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?

 

[Defiant]

As far as slack inbetween the cam gears, i'd say there is 1/2 to 3/4 inches from pushed down to pulled up.

http://www.dsmtuners.com/forums/showthread.php?t=233580

 

[TurboBlue]

Well thank you everyone for your input. I'm driving the car again. I rotated the crank to check the timing, and you wouldnt believe it, the belt tightened up again. I started to think of the theory that the cam was just sitting funny due to the valve springs. And just for reassurance, I had the guy who built my motor come and take a look at it. He said the same thing, dont worry about it, drive it. So I am, and I will be untill something else breaks.

But anyways, thank you all again for your help...

 

[Defiant]

So I am, and I will be untill something else breaks.

This should be a very enjoyable week for you.

 

[vr4play]

Did a search but did not find my answer.

I had the car down for a couple of months doing various mods and maintenance. One of which was timing belt change. A couple of days after the t-belt change, the belt got loose across the cam gears. I thought it had to do with the compression drop, so I didn't worry about it. I started the car up, but the belt stayed loose and fluttered. I went back in and noticed the tensioner was bottomed out (plunger all the way in). I reset the tension and put everything back together. Tension stayed good for a couple of hours. Started the engine, tension stayed good. Took a couple of short drives around the block, checked the belt and tension still looked good. Went back to check several hours later and the belt was loose again. Started the car up, and the belt stayed loose and fluttered. Went back in and the tensioner was bottomed out again (plunger all the way in) .

Does this sound like a bad tensioner?

 

[nightspeed87]

sounds like your bout to mess your engine up if you dont fix it soon.
If the tensioner is going in then maybe you should just replace it. You dont want your timing to jump on you.

 

[Splitpi]

Its a cheap enough part to replace and far cheaper than a new head and piston. Check your belt as well for a missing or a damaged tooth and that it is indeed the correct size and part. Also check the that the pullies are tight, I believe specifically the left (front of car side) pully that it is properly tightened (tensioner pulley).

And above all else, stop trying to start your car if it seems loose.

 

[vr4play]

I am going to replace the tensioner. Dealer will give it up for $85. I was just wanting some additional info from someone with experience dealing with timing belt issues.

I inspected the belt before I put it on, and inspected it as I turned the engine (procedure after installing belt). I also matched it up with the one I pulled off to make sure that the teeth count is correct. The tensioner pulley was tight against the belt when I set the tension.

I was starting the car to see if the compression would remove the slack, but it wasn't the compression dropping causing the problem.

 

[nightspeed87]

man im having timing problems also....

 

[vr4play]

Update -- I pulled the tensioner off and it checked out good. The only thing that I can think of is that I was setting the tension with the belt zip tied to the cam gears. This time I removed the zip ties before setting the tension. Right now the belt tension is set and has been good about 2 hours now. If this afternoon the tension is still good, I will start the engine and let it run for a little, then let it sit again. Hopefully by tomorrow, everything will still be good and I will put everything back together.

 

[DevilSperm]

I went cheap once and didn't replace my tensioner on a T-belt change. 1 week later I found myself swapping heads. Its ALWAYS a good idea to change that when you do the job.

 

[Shaggy_357]

Now this may NOT be the best idea, but I use the allen key at the bottom, top it off with a nice thick motor oil, replace the screw and viola! Good as new, haven't had one fail me yet.

 

[vr4play]

Update -- I have ran the car a few times and the belt tension still seems to be good. Lesson learned... remove zip ties before setting the tension.

My tensioner was changed last timing belt change. I will change it on the next (since I am going to start changing the belts every 30~40k).

Is performing maintenance on the tensioner a common practice?

 

[nightspeed87]

is there a way to tell if the tensioner is going? Like will the belt gradually loosen up or will it just go and your instantly screwed?

 

[Splitpi]

Update -- I have ran the car a few times and the belt tension still seems to be good. Lesson learned... remove zip ties before setting the tension.

My tensioner was changed last timing belt change. I will change it on the next (since I am going to start changing the belts every 30~40k).

Is performing maintenance on the tensioner a common practice?

I just replace the tensioner, my bud who works on DSM for a side side job will only do timing belts if the tensioner is replaced in the job.

As far as removing the zip ties.... ya that makes sense and I should have remembered that to warn you about it... oops. Would have saved you some hassle.

 

[Mentow]

Update -- I have ran the car a few times and the belt tension still seems to be good. Lesson learned... remove zip ties before setting the tension.

My tensioner was changed last timing belt change. I will change it on the next (since I am going to start changing the belts every 30~40k).

Is performing maintenance on the tensioner a common practice?

Man are you sure? The zip ties i have used are very weak, i dont think they could do some like distor the belt tension....well i'll try that.

Btw, dont your timing belt do any vibrating noise or movement around 1500-3000rpms anymore? Any at all? Would you take a closer look for me please? Accelerate the engine gradualy, and looking straight to the timing belt side, pay attention if you can see the belt shaking up and down when you go through 1500-3000rpms...mine just got crazy around that!

We've tryied a dozen times to adjust the timing belt tension, but we can get off that vibrating, wich concerns me since i think that could be causing damage to the t.belt.

Regards!

Michel

 

[vr4play]

I am positive that the zip ties were the reason. I had two on each cam gear... 1 at the twelve o'clock position on each and 1 at 8:00 (exhaust) and 1 at 4:00 (intake). This prevented belt tensioning between the cam gears. After the belt tension settled, I could just rest my finger on top of the belt and it would sag about 15mm. When running, the belt would flutter like crazy.

I have 30mi/2days on the car since the belt change (without zip ties), and the tension is as it was when it was set. there is slight vibration in the belt if you look close, but that is because the belt isn't sling shot tight (it isn't suppose to be). The "finger tension" on the belt is the same as it was with my previous belt, so I am sure that the slight belt vibration is normal... the fluttering belt is not.

 

[Mentow]

Hmm maybe in just exaggerating at how much the timing belt is fluttering, maybe nothing like "crazy" as i said before...at least, nothing like 15mm on just sitting the finger, mine is pretty tensioned between the cams. Actually, its about 2-3mm of fluttering on that range of rpms, maybe thats normal just like you said.

One last question: when you´re driving about 2-3k rpms, can you hear anything different from inside of your car, in case, that small vibration im talking about? Because, well...the fluttering in my belt is very small, but if i pay some attention, i can hear that vibration in that range of RPMS

Thanks for you help!

Michel

 

[vr4play]

No noise, but at 2-3k my exhaust usually drowns out any engine noise.

 

[Mentow]

ok, thanks again!

Regards,

Michel

 

[95 'clipse RS]

ok, i think i have a problem. not quite sure tho, being that im not so familiar with the 4g63. anywho, i just rebuilt the head due to timing failure, and its been back together now for about a week. and between the cam sprockets the timing belt seems pretty loose, like about 1/2 inch to 3/4 in one direction. so i thought that it may be because the cams may have found a resting point, so i hit the starter a few times, and it still seems loose, its keeping timing still, but i just wanted to know if there is some spec that the deflection should be at or if this is an indication that the timing tensioner is failing.

any help is appreciated, i dont wanna have to go through another head for this...

thanx all

 

[perley03]

That is too much. Your tensioner is junk. Mine did the same thing, however i caught it in time due to a funny noise coming from the cam cover area. Took that off and started it and saw the timing belt moving up and down. I pulled the motor and took the tensioner off, i could push the plunger in with my thumb. I highly suggest you take your tensioner off and replace it, and mine as well do the balance shaft belt, idler pulley and tensioner pulley while you are in there anyway.

 

[95 'clipse RS]

well... i have all new idler pulleys, belts, etc. except that tensioner. but see heres the thing, the plunger is still sticking out, in the specified range, 3.8 to 4.5mm. from tensioner body to the tensioner pulley arm. and that tensioner was a b**** to compress to get the pin through it. but is there the possibility that its still bad?

also, right after its been running for awhile, its quite a bit tighter. but still not what i would expect. any suggestions would be very helpful.

thanx

 

[VisegripMech]

Whew. Glad that's finally over with...

I hope.

By the way, about belts expanding when they warm up, they don't. Rubber contracts as it heats. This could mean that a tight belt at shut-off is a slightly looser belt six hours later. Counter intuitive, but there you have it.

<Fiendish "Snidely Whiplash" Laugh>Over? HA! fools!IT will never end!

Just Kidding!

But seriously, does this imply that all adjustments or settings should be made while the belt itself is cold? I saw a demonstration of this (rubber contracts when heated and expands when cold) on "Bill Nye, The Science Guy" or some kiddie show years ago. Is it possible that a new belt, laying on a sunlit fender, just prior to installation, and the same belt, later that year/month/day in a cold garage, could cause a few of the more extreme examples in some of these posts?

and please pardon my enormous newbie hat.

 

[telnut]

Do you mind explaining exactly how you adjusted the tensioner? I don't mean, did you perform it the way that's listed in the manual or not, but how did you do it in your own words. I mean, not to say you don't know what you're doing but everyone makes mistakes. It DEFINATEYLY seems as though the tension isn't right on that belt. It definately seems too loose. Regardless of where the timing marks line up, there's still some slack in the belt.

I go by the VFAQ but I use a 5/32nd drill bit for the tensioner cause I don't have any metrics and the 5/32nd is pretty close. And until you get it right, you definately shouldn't drive it if it looks like that unless you like pulling the head for a valve job.

Two things measure it like he says and the other thing is when you put the new belt on with all marks lined up pull the pin in tensioner rotate the crank 6 times and WALK AWAY for about 30 minutes. After 30 minutes measure distance between end of tensioner arm and top surface of hydralic tensioner with 5/32nd drill bit it should be snug if not collapse hydralic tensioner with 8inch piece of 8mmX1.25 all thread through hole in side cover until you can re insert pin, do this slowly it doesn't take much to push hyd tensioner in, if you crank on it to much you'll bend the all thread. Go to the tensioner wheel, the one with the two holes and push it a little tighter.(There is a special tool for doing this, but I have done it with a small pick with a 90 degree bend.Insert it into the small hole and push to the right) Specs are only about 22 inch pounds not much, retighten center bolt pull hyd tensioner pin, rotate crank 6 times, let set and recheck all marks, and measure as before with 5/32 inch drill bit. If this is done correctly tension is correct and a little slack is normal between cam gears because of exhaust cam creep. It is a good idea to check timing belt tension and adjust periododically in the same manner. The timing belts will stretch over time especially after hard useage and the hyd tensioner will go beyond it adjusting limits. My experience is most failures are due to timing belt stretching and not being adjusted for stretch.
I tried to go to vfaq to see if this was covered but couldn't get there
Hope this helps.

Telnut
"Motor oil in my veins, nuts and bolts in my brain."

 

[brrrnntsshhhh]

i just installed the t-belt and drove maybe 50 miles, i am almost pisitive i had all the tensioner specs right and everything. right now i have ALOT of slack after it sitting over night (much like the guy with the 1st set of pictures), i bought the tensioner from mitsu a long time ago and just got around to doing the timing belt, thing is the tensioner looks different than the one in the vfaq and the original one. is it possible that i have the wrong tensioner or did they change the design in them?