How to: SOHC V6 Timing Chain Parts Removal Procedure

[2000StreetRod]

Remove right cassette

Remove right cassette (camshaft sprocket, guide assembly, chain and jackshaft sprocket). The photo below of my guide assembly at approximately 150,000 miles illustrates why the traction side needs to be reinforced with metal.

The tensioner (slack) side of the guide assembly is in good condition with less than one tenth of the depth of the chain contact surface worn away by the chain. The slack side could easily last for another 500,000 miles from a wear standpoint. The wear on the traction side of the guide assembly is comparable to the slack side and the depth of the remaining chain contact surface is about the same. The traction side cause of failure was structural possibly from physical stress, vibration, heat or a combination of all three. I suspect the reason the timing chains break is because a large piece of guide fragment gets wedged between the moving chain and some stationary item such as the block or head. If the plastic had been bonded to a metal backing in a manner similar to the way brake material is bonded to a brake shoe the guide would still be intact.

 

[2000StreetRod]

Loosen jackshaft front sprocket bolt

Loosen (counter-clockwise) the jackshaft front sprocket retaining bolt while preventing crankshaft or jackshaft from rotating. The Ford camshaft timing procedure utilizes a special tool crankshaft holder 303-674 to prevent the crankshaft from rotating when loosening the jackshaft front sprocket retaining bolt. The improvised tool shown in the photo below is suitable for preventing rotation of the crankshaft while loosening the sprocket retaining bolt.

A scrap bolt with washers on both sides of the chain link is screwed into the head. Another scrap bolt with washers is passed thru a hole in the sprocket and chain link and secured with a nut.

 

[2000StreetRod]

Remove jackshaft chain tensioner & guide

Remove jackshaft chain tensioner & guide

There appeared to be less than 15,000 miles of wear on the tensioner and guide plastic surfaces instead of the 150,000 miles indicated on the odometer. I began to wonder if I had wasted a lot of money purchasing the primary timing chain kit and wasted a lot of time removing the timing cover. At first I suspected that the tensioner must have been replaced recently until I noticed from the base that it was the old obsolete design. The photo below is a closer view of the tensioner and guide after being removed from the engine.

How could the rear chain guide be totally destroyed and there be so little wear on the front tensioner? Well if you look again at the photo above you'll realize that the tensioner spring is broken and was not exerting any force on the chain at all. This is why I say that Ford should have continued to utilize an oil pressurized tensioner. The slack side of the chain was merely conforming to the shape of the tensioner contact surface. When I started to remove the guide I noticed that the upper mounting bolt was not even finger tight. Apparently it had vibrated loose over the years. There's a locating plug on the back of the guide about midway lengthwise. The plug fits into a 1/4 inch diameter opening (identified by the green arrow in the photo below) to the oil line that runs horizontally across the front of the block. If the guide were to get loose enough to unplug the opening, oil pressure would drop significantly.

After removing the tensioner and guide I attempted to lift the chain off of the jackshaft sprocket and then off of the crankshaft sprocket. There was not enough slack in the chain to do either. I concluded that it is extremely unlikely that the jackshaft chain would ever slip a tooth on either gear.

 

[2000StreetRod]

Remove left hydraulic/spring tensioner

Remove left hydraulic/spring tensioner as shown in the photo below by shelbygt.

 

[2000StreetRod]

Remove jackshaft front sprocket bolt

Remove (counter-clockwise) the jackshaft front sprocket retaining bolt shown in the photo below by janolsson.

The photo shows the significantly improved new style primary chain tensioner.

 

[2000StreetRod]

Remove primary sprocket assembly

Remove jackshaft front sprocket, chain and crankshaft sprocket as an assembly

 

[2000StreetRod]

Remove balance shaft components

Remove the balance shaft guide (below and left of primary tensioner) as shown in the photo below by KC90. The primary chain components (tensioner, guide, crankshaft sprocket and chain) should already be removed.

Remove the balance shaft tensioner below the balance shaft guide.
Remove the balance shaft chain and crankshaft sprocket

 

[2000StreetRod]

Loosen left camshaft sprocket bolt

Loosen (counterclockwise) left camshaft sprocket retaining bolt. A universal sprocket holder similar the one shown below may be used to prevent the sprocket from rotating.

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.

 

[2000StreetRod]

Remove left guide assembly upper mounting bolt

The photo below by CDW6212R shows the lower section of the cassette after removal of the primary chain and sprockets assembly.

Remove left guide assembly upper mounting bolt located in the head below the camshaft sprocket.

 

[2000StreetRod]

Remove left guide assembly lower mounting bolt

Remove the left guide assembly lower mounting bolt located in the block between the head and the cassette lower sprocket as shown in the photo below by CDW6212R.

 

[2000StreetRod]

Remove left camshaft sprocket retaining bolt

Remove (counter-clockwise) the reusable left camshaft sprocket retaining bolt.

 

[2000StreetRod]

Remove left cassette

Remove left cassette (camshaft sprocket, guide assembly, chain and inner jackshaft sprocket)

 

[ford007]

Do you know the name of the plug that you have to remove to get to the rear jack shaft bolt it looks like a freeze plug. I need a new one and the dealer told me the only way to get it is to buy a new jackshaft 1998 ford explorer 4x4 4.0 sohc

 

[2000StreetRod]

jackshaft rear plug

Do you know the name of the plug that you have to remove to get to the rear jack shaft bolt it looks like a freeze plug. I need a new one and the dealer told me the only way to get it is to buy a new jackshaft 1998 ford explorer 4x4 4.0 sohc

Cover assy/rear of block jackshaft opening plug F77Z6026AB
I just checked tascaparts.com and they sell it for $10.67

See: SOHC V6 Timing Chain Related PNs

 

[Brentiya725]

Hello, My explorer is 2004 and timing chain failed, so far it looks like just the right side rear but i dont have the front timing cover off just got the engine out yesterday. So far the Haynes manuals black and white pictures do not do any justice to the repairs needed. The pictures that you have provided are great. In the Haynes manual the assembly procedures are not very good. I am at your second page and was hoping to read on another half hour or so to get a better understanding of timing everything while going back together. Special timing tools required the Haynes manual explains, I was hoping that you had assembly and timing procedures? So far everything looks the same in my engine as in yours even though the years are different. I have also found while looking up parts that some depend on the production date of the engine, how can i determine this on mine? I looked up the vin on FORD site but it does not breakdown the engine? Any help you can give would be greatly appreciated. Thank you

Brent, ASE Master Certified Truck Technician (nothing on cars or light trucks)

 

[2000StreetRod]

SOHC V6 assembly instructions

If you PM me your email address I'll send you a copy of the 2005 Mustang SOHC V6 assembly instructions.

 

[icelos1980]

Just wanted to say thanks for this write up! Awesome!

My wife and I bought this 03 explorer with engine failure from craigslist sitting at a repair shop. Mechanic speculated it was timing chain failure, but owners didn't want to pay to find out. A few bucks later it was ours.

With this write up (and a bunch of others, including harmonic balancer and new motor swaps) I was able to diagnose, remove motor, and ended up swapping with newer motor over a period of about 2 weeks.

This site is packed full of good stuff! Now.. about that tranny..

 

[tsortor]

Cassette Won't Come Out!

Remove left cassette (camshaft sprocket, guide assembly, chain and inner jackshaft sprocket)

Am I missing something? I've disconnected everything, got the sprockets and chain out, but after 30 minutes of fiddling with this goddamned thing, cannot get this mother f-ing cassette out. The pivot point on the cassette is wider than the opening that it is supposed to fit through. It appears as if I have to remove the head to get this damned thing out.

 

[2000StreetRod]

tight fit

Some other members have experienced the same problem. I had problems installing the new rear cassette but no problem removing either cassette. See posts #252 thru #256 of this thread: SOHC V6 Timing Chain Saga Apparently there is some variation in the head castings and the openings don't match the block. So far everyone has been able to eventually extract the cassette without removing the head. I'll try to locate the thread that discusses the problem. Are you having problems with both cassettes?

See posts #19 thru #28 of the following thread for one problem: SOHC V6 Rear Cassette Replacement

This thread probably describes the problem you're having: Help! SOHC front timing cassette removal with head in?

 

[Killerz6]

Loosen (counter-clockwise) the jackshaft front sprocket retaining bolt while preventing crankshaft or jackshaft from rotating. The Ford camshaft timing procedure utilizes a special tool crankshaft holder 303-674 to prevent the crankshaft from rotating when loosening the jackshaft front sprocket retaining bolt. The improvised tool shown in the photo below is suitable for preventing rotation of the crankshaft while loosening the sprocket retaining bolt.
View attachment 64479
A scrap bolt with washers on both sides of the chain link is screwed into the head. Another scrap bolt with washers is passed thru a hole in the sprocket and chain link and secured with a nut.

hi, i really appreciate the write up you have made, but i am only having one problem, i am trying to remove the primary cassette. and i noticed above you said it takes an EXTERNAL E-30 socket. i cannot seem to find this socket, i was wondering if you could tell me where you bought this socket or if you have a link or if you even would like to sell it. i am stuck at this part and cannot find the correct external socket size to remove the primary chain. i appreciate ALL of this write up and everything has helped me 100%.

if you could get back to me ASAP i would be much appreciative i have school next week and have the motor out of my car lol