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How to: SOHC V6 Timing Chain Parts Removal Procedure

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Hello all. I'm elbow deep in a front cassette and tensioner replacement. After tear down I've found the balance shafts tensioner is broken. I have not pulled the more due to the rear cassette is in good shape. I have read some people have successfully replaced the balance shafts tensioner without removing the motor by removing the actual spring and plastic from the bracket and installing in on the existing bracket. Has anyone attempted this and if so how was it achieved? My thoughts on it were made I could cut the chair off install the new tensioner and then install the new chain. In doing that I wasn't sure how to remove the crankshaft gear and once it is removed if the chain has enough slack to fit on the balance shaft and then be able to slide back on the crankshaft without bending the chain. Any input would be great. This forum has been a lifesaver for many people I hope it's as useful for me as everyone else. Thanks
 



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balance shaft chain tensioner

I couldn't find the original post but:

Replacing the entire balance shaft chain tensioner requires removal of the block cradle since the tensioner base retaining bolts are in the vertical position. Item 2 below.
Timing3.jpg

Some members have successfully replaced just the spring portion of the tensioner by bending the pivot post out of position, sliding off the old spring section, sliding on the new spring section, and then bending back the post.
BlncShft.jpg

It is unknown how much the stress of bending the post reduces its reliability. Some members have just cut the balance shaft chain rather than remove and reinstall the block cradle to correctly replace the tensioner. There has been much discussion on the forum about the need for a functional balance shaft because of the difficulty associated with chain tensioner replacement or because of the desire to replace a balance shaft equipped engine with an available engine with no balance shaft (or vice versa).
It may not be possible to remove the chain without removing the balance shaft chain sprocket on the crankshaft.
SOHCvalvetrain.JPG

In order to do that the crankshaft to jackshaft chain sprocket must be removed which means the camshafts will have to be retimed.
 






Thanks for the input 2000StreetRod you have been so helpful to many over the years. One other question. Is a regular gear puller used to remove the balancer sprocket off of the crankshaft? It moves until it comes into contact with the crank keyway. I wasn't sure if it had to be rotated with the chain off to remove or it had to be removed with a puller. I was thinking that I could cut the old chain remove the gear then install the tensioner or just pull the gear far enough to squeeze the tensioner behind it. I could see bending the post down far enough to get the clearance to slide the tensioner on. My only concern is getting the tensioner to fit under the chain between it and the tensioner bracket. it's pretty tight in there. I know you haven't tried this yourself so your input is limited so if you remember anyone who has successfully done it please send them my way. Thanks again
 






used old chain

I think the two members that bent the pivot post left the balance shaft chain in place to avoid retiming the camshafts. The Woodruff key for the crankshaft to jackshaft chain sprocket should be removable by prying. If you remove it I suggest replacing it with a new one. I'll look thru my workshop manuals about removing the balance shaft chain.
 






keyed sprocket

The workshop manual wasn't any help but Tasca Parts has a photo of the balance shaft chain crankshaft sprocket.
BalanceShaftChainCrankSprocket.jpg

The key is part of the casting and must fit in the same slot on the crankshaft as the crankshaft to jackshaft chain sprocket
PrimaryChainCrankshaftSprocket.jpg

and the harmonic balancer which both depend on a Woodruff key. So you'll have to remove the crankshaft to jackshaft chain sprocket, then the Woodruff key in order to remove the balance shaft chain sprocket.
 






OK I'm going to try it today. Thank you for the input. I will post my results good or bad. Hopefully good.
 






pulling motor 4.0 SOHC

2000streetrod, I'm pulling out my motor in my 2000 4.0L SOHC 4wd tonight. Have the timing chain kit, head gaskets, ect.... your article you wrote up was great! You mentioned something about sending a email with the info in it. would very much appreciate your help! ajrickey@gmail.com.
 






First let me say what an excellent thread I have to say it's equal to or better than the Ford shop disc for reference and procedure.

The only thing I did not see made reference to or maybe I have one someone worked on in the past but just about every single bolt I touched had red thread lock used on them including the bell housing bolts which I ended up mangling the heads 2 had to have nuts welded on them to get them off. I even found thread lock on the motor mount brackets today.

Anyhow my question is all three of my left/driver side pistons have a 2 stamped on the piston heads at the 3 o'clock position looking at the engine from the flywheel end. There are other marking and a arrow pointing forward on all the Pistons which was to be expected.

Any suggestions what the #2 means?

Again great thread, thank you for it.

24%20pistons%20009_zpsk94axjtb.jpg


24%20pistons%20011_zpswxgr5ttm.jpg




Just as an update I believe my problem started with the rear jackshaft bolt breaking, my slide material all looked good and all the mounting bolts were in tact but the metal was ripped apart on all the tensioners at the mounting bolts.



engine%209_zpsb24c0oun.jpg


engine%207_zpswbbgndf2.jpg


engine%206_zpsyokf1lsv.jpg
 












That could very well explain the thread lock on all the mounting bolts, the new bolts from Ford were all bare threads.
 






One suggestion I'd like to make that I have not seen in any of these threads but consider stuffing something into the cylinder head oil return ports when using the OTC tool kit, it would be a bugger to drop one of the small bolts into the engine being that close to being finished with it (I did not drop anything into the engine).

My almost finished project

image_zpsia9zzuad.jpg
 






jack shaft replacement

Great posting. You've saved me a world of headaches. I am trying to find a replacement jackshaft plug. Not finding it listed. What did you search for to order a replacement?
 






jackshaft rear plug

Great posting. You've saved me a world of headaches. I am trying to find a replacement jackshaft plug. Not finding it listed. What did you search for to order a replacement?

cover assembly - rear P/N F77Z6026AB
 












Background:

The Ford 4.0L single overhead camshaft (SOHC) V6 engine manufactured in Cologne, Germany was available in the 1997 thru 2010 Ford Explorer and Mercury Mountaineer, 2001 thru 2011 Ford Ranger and Mazda B4000, 2005 thru 2010 Ford Mustang and 2004 thru 2008 Land Rover LR3/Discovery 3. Any SOHC engine requires periodic replacement of the camshaft timing mechanism. The possible mechanisms used to enable the crankshaft to rotate the camshafts are gears, chains and belts. Metal gears would be the most reliable but are not practical due to the distance between the crankshaft and the camshafts. Early dual overhead cam engines incorporated dual row roller chains with tensioner(s) to connect a sprocket mounted on the crankshaft to sprockets mounted on the camshafts. Many modern SOHC engines utilize a timing belt that must be replaced every 70,000 to 100,000 miles. High performance engines incorporate increased valve lift and higher compression ratios. Failure to replace the camshaft timing mechanism at the recommended interval risks timing chain/belt slip or total failure resulting in the pistons colliding with the valves.

The Cologne SOHC V6 replaced the overhead valve (OHV) V6 camshaft with a jackshaft that transfers crankshaft rotational forces to the left camshaft sprocket at the front of the engine and the right camshaft sprocket at the rear of the engine via multiple chains and tensioners. The primary (crankshaft to jackshaft) timing chain components consist of crankshaft sprocket, jackshaft sprocket, connecting chain, and a chain guide and tensioner as shown in the photo below by White98.
View attachment 64389
The above photo shows the original style tensioner that has failed.

An assembly consisting of a jackshaft sprocket, camshaft sprocket, connecting chain and chain guide constitute a cassette. The camshaft chain is kept taught by a spring loaded hydraulic tensioner utilizing engine oil pressure. A photo of the left cassette is shown below.
View attachment 64595

A photo of the right cassette with the metal reinforced tensioner (slack) side is shown below.
View attachment 64390

The engines in the 4 wheel drive models and a relative few number of 2 wheel drive models incorporated a balance shaft driven by a chain connected to an additional crankshaft sprocket. There is also an associated chain guide and tensioner.

Normally, chain driven overhead camshafts would be more reliable than belt driven overhead camshafts. However, many failures occurred during the first few years of the SOHC V6 engine production. Ford implemented a series of tensioner and guide improvements to increase reliability and recalls to install them. All of the timing chain related improvements were incorporated in the 2002 and later production models. The base of the primary tensioner was strengthened and the number of leaf springs was increased from 3 to 6. The photo below compares the improved and original primary tensioners.
View attachment 64501

The spring loaded hydraulic tensioners were modified. The camshaft guides constructed of a plastic type material were reinforced with metal. Unfortunately, the traction side of the right guide assembly was never reinforced with metal and can break due to heat and vibration fatigue. Replacement of the right guide requires removal of the engine or the transmission since the guide lower mounting bolt is under the transmission bellhousing between the rear of the engine block and the flywheel/flexplate. Removal of the engine, replacement of the timing chain components, timing of the camshafts and the reinstallation of the engine is a complicated and labor intensive process which performed by a dealer or repair shop may cost more than the market value of the vehicle after repair. A special camshaft timing tool set (OTC 6488) reduces the complexity of the process but is normally not available on a rental basis.

There are well documented procedures available for assembly of the SOHC V6 engine. If anyone needs one just PM me your e-mail address and I will send you a copy. However, I have not found an adequate description of how to remove the timing chain related components. This thread will attempt to provide a SOHC V6 timing chain components removal procedure. It is based on my experience from replacing the timing components in my 2000 Explorer Sport engine and information I have obtained from my Haynes Repair Manual, the Explorer Forum, and other internet resources. The procedure has not been validated and I caution you to use it at your own risk. Some steps should be performed in the order indicated while for others the order may not matter. I will add text and photos as time permits and will attempt to give credit when photos are not my own. I am no expert on this engine and make mistakes like anyone else. I would like to improve the quality of this procedure over time by incorporating your constructive comments/corrections.
Hey bud can you send me the procedure you were talking about? I have a good grasp on it but would like to go by some directions.
 






Hey bud can you send me the procedure you were talking about? I have a good grasp on it but would like to go by some directions.
Unless things have changed with the new website format, I can't send attachments via PMs. If you PM me your email address I'll send you the assembly instructions.
 






Remove valve covers

Remove the right valve cover.
View attachment 64499
The bolts on the later model valve covers have retainers to keep them from falling out.
View attachment 64482

Remove the left valve cover.
View attachment 64500
Make sure #1 cylinder is on the compression stroke by checking the camshaft position sensor "nub" on the left camshaft identified by the green arrow in the photo below by shelbygt.
View attachment 64402
The nub should be above the axis of the camshaft. If it is below the axis then rotate the crankshaft clockwise 360 degrees to TDC.
Hey Buddy I have tore my 4.0 v6 down already and am getting ready for reassembly. I have a few questions for you. I understand that the notch has to be above the axis for the camshaft to be properly timed. But what about the other cam ? And also could you provide me the documented reassembly procedure you mentioned? I'd appreciate your time !
 












Send your email address to dclinbeard@bellsouth.net and I'll send you the assembly instructions.
I no this is old but I'm working on replacing the heads on one and im already ready for re assembly is there anyway you could send me the instructions for timing it all I have off is the heads and the engine is out already also I don't have any of the special tools
 



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Remove jackshaft front sprocket bolt

Remove (counter-clockwise) the jackshaft front sprocket retaining bolt shown in the photo below by janolsson.
View attachment 64480
The photo shows the significantly improved new style primary chain tensioner.
Loosen right camshaft sprocket bolt

Loosen (clockwise) right camshaft sprocket retaining bolt. A universal sprocket holder similar the one shown below may be used to prevent the sprocket from rotating.
View attachment 64396
If you have the OTC 6488 timing tool kit camshaft gear holding tool (6478) and camshaft gear holding tool adapter (6482) can be used to prevent the sprocket from rotating.
 






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