Setting Timing Chain Help - SR20

[Red Dragon3]

Problem: The timing chain seems to jump a link every time i rotate the crank.

I set the no1 piston on TDC. I pulled the head off to replaced the head gasket. I then assembled everything back together. I set the timing chain as stated in the FSM, where the 2 silver links line up with the dots on the camshaft gears. I put the chain tensioner in, and the CAS back on. I go to rotate the crank shaft to check if every thing is ok. What i notice, is that everytime i rotate the crank the silver links jump on link to the right. The dots on the camshaft no longer correspond to the silver links.

Why is the timing chain jumping links? What am i doing wrong??


Thanks

[Red Dragon3]

BTW this is for an S14 SR20DET

[90hatchie]

did you install the tensioner?

[yabeet]

When you set all the dots on the gears to the links on the chain, after you turn the crank pulley 720degres [your cams go round 180 for every 360 of the crank] the links and dots will not line up again.
It is still timed but you have to keep going around and around and around and the dots and colored links will evantually line up again.

So in a nut shell you were setting the marks, then turning the crank 360 and checking the marks again?

[jspaeth]

When you set all the dots on the gears to the links on the chain, after you turn the crank pulley 720degres [your cams go round 180 for every 360 of the crank] the links and dots will not line up again.
It is still timed but you have to keep going around and around and around and the dots and colored links will evantually line up again.

So in a nut shell you were setting the marks, then turning the crank 360 and checking the marks again?


This is exactly correct. As long as the chain isn't physically skipping links you are fine.

The length of the chain and the size of the gears is such that when the links come back around after one rotation (of the whole chain), the mating marks will NOT line up until you repeat the cycle for a good number of times....you could calculate this easily by noting how many links are on the whole chain and noting how many links off the colored links are when they get back up near the top.

[Red Dragon3]

Yes i have installed, the chain tensioner and CAS.

I have been rotating the crack a few times. I understand the crank and cam shaft are not a one to one ratio.
After a few rotations, the silver link appears to have moved a link to the right of the dots.
I rotated the crank a few times now, and the silver links is now 4 links to the right of the camshaft dots.

[Red Dragon3]

When i rotate the crank it feels hard and then soft. is that normal??

[CamryOnBronze]

^ i believe this is normal, depending on if you are turning on a compression stroke or not. Forgive me if this info is wrong, I just learned this myself about two weeks ago. >.<

[Red Dragon3]

Can some one confirm that No1 at TDC is when the crank pulley is at the second tick (reading from left to right) with the 2 silver links up at the top??

I think i am going to pull the timing chain off again. Set the No1 piston at TDC. Then set the camshaft in the right position. It will be the 3rd time setting the timing chain. I can seems to get it right. This is my first engine build. I dont really know what i am doing.

[jspaeth]

Yes it gets hard then soft....like someone said this from when each cylinder is in compression.

[yabeet]

If you are finding it hard to turn the crank [hard, soft, hard, soft is normal from compression] take out the spark plugs and then try, it will be much easier.

[jspaeth]

If you are finding it hard to turn the crank [hard, soft, hard, soft is normal from compression] take out the spark plugs and then try, it will be much easier.

True, but even the cams pressing the springs makes it go hard, soft, hard, soft. It will never feel completely smooth at the speed that we mere humans can turn the crank manually.

[iiEddieGii]

Can some one confirm that No1 at TDC is when the crank pulley is at the second tick (reading from left to right) with the 2 silver links up at the top??

I think i am going to pull the timing chain off again. Set the No1 piston at TDC. Then set the camshaft in the right position. It will be the 3rd time setting the timing chain. I can seems to get it right. This is my first engine build. I dont really know what i am doing.

The crank being positioned precisely on the tick mark isn't that important. Basically as long as you know that the #1 piston is up and you have all 3 links lined up on the crank and cams then your timing is set right.

When I was disassembled my motor, as soon as I took out the chain tensioner, one of the cams jumped one tooth due to the compression. This is pretty common.

[s14unimog]

you said the links actually jumped. Like you actually heard them skip over the teeth. this actually happened to me once, while installing cams, the reason, for me, was b/c the latch didn't disengage when the tensioner was installed. Make sure the tensioner is actually pushing on the chain. If you try to rotate the assembly without the tensioner, you will have a mess on your hands.

TDC on the number one is 2 mark from the left, with the number one cams lobes apposing each other.

Surely you are assembling this without plugs in. You shouldn't feel much resistance when rotating. Be careful, if the mechanical timing is off, you could be contacting the piston.

I did this write up a little while back, maybe there is some helpful information. http://zilvia.net/f/engine-tech/287215-head-gasket-installation-sr20det.html

[hatchbaak]

Is this the same for the lower chain also? Do you have to crank it around and around and around for the colored links to match the timing chain marks again? Thanks!!

[mastashake]

Hey I'm about to replace my timing chain(S14 SR) soon and was wondering if it's really necessary to remove the head like it says in the FSM?

[sr24det]

the hard and soft of the crank is normal thats the compression strokes

as far as the links not lineing up again thats normal.
someone figured out the math once but it is a shitload of turns before they all line up again so dont worry about that just set them correct at tdc and make sure your tensioner is tight and line the cas up correct and let her rip!!!!!!