Harmonic Balancer

Texasmark1

Well-known Member
Never had a bad one and had tractors back to the Farmall Super A, MF TO-20. New 1988 3910 acquisition has the 192 cu. in. (I think) diesel engine, and besides being a very noisy engine, vibrates way more than my 2000 and 3000.

Suspect the Balancer has dried out and isn't balancing. Hard to see down in there without tearing things out, radiator, fluid hoses and such....... and if I go that far I will have a new one handy. Besides fan and alternator, the belt attached drives a PS pump, no biggie on the load thing. Fan belt is a ?" wide HD however.

Any of you guys have problems with HBs on these engines? My first possible experience in 40 years.

One thing that may have caused it to fail prematurely, if that's the case, is the fact that the tractor has an accelerator pedal just to the right of the right foot platform that is easily hit with the right foot, meaning over it's 30 years of life (900 proven, actual engine hours however).

The engine accelerates like a hot rod......may be due to it being the "over square" 4.4 x 4.2 bore-stroke design, like under square hot rod gassers. That could have placed undue stress on that pulley that normal under square, slow accelerating normal high torque diesels don't apply and is why I suspect it to be the cause of the vibration. The other thing is that the vibration changes over the rpm range as would happen with resonances in the engine which the damper is designed to dampen.

On the noise, it's just loud. It apparently is built in UK and has the 10" oval, horizontal muffler (new) and non-view obstructing, down the side exhaust system. Checked the exhaust, manifold and gasket fine, exhaust pipe is without defects, new muffler, blows a stream 4-5 foot behind at 1000 rpm I know that these engines won't run with back pressure, idles down to 300 on a test, nice and smooth, checked valve condition with a piece of paper at the muffler outlet...passed that, little valve noise but I like to hear them tick...don't see a problem there. Starts just about as fast as you can get your fingers off the key even after sitting overnight.

Thoughts appreciated.

Thanks,
Mark
 
While you're at it, I'd appreciate the OEM PN of the balancer if you guys having access to such wouldn't mind.

Thanks again,
Mark
 

Ford made some changes in to those engines in the 80's, I'm thinking to the inj pump, they start super fast but are real rattly.
A lot noisier than the older 60's-70's engines.

I've got a 192 from a 94 3930 setting in the shop, I'll look at the balancer on it to see if it different from the older engines, but on the older engines the balancer is solid, nothing to slip.
On the older engines the 192 balancer is different from the 201 balancer, I'll post back my finding when I get back later.
 
No balancer, just a pulley. https://partstore.agriculture.newholland.com/us/parts-search.html#epc::mr57461ar361255. Your going to have to do some more diagnosis.
 

I just read on another thread where you said you'd installed a 188 engine on a 3910, the 188 has a long 4.4 stroke of a 201 stroke with the smaller 4.2 bore of a 175.
The balance is different on that engine, which front pulley and flywheel did you use.
 
I'm almost certain that there is no balancer on that engine. As for the noise, that's called horsepower. All of those later 3 cylinder engines are that way.
 
188 was the thermostat opening temp. vs the OEM recommended for most all usage of 168F (again as I recall...been through a lot of numbers on the
different stats, engine applications, degrees C to F and all).

The engine is the 4.4 x 4.2 192 cc.
 
Bern, agree with you on both counts. Looked up the CU IN on the 2000 and 3000 and yes there is a difference. I got in with a mirror and flashlight awhile ago and the pulley is solid cast. It has 4 holes about midway out on the circumference where I suppose a front mounted PTO like for a hyd. pump , maybe snow blower could be mounted. With that being the case, you couldn't have a harmonic balancer rubber insert.

Next thing is the I3, being half an I6 which is supposed to be the premier design for inherently balanced engines, should be smooth from the drawing board.
 
You're right, 3 cylinder engines are naturally better balanced, much more so than 4 cylinder engines. This is why you don't hear any gear rattle on a 3 cylinder tractor like you do on 4 cylinder versions.
 

Here's a photo of a 94 model 192 balancer/pulley.
Notice half of the hub is solid where the other half has the open slots.
I have a 69 192 gas short block that has the same balancer/pulley.
On a 201 engine all 4 slots are open.
Even though they are solid with no rubber damper ring they do have some effect on engine balance.


18626.jpg
 
I don't know about the I3, but the in-line six was almost the main reason
a vibration dampener was invented. The damper soaks up torsional vibration,
doesn't do anything for unbalance. Of course, early crankshafts were like
bent coat-hanger wire. Early V8's had a single plane 4 cylinder type of crankshaft
with two cylinder blocks set at an angle. Those vibrated a lot.

In four cylinder engines, there are critical rpm's where vibrations can set in.
Usually quite above the operating speeds. Race engines just blast through that
zone, but then they don't need to last very long either.
 

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