Finding Top Dead Center on each cyl

mmmkay325

Well-Known Member
Joined
Jul 16, 2005
Location
Waxhaw
I'm trying to get each cylinder to TDC to do a leak down test on my cherokee 4.0. I know for cyl# 1 tdc to get the timing mark to zero and verify i'm at the 5 oclock position on the dist. but my question is how to check 2-6 cylinders. I've heard I can pull the plugs and put a rod down there to watch the piston come up/down but how will I know i'm on the compression stroke and not exhaust? Am I suppose to reference the firing order for the dist block or timing marks??
 
Disconnect coil wire(s)
pull plug
put finger or thumb over plug hole
Rotate crank until the compression builds up and blows the seal you have over the hole.
TDC

At least that's how I have done it in the past
 
that works and also the firing order for the i6 is:153624. after your done with 1 move to 5. pull the plug out. place either a thumb over the hole or i just put a long screwdriver into the plug hole. usung a ratchet or wrench just hand crank and watch the screwdriver until it reaches its highest point.
 
gt500swim said:
that works and also the firing order for the i6 is:153624. after your done with 1 move to 5. pull the plug out. place either a thumb over the hole or i just put a long screwdriver into the plug hole. usung a ratchet or wrench just hand crank and watch the screwdriver until it reaches its highest point.
Click to expand...
same as he just said!
somtimes its near impossible to keep the crank from rotating when air is applied and if that's the case you can use a beaker bar on the crank bolt to hold it but dont let it swing around and hit ya.or just remove all the rocker arms then it wont really matter where you put tdc.
 
Same as said above on all of them, but just be careful with the screwdriver so you don't gouge the top of the piston I like to use a long straw or thin wooden dowel to check for when the piston gets to TDC, but i've used the screwdriver before also, just another idea.
 
appreciate ya'lls help:beer:...worked like a champ. I used the straw method down in each cylinder to get me close then I just used a flash light to watch the piston come up and stop before it went back down to get tdc. Doing a leak-down test works a lot better when you get each cylinder to TDC:rolleyes:
 
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