balanced 4.0 flexplate- how to install

[badtxz]

Everything I've read says to mark the flexplate and crank before removing the plate. I have a junkyard motor with no flexplate and the flexplate from my old motor. It is clearly marked balanced. How do I line it up? The only distinguishing thing on it is an extra hole near one of the bolt holes. It's a 1990 motor with a 6-bolt crank. Please help. I've got a motor hanging on a lift.

 

[Big Jim M]

Is there a mark on the crankshaft where that extra hole was when the old flexplate was on it? Just a simple mark, from the hole laying against the crankshaft?
If it truly is out of balance due to being part of the balance system for the engine then there should be a PIN where that extra hold is to reside. If not then it should be balanced to itself only and should go anywhere..
Big JIm

 

[badtxz]

Thanks Jim. The hole I'm referring to is on the outer edge close to one of the torque converter stud holes. It looks like it was drilled with a tapered drill bit to remove material. If anyone has 4.0 out of a90-95 ranger/expl, I need to Know what relation that hole has to the marks on the balancer. Meaning inline with. There is know notch, pin, key, or mark yo line up. The bolts are evenly spaced; 6-bolt pattern.

 

[Big Jim M]

My giess is the thing is evenly balanced.. Get a screw driver and stick it in the center hole and spin the thing on the screwdriver shaft a few times to see if it is apparently OUT of balance. If it is in true balance it can be installed any whichaway.. If it is OUT of balance it needs to be installed in a certain way.
I installed the wrong flywheel once.. WOW! It had to come back out real quick.
Big JIm

 

[badtxz]

Right on! That's a good idea.

 

[Psychopete]

Make sure that there isn't only one way that the flexplate can go on. I am pretty sure my 5.0L was this way as well as my 2.9L. Regardless I never marked either of them when I rebuilt, and I do recall the bolt holes only lining up a certain way. Not too sure on the 4.0L though, but couldn't hurt to go out and just try it and see what you come up with.

Edit: Now that I think about it, a Chevy 262ci (V8) -> 327 swap I did a long time ago was the same way IIRC. Used the TH350 flexplate on the 327, just turned until the bolt holes lined up then bolted it up.

 

[mjonesjr]

The flex plate on 4.0's are NOT balanced, hence why the 4.0 has the counter balance on the crank pulley.

 

[badtxz]

It has "balanced" stamped on it. It is a symetrical bolt pattern. A chevy 350 is internally balanced. A 400 is externally balanced. The flexplate and balancer have counter weights.

 

[mjonesjr]

The Ranger 4.0 is balanced via the crank pulley. There is a balancer built into the pulley. The 4.0's flex plate and flywheel are NOT balanced.

Here just to prove it.
http://www.stuffforyourranger.com/s...age=product_info&cPath=4_30_37&products_id=40

 

[badtxz]

Every motor has a harmonic balancer on the front of the crank. I dont need proof.

 

[mjonesjr]

The flex plates and flywheels are not balanced. They do not have balancing weights on them from the factory.

 

[badtxz]

I'm bolting it on and dropping the motor in the truck right now. Thanks for everyone's input. I won't give up my guns either.

 

[fastpakr]

The flexplate is, of course, balanced. However, it is not balanced with the other internal engine components. It, by itself, is balanced. It can be bolted on in any position.

 

[AllanD]

The flexplate is, of course, balanced. However, it is not balanced with the other internal engine components. It, by itself, is balanced. It can be bolted on in any position.

all components of a Cologne engine are "Balanced" but they are "Neutrally balanced"

Components of some engines, the early 302 ford, the later 5.0 ford,
the 1973-74 Chrysler 340 engine, the 5.8 ford and the 400 SBC are "externally balanced", meaning part of the engine balance is included
as a weight on either the crank damper or flywheel (or both)

This type of balance used to be refered to as "detroit balanced" meaning that it was balanced as an assembly.

The fact that the flywheel uses a symetrical bolt pattern is all
you need to know.

If the flywheel/flexplate needed to be "clocked" a specific way like the
50oz/in imbalance of a 5.0 Ford there'd either be an assymetrical bolt
pattern (Note that the early 5.0/302 was also externally balanced, but differently and uses a different bolt pattern as does the 5.8 engine)
or a dowel pin.

AD