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tdc on a 88 cherokee 4.0

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Old Feb 14, 2013 | 01:16 PM
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Default tdc on a 88 cherokee 4.0

do we set tdc at 0 on the timing cover or do we use the peep hole on the cover. i set the dizzy up by using 0 and the jeep started and idled but it would pop when you opened the throttle . had to move the rotor 1 tooth cw to get it to run right ?
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Old Feb 14, 2013 | 01:36 PM
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You set up tdc on compression stroke cylinder no 1 . dont look at timing mark untill after thats been done then you set mark on balancer to "0" on cover .It should be pretty close all ready.
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Old Feb 14, 2013 | 03:32 PM
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allready did that ,the motor will start and idle but when you give it thottle it will pop and sputter. i have to move the dizzy one tooth cw to get it to run .
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Old Feb 14, 2013 | 03:35 PM
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Originally Posted by ck88jeep
allready did that ,the motor will start and idle but when you give it thottle it will pop and sputter. i have to move the dizzy one tooth cw to get it to run .
Rotor does not point directly to no 1 piston like older cars you know ?
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Old Feb 14, 2013 | 04:37 PM
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Setting Your 4.0 at #1 TDC
 

With #1 spark plug removed, turn the engine over clockwise using the 3/4" front crankshaft bolt. You will see the degree marks on your front cover. You will see the timing mark on the balancer. Mark them with chalk or white-out. While turning the engine over, put your finger/thumb over #1 spark plug hole. As the mark on the balancer approaches the marks on the front cover, if you are coming up on #1 TDC, pressure in the cylinder will push on your finger. If there's no pressure, you're at #6 TDC and need to crank the engine over until you see the marks coming together and you get pressure. Set the mark on the balancer to the 0 mark on the front cover.
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Old Feb 15, 2013 | 12:00 PM
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ok 0 it is. now i have to figure out why its not lining up like it is suppose too. is there a easy way to check the cam timing with out pulling the timing chain cover.
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Old Feb 15, 2013 | 05:18 PM
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Originally Posted by ck88jeep
ok 0 it is. now i have to figure out why its not lining up like it is suppose too. is there a easy way to check the cam timing with out pulling the timing chain cover.
What's not lining up?
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Old Feb 16, 2013 | 12:40 PM
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Originally Posted by cruiser54
What's not lining up?
the rotor is not lining up like you have in your dizzy setup with the crank set at 0 it is in the middle of 1 and 5 post on the dizzy. seems to be 1 tooth off. thats why i was asking if it lined up in the middle of the peep hole below the 0 mark on the timing chain cover.
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Old Feb 16, 2013 | 07:03 PM
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Originally Posted by ck88jeep
the rotor is not lining up like you have in your dizzy setup with the crank set at 0 it is in the middle of 1 and 5 post on the dizzy. seems to be 1 tooth off. thats why i was asking if it lined up in the middle of the peep hole below the 0 mark on the timing chain cover.
The rotor turns clockwise. The TRAILING edge of the rotor should be .020" PAST the #1 terminal on the cap.
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Old Feb 16, 2013 | 08:10 PM
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CK..just in case it helps, keep in mind the books and diagrams are all wrong. #1 is at 5:00 as viewed from the side.


Hey! You did save my photo VVV

Last edited by DFlintstone; Feb 16, 2013 at 09:05 PM.
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Old Feb 16, 2013 | 08:14 PM
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Originally Posted by DFlintstone
CK..just in case it helps, keep in mind the books and diagrams are all wrong. #1 is at 5:00 as viewed from the side.
And, it's the one terminal with the #1 plug wire hooked to it.

And, the decent caps have a 1 on them.
Attached Thumbnails tdc on a 88 cherokee 4.0-renix-firing-order.jpg  
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Old Feb 16, 2013 | 10:51 PM
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found the problem why it would not line up .The hb had moved about 20*. thanks for all the help. now on to the next problem.
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Old Feb 16, 2013 | 11:48 PM
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Hey, good catch. Glad you gotr'. For anyone following...a straw in the plug hole can be helpful to find TDC. (roughly anyway)
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Old Feb 17, 2013 | 06:14 AM
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Originally Posted by ck88jeep
found the problem why it would not line up .The hb had moved about 20*. thanks for all the help. now on to the next problem.
Did it look like this?
Attached Thumbnails tdc on a 88 cherokee 4.0-harmonic-balancer-failure.jpg  
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Old Feb 17, 2013 | 12:40 PM
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no, the rubber was alittle cracked. but i did notice i could not see the timing mark very good . the darn thing is starting to walk to the inside.
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