timing mark question

[1Gina2G]

doing my first timing job, I'm putting on the main belt and everytime I get the tensioner pulley ready with the special tool and tightened, the crank moves the tiniest bit clockwise from the mark, I was wondering how exact it actually is?
Should I redo the timing? Or should it even matter since the valves still deffinatley wouldn't get hit or anything?

 

[jcarmichael]

DSM Graveyard 4g63 Timing Belt Tutorial - YouTube

it should line up perfectly, if you haven't watched that video you might check it out. there is plenty of how to's such such as vfaq's. however I am more of a see it and do it type of person.

 

[bryanwheat]

Put the belt around the cams first, and lock them in place with the big jaw style paper clips. Before sliding the belt on the crank pulley roll back a half a tooth counter clockwise. When you get the belt around it while holding the belt on the pulley roll the crank back to the timing mark. That will take the tension out the belt on the idler side. From there set your tension.

 

[1Gina2G]

I'll go ahead and reset the tensioner now, but just curious to why it matters? Does the #1 piston not fire right if it's not flush with the block?

I've watched all the timing videos on youtube and the dsmgraveyard one above is actually kind of bad for the fact it's imcomplete.

 

[jcarmichael]

I'll go ahead and reset the tensioner now, but just curious to why it matters? Does the #1 piston not fire right if it's not flush with the block?

I've watched all the timing videos on youtube and the dsmgraveyard one above is actually kind of bad for the fact it's imcomplete.

a little off on the crank, in my mind would cause it to be way off in the end. Once you have it set and you rotate it, it can take up to 6 times around turning the crank for the cams to be back TDC and the crank at its timing mark. So when the crank is spinning a little off each time the cams would be a little off as well.

 

[pauleyman]

It's not possible for it to be off a little bit unless the head has been milled a bunch. What is possible is that you still have slack in the belt on the idler side. There are countless threads, vfaqs, etc on this. I got tired of reading about it and posted http://www.dsmtuners.com/forums/newbie-forum/429897-why-do-people-still-screw-up-timing-belt-jobs.html

 

[turboglenn]

bryanwheat has the whole thing summed up and dead on in that simple post.. i'll elaborate and give some more info on it

IT has to be exact as stated, although it will run when off a little bit.

I've found it nearly IMPOSSIBLE to get the marks correct without the trick outlned in the timing belt VFAQ (please use that as a guideline)it gives only a paragraph on this but it is as followsin short, it says to clamp the belt to the exh. cam gear and then rotate the gear a tooth clockwise from the poitn where the cam gear marks are lined up. then clamp the belt to the int. cam gear while holding the exh. one a tooth advanced.. once the belt is on both gears you rotate the cam gears together top being the exh. cam gear back towards the alingment spot. at this point the exh. cam gear will be a half tooth advanced and the intake gearwill be a half tooth retarded (counter clockwise from aligned)
Hold the gears there with their marks "off" and align the crank and install the belt

once the belt is on and you tighten the tensioner, the way the system pulls the belt it will make everything line up perfectly.. rotate the engine through a full cycle and re-checl alignment, they all should be dead on at this point

This is the ONLY way i can ever get them all to line up perfectly and i can't tell you how many times i've seen the cam gears setup perfectly and the crank will be a half tooth ahead or behind the mark, and although the car will run this way you are always eitehr giving up top end for bottom end and spool, or the opposite,having them perfect makes the engine in time and balanced, and THEN you can adjust camtiming to suit the powerband you want if you have adjustable cam gears

 

[pauleyman]

It's still all about relative position. Every single timing belt I've ever done all the marks are dead nuts. No half tooth anything. One trick I've used over the years is get the marks all on and yes one may "appear" to be off but this is the trick. Once the belt is on I put a wrench on the exhaust cam and rotate ccw a few teeth. THEN I rotate the crank CW again until the crank mark lined up again. You should notice the cams are dead nuts now. Why? You remove ALL slack on the idler side when you do this. This is what you should do BEFORE you set tension. What you should find when all said and done is you rotate 6 cranks afterwards, it's still dead nuts and then and only then you check the tensioner protrusion. It's either right or it's not. If it isn't loosen tension and do it again.

 

[DSM_love_GST]

I think I am going to to a full tutorial. If you still have your bs, make sure to check that it is timed by sticking a Phillips in the back of the block, or you will feel some weird vibrations.

 

[turboglenn]

It's still all about relative position. Every single timing belt I've ever done all the marks are dead nuts. No half tooth anything. One trick I've used over the years is get the marks all on and yes one may "appear" to be off but this is the trick. Once the belt is on I put a wrench on the exhaust cam and rotate ccw a few teeth. THEN I rotate the crank CW again until the crank mark lined up again. You should notice the cams are dead nuts now. Why? You remove ALL slack on the idler side when you do this. This is what you should do BEFORE you set tension. What you should find when all said and done is you rotate 6 cranks afterwards, it's still dead nuts and then and only then you check the tensioner protrusion. It's either right or it's not. If it isn't loosen tension and do it again.

the method i describes (that's from the VFAQ) is just another way of pulling this slack out that is simple enough to read by the marks and get right every time. the "half tooth" is just visualization for a begginer to know how much to turn the things to take out that slack. Doing it this way you don't have to loosen and do it again they come up right every time.. I got sick of having to check and re-do them and this is the way that made it to where i only verify and re-assemble the rest of the stuff around the t-belt. doing it the old way sometimes i had to re-do the setup 5-6 times, i've never had to re-do them a single time using the rule above after i learned it from the vfaq

 

[NHerron]

When I was having trouble with the timing belt and the gears not lining up I found one of turboglenns posts mentioning the VFAQ tip and damn did that help. It's all about that slack I just couldn't get out without setting the cams up this way. Worked out perfectly once I did it that way.

bryanwheat has the whole thing summed up and dead on in that simple post.. i'll elaborate and give some more info on it

IT has to be exact as stated, although it will run when off a little bit.

I've found it nearly IMPOSSIBLE to get the marks correct without the trick outlned in the timing belt VFAQ (please use that as a guideline)it gives only a paragraph on this but it is as followsin short, it says to clamp the belt to the exh. cam gear and then rotate the gear a tooth clockwise from the poitn where the cam gear marks are lined up. then clamp the belt to the int. cam gear while holding the exh. one a tooth advanced.. once the belt is on both gears you rotate the cam gears together top being the exh. cam gear back towards the alingment spot. at this point the exh. cam gear will be a half tooth advanced and the intake gearwill be a half tooth retarded (counter clockwise from aligned)
Hold the gears there with their marks "off" and align the crank and install the belt

once the belt is on and you tighten the tensioner, the way the system pulls the belt it will make everything line up perfectly.. rotate the engine through a full cycle and re-checl alignment, they all should be dead on at this point

This is the ONLY way i can ever get them all to line up perfectly and i can't tell you how many times i've seen the cam gears setup perfectly and the crank will be a half tooth ahead or behind the mark, and although the car will run this way you are always eitehr giving up top end for bottom end and spool, or the opposite,having them perfect makes the engine in time and balanced, and THEN you can adjust camtiming to suit the powerband you want if you have adjustable cam gears

 

[pauleyman]

If you're talking about just getting all the marks on I don't even know what the procedure for that is anymore. I used to do the marks on the old belt but I don't even do that anymore and I haven't looked at the vfaq in more than a decade. I'm sure it's frustrating getting the belt on the first time let alone getting the tension right. For a beginner I'd still suggest tranfering marks from old belt to new to make sure you're in the right position and then remove slack from the idle side. Regardless of the method you choose as long as the end result is good it shouldn't matter. Honestly I'd rather see somebody make a few mistakes and correct them so they can understand the process. The only thing I never understood is people who are nervous before they start the car after this job. The doublecheck to make sure it's right is so blatantly objective I don't think it's possible to screw it up if the check is followed. The first time I did a belt I had to take it off a couple times because I couldn't get the marks lined up correctly. I figured out the tension part pretty quickly and got it set per the manual after a few tries. Wasn't a big deal. I followed the double check in the manual and I was quite certain what I had done was right. I was not nervous one bit when I started the car.

 

[steve]

Transferring marks from the old belt just means that if the last guy did it wrong you'll copy their mistake. And if you make a mistake copying the marks you'll f-up.

The trick is in making sure you have eliminated all the belt slack at each step in installing it. If you do so there is nothing left at the end to permit things to move when you tension the pulley. To do this you have to start at the point just after the tensioner pulley, ie the exhaust cam on the 4G63.

Put the belt on the pulley and clip it in place. Hold the exhaust cam sprocket still and adjust the intake cam sprocket about a half tooth retarded to make it easy to fit the belt on the new sprocket.

Once the belt is on clip it in place and while still holding the exhaust cam still move the intake cam to the correct timing mark and make sure it won't go past where the two cam marks align. If they don't reach your a tooth too short, if they go past your a tooth too far. Reset the belt on the intake cam sprocket as needed until it's perfect.

Route the belt around the idler pulley and move to the oil pump sprocket. Repeat the same steps, create slack to make it easy to get the belt on the sprocket, remove the slack to make sure the timing the correct.

Same deal now at the crank.

You'll have a loose belt between the crank and exhaust, route it around the tensioner pulley and take up the slack. If anything moves and the marks don't all still align, you really didn't make sure the slack was out at each step.

You can't put the belt on wrong following this process. You can't stretch the belt by hand so if there is any give you haven't pulled the slack out.

This is how I do both the 4G63 and the DOHC V6 6G7X engines where you have to make sure you aren't off a tooth between the front and rear banks with the water pump between the two. If you don't keep things tight it's easy to be off a tooth or more.