Timing marks

[Vikingone]

So I pulled the timing cover off to check the chain. Set the engine to 0 degrees TDC. Distributed rotor lined up to cylinder #1. Once I got the timing cover off marks on the gears weren’t lined up. Lined up the marks on the timing gears and found the distributor rotor lining up to cylinder 3


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[Lumpy Grits]

Did you confirm TDC?
I usually remove the valve cover to watch the valve movement.
I will also remove the #1 cyl spark plug and use a 'straw' to confirm piston height.
I'm I see'n rust spots on the chain?
LG

 

[Vikingone]

Did you confirm TDC?

I usually remove the valve cover to watch the valve movement.

I will also remove the #1 cyl spark plug and use a 'straw' to confirm piston height.

I'm I see'n rust spots on the chain?

LG

You’re absolutely right. I have to pull a plug and confirm TDC. I noticed the rust spots on the chain as well. Was thinking it just was from sitting and south Florida humidity.


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[mriplaybass]

I'm pretty sure your 85 timing is set the same as our 79, and unlike most timing chains in other vehicles, the marks on the gears are not supposed to line up. The crank gear is supposed to be at 12:00 and the cam gear is supposed to be at 3:00. Then you count 21 chain pins between the 2 marks to make sure position is correct.

 

[Lumpy Grits]

I'm pretty sure your 85 timing is set the same as our 79, and unlike most timing chains in other vehicles, the marks on the gears are not supposed to line up. The crank gear is supposed to be at 12:00 and the cam gear is supposed to be at 3:00. Then you count 21 chain pins between the 2 marks to make sure position is correct.

That picture is the AMC 304 V-8.
The AMC 258 i6 / 4.2l is different.........
https://www.autozone.com/repairguid...n-or-Gears-and-Tensioner/_/P-0900c1528004af62

OP-You REALLY need to get a copy of the FSM, MR-252.
https://collinsbrosjeep.com/84-86-jeep-service-manual-body-chassis/

LG

 

[Vikingone]

That picture is the AMC 304 V-8.

The AMC 258 i6 / 4.2l is different.........

https://www.autozone.com/repairguid...n-or-Gears-and-Tensioner/_/P-0900c1528004af62



OP-You REALLY need to get a copy of the FSM, MR-252.

https://collinsbrosjeep.com/84-86-jeep-service-manual-body-chassis/



LG

I was just about to post the same thing. AMC 258 i6 / 4.2l is different.


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[mriplaybass]

My bad! I failed to look at your Jeep's configuration. Senior moment!

 

[Lumpy Grits]

My bad! I failed to look at your Jeep's configuration. Senior moment!

No worries--
I find that I'm move'n from CRS, to CRAFT.....
LG

 

[Vikingone]

When the alignment marks are lined up on the sprockets should it be in conjunction with the exhaust stroke or compression stroke? If the cam moves one full rotation for every two rotations of the crank. Wouldn’t the mark on the cam be 180 degrees from the mark on the crank sprocket? Thus aligning the distributor rotor with the post on the cap for #1 cylinder?


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[Lumpy Grits]

Comp, stroke.
LG

 

[Vikingone]

Comp, stroke.

LG

So went back into the garage and rotated the motor over by hand and set to TDC compression stroke. (Just did the old thumb over the hole trick and used a straw to confirm.) Well good news is the rotor lined right up to the number one cylinder post on the cap. BUT the camshaft sprocket mark is 180 degrees from the crankshaft mark.


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[Lumpy Grits]

Post #4.....
https://www.jeepforum.com/forum/f8/replacing-timing-chain-issues-883437/

And this.......
https://www.jeepforum.com/forum/f8/timing-6-something-wrong-881711/

You REALLY need to get that FSM ordered

LG