timing chain/sprocket removal
#1
Thread Starter
Senior Member
Joined: Jan 2010
Posts: 613
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From: Westminster Colorado
Year: 1991 (2-door)
Model: Cherokee
Engine: 4.0L
timing chain/sprocket removal
Since Im disassembling my 4.0 to build a stroker, do I need to worry about how the timing chain, sprocket and crank sprocket are alligned when I remove them? Im reading in the manuals and it says make sure not to turn the crank or the cam after the timing chain is removed. Im guessing since Im putting in a 258 crank and new cam, I do not need to worry about this or the allignment of the sprockets?
#4
CF Veteran
Joined: Aug 2010
Posts: 1,168
Likes: 3
From: Williamsport, Pa
Year: 1997
Model: Cherokee
Engine: 4.0L
You will need to align them properly when reinstalling them. A word of warning though, when I purchased my new parts (cam/timing set) I found a couple things that didn't follow the manual exactly.
First, the manual describes how to count timing chain pins and says there should be 15 pins on the chain between the two timing marks on the gears. My new gear set had a 24 tooth crank gear and a 48 tooth cam gear, this ment that there ended up being 20 pins on the chain between the two timing marks. Be sure the marks are lined up facing each other when installing the timing set.
Second, most aftermarket cam manufactures don't index their distributor drive gear. What happens is when you install the distributor the mounting tab doesn't line up with the mounting hole in the engine block. Two ways to solve this problem... one is to just drop the distributor in where ever it will fit and allow you to use the mounting hole and footplate to secure it (being sure to use the alignment hole in the cam sensor and distributor body while installing it) then follow the correct firing order. Other way is to grind off part of the distributor footplate so it can be mounted in the normal position (with #1 plug wire close to the 5 o'clock position) ALWAYS USE A PIN THROUGH THE CAM SENSOR AND DISTRIBUTOR BODY WHEN INSTALLING THE DISTRIBUTOR. This will insure the correct timing for the fuel injectors and allow the computer to advance timing as needed. Lining up the dots on the cam and crank gears will insure the pistons are timed with the valves.
First, the manual describes how to count timing chain pins and says there should be 15 pins on the chain between the two timing marks on the gears. My new gear set had a 24 tooth crank gear and a 48 tooth cam gear, this ment that there ended up being 20 pins on the chain between the two timing marks. Be sure the marks are lined up facing each other when installing the timing set.
Second, most aftermarket cam manufactures don't index their distributor drive gear. What happens is when you install the distributor the mounting tab doesn't line up with the mounting hole in the engine block. Two ways to solve this problem... one is to just drop the distributor in where ever it will fit and allow you to use the mounting hole and footplate to secure it (being sure to use the alignment hole in the cam sensor and distributor body while installing it) then follow the correct firing order. Other way is to grind off part of the distributor footplate so it can be mounted in the normal position (with #1 plug wire close to the 5 o'clock position) ALWAYS USE A PIN THROUGH THE CAM SENSOR AND DISTRIBUTOR BODY WHEN INSTALLING THE DISTRIBUTOR. This will insure the correct timing for the fuel injectors and allow the computer to advance timing as needed. Lining up the dots on the cam and crank gears will insure the pistons are timed with the valves.
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