I agree with hydrashocker timing off just a link will not give you zero compression.

 

The shop is no longer blaming me, after seeing the valve. he did not know why it didnt seat, but swore up and down he did all necessary pressure testing. hydra--the surfaces are within specs, i think this guy did not test the valves before letting the heads go. this whole experience is draining my finances and my patience. i pray after i get it back together this time that all is well. will check in when it is done---or i have another snafu!!

 

While the head is off get in there and look REAL CLOSE at the cylinder, as well as the adjoining ones. Put the piston to the bottom of the stroke and look for scores / cracks in the block. Clean off the top of the piston with a NON METAL scour pad (scotch-brite works good) and look for cracks.

What did the intake valve look like? If you had the timing chains off enough to affect compression then you've already hit a valve with the piston.

My bet is a bad intake seat, missing stem seal, or severely warped head. You sure you torqued ALL of the head bolts & didn't miss one? Zero compression is a big leak, should be pretty easy to find.

EDIT: Sorry, just saw that you've posted again and the problem was a valve. Make the shop replace the gaskets and head bolts..... they caused the problem.

Bob

 

ok. figured out why #6 was bent. when i installed the head, the cam shaft was rotated to far around and when i rotated it in to place to put on the sprocket, the valve hit the piston and bent it. the timing was correct so everything worked and i did not notice until it did not run right. Took the head in and he replaced the valve. got the head and timing put back together today and decided to test to make sure i have compression before putting it all back together. got good compression on all but #2 now. peeked in the intake port and the valve is not seating. i am beyond frustrated with this nightmare as i now have to get #2 replaced plus new head gasket/bolts---AGAIN. i made sure everything was right this time when i did the timing. i know #2 is down in the cylinder when #1 is at TDC, so how the f did the valve bend? AAAARRRRRRRGGGGGH!!!

 

Alright, take a step back and breath deeply.

As you've learned already, the 4.7 is an interference fit engine and parts *will* hit if it's assembled wrong. The most trouble free way to reassemble is to put the engine at TDC and LEAVE IT THERE. Now, before you put the heads back on, set the sprockets on the cams and rotate them to the TDC position (V8 facing up) and LEAVE THEM THERE. Note that they are going to rotate slightly away from each other (about 2-3 degrees) because of valve spring pressure, that's OK as nothing will hit. You're not going to turn the engine over yet anyways.

Now put the heads on and start working on your timing components. The crank chain goes on first and is easy to line up as the upper gear can be rotated by hand. After that one is set, do the other chains one at a time, all you should have to do is rotate each camshaft SLIGHTLY to get the chain links to match up & have the V8 marks pointing up. A second pair of hands helps here as you need to fight the valve spring tension while pushing on the gear/chain AND keeping the silver plated links in the right position. A zip-tie or two also comes in handy to hold the chains in place, just make sure you collect all the pieces when you cut them later.

Once you're sure everything is right, release the pins from the chain tensioners and SLOWLY rotate the engine by hand ONLY IN THE DIRECTION IT NORMALLY RUNS for two complete crank revolutions. If you feel ANY resistance at all, stop and investigate it. Make sure all the plugs are out of the engine when you do this so you're not fighting compression.

As long as the marks line up after two rev's, you're all set.

The only way that you've bent an intake valve is that the timing was off somewhere when it was assembled. It's frustrating, but it's a complicated timing arrangement that needs to be precise. Hang in there......

Bob

 

One more (bad) thought.... by chance could you have gotten the camshafts mixed up? They're unique to their respective sides of the engine, and if swapped would most certainly cause strange interference issues. I have NO idea if the engine would run or not, it's just a random thought because of the issues that you're having getting it assembled.

Bob

 

Found this in the removal of the cam on the left side. After you are at #1 TDC you turn the cam to remove it so it has no load.

Removal CAMSHAFT(S) - LEFT
DESCRIPTION
(7) Using the pliers, gently allow the camshaft to
rotate 15° clockwise until the camshaft is in the neutral
position (no valve load).
(8) Starting at the outside working inward, loosen
the camshaft bearing cap retaining bolts 1/2 turn at
a time. Repeat until all load is off the bearing caps.



INSTALLATION
(1) Lubricate camshaft journals with clean engine
oil.
NOTE: Position the left side camshaft so that the
camshaft sprocket dowel is near the 1 o’clock position,
This will place the camshaft at the neutral
position easing the installation of the camshaft
bearing caps.
(2) Position the camshaft into the cylinder head.
(3) Install the camshaft bearing caps, hand tighten
the retaining bolts.
(4) Working in 1⁄2 turn increments, tighten the
bearing cap retaining bolts starting with the middle
cap working outward (Fig. 29).
(5) Torque the camshaft bearing cap retaining
bolts to 11 N·m (100 in. lbs.).
(6) Position the camshaft drive gear into the timing
chain aligning the V8 mark between the two
marked chain links (Two links marked during
removal) (Fig. 30).
NOTE: When gripping the camshaft, place the pliers
on the tube portion of the camshaft only. Do not
grip the lobes or the sprocket areas.
(7) Using the adjustable pliers, rotate the camshaft
until the camshaft sprocket dowel is aligned
with the slot in the camshaft sprocket. Install the
sprocket onto the camshaft (Fig. 31).

CAUTION: Remove excess oil from camshaft
sprocket bolt. Failure to do so can cause bolt overtorque

(8) Remove excess oil from bolt, then install the
camshaft sprocket retaining bolt and hand tighten.
(9) Remove Special Tool 8350 timing chain wedge
(Fig. 32).
(10) Using Special Tool 6958 spanner wrench with
adapter pins 8346 (Fig. 33), torque the camshaft
sprocket retaining bolt to 122 N·m (90 ft. lbs.).
(11) Install the cylinder head cover.
resulting in bolt failure.

 

Hydra,

Once you remove the timing chain(s) the cam will roll back to a relaxed position by itself. Looking back, I did have the cam "locked" with a set of vice grips when removing the chains, so mine never "snapped" back by itself. Not sure if it really would matter if it did.

I didn't think it was as far as 15 degrees, but I suppose it could have been. Either way you put the head on the engine (with cam or without cam installed) you still have to manipulate the cams slightly to get the timing chains / marks to line up. As long as you don't turn the crank you won't have any mechanical interference / do any valve damage.

FWIW, bad practice to put vice grips right on the shaft. Wrap it with an old piece of leather first. (glove, belt, etc) to protect the surface from scratches which could be potential stress crack points in the future.

Bob

 

The left bank (drivers side) needs to rotate 15 degrees counter clockwise and the right bank (pass side) needs to be rotated 45 degrees clockwise in order to line up the camshaft sprockets properly. It was VERY difficult to turn. Took the head to a different shop yesterday, and he said that since the heads sat for a while (almost 3 weeks) the lifters seized up. They are very gummed up and stiff and he seems to think that this would cause a valve to stick open. He is going to bleed all the lifters and we will see what happens. If there is still a problem, I may just replace the lifters. At least I know I did not screw it up this time. Off to buy new head gasket and bolt set. I now own 4 sets of TYY bolts if anyone is interested? I have just been turning the cam with vice grips and a rag, still leaves marks tho and sometimes slips. Guess if it turns a little easier after the lifters are bled, I should not have to try so hard to get it to turn into position. I currently have the engine at TDC for #1. Spent ten minutes making sure it was absolutely so. I now await the head and hope and pray all goes well this time. Been w/ out a Durango since July 10!!!! Will keep all posted. thanks again guys and gals, you have been my confidence through this whole ordeal!!

 

Its ALIVE! Finally, my work has paid off. She started right up and runs like she should. I have some minor leaks here and there to shore up, but she purrs like a kitten---with a tick. It is the lifters on the pass. side and they will quiet down once I hit the highway. They need to fill up and I hope the knock will dissipate. Now, all I need to do is stop the annoying locking/unlocking thing. I have read through the other threads and the TSB is helpful, but I cant figure out where the short is, or if there is one. I tore the driver side door apart and found nothing corroded or out of order. I did have to fix the tailgate mechanism, due to the fact it would not open manually. Lot of rust and corrosion. Wondering if I did something to cause a short or malfunction. It happens all the time, not just when it is raining or going through the wash. The vehicle has been in a garage for 3 months and it still does it. Short in a wire?