Timing belt issues

[AWDlaserRS]

I figured this is probably the best forum to put this in, Okay so heres the situation>

When I first put the new engine in the car a long time ago and I put the timing belt on it was literally imposible to get it to line up EXACTLY right on the cam gears it was always like 1/2 - 1 tooth off so the cam gears were always angled toward each other ever so slightly or away from each other the same way. I just figured this is the best it can be so ill use it like this. Well it worked fine but I was getting kinda low compression, 120-130. One cylinder was lower at about 90 so I tore it down and discovered that cylinder had bad valve guides so I went ahead and rebuilt the head, lapped all valves, reground all seats, new guides, ect,ect. Well anyways there was some drivetrain stuff I had to fix too and that took a while to get done. Anyways im at the point where all I have to do is put the head back on and i dont know whether that low compression across the cylinders before was because of the timing belt being ever so slightly off or because of the head, I need to know when you guys change your timing belts do your marks on your cam gears line up exactly in a straight line or are they angled in slightly? By the way I was running it with them angled in slightly because i figured it will wear over time and be perfect. Also this was a goodyear gatorback belt. Any and all input is greatly apreciated, as this is concerning me, im sick of taking this thing back apart.

 

[Diceman19]

mine lined up exactly. i would say that you should tweak the cam gears a little more either way. it is a very picky spot that they have to be in and they have to be JUST RIGHT, but you will get it as long as you keep tring. btw, you will know when you get it right, it will just feel right once you do, plus, you will then also realize that you woulda been way off any other way. ;-) good luck.

 

[AWDlaserRS]

mine lined up exactly. i would say that you should tweak the cam gears a little more either way. it is a very picky spot that they have to be in and they have to be JUST RIGHT, but you will get it as long as you keep tring. btw, you will know when you get it right, it will just feel right once you do, plus, you will then also realize that you woulda been way off any other way. ;-) good luck.

Believe me I messed with it for a long time it just wont line up exactly, its like the belt is 1 tooth or 1/2 a tooth short, what type of belt did you use when you changed yours? Im starting to think that maybe its this goodyear gatorback belt.

 

[LousyDriver]

I'm litterally in the middle of a timing belt change right now. I haven't removed the old belt yet, but I got the engine positioned so that the cam gears are lined up, and the balance shaft is in the right place (plug/screwdriver method) and I have a similar dillema. The cam gears line up, but the oil pump sprocket and crank sprocket timing marks don't line up perfectly, they are about 1/2 cog clockwise from where they should be.

At first I Thought that the belt must have stretched slightly, so I checked the tensioner clearance, but it's right on spec. The car ran perfect the way it is, but if I line up the lower marks, the cam marks don't line up anymore.

I don't know if the shop that did the last timing belt screwed it up, or if the belt is on the way it's supposed to be. Wouldn't there be obvious problems (such as bent valves) if the cam had been installed one notch off? not to mention poor performance?

I have to take another look at it to see if the cam marks could be 1 tooth off. I was going on the assumption that it was right.

I appreciate Diceman's feedback, anyone else have experience to share. Did your marks line up exactly, or did you find a problem?

 

[Diceman19]

i am telling you, i had the same things happen to me. it happens to everyone that changes a timing belt. if your oil pump/balance shaft stuff doesnt line up right when the cam gears LOOK straight, then the cams arent straight. i faced it too. you have to tweak one cam or the other until you find a combination that fits. it is a PITA, but you will know when it is right on. i cant stress enough that the cam gears are the worst part because you can be off just a hair and the whole deal will not fit right.

 

[IMMORTALSPYDER]

In my last car i was always 1/2 a tooth off. Without cam gears. Never could figure it out.

 

[AWDlaserRS]

i am telling you, i had the same things happen to me. it happens to everyone that changes a timing belt. if your oil pump/balance shaft stuff doesnt line up right when the cam gears LOOK straight, then the cams arent straight. i faced it too. you have to tweak one cam or the other until you find a combination that fits. it is a PITA, but you will know when it is right on. i cant stress enough that the cam gears are the worst part because you can be off just a hair and the whole deal will not fit right.

I dont think you are understanding, even if the oil pump or cam gears are way off you can still have the belt on the cam gears and have the marks line up straight acrosss, My dilemma is that if you take the timing belt and lay it across the cam gears they are always angled inward or outward so if they are angled outward and you lose one tooth between them then they are now angled inward too far, its like the timing belt is either 1/2 a tooth too long or too short. No matter what the cam gears cant be perfect, always a little bit off. they arnt off enough to bend valves or anything but if you lay a ruler across the marks you cant get them all in a straight line as they should be. This is the best I can possibly explain it without showing you.

 

[my97mitsGSX]

i noticed i'm always a half tooth off.. i ran the motor and it has no problems.. the belt inbetween the two cam gears has less tension then the rest of the belt, but its still tight enough where the belt won't come off.. its the only way i can get the marks to line up properly...

i start the belt on the gears, wrap tape around the belt to secure it to the cam, then get it around the crank and oil and try to put it around the idler and tensioner pulleys later.. i find it to work best that way..

 

[loreak]

i use the wheel of fortune method, i just give it a good spin and where it lands is where it goes

i got like 3 heads with bent valves tho hah

 

[Diceman19]

I dont think you are understanding, even if the oil pump or cam gears are way off you can still have the belt on the cam gears and have the marks line up straight acrosss, My dilemma is that if you take the timing belt and lay it across the cam gears they are always angled inward or outward so if they are angled outward and you lose one tooth between them then they are now angled inward too far, its like the timing belt is either 1/2 a tooth too long or too short. No matter what the cam gears cant be perfect, always a little bit off. they arnt off enough to bend valves or anything but if you lay a ruler across the marks you cant get them all in a straight line as they should be. This is the best I can possibly explain it without showing you.

ok, whatever. i dont know what you are talking about then. i only took it apart and put it together 5 times in 2 months. oh yea, i also dealt with your problem 5 out of 5 of those times. but disregard my post and information.....

 

[AWDlaserRS]

Diceman I dont mean any offense, I have ripped this engine down to the block several times so Im not ignorant, you just wern't refering to my problem when you replied. Okay say your head is off the car so disregard the crank and oil pump gears and you lay your timing belt across the cam gears, you obviously know that the marks on the cam gears have to line up in a straight line across the gears like you take a ruler and lay it across the marks and they are all in a straight line. Anyways this is what is happening, you eyeball it and lay the bet on and then check it with a ruler, its off by 1 or 1/2 a tooth and the cam gears are angled away from each other, so ok you figure just take away one tooth on the belt in between the gears and you should be good. You do this and check the marks again, now the gears are angled toward each other. There is no fine adjustment, its one tooth in either direction and its wrong both ways. Diceman what type of timing belt did you use when you changed yours?

 

[Diceman19]

i used a gatorback. my solution to the problem was to move only one cam at a time to see if the belt would fit right all around. the way i saw it, since the lower part of the timing belt section didnt move after the old belt was off, the cams had to fit right somehow. after FINE adjustment of one or other cam, i finally got it right. instead of moving both cams to try and make it fit, get one cam as flat as you can, then move the other one till the belt fits, have someone hold, step back and take a look, if it looks flat across and it fits below, you should be ok. i never used the ruler method. btw, always check your timing with a timing light too just to double check, no sense it messing your head up by accident. ;-)

 

[AWDlaserRS]

Okay I think it dousnt matter if its 1/2 a tooth off then, because unless you take a ruler and check the marks then you wouldn't really notice the marks being angled inward or outward and you said you just got it so they looked straight across. Did anyone else who noticed the belt being 1/2 a tooth off ever do a compression test? I dont really think the very small amount it is off can effect the engine though, and if all these other people had their TB the same way and their engines ran fine too than I guess its too little to make a difference. Just out of curiosity Diceman, if you have the time too, check your cam gear marks with a ruler and see if they are angled inward or outward.

 

[Diceman19]

you might also take into account that the cam gears may not be perfect. manufacturing tolerances and all. even stock isnt going to be perfect.

 

[AWDlaserRS]

Yeah, that is possible. It still bothers me though as Ive spent lots of money on this engine but then again it might be nothing. I just dont want to take it apart again. At any rate I already know it wont hurt anything mechanically to be off by that little, I was just worried about compression. Im going to go out right now and see if 1/2 a tooth makes any real difference in the valves sealing properly.

 

[loreak]

it could be quite a few teeth off and not bend valves, half a tooth to 1 tooth off isnt going to effect anything but maybe a couple hp depending which way its off

 

[AWDlaserRS]

Yeah I looked at it last night and 1/2 a tooth really doesn't make any difference at all so I suppose I just wont worry about it.