Balance Shaft myth debunked!!

[Hunz]

Well fellow xplorers, it seems as if we have finally put this myth to bed about negative side effects of 2wd engines in 4wd xplorers. I have been driving my 98' xplorer for 3,000+ miles now with a non-balance shaft motor in a 4wd X and no negative side effects

 

[Hunz]

Just wanted to post an update on the 4wd ex with a 2wd sohc engine. 11,000 miles after install and she still runs like a dream

 

[99SportX]

Good to hear. I wonder if one could remove the balance shaft from the SOHC? It seems to me that these motors have enough parts already so the less parts the better IMO. I could care less if I have a minor vibration. There are already plenty of other vibrations. One of my friends did a balance shaft delete in his saab motor to rid of a little rotating mass. Plenty of folks do it to 4cyl motors. I don't think a 6 would be much different.

 

[hazmat456]

kind of like a harmonic balancer,I guess you could run a motor without one but for how long?

 

[Kris Guilbeaux]

Yes, a few posts up you would see I removed a balance shaft from an SOHC motor and is running fine in a 99 Sport.

Good to hear. I wonder if one could remove the balance shaft from the SOHC? It seems to me that these motors have enough parts already so the less parts the better IMO. I could care less if I have a minor vibration. There are already plenty of other vibrations. One of my friends did a balance shaft delete in his saab motor to rid of a little rotating mass. Plenty of folks do it to 4cyl motors. I don't think a 6 would be much different.

 

[99SportX]

Ok, sorry. I guess I missed that post. I may try to remove this stuff when I open my motor up to work on the tensioners/guides sometime this year.

How did you go about plugging the oil passages? Can you just tap the holes and install some allen head set screws with threadlock?

 

[CDW6212R]

It seems like another Ford NVH issue, like the various weights that hang underneath most Fords.

 

[Kris Guilbeaux]

the holes are threaded from the factory. I used the plugs from the a 2wd sohc motor.

Ok, sorry. I guess I missed that post. I may try to remove this stuff when I open my motor up to work on the tensioners/guides sometime this year.

How did you go about plugging the oil passages? Can you just tap the holes and install some allen head set screws with threadlock?

 

[bluestream1]

Kris, can the balance shaft be left in place if the chain that drives it is removed? Say for someone who does not want to take out the upper oil pan, but does not want to replace the tensioner.

I always assumed the balance shaft was a minor thing the sales guys would use to up-sell people to 4WD. Looks good on a sales brochure...

 

[gijoecam]

I always assumed the balance shaft was a minor thing the sales guys would use to up-sell people to 4WD. Looks good on a sales brochure...

Yeeeeaaahhh... Sure... because the engineers went through all the troouble of designing, engineering, and testing a balance shaft, as well as the lubrication, drive mechanism, and tensioner assembly because the salesmen thought it was a good idea.... Riiight!

I'm quite sure the engineering world doesn't work that way. The engineers obviouslt determined that there was a need for it on the 4x4s. They wouldn't have taken the time and expense to design and engineer such a thing if there wasn't a need for it. It's not like they just snagged a part off the shelves at Tractor Supply and drilled and tapped a couple of holes to accommodate it. It surely cost hundreds of thousands of dollars in R&D work to make it happen. They wouldn't spend that kind of money so that the salesmen could tout it as a 'feature.'

Hell, I'd bet that most salesmen couldn't tell you what a balance shaft is to start with!

 

[Kris Guilbeaux]

Im gonna say no to that seeing you have to plug the oiling holes if the chain is removed I would remove the shaft completely and plug the holes.

Kris, can the balance shaft be left in place if the chain that drives it is removed? Say for someone who does not want to take out the upper oil pan, but does not want to replace the tensioner.

I always assumed the balance shaft was a minor thing the sales guys would use to up-sell people to 4WD. Looks good on a sales brochure...

 

[snoranger]

Kris, can the balance shaft be left in place if the chain that drives it is removed? Say for someone who does not want to take out the upper oil pan, but does not want to replace the tensioner.

Thats my plan when I go in to do my jackshaft chain and tensioner. (If I pull this motor again, I'm dropping a 5.0l in its place.) I think it will work. Your not changing the way the oil flows, your just not spinning the shaft anymore. Im gonna check it out on my spare motor one of these days.

 

[gijoecam]

Thats my plan when I go in to do my jackshaft chain and tensioner. (If I pull this motor again, I'm dropping a 5.0l in its place.) I think it will work. Your not changing the way the oil flows, your just not spinning the shaft anymore. Im gonna check it out on my spare motor one of these days.

Depends on what provisions it has for lubing the chain (and tensioner?) and gears. So long as that stuff doesn't open up an oil gallerey plug, then yeah, I see no reason why it wouldn't work to just disconnect the chain. May need to rig up some way to keep the tensioner in place if removing it would expose an oil passage though...

 

[CDW6212R]

Someone here already did away with the balance shaft. They plugged whatever holes are in the block above the balance shaft. The chain and tensioner you simply discard.

Don't remove that chain though unless you are ready to retime the balance shaft with the crank. There is a procedure to line up points on the gears with the block, it's in the manuals.

 

[Kris Guilbeaux]

I think when the shaft is spinning it pumps the oils through the gallery. there has to be a reason the holes are plugged up on a 2wd motor

 

[bluestream1]

I think when the shaft is spinning it pumps the oils through the gallery. there has to be a reason the holes are plugged up on a 2wd motor

Would the holes not be supplying oil to the balance shaft bearings? After all if the bearings wear, you will lose oil pressure in the whole system as it leaks out past the balance shaft bearings. I would think that there would be no difference if the shaft was left in place (and chain removed)and the holes not plugged, or shaft removed and holes plugged. If the balance shaft chain were to break during driving, I don't think the engine would seize.

 

[bluestream1]

Yeeeeaaahhh... Sure... because the engineers went through all the troouble of designing, engineering, and testing a balance shaft, as well as the lubrication, drive mechanism, and tensioner assembly because the salesmen thought it was a good idea.... Riiight!

You have obviously never worked in marketing for a major corporation...

 

[Hitchhikingmike]

Good thread. I myself have wondered about this for some time.

The engineers that developed the engine spent tens of thousands of hours doing NVH testing under a whole lot more widely varied operating conditions than your 2000-3000 RPM test, and determined that the balance shaft was necessary for some specific reason. It's likely that the extra weight/inertia/shape/polar moment of the transfer case added to the driveline, or possibly the front half of the driveline adversely affects the vibration of the engine, or the engine itself transmits vibrations in some undesirable way to some component (be it the engine itself, the mounts, the passenger compartment, or any of a thousand places) and tha undesirable vibration is unique to the 4x4 drivetrain in some way.

Actually, I doubt the balancer is crucial to anything at all. Remember, these explorers were built for the people to travel from mall parking lot to mall parking lot and for other who purchased them just to "feel safe on the highway". With that being said, I would say Ford took this into consideration once they discovered that this was the main buyers of their Explorers, so I would say the balancer just reduces vibration to some extent and just left it on the higher end models for a smoother running engine (i.e. you must purchase the 4x4). Sure, we may not be able to tell any significant difference with out without it, but I'm sure the Ford engineers came up with a slew of sinusoidal equations where the balancer made sense on paper. I'm sure if sensitive equipment was put on the engine in the lab the engineers also noticed a lab proven smother running engine. But I bet the gains were somewhat negligible that they took decided it was a cost effective to take it off the lower end explorers for those who were not that concerned about comfort but about price and vice versa for the buyers of the higher end ones.

The original intent of the balancer still may be to reduce 4x4-drive-train specific vibrations, but I still don't think it's crucial to the 4x4 drivetrain.

 

[Hitchhikingmike]

Maybe one day I'll attempt to track down the powertrain guys that work on the Explorers...

That trail to track them down might take you to Germany! I don't think German engineers like to be questioned....

 

[bluestream1]

My last explorer was a 1991 that I bought new. That engine (like most V6 engines) did have minor vibrations at certain RPM's. Very minor, I could notice them, but no other people even noticed it except one friend of mine is knows cars very well. Having said that my current engine does not have any vibrations of note at any speed. I assume the difference is the balance shaft doing its job. The difference is so small as to be negligible, but it would be an asset to a new buyer taking that first test drive off the lot I suppose. I would not hesitate for one second to install a non balance shaft engine in a 4x4 truck.