Top Dead Center Question ?

JeepXJ2001 · 04-09-2009, 07:07 AM

So I am planing on taking the valve cover off my 2001 xj 4.0l auto and remove the rocker arm components in order to reach the head. In the Haynes manual is talking about the Top Dead Center on the jeeps that have a distributor cap.

How does this work on the xj with the coil packs.

Please help I have no idea how I would get the engine on the top dead center...

I am a newbie

lifted89xj · 04-09-2009, 07:14 AM

take your #1 spark plug out, thats the one clostest to the front of the jeep/motor take a metal clothes hanger, cut the botom straight part off of it. its like 18" or something. once you have a feeler rod do these steps.

steps.
1 remove plugs
2 take socket and ratchet on crank pulley bolt
3 put feeler rod in #1 cyl "first cyl in front of jeep. under AC pump.
4 slowly turn motor clock wise and watch the clothes hangar drop then it will come back up, once up it will peak out then drop again. then turn ratched the other way of you go over or keep going cloclwise either way you my half to go around 2-3 times to get TDC

but its as easy as that.

hope that helps.

jeeptown · 04-09-2009, 08:56 AM

You failed to mention that top dead center is on the compression stroke. You will need to put your finger over the s/p hole. while turning the engine you will feel air pressure coming out of the hole, that is how you know you are on the compression stroke. The top of that stroke is TDC. This is very important or you will be 180 degrees off.

JeepXJ2001 · 04-09-2009, 01:09 PM

does everyone agree with these methods?

**XJH-007** · 04-09-2009, 01:19 PM

Quote:

Originally Posted by JeepXJ2001

does everyone agree with these methods?

Yep.

If you end up 180 off it won't start...will pop and backfire at you...then you know you are 180 off.

The 'finger' trick will ensure it is the compression stroke and not exhaust. This way you don't have to take the valve cover off to figure out what the valves are doing.

JeepXJ2001 · 04-09-2009, 03:09 PM

The only thing is somehow I am not feeling so comfortable with the idea of dropping in a feeler rod in the engine I wont it wont drop in all the way I hope.

So I will take out the spark plug# 1 and I will put the rod in. Once the rod goes up, I will take it out and put my finder on it and turn it 180 degrees until there is compression...

Do i get this right?

JeepXJ2001 · 04-09-2009, 04:27 PM

crank pulley bolt is very hard to reach, i was did turn it maybe about 10 degrees but its super challenging, is there a special tool for it or something? How to reach it so its a little easier?

JeepXJ2001 · 04-09-2009, 05:09 PM

Ok, I did not take all the spark plugs out that's the problem!

JeepXJ2001 · 04-09-2009, 06:06 PM

Quote:

Originally Posted by XJH-007

Yep.

If you end up 180 off it won't start...will pop and backfire at you...then you know you are 180 off.

The 'finger' trick will ensure it is the compression stroke and not exhaust. This way you don't have to take the valve cover off to figure out what the valves are doing.

I could take the valve cover out, i will eventually have to take it out, if it will make it easier to see if the #1 is at the top dead center.

I will just keep on trying the steps mentioned above anyways...