4.7 wj timing - JeepForum.com
 
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post #1 of 12 Old 10-11-2019, 02:30 PM Thread Starter
swynx
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4.7 wj timing

2002 grand cherokee dropped a valve seat at 147k, so i bought a new head and timing kit, made sure all the marks were lined up and buttoned it up. ive confirmed spark and fuel, but it wont start. so i compression tested it and got some odd results. ive done about 20 timing jobs on ohc engines and got them all right, but perhaps i messed this seemingly simple one up.

drivers side from front to rear. 105/120/140/55 (80 wet)

passenger front to rear. 165/110/0 (90 wet)/ 100

that i believe #6 cylinder on the passenger side, will bump to 30 and fall to 0 before the next compression stroke. so i put oil in and it went steady to 90.

any advice? im going to pull off the valve covers and make sure the 2 cams both line up at 12. i turned it over several times before putting it back together to make sure the 2 lower sprocket marks lined up at tdc, and as far as i know it takes a random # of revolutions for the cam sprockets to both match the chain and be at tdc.

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post #2 of 12 Old 10-11-2019, 03:47 PM
jtec
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All you can do is keep going till you get all the answers - think positive.
pulling the valve covers would be a next step.
With the valve cover off be sure valves are seated closed, use a compression leak down tester to determine where 'leak' is, Valves, piston, rings, head gasket etc.
I gotta ask Which cylinder dropped a seat?

When I see the price of OEM I think aftermarket.
When I see the quality of aftermarket I think OEM.
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post #3 of 12 Old 10-11-2019, 05:05 PM Thread Starter
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Quote:
Originally Posted by jtec View Post
All you can do is keep going till you get all the answers - think positive.
pulling the valve covers would be a next step.
With the valve cover off be sure valves are seated closed, use a compression leak down tester to determine where 'leak' is, Valves, piston, rings, head gasket etc.
I gotta ask Which cylinder dropped a seat?
it was cylinder #2 that dropped a seat. vehicle ran great before that. i was just watching the cloyes timing chain video, trying to figure out where i might have messed up. i noticed it says "tdc #1 on exhaust stroke" ill be honest, im pretty sure i just set it at tdc #1 whatever stroke. maybe thats where i messed up?

i know that the cams were in the 10/2 position and the crank was at about 2.
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post #4 of 12 Old 10-11-2019, 06:50 PM Thread Starter
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got the valve covers off and first thing i noticed was that when comparing the new/old sprocket for the camshaft position sensors. they are different. none of the holes line up, and when i line up the new/old sprockets together, the mark i made on the oem sprocket doesnt line up with the mark i wouldve made on the oem cam. its about 90* off.

i knew that there was a jtec kit and a ngc kit. checked my order and i ordered a jtec kit.

that being said, does any one know if there is any difference in the 2 kits, aside from the target wheels being different? im hoping that the chains and sprockets are the same. i know that later on the chains switched to a roller style instead of inverted teeth. but thats not an issue for me.
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post #5 of 12 Old 10-13-2019, 07:36 AM
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There's only one camshaft position sensor on the 4.7L and it's on the passenger/right side of the engine. All the 4.7L timing component part numbers in the factory manuals for 1999, 2002 and 2004 are the same. I've just verified that and it's also mentioned in this thread:

https://www.jeepforum.com/forum/f310...g-set-3163729/

As far as I know, the only mechanical difference between the JTEC and NGC configurations for Grand Cherokee WJs from '99 to '04 is the crankshaft tone ring, which is a ring mounted to the crankshaft. They're different and not interchangeable, with the JTEC one having 16 teeth and the other having 32.

Having said all that, apparently there is an NGC target wheel that was used on the 4.7L in Dodge applications and on Jeeps beginning with the 2005 model year, and there is a way to identify the different wheels. Have a look here:

http://www.airram.com/product.php?ca...productid=1479

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99 WJ Limited 4.7/NP242
01 WJ Laredo 4.7/NP242
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post #6 of 12 Old 10-13-2019, 10:58 PM Thread Starter
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tore it apart tonight got all the chains and what not off of it. the kit i bought off amazon said it would fit ram pickups, durangos, dakotas, and wj's bunch of years. the 2 wheels are different. so going to swap those and redo the timing kit, see what happens. thankfully all the gaskets are reusable.

getting pretty good at working on the wj with a 4.7, the first time around i was yelling and throwing crap. this time around it only took about an hour to get down to the timing chains.

hopefully these pictures arent monster sized.
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post #7 of 12 Old 10-14-2019, 08:32 PM
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Well that's no doubt your problem right there. The cam sensor is dutifully reporting the wrong position information to the PCM.

I understand what you mean about 4.7 familiarity, unfortunately. I bare block rebuilt one a couple of years ago. After putting it all back together and reinstalling the engine (with all the accessories, etc.) and driving it about 10 miles it was leaking oil and steaming coolant very badly. After a week or two of self-doubt and despair, I still wasn't sure exactly what I had messed up so I mustered the resolve to dig back into it only to discover … absolutely nothing wrong.

In the end I decided I hadn't gotten the heads torqued down tight enough because I did exactly what the factory procedure in the manual said to do - torque plus angle, which DID NOT WORK. Initially I suspected something else and so I pulled the engine and removed the heads unnecessarily when I probably could have just pulled the valve covers and further torqued down the head bolts. I just didn't realize it at the time.

Anyway, that was the second or third time I set the timing. By that point, I needed no guidance and could do it in a few minutes with only my two hands and some rubber bands and zip ties, whereas the first time I was like … "uhhhh" following the FSM slowly and re-watching You-Tube videos, feeling a bit like a dummy.

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99 WJ Limited 4.7/NP242
01 WJ Laredo 4.7/NP242
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post #8 of 12 Old 10-15-2019, 12:37 PM Thread Starter
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i have read quite a few threads with people reporting that after working with a 4.7 wj, they just got aggravated and sold the vehicle, even if they finished the rebuild. which to be honest i have already decided that when this 4.7 fails again, im just going to ls swap it. i already have a 5.3 and a 4l80 that i need to refresh. and after this whole process i kind of wish i would have just gone that route in the beginning.

i also despise of the torque plus angle method for bolts. i know they do it because not all torque wrenches are equal. but i like numbers, and i dont want to spend big money on a fancy torque wrench that tells me angles. so for future reference, and this really helps if your doing things in vehicle, what i do, is find the bolt im most certain i got the torque plus angle correct on, then readjust my torque wrench 5 lbs at a time, till it no longer clicks. then just torque the rest to that number. for me the 4.7 was i believe 75 ft-lbs
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post #9 of 12 Old 10-15-2019, 01:17 PM
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I can't remember for sure but I think after Googling around for a number I ended up settling on either 85 or 90 ft. lbs.
Those head bolts have got to be TIGHT.

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99 WJ Limited 4.7/NP242
01 WJ Laredo 4.7/NP242
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post #10 of 12 Old 10-15-2019, 04:08 PM Thread Starter
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i had a hell of a time doing them in vehicle near the firewall. the angle is all wierd, trying to get enough grunt on the torque wrench without busting my knuckles made me break a sweat
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post #11 of 12 Old 10-16-2019, 07:11 PM Thread Starter
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got it put together enough to fire up today. it started right up. has an odd sound, but sounds more like an exhaust leak. can only hear it at idle. anything over 1000 rpm and you cant hear it.
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post #12 of 12 Old 10-17-2019, 01:07 PM Thread Starter
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after doing some thinking, im going to tear off the timing cover and start the rig with it off. see if one of the hydraulic tensioners is making noise. when i originally tore the engine apart there was no restrictor plate on iether tensioner. so ill take the restrictor plate off so the tensioner gets full oil pressure and see if it still makes noise.
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