Im starting to really hate timing. Been reading and searching threads and everything but i dont understand. Okay so the helms manual says set to tdc. So i line up the pointer to the TDC mark on the crank pulley. Then I set the cam pulley to tdc. I have a question about that first, should the cam pulley be at a very slight angle to line up with the head ? Or should the UP be exactly straight up with the 2 lines completely flat? So after I set the cam pulley to TDC, and the crank pulley to TDC, i slide on the belt with the tensioner loosened. The manual says rotate the crankshaft counterclockwise 3 teeth on the cam pulley. Okay, right here is where im lost. So if both pulleys are exactly where they need to be and i rotate the crank with slack in the timing belt, the cam isn't going to move at all because im just pulling the slack out of the belt and its not going to move the cam with it. But yet the crank is moving since im spinning it. So when there is finally enough tension, the cam finally moves but the crank is already way off by the time the cam catches up. I'm so confused! Is this what im supposed to be doing or can someone explain to me. I feel like im just missing something dumb. D16a6 CRX Si btw.

 

First, you don't take off the timing belt until you have the crank at TDC and the cam marks lined up. The crank rotates twice for each cam rotation, so you can have the crank lined up and be 180 degrees off on the cams. The "up" on the cam gears tells you if you're cams are in the right position. Get that part right first, then take off the belt.

Don't rotate anything with the belt off.

When you are putting the new belt on, the reason for moving the crank 3 notches is that that's about the estimate of how much belt slack there will be to take up with the tensioner. I usually ignore that part and just eyeball things. Put the belt on and tension it - see where the marks wind up or move to. You'll probably have to detension it and slip the belt back off to correct for movement, then tension it again and recheck. Its normal to have to do that two or three times, especially if you haven't done it before.

The marks need to wind up perfectly lined up when its tensioned. If you have dual overhead cams it will have marks that line up on the inside, and usually marks that are on the outside as well. You can ignore the outside marks, but make sure the inside marks line up with each other, and you should be able to draw a line between the two cam gear center bolts that perfectly crosses the inside marks facing each other.

 

maybe it's the way you worded it but although this is correct, reading through it quickly it just sounds wrong... haha.

basically you're saying that the lines on the cam will line up with the VC surface on the head twice in a rotation which is why the "UP" mark must point up.

like you said, crank aligned and "UP" mark up the OP should be set.

 

What im not getting is if you have cam and crank at perfect tdc where you want it to be and the theres slack in the belt, i dont get how you are supposed to turn the crank pulley without messing up your timing. Like if both are at tdc and you need to move the crank to get the slack out, the cam isn't even moving because first its gotta have enough tension on it to move with the crank. So once you have the slack out, the crank is moved out of its tdc position, but the cam is still in its tdc position. So it will barely be starting to move while the crank has already been moving. How are you supposed to line them up like this? Are you supposed to turn the crank farther clockwise past TDC, so when your turning it ccw it will finally line up with the TDC mark once tension is out? That way the cam and crank will line up?

 

I believe the approved method is to lock the cams down with a special tool before you remove the belt. Since you can't move the cams then to take up the slack on the new belt, the crank has to move. Ideally then, if you have the cams locked and the crank rotated back, and slide the new belt on and tighten the tensioner, taking up the slack will turn the crank back to the correct TDC position.

I don't generally use a tool to lock the cams down, so I more or less wing it and that works well enough on most engines. You might have to guess and test a bit to get the marks lined up, but if you're careful its not too hard. Once you do it a few times its no big deal.

 

The timing belt tension is spring loaded. You set everything to tdc, tighten the adjusting bolt, then put the crank pulley back on and turn the crank pulley CCW so the CAMshaft moves exactly three teeth. Then you loosen the adjusting bolt and the spring will tension the belt. Then immediately tighten the adjusting bolt to spec and you are done. The spring is designed to tension the belt exactly to spec so just let it.

 

I dont understand what a single method says so far, anyone have a video?

The d16a6 single cam is supposed to be easy but I aswell would love to know how to do this confidently.

What if you rotate to much ccw, can you spin it back clockwise? or is it not good to spin the engine that way

Youd think they would make it so you set the cams to tdc, crank to tdc, slip the belt on, loosen the tensioner and let it spring, tighten the tensioner, done.

Why is there other bs?

 

It's no big deal spinning it clockwise if you need to line it up a few teeth.

Whenever you do a timing belt you always set it at tdc or atleast close to it before removing the old belt. It doesn't need to stay there but it makes it very easy to line it back up before installing the new belt without having to move anything with the belt off, which is a big no-no when you need to move it more than a few teeth since there could be valve and piston clearance issues.

If you're within a few teeth, which I'm assuming you are, just line up the cam and the crank and then proceed with my method, which is straight out of the Helms.

If you absolutely want a video, there are numerous vids on youtube.

It's perfectly normal on dohc engines for the belt to be so tight putting it on that the crank and cams move a tooth or so and you gotta line them back up again before retrying. Normal.

Sometimes you can put a pin, drill bit, or punch through one of the cams through a hole and into the head to lock the camshaft in place. Just look for an opening in the camshaft.

 

When i put the belt on, it has a good amount of slack in it. Enough slack so that the crank can rotate for a while without even moving the cam. So that means the crank is moving already, but the cam hasn't so its still in its TDC position while the crank is already off it. So im moving the crank, but all its doing is tensioning the belt and it isnt moving the cam with it instantly. The delay in movement just messes up all the timing marks and everything

 

Have you found the tensioner adjuster bolt at all yet ? Or are you trying to do everything humanly possible not to touch the tensioner adjuster bolt ?

When you manage to find it you will see when you loosen it a half a turn that the tensioner pulley can slide in and out which is how slack is taken up when you use the timing belt adjustment method spelled out in the Helms and posted earlier in this thread by me.