Timing belt is skipping, Need help

[Catoboli]

Ok so heres the deal, i have a heavily modded 95 GSX (none of that really matters here) but ive recently had this problem where my timing belt will skip a few teeth, at first it would skip on the intake cam sproket, the funny thing is it does it somewhere between turning the car off and starting it back up, (i think its turning it on but not sure) never while driving, (luckily, cuz i havent bent my valves yet because of that) so i was like WTF so i replaced my timing belt, turns out i needed a new hydrolic tensioner, so i bought that and put everything in right. now after driving the car for 2 days it does it again, but this time it skipps like 5-7 teeth on the crank sproket, any ideas as to whats up, or what else i might need to replace, this is really starting to annoy me, fixing ur timing belt once is a pain but doing it twice is a kick in the A**, the belt is tensioned to spec and there is no oil on any of the sprokets, tensioners, pullies, or the belt itself.

 

[skelly]

I'm just curious, but did your "heavily modded" GSX ever go through having the heads and/or block shaved in an effort to increase the static compression ratio, or to straighten out significant warpage? On an engine with normal geometry I would think that replacing the belt and tensioner would take care of the problem, but since that's obviously not the case I am forced to wonder about the geometry.

The only other thing that would occur to me is some situation where the OEM style belt is not strong enough to reliably turn the cams. This might be the case with significantly upgraded valve springs putting so much pressure against the cam lobes as to require more to keep the cam turning than the belt can deliver at low rotational rates (such as during start-up). This is totally a shot in the dark, but both comments illustrate that perhaps indeed your modifications are relevant to the diagnosis, so you should give the breakdown on what's been done to the engine.

- SK

 

[Catoboli]

The head on the car is a fully port and polished 1g head with stock g1 springs and cams, so i dont think thats a factor. also i dont believe the head has been shaved but i have a thicker head gasket so if it were shaved the gasket would compensate for that.

 

[project_tsi]

maybe try a kevlar timing belt? Also check to see if the adjustable tensioner pulley is correctly tensioned and make sure the bolts arent backed out any or bent causing it to mis-allign itself

 

[Defiant]

the belt is tensioned to spec

Apparently not.

 

[Catoboli]

i think i fixed it but im not sure, it hasent skipped yet, i just made the timing belt tighter, honestly it feels a little tighter than it sould be, are there any drawbacks or possible hazards to this. also the car wont start now, all marks are lined up and timing looks great could the super tight timing belt cause that....

 

[project_tsi]

i think i fixed it but im not sure, it hasent skipped yet, i just made the timing belt tighter, honestly it feels a little tighter than it sould be, are there any drawbacks or possible hazards to this. also the car wont start now, all marks are lined up and timing looks great could the super tight timing belt cause that....

my guess is that when the crank gear skipped 5 or 6 teeth, you smacked a few valves. Thats why is isn't starting.

 

[Catoboli]

see thats the thing due to when it happens i think its cuz im not driving, idont bend the valves, ive puld my head off every time this has happened and there fine, i just got the car started but im still curios about having the timing belt too tight, is that bad and can it cause any harm...

 

[Talesin]

Could cause it to stretch or snap, theoretically. You might want to replace your hydraulic tensioner if you haven't already... if it's getting worn, it could be causing the behaviour.

 

[Catoboli]

yeah id did replace the hydrolic tensioner the first time i did the timing belt though it fixed the problem till itdid it agian a few days later.

 

[Talesin]

Maybe you got a bad (or cheap) tensioner? I mean, if it worked for a couple days, then something in the process of replacing that tensioner touched on whatever broke.

 

[Bostedquest]

if it is skipping teeth you did not tension it propperly.
When I did mine, I got it tight enough that it actually compressed the tensioner a little after 6 spins, at least enough to pull the keeper out with -0- effort.

Also, if you apply tension on the tension idler in the wrong direction, it will simply come loose again.

I am not going to misquote the direction, nor do I feel like looking it up on Vfaq. You have internet look it up yourself.

 

[Bostedquest]

yeah id did replace the hydrolic tensioner the first time i did the timing belt though it fixed the problem till itdid it agian a few days later.

you tensioned the idle bearing in the wrong direction. Yes it does matter. Look on Vfaq.

 

['92-RiceEater]

Ok so heres the deal, i have a heavily modded 95 GSX (none of that really matters here) but ive recently had this problem where my timing belt will skip a few teeth, at first it would skip on the intake cam sproket, the funny thing is it does it somewhere between turning the car off and starting it back up, (i think its turning it on but not sure) never while driving, (luckily, cuz i havent bent my valves yet because of that) so i was like WTF so i replaced my timing belt, turns out i needed a new hydrolic tensioner, so i bought that and put everything in right. now after driving the car for 2 days it does it again, but this time it skipps like 5-7 teeth on the crank sproket, any ideas as to whats up, or what else i might need to replace, this is really starting to annoy me, fixing ur timing belt once is a pain but doing it twice is a kick in the A**, the belt is tensioned to spec and there is no oil on any of the sprokets, tensioners, pullies, or the belt itself.

I'm sorta glad and not at the same time, glad that i found another car with the SAME EXACT PROBLEM, i put a new tensioner on it, new OEM mitsu. belt, and i couldn't figure it out, my car would run good for about a week then it would skip, and then my buddies car started doing it, so it wasn't just a like freak occurance, but the last time my car skipped it skipped by 6-7 teeth....... i did a compression test after timing it out...... 0 across the board, now its back to step one. If anybody has a solution to the problem please let us know, i'll look up on VFAQ tonight and see if i did anything wrong.

CATABOLI, do a compression test.

 

['92-RiceEater]

you tensioned the idle bearing in the wrong direction. Yes it does matter. Look on Vfaq.

What do you mean? I'm looking on VFAQ now and trying to find it. Could somebody please explain?

-Lawrence

 

[Bostedquest]

[QUOTE='92-RiceEater]What do you mean? I'm looking on VFAQ now and trying to find it. Could somebody please explain?

-Lawrence[/QUOTE]
For 1G
Rotate the tensioner pulley in a clockwise direction until the belt is taut and tighten the center bolt (Figure 18).

For 2G
Rotate the tensioner pulley in a counterclockwise direction until the belt is taut and tighten the center bolt finger tight (Figure 18).
(right from Vfaq)

If you go the other way, the rotation of the belt will loosen/apply force to rotate the bearing in the oppisite direction possibly releasing tension.
Yes i have seen it happen IN PERSON.
SO yes, the direction you tighten in DOES MATTER.

 

['92-RiceEater]

Alright i see it, thanks alot, now i just have to get that damned tool.

 

[Catoboli]

thanks for all the help, i think ur right i think idid tighten the pully in the wrong direction, car seems to be working great now, oh my cpompression is fine, just did the test today...

 

[Bostedquest]

thanks for all the help, i think ur right i think idid tighten the pully in the wrong direction, car seems to be working great now, oh my cpompression is fine, just did the test today...

glad to be of service.