Timing chain replacement and balance shaft delete

[JakePSD]

Alright here is what I mean. Here is the crank with the balance shaft sprocket. Notice the balance shaft sprocket sticks out a bit.

Here are the 2 crank primary sprockets. Old on the left, new on the right.

It looks to me like the extra bit sticking out on the new primary sprocket compensates for the lack of the balance shaft and the little extra bit it sticks out. Am I right? Do I need to just remove the key, take off the balance shaft sprocket and put the new sprocket on and put the key back in? The key prevents the balance shaft sprocket from coming out.

 

[2000StreetRod]

crankshaft part numbers

I looked up the crankshaft part number for a 2002 Explorer with the 4.0L V6 (5L2Z-6303-AA) and it is the same as for the crankshaft for the 2007 to 2010 Mustang V6. Only a very small number of 2005+ Mustang engines had the balance shaft. I suspect that the width and offset of the RWD crankshaft sprocket when installed is the same as when the balance shaft sprocket and the 4WD crankshaft sprocket is installed. If so, then you can just remove the woodruff key and the balance shaft sprocket, reinstall the woodruff key and then install the RWD crankshaft sprocket.

 

[JakePSD]

How's that key come out? I tried gently tapping on it but it didn't budge. Tap harder?

 

[2000StreetRod]

exposed gap?

Is there an exposed gap at the front of the key that allows prying between it and the crankshaft?

 

[JakePSD]

Yeah. I managed to get it. That key is a tight fit. I had to just tap harder. I also answered the question about the sprockets. Remove the balance shaft sprocket and use just the crank primary. The extra bit does compensate for the lack of the balance shaft sprocket.

 

[CDW6212R]

Yes those gear pieces have to mesh right to have the gears line up, plus the front surface of the outer gear at the proper depth to mate with the balancer. You are working with two different crank gears due to changing from 4WD to 2WD parts.

I learned that last little part the hard way, putting the 4WD crank gear in wrong leaves the balancer put too far(one belt rib). It took me a while to figure that out, the inset of the 4WD crank gear has to be outward.

 

[JakePSD]

Bet that was fun to fix. I'd have been pissed haha.

Thanks for all the help so far. Unfortunately I'm at a stand still til my bolts come in Monday. I did notice that the instructions I've read all say the flywheel/flexplate has to be removed. Unless there is something I'm forgetting to do it doesn't have to come off. Granted I don't have an engine stand therefore is sitting on the floor but mine is still on the motor.

 

[2000StreetRod]

removing rear cassette guide

In order to replace the rear cassette guide the lower mounting bolt (shown below) must be removed.

There may not be enough room to remove it with the flexplate in place.

That may also be true for the jackshaft rear plug and sprocket retaining bolt.

 

[JakePSD]

Hm. I had no issues. Flex plate almost got in the way removing the lower cassette bolt but I got it out just fine. Of course I've been playing mechanic at home for 12 years and have dealt with way harder to get to bolts than that one. I was worried I forgot something.

 

[JakePSD]

I had a crazy idea this morning that might work that would make these engines last forever regarding the timing chain. Why couldn't one take the right head off the motor and put a head from the left side of another motor on in its place, then use a left (front) cassette assembly on that side as well since no aftermarket company has had enough brains to reenforce the rear? The only problem I see is that the tensioner would be on the traction side on the rear set.

 

[Tech By Trade]

Thats how they do it already, you have to give it a 180 deg to fit. The left and right are almost identical. That's where the problem comes from in the first place. They were to cheap to cast a new head for the right and side and run a long chain around the front like the V8. Because Quality is job 2, job 1 is saving a buck.

 

[CDW6212R]

The DOHC 2.9 Cosworth engine is a close cousin to the SOHC 4.0, and it has a good valvetrain system. If the heads of the little DOHC would flow 300cfm and you could get a better intake manifold made for it, that could be a fine upgrade for the 4.0 V6. But the options aren't good, which is why people make do with the existing SOHC parts.

If you keep very good maintenance of these engines, they will run great. But you can't be slack with the oil changes or quality, or put off the valvetrain until a symptom appears.

 

[JakePSD]

You think 5000 mi is safe on these with good oil? That's typically what I run.

 

[JakePSD]

Thats how they do it already, you have to give it a 180 deg to fit. The left and right are almost identical. That's where the problem comes from in the first place. They were to cheap to cast a new head for the right and side and run a long chain around the front like the V8. Because Quality is job 2, job 1 is saving a buck.

But the holes aren't drilled out the same. That's why I suggested just using a left head since all the holes youd need are there.

 

[JakePSD]

By the way, what is the crank damper bolt torque. Some sources say 33 ft lbs + 90°, others say 44 + 90°

 

[2000StreetRod]

torque specs

SOHC V6 Torque Specifications

 

[JakePSD]

I checked that one too, I just wanted to verify. I don't wanna under torque it and have it come loose, but don't wanna over torque it and break it.

 

[CDW6212R]

You think 5000 mi is safe on these with good oil? That's typically what I run.

That's fine with a synthetic oil. Use the best air filter you can also, most of what makes oil dirty comes through the air filter. The better the air filter you have, the cleaner the oil will be.