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Help Timing Cam vs Crank position

Old 12-12-2009, 03:54 PM
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Default Help Timing Cam vs Crank position

I have a 96 Cherokee Sport 4.0 High output, I had to install a new cam. In the process i moved the Crank Shaft after removing the Timing Chain And Cam. Now I can't figure out how to position the Cam gear and Crank Shaft gear.
The two Manuel I have from Napa are Chiltons and Hearn or something like that.
Chilton says to position the crank mark at 3oclock and the cam mark at about 1oclock and that i should have 15 pins between them
The other book Hearn or something like that says to point the timing marks at each other place the chain and sprocket complete as one unit and then rotate like it say in the Chilton book and confirm that i have 15 pins between them.

I alway end up with 20 pins between them futher more i don't have dots like they show on the book i have a groove instead.
I put it together like Chiltons, with 15 pins and it won't start.
Old 12-12-2009, 04:54 PM
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what brand chain?
how i always do it is bring the #1 piston to Top dead Center...which should bring your dot at 12 O'Clock then just line the cam dot onto that....not exactly sure where the teeth counting thing comes into place unless you turning it 180 than counting the number of teeth the cam has turned....either way cam spins twice for every 1 revolution of the crank.....
Old 12-12-2009, 06:50 PM
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Originally Posted by 98 JeepJeep
what brand chain?
how i always do it is bring the #1 piston to Top dead Center...which should bring your dot at 12 O'Clock then just line the cam dot onto that....not exactly sure where the teeth counting thing comes into place unless you turning it 180 than counting the number of teeth the cam has turned....either way cam spins twice for every 1 revolution of the crank.....

Actually the cam spins 1 revolution for every 2 revolutions of the crank.
Old 12-12-2009, 07:27 PM
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AS 98 JeepJeep stated, place number 1 cylinder at TDC. The crankshaft timing mark will be at the 12 o'clock position. Install camshaft sprocket with timing mark at 6 o'clock position. The two marks should be opposite each other. Then turn the crankshaft until the camshaft timing mark is at the 1 o'clock position. The crankshaft mark should be at the 3 o'clock position. The chain pins between the two marks should count to 15. The pin count is just verify that the timing is good. This is per the Haynes manual.
Old 12-13-2009, 08:21 AM
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Default Response 1

Ill have to find the box for the timing chain today, As for the #1 @ TDC and the dot on the crank @ noon, positioning the cam @ six, iil try that today.

98 JeepJeep it not teeth Hayne book refers to it's the "pins that hold the chain together.

Again I don't have dot, I have strike marks and if I turn the Crank to the 3oclock position and the Cam @ 1oclock position I end up with 20 pins between them.

Before assembling the rest of the engine is there someway to confirm i have correct?
Old 12-13-2009, 08:34 AM
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Does this help? this is what it should look like.
Old 12-13-2009, 09:07 AM
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Originally Posted by g.mccormick
Actually the cam spins 1 revolution for every 2 revolutions of the crank.
good catch...always get that mixed up...was thinking it correctly in my head.
Old 12-13-2009, 09:18 AM
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That how I have it right now as we speak timing cover off, if I rotate it to confirm the 15 pins bettween the two markers, I end up with 20 pins?

Will #1 compresion @ 130psi confirm, or no
Old 12-13-2009, 12:17 PM
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When you brought #1 up the tdc, are you sure that you had it at tdc compression? If you had tdc overlap, your timing will be 180 out.
Old 12-13-2009, 12:26 PM
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its really not as hard as most think....1 on TDC this can be verified with a piston stop.(which you wouldnt need to anyway because 1 full revolution will bring you back to TDC) with the timing chain removed compression stroke/exhaust stroke are erelivant. BECAUSE at that point you would put the crank sprocket on and then the cam sprocket and line the cam dot up with the crank dot which should already be at 12 o'clock. no way for the cam to be 180 out.....

Last edited by 98 JeepJeep; 12-13-2009 at 12:29 PM.
Old 12-13-2009, 01:42 PM
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Default Got it

I think I got it! I set it like the diagram show inthe above thread by Capitainwoot. put everything together and it started right up! And seem to be running right

I still have 20pin difference which I don't understand? But lets see what happens, NFL Football started so i'm going to button it up tomorrow "Hood, Grill, Fan Shroud, ETC".
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