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Unread 09-13-2013, 08:47 PM   #1
mustanggarage
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urgent questions about timing chain install

Hello. I am posting this thread here and in the engine section because I really need some help as soon as possible.

I am in the process of doing a head swap 4.0 onto a 4.2 and doing the MPFI conversion at the same time.

I set the engine at TDC and took the distributor cap off confirming that the rotor was pointed at number 1.

so I pulled the head. then I checked the timing chain and found it had a bit too much slack so I pulled the harmonic balancer and the timing cover.

when I pulled the timing cover I found the crank sprocket positioned with the dot toward the cam sprocket. the cam sprocket dot however was 180 out. I rotated it around so the two dots are aligned. here is the pic.



however the rotor looks like this.



now keep in mind this engine was running just fine when I took it apart. but this as far as I know looks like the distributor is in 180 out of time. I called Hesco and asked them about it and they said to just re install everything like I took it out.

so I swapped the timing chain. it looks like this now.


the distributor looks like this.



before reinstalling the head I rotated the engine so the cam sprocket was at 1:00 and the crank sprocket was at 3:00 and counted pins. 15 count just like it should be. reinstalled the head, torqued it properly.

now I need to pull the distributor. the new distributor has a pin in it to keep it from rotating. My concern is that this looks like it is 180 out to me. should I reinstall it like it was? I know it is not that big of a deal to pull the distributor and swap it 180 but I wanted to get some more opinions before I pulled the distributor.

so anyone out there have any opinions?

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Unread 09-13-2013, 09:06 PM   #2
Old4X
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You do not line up the marks on these engines like most other engines. The proper timing procedure is in the factory maint manual (free download link on this site via search).

Had you left it alone, you would have been fine. Now that you moved stuff, put it back by the book. If you are even one tooth off you will have problems.
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Unread 09-13-2013, 10:30 PM   #3
mustanggarage
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first of all thanks for the reply. I did not remove anything until I could see what was going on. and once I pulled the timing chain off I put the new one back on exactly as I took the old one off. at this time I have changed the timing chain but the orientation of everything is the same, and I did check the timing like the factory service manual instructs, in order to do that you have to rotate the engine until the cam mark is at the 1 :00 position and the crank mark is at 3:00 then count the teeth. that is what I did. I have not moved the distributor yet. I am waiting on input about my question about the timing marks and the position of the rotor before I do anything more. I don't know what else you are saying I should have done differently. again I read and followed the factory service manual instructions but the way it says does not correlate with the way it was when I took it apart.
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Unread 09-14-2013, 06:14 AM   #4
Old4X
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Sorry, I must have misread. I understood you re-oriented the cam gear relative to the crank gear. If you are as recommended by the maint manual, you are good to go.
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Unread 09-14-2013, 11:53 AM   #5
mustanggarage
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thanks. I appreciate your response, and I have some more info. basically I am pretty sure everything is fine. I just don't understand why those timing marks on the timing gears are the way they are. anyway I rotated the engine around so the rotor is pointing where the number one cylinder should be. when the head was off so there is no question the engine is at TDC on cylinder one. the timing marks on the sprockets are like this now.




I reinstalled the pushrods and the new head. (before anyone asks I did fill the water jackets as described on jeep forum). torqued everything down. I did not think to do this last night but today since the head is on but the intake and exhaust manifold aren't I can look down inside the head and I can see that both valves on number one are closed. so I am at TDC on the compression stroke of number one. the rotor is pointing where it should be pointing for number one like this.



so I believe everything is right. what I don't understand is why the timing marks on the gears are like this. is this the way it is supposed to be? I have been a Ford guy my whole life and spent most of my time working on mustangs so this jeep thing is new to me. so forgive my ignorance. I am pretty sure everything is set right I just would like to know if that is the way it always is.
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Unread 09-14-2013, 12:38 PM   #6
Old4X
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IDK why, just remember from when I did my chain and gears that the marks were not what I was used to seeing from most other engines. I followed the maint manual and everything worked perfect for me.
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Unread 09-14-2013, 02:32 PM   #7
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Not really knowledgeable on this but are you sure that you were actually TDC and not 180 out when you started this? I mean, the piston is at the top at both the end of the compression stroke and the exhaust stroke, right?
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Unread 09-14-2013, 02:39 PM   #8
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Never mind. I didn't read closely and see that you said:

"I can see that both valves on number one are closed. so I am at TDC on the compression stroke of number one"
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Unread 09-16-2013, 01:01 PM   #9
mustanggarage
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well I put my thumb over the number one spark plug hole and rotated the engine with the harmonic balancer bolt. there is no question that I am at TDC on the compression stroke of number one cylinder. so everything is good. I posted this same question on Hesco's forum and leee one of the hesco forum moderators said this
"
The timing dots when aligned has the engine at TDC firing #6, also at this time the #1 valves should be a "SPLIT OVERLAP" (that means the exhaust is almost closed and the intake is starting to open). Most engine builders use this to rough degree a cam in.

You should have pre oiled the lifters if you installed new ones, if not they will bleed off after a minute.
The push rod pre load is a major item when changing heads (has more to do with condition of head)
Very simple to check (rotate engine till you are sure the lifter is on the base of the cam, with the rockers in place but not tighten down measure the distance from the head to the pivot with a feeler gage) should be mim .040 and max of .080. The engine will run with more preload but will wear cam faster."

so again I am pretty sure everything is good. I will check the lifter preload tonight but from everything I have read I should be good since I re-used the old 4.2 pushrods.

thanks for the help guys.
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