Timing replacement trouble
Sep 19, 2015 | 11:11 AM
#1
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From: Tacoma WA
Timing replacement trouble
My timing chain busted and i got around to replacing it last night using the factory service manual i have , i set the #1 cyl to TDC aligned the links put it all back together and it wont start i did a spark test no spark , i took the valve cover off this mirning the two bright links are a couple off the the right but the timing mark when at tdc is slightly left so marks shouldnt matter? Tried adjusting the ignition timing a bit got nothing
I did take a video of me trying to crank it over with the valve cover off And noticed somthing weird with the chain like it was slapping or tighting up and loosening and clicking on the right side idk i spent close to 9 hrs last night taking all that apart and i can only work on it on the weekends so i apreciate your fast replies
I did take a video of me trying to crank it over with the valve cover off And noticed somthing weird with the chain like it was slapping or tighting up and loosening and clicking on the right side idk i spent close to 9 hrs last night taking all that apart and i can only work on it on the weekends so i apreciate your fast replies
Sep 20, 2015 | 11:15 AM
#2
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Hey I'm also in the middle of some work, including a timing chain replacement. My truck is almost on the road again, and I had your problem for a while.
Couple things to triple check: make sure your distributor is inserted correctly. I had mine off, and it wouldn't start. Did you detach any other wires? On my 22r, there's a ground wire near the back of the head that screws to the firewall.
Couple things to triple check: make sure your distributor is inserted correctly. I had mine off, and it wouldn't start. Did you detach any other wires? On my 22r, there's a ground wire near the back of the head that screws to the firewall.
Sep 22, 2015 | 07:50 AM
#4
The bright links won't line up each turn. Here is some math to help you understand why...
The chain is 98 links long, the cam gear has 36 teeth and the crank gear has 18 teeth.
It takes the cam gear 49 rotations to "rest" the bright links back to the original marks on the cam gear (highest common denominator being 2 so the chain has a ratio of 18:49 on the cam gear). So for each turn of the cam gear, the chain travels 0.367347% of its length and is short of returning to the timing mark on the gear by 62 links.
It also the crank gear only 49 rotations to "rest" the bright links back to the original marks on the crank gear (highest common denominator being 2 so the chain has a ratio of 9:49 on the crank gear). So for each turn of the crank gear, the chain travels 0.183673% of its length and is short of returning to the timing mark on the gear by 80 links.
Now... given the fact the for every rotation of the crank gear, the cam gear only makes one half of a rotation (1:2 ratio crank to cam ratio - thus your 4 strokes), you would have to turn the crank 98 times for the bright links to align on both the crank and the cam gears. The crank may align at 49 rotations; however the cam would be "180" out and need another 49 rotations.
For your issue, you may be 360* out - combusting on you intake stroke, exhausting on your compression stroke, intaking on your combustion stroke and compression on your exhaust stroke. To check, Make sure that you have set the crank at TDC on the #1 cylinder (stick a piece of wire or something in the spark plug hole and make sure the cylinder is up) and then check rocker arms on #1 and #4. Both rockers on #1 should be loose and both on #4 should be loose. In fact, #1 intake, #1 exhaust, #2 intake and #3 exhaust should all be loose with #2 exhaust, #3 intake, #4 intake and #4 exhaust tight. If they are the opposite then you are 360* out and will have to reset your timing chain.
The chain is 98 links long, the cam gear has 36 teeth and the crank gear has 18 teeth.
It takes the cam gear 49 rotations to "rest" the bright links back to the original marks on the cam gear (highest common denominator being 2 so the chain has a ratio of 18:49 on the cam gear). So for each turn of the cam gear, the chain travels 0.367347% of its length and is short of returning to the timing mark on the gear by 62 links.
It also the crank gear only 49 rotations to "rest" the bright links back to the original marks on the crank gear (highest common denominator being 2 so the chain has a ratio of 9:49 on the crank gear). So for each turn of the crank gear, the chain travels 0.183673% of its length and is short of returning to the timing mark on the gear by 80 links.
Now... given the fact the for every rotation of the crank gear, the cam gear only makes one half of a rotation (1:2 ratio crank to cam ratio - thus your 4 strokes), you would have to turn the crank 98 times for the bright links to align on both the crank and the cam gears. The crank may align at 49 rotations; however the cam would be "180" out and need another 49 rotations.
For your issue, you may be 360* out - combusting on you intake stroke, exhausting on your compression stroke, intaking on your combustion stroke and compression on your exhaust stroke. To check, Make sure that you have set the crank at TDC on the #1 cylinder (stick a piece of wire or something in the spark plug hole and make sure the cylinder is up) and then check rocker arms on #1 and #4. Both rockers on #1 should be loose and both on #4 should be loose. In fact, #1 intake, #1 exhaust, #2 intake and #3 exhaust should all be loose with #2 exhaust, #3 intake, #4 intake and #4 exhaust tight. If they are the opposite then you are 360* out and will have to reset your timing chain.
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