OK I just set the timing and rotated the engine, it rotates fine no problem, but the the marks on the timing chain do not line up again after several turns. I had the crankshaft timing gear mark at 6 put the chain on making sure the colored link was at the mark. then routed the timing chain up to the cam sprockets and everything was lined up on both sides. got the tensioners back in. then I rotated engine by the harmonic balancer bolt a few times just to check my work. it rotates fine no problem but the marks on the crankshaft timing chain sprocket and camshaft sprockets don't aline again with the colored links. Is there a certain amount of turns till it lines up again.
Timing Question... Help ASAP
- Thread starter SFC.Kill
- Start date
squeak93
15 Year Member
They should line up every time they pass. Redo it.
Its very easy for it to jump timing when u let the tension loose.
Its very easy for it to jump timing when u let the tension loose.
trinity_gt
10 Year Member
I don't believe this is true. Two complete revolutions of the crankshaft will put the timing marks on the sprockets back where they should be but the chain links will not be at the same points in space anymore. The cam and crank phasing will still be correct but those colored links won't match up.
The chain has 58 links and the crank sprocket has 21 teeth with one link essentially using up 2 teeth. One complete revolution of the crankshaft drags 10-1/2 links worth of chain down. So two complete revolutions, which puts the cam and crank marks back into alignment, only moves the chain 21 links which is less than half its length.
In order for the links to end up in the same spot, the crank sprocket would have to move 58 links' worth of rotations or 58/10.5 or 5.5238... rotations. Of course, because this isn't an even and integral number of rotations, the crank and cam timing marks aren't going to point anywhere recognizable (even though they're still in phase with each other...) In order for everything to line up -- the timing marks to be oriented correctly and the colored links to land right where they were at initial setup -- a large number of crank rotations would seem to be required and this number has to be both integral and even (to represent complete cycles) and must also meet the length criteria of the chain.
If one chain length is 5.523809524 rotations of the crank and we know we need an integral number of these to get the colored links lined up, how many of these numbers would result in a number of crankshaft rotations that is also integral and even? 21? 21*5.5238... = 116, meaning after 116 crank rotations everything would be back in line?
I dunno..I probably messed up the math but this is the idea. As long as the marks are set up correctly initially and the timing marks -- not coloured links -- come back into alignment after a coupld of rotations, he should be good to go. Hopefully the OPer will turn his crankshaft 116 times and let me know if the chains come back into line as well.
BTW, this does make a degree of sense from a wear perspective. Any two meshing surfaces -- chain bushings and sprocket teeth -- only come into contact occasionally, which helps to distribute wear. In gear systems this sort of thing is termed "hunting tooth" mesh or something like that...
My head hurts. I'm going to lie down now.
Every time I bring the timing mark around to TDC on the damper, both cam sprockets look in perfect position but the colored links don't line up. I did the timing chain install 3 times just to make sure. I agree with trinity_gt. 2 revolutions on the crank put back the colored link I think it was 2 teeth on the cam sprockets. the more I turn the farther the colored link falls back.
i set mine up like this and now i have broken cam followers and bent valves....
to the op do not try to crank the motor untill the color links match up every 2 rotations of the crank.... make sure you turn the crank plenty of times to make sure it stays lined up....
let us know how it works out
squeak93
15 Year Member
The cam and crank are on a 2 stroke cycle... sorry i wasn't more clear, figured that didn't need to be said. When your releasing the tensioner, is it slaping the chain or are you easing it down softly. When you put tension on the chains to quick, esp the pass side, they are known to jump timing.
They way I read it is confusing to me. Are you saying that once the tension is on the chains it all lines up.... then when you turn it, things get out of wack. That tells me you must be off a link or tooth on our chain counting.....
Did I read ur post right?
They way I read it is confusing to me. Are you saying that once the tension is on the chains it all lines up.... then when you turn it, things get out of wack. That tells me you must be off a link or tooth on our chain counting.....
Did I read ur post right?
Once I released the chain tensioner everything was still lined up. Then with each rotation the colored link falls further from the alignment marks on the cam sprockets. If I line up the harmonic balancer with TDC mark on the timing cover, my cam sprockets alignment marks are where they are suppose to be, the colored link on the chain is no where to be seen because I've turn it so many times now. Thats why right now I'm agreeing with trinty's post.
trinity_gt
10 Year Member
i set mine up like this and now i have broken cam followers and bent valves....
It wasn't set up correctly initially, the timing jumped when the tensioners were released or the tensioners themselves were defective and failed to take up the slack resulting in a skip.
It will never do that in two rotations.
The crank sprocket has 21 teeth so two rotations is effectively 42 teeth. A link of the chain effectively requires 1.5 teeth per meaning you could wrap 10-1/2 links of the chain around the crank sprocket. Thus, two rotations of the crank sprocket only pulls along 10.5*2 or 21 links of the chain. Since the is 58 links long, two rotations doesn't even pull the chain half its own length. There's no way those links will line back up again after just two rotations.
The key after the initial setup is to ensure that the timing marks themselves line up.
The dot on the crank pulley facing down, the keyway pointing to cylinder 1 TDC, the keyways and/or marks on the cams are what really matter, not the colour codes of the links. Use the coloured links for the initial setup and if you did it right, then after 2 or 4 or 6 or whatever crank rotations, the marks will line up. The coloured links won't anymore but that doesn't matter.
stangalator
New Member
i have to check mine, i think i might have turned one of my cams by one tooth, what are the symptoms of one cam skipping a tooth?
bent valves and broken cam followers.... its not fun. i really dont have it all ironed out yet i was just trying to warn the op because i thought i had mine set up right and it blew up in my face.
so if im reading right the marks will never line up again or every 8 turns? I still need more info on this because i will have to set my timing up again here in a few weeks
stangalator
New Member
even if its off by one tooth, i thought it took more like 3 teeth or so to do that.
I think mine was only off 2 teeth
but if the case is that the colored links do not line up every time then i may have had the timing right this last time but had bent the valves from a previous time i tried to set it....... i re-did it like 4 times
trinity_gt
10 Year Member
The cam and crank marks will align as in the image above every two rotations of the crank. If you start there and turn the crank exactly twice, you'll see the marks in the sprockets lined up again.
However, the colored chain links will not be in their original spots.
Because the tensioners are released when the chains are installed, the two links give valuable information indicating how much chain should be between the two sprockets (crank and cam) to ensure you don't end up with too much slack on the drive-side initially. The crank turns clockwise so during normal running, the "right" (as viewed from the front) side of the chain are drawn "straight" and the curved guide takes up the slack on the tensioner side.
With the tensioners out, you probably could install that chain so that you initially had too much slack on the drive-side and would end up out of time as the crank started to turn and left the cam sprocket behind. The two colored links ensure that the correct number of links connect the crank and cam sprockets at initial setup. For the reasons listed above, it would be a considerable number of turns before these came back into alignment after the engine's been turned.
It's just that initial set up, making sure the number of links between the two sprockets on the drive-side is correct that's really critical and where those link colors matter.
hotcobra03
Active Member
timing marks/links
as already stated ,,,they will come together after 8 times around...or so...
look how long the chain is and how small the sprockets,,,,,, now thing about it?????????old school the gears almost touch
as already stated ,,,they will come together after 8 times around...or so...
look how long the chain is and how small the sprockets,,,,,, now thing about it?????????old school the gears almost touch
hotcobra03
Active Member
left/right
for the ones having trouble...look at the pic....you see a cam on the left,than a cam on the right,,,than they come to bottom and loop around gear,,,, the cam on the right in pic is the left hand chain.....than the one on left is the right hand chain.....
instruction say set leftside cam at 12,and rightside at 11....i watched someone do this wrong over and over on a 5.4....
for the ones having trouble...look at the pic....you see a cam on the left,than a cam on the right,,,than they come to bottom and loop around gear,,,, the cam on the right in pic is the left hand chain.....than the one on left is the right hand chain.....
instruction say set leftside cam at 12,and rightside at 11....i watched someone do this wrong over and over on a 5.4....
trinity_gt
10 Year Member
Great news. Good job getting her together and running. That's a good combo, the NPI shortblock with PI heads and intake.
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