Replaced timing chains but still wont crank

[Keith89]

My vehicle is 2004 ford explorer xlt 4x4 with the 4.0 sohc
Just purchased a few weeks ago the previous owner thout it had jumped time or had broked chain.i initially did a compression test and it came up 0 on both banks.When i got into it all the plastic guides were broken as well as the left
tensioner it had completely come apart. The previous owner told me it just wouldnt start one day and that up to that point no unusual noises , rattling anything. So i dont know how accurate that could be given that all the guides were shattered. The balance shaft was the only one still in time so i just replaced the tensioner and guide on that one. The rest was completely replaced all new sprockets chains tensioners and guides. I understand th obvious did i put it back in time correctly. Yes to the best of my knowledge. I did not use the otc tools but managed . I had no. 1 at tdc and both cams were held in place with slots parallel with the heads with the small off center side down. I knew about the possibility of bent valves but they seemed to be working correctly when manually turning crank also looking into exhaust and intake ports i could see no signs off being warped . I dont know how reliable that observation is though i know normally one would have to remove head. Anyway everything appeared to be good after replacing chains - cassettes so i put it all back together and hooked it back up in my explorer. Im almost positive everything is where it should be ive researched and triple checked. I replaced coil , wires, water pump, harmonic balancer whivh was aftermarket from dorman i believe. It didnt have the degree markings only one small white line etched so i assumed it must be 0. Everything is back in the truck and where it should be and when i went to start for the first time it wouldnt crank only turn over which was smooth at least. So checked if getting fuel it was then spark yes then checked compression again with cylinder 2 and 5 both were at 0. I just dont know what to do now or if there is a way to know for sure if its the valves before tearing it all back apart.

 

[boominXplorer]

I've never seen a 4.0 sohc go out of time enough to stop running and not bend valves. I've had about 20 of them come in locked up to my shop.

 

[Keith89]

Yeah thats what ive heard . Is there a way to know for sure without pulling the engine back out. When i originally had it out i looked in both intake and exhaust ports with scope and just by eye with flashlight and couldnt see anything out of ordinary. There was however alot of carbon build up and on left bank only inside intake ports instead of being dry carbon deposits it was like a tar coating. I have about 700 in parts already with about 30 hours on the rebuild i just want to find out without spending more time on this engine and maybe just buy a reman. Depending on what i find out

 

[boominXplorer]

If you have 0 compression on 2 cylinders then your either out of time or you have bent valves.

 

[Keith89]

Other than just the compression test how can i know for sure its the valves without removing heads

 

[boominXplorer]

There's nothing else it could be. These things cough and bend valves just barely out of time.

Pull the Schrader valve out of your compression tester and hook up an air line instead of the gauge. Make sure the engine is at a point where the rockers are loose and see where the air comes out. You'll hear it hiss a little past the rings but if you hear it out the intake or exhaust you can bet you have bent valves.

 

[Keith89]

Thanks i will try ,Also i dont know if this would make a difference but after i got the motor back in i noticed on the new harmonic balancer the raised spline or whatever i dont know what its called but it was bent bad so i attempted to correct it which i did as far as i could tell . If i didn't get it back the way it was supposed be what is the worst that would cause.

 

[Josh P]

A small camera down the spark plug holes would allow you to see if the valves made contact with the pistons.

 

[boominXplorer]

A small camera down the spark plug holes would allow you to see if the valves made contact with the pistons.

Unless you have a nice high quality inspection camera it's going to be hard to see the valve mark in the carbon.

You say something was wrong with the crank key? That's not good as it's the same one for the crank gear and balancer. You could be back out of time if the keyway broke.

 

[Keith89]

No not crank key .https://drive.google.com/file/d/0BxuVFHCwoeKgeWEzQmlUcXRCWjg/view?usp=drivesdk

 

[boominXplorer]

Oh that's the crank trigger for the crank sensor. It might give you ignition issues but 0 compression still is a different more pressing issue.

 

[Keith89]

Well i just bought a good inspection camera so tomorrow i will find out thanks everyone for suggestions and info

 

[Drewmcg]

If you got all of the broken timing guide bits out and put in new timing chains, water pump, etc., I'd be surprised if it wouldn't be more cost-effective to leave that engine in, pull the heads, send them to a machine shop for valve repair/pressure test, etc., and reinstall with new head gaskets & bolts. The German cast iron blocks and lower end of these engines are solid, and you'd have rebuilt the parts of the engine that fail without having to again pull/reinstall the engine(s).

I'm trying to remember what I paid the local machine shop to do both heads on this engine; I think it was $300-$500 (including a few new valves and new sleeves). The felpro gaskets are good and not too expensive @ Rockauto.

 

[Keith89]

Just wanted to give yall an update. So after running a high resolution camera in each spark plug hole ive found that one my valves arent bent and there is no damage to pistons . There is one valve stuck in every cylinder. Only 2 had both open . Im pretty sure it's the exhaust valves open closest to spark spark plug hole but weird thing is they are all stuck at different points or distances but none ever made it far enough to dent pistons. Now my question is how the heck to free them up without removing heads.

 

[Josh P]

Just wanted to give yall an update. So after running a high resolution camera in each spark plug hole ive found that one my valves arent bent and there is no damage to pistons . There is one valve stuck in every cylinder. Only 2 had both open . Im pretty sure it's the exhaust valves open closest to spark spark plug hole but weird thing is they are all stuck at different points or distances but none ever made it far enough to dent pistons. Now my question is how the heck to free them up without removing heads.

How did you determine they are stuck?

 

[Keith89]

I havent yet i just know they arent bent. I will put the camera back in tomorrow and rotate crank manually to see if they are truely stuck

 

[Keith89]

So all my exhaust valve stems were no longer seated properly in the rocker arms. My timing was spot on though however i just ordered new pre assembled heads. All should be well after that . Thank for eveyones help

 

[boominXplorer]

The exhaust valves are probably bent and not seating all the way keeping the stems from returning to normal height. It's what's allowing the followers/rockers to have slop.

 

[Drewmcg]

So all my exhaust valve stems were no longer seated properly in the rocker arms. My timing was spot on though however i just ordered new pre assembled heads. All should be well after that . Thank for eveyones help

Umm . . . if your timing chain did not fail (resulting in bent valves)--then how did your vavles get bent?

No matter--you'll need to re-time everything with the new heads anyways. But you should probably at least replace the front timing cassettes (primary and secondary), and the rear one, too, if you decide to pull the engine. Good luck

 

[Keith89]

The left tensioner was bad and all plastics were broken front and rear. I replaced it all already but my exhaust valves wont close all the way so now im just replacing both heads with all the valvetrain