket, and then slipped it on the tensioner pulley and set the tension. You should have installed it in that exact order. It sounds to me like you installed it backwards allowing all of the looseness to be around the idler pulley instead of the tensioner pulley. Not sure about the NT cam sprockets though. I would think they would be the same size, but have no idea. Good luck!

 

[tsidrift1]

i put the belt on in the order that the haynes manual says to do. like i said before the car runs great, real strong and everything, but the belt noise is annoying

 

[mark95turbo]

Did you replace\inspect the tensioner? That would be my final solution! Good luck!

 

[Talon007]

Do not use the Haynes!!!!!!!

www.vfaq.com

 

[BUCK]

http://www.dsmtuners.com/forums/showthread.php?t=125194

 

[tsidrift1]

i got a new tensioner and i still have a loose belt. the first night i drove it the oil pump sprocket nut came off and oil went everywhere, including the belt. could the oil possibly stretched the belt and now it is not the right size.

 

[luv2rallye]

Oil on a new belt won't stretch it out as there are many high strength wires inside it. It may damage it in other ways however - if you wash it off and dry it you should be ok unless it is really impregnated. You obviously never got the tension correct and never should have even started it that way. Your other major problem is you are using a Haynes or Chilton's manual. Never use these manuals as they are natoriously wrong on critical engine items!
Correct Timing belt directions:
1G: http://www.vfaq.com/mods/timingbelt-1G.html
2G: http://www.vfaq.com/mods/timingbelt-2G.html
!!! Start over and USE THEM!!!

 

[91awd]

My friend had an oil leak and it got all over his timing belt and it was really loose after that. I would say that it streches it, we put a new belt on after we fixed his oil leak and it's back to normal. And don't drive your car until you get this fixed you have been lucky so far but it will skip some day and you will be pissed.

 

[luv2rallye]

I'm sorry - yes oil on the timing belt may stretch it and will definately ruin it. I was thinking of coolant on the belt which just happened to me on a DSM I recently fixed needing a water pump and temporarily poured all over the belt when I took the pump off. You know when you get over 50, your mind starts to go...
If you can't get the tension correct using the correct proceedure, you've got something really out of wack. I don't know about the camshaft sprockets. Call the dealer and see if the part #'s are the same. Also not using a dealer timing belt and pulleys has caused people endless problems and in my opinion just not worth the $ savings. I know the after market tensioner pulley and idler pulley are not exactly the same as the dealer ones. If you hold them side by side you will see differences. I made my friend return the after market ones for the dealer ones because it made the belt run at an incorrect offset and slightly rubbed against things.

 

[2000gtxer]

Hey,
I asked a few mechanics about this and it is possible that the belt is too loose. However, i have also found out that the dsm motors from 89-93 had a problem with the oil pump sprocket. The pump pulley mounts onto the shaft one way by having a slit on the edge. This can, over time, round off causing the pulley to have play. It's a possibility!!

 

[BUCK]

^ I fail to see how that would change Tension till the Cog fell off. Check the Thread on my earlier post on this Thread for how to properly set Tension.

 

[1fast97gsx]

Figured while I was at bring threads back from the dead I'd bring another one back. My timing belt was installed via vfaq instructions and was very tight. I left my timing covers off and last night I just kinda touched it for the hell of it. It was very loose. ( car has 500 miles since the install )

I had read about this before and I remember seeing that once you start the car it will tighten back up again. I checked my timing and it's still dead on ... but I want to avoid any future problems. Can someone explain why over time it gets this loose and why it tightens up when the car is started? I don't think it's going to skip any teeth or anything like that ... but when the car is cold and I wiggle it it really scares me :thumbdown . Any advice or way to measure to make sure it is still ok and won't skip?

 

[UNDR PSI]

depending on where the pistons are at and the valves and whatnot, the belt will be tight or it will be slightly loose. Turn the crank by hand a little and it will tighten up. It just depends on where it is at. If it is really loose, you might have a bad tensioner. When you installed ur timing belt, did you put a new tensioner in or use the old one. If you used the old one, it should have been a pain in the a$$ to squeeze back into place. If it wasnt then you need a new one.

 

[1fast97gsx]

Its a brand new tensioner and it had the pin in it already when I picked it up from my dealership. Anyways .. if I run the car and let it warm up and then shut it off the belt is tight. If I just leave it sitting for a while and then mess with the belt again it's loose again. Without turning the crank or anything. I think I don't have anything to worry about .. I'm just being paranoid I guess.

 

[NOSLO2PT0]

Tension on the belt should NEVER vary. If it does, time to replace the auto tensioner.

 

[1fast97gsx]

Yea but this is a brand new autotensioner. Only 500 miles on it. Could the tension pulley just not have been tight enough or something? I still find it strange that once the car is started it retightens again. Maybe it was just too loose to begin with and now the belt stretching is making it even looser?

 

[98TsiAWD]

Its a brand new tensioner and it had the pin in it already when I picked it up from my dealership. Anyways .. if I run the car and let it warm up and then shut it off the belt is tight. If I just leave it sitting for a while and then mess with the belt again it's loose again. Without turning the crank or anything. I think I don't have anything to worry about .. I'm just being paranoid I guess.

This is the exact thing my car does, now has 500 miles on it. Been doing it since about 50 miles tho. I can drive the car, get it fully warm, park it and pop the hood its tight. then come out the next day and its looses. Without touching anything like he said.

Maybe its normal? Im gonna check it out on my 98.

 

[1fast97gsx]

let me know whats up man. I'm about to go out and take it back apart .. but I'd really rather not. Maybe the belt is stretching a little from it getting worn in and our belts were a tad to loose to begin with? I don't know but if I start the car and let it run and shut it off it's fine so I'm assuming it's nothing to worry about since the tension only seems to be important when the engine is running?

 

[Defiant]

A 4-cylinder, inline engine very often stops rotating at the same spot, as the inertia (momemtum? dammit) in the flywheel is used up and the pistons have lost the fight against cylinder compression. The other big resistance to crank rotation is valvetrain mechanics: it takes no small amount of force to work against 8 valve springs at a time. Consequently, once the engine stops, it's usually at a point where the exhaust cam is being pushed forward and the intake cam is being pushed backward (by the cirumstance of where the followers are on the cam profile), making the few inches of cam belt between them go slack. It's routine stuff. Keep the cover on there so you don't have to see it.

 

[BoostinAWD]

Lol mine just did that, so I went and abought another belt and redid it all.
Didnt even have 1 mile on the belt yet. Everythings new, gonna finally run tomorrow.

 

[BISHILVR]

it's normal!!! NOW put the cover back on and quit worrying about it.....

 

[1fast97gsx]

A 4-cylinder, inline engine very often stops rotating at the same spot, as the inertia (momemtum? dammit) in the flywheel is used up and the pistons have lost the fight against cylinder compression. The other big resistance to crank rotation is valvetrain mechanics: it takes no small amount of force to work against 8 valve springs at a time. Consequently, once the engine stops, it's usually at a point where the exhaust cam is being pushed forward and the intake cam is being pushed backward (by the cirumstance of where the followers are on the cam profile), making the few inches of cam belt between them go slack. It's routine stuff. Keep the cover on there so you don't have to see it.

Thats what I figured too but here's what threw me off. If the belt indeed does stop and the intake and exhaust cams are a little more towards each other causing the top part to feel a little loose and I can even understand the part between the crank and the exhaust cam being sorta loose ... but shoudn't the section between the intake cam and the oil pump sprocket be extra tight? I can only wiggle it a little bit between the intake cam and the idler pulley because there isn't a lot of room ... but that's what originally worried me. If all the other sides are looser shouldn't that side then be tighter?

 

[1fast97gsx]

it's normal!!! NOW put the cover back on and quit worrying about it.....

I would but when I got my 1g head I wasn't paying attention to the covers when I put it all together and didn't realize the brackets that the cover bolts to weren't on it. I got them now but I don't want to risk dropping a screw in the timing cover trying to install them :laugh:

 

[1fast97gsx]

This is the exact thing my car does, now has 500 miles on it. Been doing it since about 50 miles tho. I can drive the car, get it fully warm, park it and pop the hood its tight. then come out the next day and its looses. Without touching anything like he said.

Maybe its normal? Im gonna check it out on my 98.

Any word on that 98 doing it or not? I'd like some reassurance before I feel safe driving my car again.

 

[sjwelna]

So last night I started installing my Prothane motor mounts. Well, I decided to do the easy one first; the one by the timing belt. So, I take off the timing belt cover to get better access to the bolts for the mount, and I see this.....