4.0 SOHC Right Side Cam Chain Head Scratcher | Ford Explorer Forums - Serious Explorations

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4.0 SOHC Right Side Cam Chain Head Scratcher

grreefkeeper

New Member
Joined
March 27, 2018
Messages
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City, State
Grand Rapids, MI
Year, Model & Trim Level
2003 Explorer XLT 4.0
Ok, so I had the engine out to replace a blown head gasket and repair all of broken timing components. I read a ton of info on here already (thanks to all) but I just can't figure out what is going on with my right side timing chain. I made a crappy video (I am going to try and get a better one). Any help would be appreciated!

 



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Ok, so I had the engine out to replace a blown head gasket and repair all of broken timing components. I read a ton of info on here already (thanks to all) but I just can't figure out what is going on with my right side timing chain. I made a crappy video (I am going to try and get a better one). Any help would be appreciated!
@grreefkeeper
Not an expert, but, I believe loosening the cam sprocket, if I understand correctly that you did, after assembly, allows an "out of time condition" to exist, whereby the valve springs under tension at that particular time twist the camshaft backwards out of time. That would explain the slack you are experiencing on the drive side of the sprocket. I hope you have not attempted to start the engine! imp
 






The engine is still in the installation stage so I have not attempted to start it. You are correct about the cam moving from valve preasure when the sprocket is loosened. The cam has been correctly lined up and timed in the video though.
 












The lower gear was not removed. Only the upper gear, tensioner, and guide.
 






Could the chain have gotten bent? If not odds are its just a lack of oil pressure in the tensioner. The internal springs are useless. You could be seeing the startup chain slap in real life. How did you get the guide out without removing the lower bolt that is behind the flex plate that holds the bottom in place?
 






The bolt was accessible without removing the flywheel. The plate between the engine and transmission was removed though. I didn't even consider that it was dry! That's the kind of help i was looking for! Thank you!
 






That's exactly what a sohc 4.0 will do if you turn it over with no oil pressure. As long as you got it timed right it's good to go.
 






Awesome! I hope you all can understand why I was worried. :)

I will check the timing for about the 10th time and throw it back together. I will let everyone know how it works out. Thanks again!
 






Ditto, there is varying tension as the engine rotates, from the valve springs and valve movements. If the engine was at TDC when the chains and head were serviced, and kept at TDC through the work, it should be fine.
 






Two observations:
  • You should pull the hydraulic tensioner, place it in a quart jar of clean 5w30 motor oil, and pump like crazy until it becomes rock hard, then re-install before reassembly/first start up (dump lots of oil or assembly lube on the guides & chain, too)
  • Did I understand you to say that you replaced the secondary right (rear/passenger side) timing chain guides and sprocket without removing either the engine or the transmission? If so, then that's a first (at least to me)! Details, please!
 






Good advice on pumping it up.

I DID pull the engine. :)
 












Very good, now go drive the heck out of it, enjoy it for a long time.
 






Great to hear. It never hurts to ask a 2nd opinion and triple checking timing marks.
 












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