Long story short, had to change my timing belt and found that i tensioned it wrong. While trying to determine if i had to much tension or not enough, belt slipped off when i started car. Car ran fine and timing was good before this happened, it just sounded like my car had a supercharger on it. Now that i have the proper instructions to tension the belt correctly, the marks wont stay align when i turn my engine by hand while tensioning the belt. Car starts, cams spins easy, no noticeable noise. Got new tensioner,spring,idler, and belt. Checked both key ways for the timing sprocket, tried pre-tensioning the belt and spinning it over to see if the marks would line up (to rule out it being something wrong with the spring) and the marks are usually a tooth off when i bring it back to TDC. Just trying to see if im missing something before i have the thought of having to tear the motor down.

I don't remember how many times you have to spin the motor over to have the marks all line up in the exact spot again on the belt but it is more than one. My memory is real foggy on this, hopefully someone else chimes in.

If you aligned the dots to their marks on the timing covers, as it's layed out in the FSM, then put on the timing belt with proper tension, you only need to rotate the crank a few times. The timing marks won't go back to their indexes or the lines on the belt after a few turns. Infact, I'm pretty certain it would take dozens of spins to get them to line up again.

My point is, if you put the belt on with all the dots lined up on the timing cover marks, you should be good to go once the tensioner is set properly.

Yea its twice with the tensioner nut loose, and im not paying attention to the timing marks on the belt, i figured they wouldnt be dead on on the belt, but its like that with the cam sprockets. ????? Maybe its me idk, i have tried setting the timing up at least 12 times no exagerating and it keeps doin the same thing.

If you are using a RB specific belt with the 3 indicator marks on the belt itself, then as long as those are lined up is good enough most the time unless it somehow does jump a tooth. Given that it doesn't jump a tooth, that's the best way to go at it. I found the metal back plate on the engine seems to be far from perfect. I noticed when tearing my engine down that the back plates after loosening all the bolts can shift around a lot. It's far from a perfect fit. Being that the marks are on this plate, that leaves a lot of room for error based on how straight the plate was bolted on to begin with. You can always make your own marks for future reference. What you do is install the belt with the 3 marks on the engine lining up with the marks on the belt. Install and tension. I usually get the tension set by rotating the crank clockwise until both cams begin to turn along and feel the most resistance. Hold the crank position there and tighten the tensioner bolt after the spring has relaxed to it's resting spot. Now after the tensioner is tightened, turn the crack back counter clockwise to line your belt up with your sprocket marks again @ tdc (crank sprocket key way pointing straight up with the block, just remember the block leans a little to the right so the key will too). Note where the marks are vs the back plate at the cam sprockets and mark them on the back plate accordingly. To mark, I usually just grab a small piece of sand paper to scuff the paint where I will place the mark and dab on a dot with white touch up paint. I usually put a third mark indicating where I had my crank sprocket too to avoid any tdc errors. Now you have reference marks if you do any needed maintenance requiring the timing belt to be moved. It will be the same (until/unless) you loosen or remove the back plate bolts.

Now you can turn the crank clockwise TWO full turns to check to see if everything is ok. To make things easier to rotate and to better feel if you have valve contact before damaging and overturning, I usually pull the plugs so that it doesn't build up any compression in the cylinders. The timing marks on the sprockets should be back to your reference marks on the back plate you made earlier.

If you would like to see if everything is still where you set it, simply turn the engine counter clockwise two turns and the belt marks etc should be back to where you set them, but the manually added reference marks should usually be enough to convince you that it's where you left it.

Yeah you gotta turn it about a dozen times it feels like when you do it if you spin it the same direction the whole time If you want the marks to line up again. Seemed like forever when I did it.

Genpac wrote:If you aligned the dots to their marks on the timing covers, as it's layed out in the FSM, then put on the timing belt with proper tension, you only need to rotate the crank a few times. The timing marks won't go back to their indexes or the lines on the belt after a few turns. Infact, I'm pretty certain it would take dozens of spins to get them to line up again.

My point is, if you put the belt on with all the dots lined up on the timing cover marks, you should be good to go once the tensioner is set properly.

Err. Unless I'm not thinking straight, I have to disagree with your above point. How would the marks not keep their same relative distances if the length of the belt was not changing?

alright koo man, ima have to give it a try. But your not thinking something else possibly wrong internally? I couldnt imagine espeacially since the only problem is the fact that it seems to keep coming out of time.

The dots on the pulley's are all that matter and they should line up with the notches on the upper rear timing cover and with the crank pulley mark every rotation. The engine would not run if this was not the case. The marks on the belt will NOT line up on every revolution, they are only there for initial installation so you don't have to count the teeth on the belt.

Ok just been able to fool with this thing, been busy and its been pretty damn cold. Anyway, i ordered and installed new spring, lined up marks on cam to timing cover, and timing belt. Rotated crank 720 degs and found that the intake cam sprocket became one tooth off, in comparison to the timing cover mark. Exhaust and crank marks lined up perfectly. Removed, intake cam valve cover to check for anything out of the ordinary and didnt find anything. Looking for the suggestions on the next step to take.

Did you count the teeth between the marks on the cam gears, and then the exhaust cam gear and timing gear? You need to count them and compare to the FSM. Then, mark on the belt where each dot needs to g. It is easy to install the timing belt off a tooth.

Ok, what i did do is, that on the tooth of where the aligning dot is on the cam sprocket, i colored that tooth in, to align with the timing covers and they all lined up. along with the marks that i lined on the sprockets the timing belt marks lined up as well. Basically all my marks are lined up perfectly before i spin the cranckshaft 720 deg, and the only mark that dont line up is the intake cam sprocket to the timing cover mark after the rotation. Im not second guessing you, but i have lined these up plenty of times to where the marks line up correctly with the reference marks i have made on the sprockets to the timing cover marks. Now what im thinking, which may be wrong, is that my problem might be my VTC solenoid. Im thinking this because the sprocket becomes advance after rotation, (a tooth before the reference mark on the cam sprocket) and if im correct the solenoid uses spring tension and oil pressure to change the timing on the intake cam right? If that is so, maybe the spring loaded when line the marks up, and after rotation they unload back into the rest position causing the mark to be incorrect. IDK sorry for the rambling, jus taking a guess, and I might just remove the solenoid and line the marks up again rotate the crank 720 degs again to elevate that being a possibilty. Ima look through the FSM and see how easy it is to remove. Thanks for the suggestions, please keep them coming.

Correction: The spring keeps the camsprocket in sync with the cam shaft, so maybe thats broken IDK just found this
http://www.google.com/imgres?imgurl=htt ... s%3Disch:1
just going to do some more inspection

Without oil pressure, the intake cam gear will not move relative to the cam. You need to count the teeth. Don't give a $hit about what the timing cover marks say, count the teeth because it is obviously causing you some trouble at this point. I don't trust my crank gear notch because it isn't exact. I count the teeth as it shows on page EN-56 of the FSM. For those that are too lazy to look it up, there is 47 valleys between the belt teeth from the crank gear dot to the exhaust cam dot. Then, there is 38 valleys between the exhaust cam dot and the intake cam dot. "0" being the valley at the dot on the gear. I advise to mark the side of the belt with a series of dots to help you keep track of counting (i.e. every 10 valleys)

You got it man, ima give it a try. Have to see what this snow storm is going to do, gotta love working out in the elements

Was just reading thru the FSM and seen what you were describing. Question i have is, is wouldnt it be easier to count out the vallie's and make my own timing marks, then install the belt? I know thats kinda like a "duh" question, but just figured i would ask, and also to see how u did it.

Well, i count the teeth on the timing belt, pre marked them and installed the belt with both cam timing marks matched up with the marks on the cover. Everything lined up after spinning the engine. thanks Darius, but bad news is, is that i think i bent a valve. Need to perform a compression test, to confirm this (i dont have a air compressor to perform a cylinder leak down test). but i found that cylinder number 1 is not burning anything, checked spark and everything, has plenty of fuel, but its miss firing along with cylinder 2. hear a tapping noise as well, car wont rev past 4,000 rpm, and sounds like its chocking.

Genpac wrote:If you aligned the dots to their marks on the timing covers, as it's layed out in the FSM, then put on the timing belt with proper tension, you only need to rotate the crank a few times. The timing marks won't go back to their indexes or the lines on the belt after a few turns. Infact, I'm pretty certain it would take dozens of spins to get them to line up again.

My point is, if you put the belt on with all the dots lined up on the timing cover marks, you should be good to go once the tensioner is set properly.

woha woha NO.

the cams are the same size and rotate at the same speed therefore the marks will line up on every full rotation.

Darius wrote:Without oil pressure, the intake cam gear will not move relative to the cam. You need to count the teeth. Don't give a $hit about what the timing cover marks say, count the teeth because it is obviously causing you some trouble at this point. I don't trust my crank gear notch because it isn't exact. I count the teeth as it shows on page EN-56 of the FSM. For those that are too lazy to look it up, there is 47 valleys between the belt teeth from the crank gear dot to the exhaust cam dot. Then, there is 38 valleys between the exhaust cam dot and the intake cam dot. "0" being the valley at the dot on the gear. I advise to mark the side of the belt with a series of dots to help you keep track of counting (i.e. every 10 valleys)

i have an rb20det and tried this, do i count the valley that the timming dots are on or the next one in? if i go to the next one in it would be about 3 marks out just to the exaust dot from the crank dot. i counted from the do to the dot and it seems to be better but i wanted to check with you first.
these are my issues at the moment

http://www.skylinesdownunder.com/forums ... hp?t=68064

The first "valley" that the dotted tooth is on is considered the 0 spot. So the next valley over is 1 and so on.