How do you modify a Vernatherm Valve on a 8V71 in 4106?

[OneLapper]

Hey guys,

Definition: Vernatherm Valve is the oil flow control valve that thermostatically (from the coolant) adjusts the flow of oil through the Tourus drive that spins the radiator cooling fan.

I'm leaving Sunday morning for a 1200 mile trip in our 4106.  The new engine runs 10 degrees plus warmer than the old engine.  I used the Vernatherm valve from the donor engine, not the original one.  I noticed that the fan does seem to spin slower.

This is a picture of the original valve from the old engine.








Can anyone tell me if there is a modification to this valve to increase the flow of oil to increase the rpm's of the radiator fan?  I recall there was a procedure to adjust this valve but I cannot find this in The Book.

Thanks!

Mark

[wildbob24]

Mark,

You don't want to increase the flow of oil. In fact, just the opposite. The vernatherm valve is open when it's cold (max oil flow) and closes as the coolant warms up. The resulting restriction in the oil flow is what operates the fan torus. The more restriction, the faster the fan turns.

You can get max fan rpms by disconnecting and plugging the oil line between the torus and the vernatherm. The downside is this will make your fan run all the time but should help if your running hot.

Bob

[OneLapper]

Ah ha!!! I had the entire concept backwards...... Hmmm must have totally zoned while reading that section.  As a matter of fact, I need to find that section in the book again. IIRC there is and adjustment that can be made to it. 

Thanks Bob!!

Mark

[Scott Crosby]

I had mine off a couple of weeks ago.  When it's cold it's closed.  At least I couldn't blow through it.  6v71. I believe when it's warm it opens and oil flows through it.  I don't know how to modify it.   

What's 10 deg warmer?  180-190?     

[OneLapper]

Bob wins!  I a cap on the fitting that the Tourus drive sends it oil to the Vernatherm (love that word!) valve and Bob had it right.  The fan spins much faster at all RPMs.  I'll let you guys know if it lowers the engine temps.

Scott, the bus used to about 180 but now it's showing 190. I'm a bit suspect of the temp gauge wiring though. If I flip on the lights the engine temps immediately jump another 10 degrees!  I recently bought a tiny adjustable voltage regulator that should help that gauge. I haven't had time to install it yet.

[Scott Crosby]

My book calls it a fluid fan drive, is that the same thing? 

I asked about bypassing it and having it run all the time on another forum a couple months ago, and got a lot of input on why not to hook it up that way.  Everything from "what makes me think I'm smarter than the engineer that designed it"  to lots of other comments like wasting horse power on the fan when it's not needed.  Regardless not one person thought bypassing it was a good idea.   If you want a link to the info let me know.

[luvrbus]

The GM fan drives are just a torque converter I have one I took apart to see how they worked lol 

I don't see why you could not run the fan off a seprate pump or even diesel fuel myself with the Tourus

I have a extra Vernathrem if somebody needs one or the whole unit from the engine block foward but you will need to put the drive back together I never did that

[Lin]

You could do the bypass for this trip and see how it affects cooling.  If it cools better, you can then consider the options of leaving it off or switching to a new one.  If turning on lights changes the gauge reading, obviously there is a problem.  Make sure the gauge has a good, clean ground for one thing.  It would also be good to have a mechanical gauge back at the engine.

[pvcces]

If I had an increase in temperature in a new engine, I would carefully check for the actual temperature; if it was a little higher than the old engine but did not overheat, then the economy of the new engine should be a bit better running warmer.

It will take you a while to break in that engine.

Tom Caffrey

[OneLapper]

Here's the official opinion.........   The bus ran cooler over the road and up the hills!  And, the oil pressure was 5 to 10 psi higher.  This was based on 400 miles in 85 temps, enough to get her warm. I'll also point out that it cooled off very quickly when going down the hills.

If I was to make this super official I would need to install the Vernatherm from the old setup to see if the difference was Vernatherm related or engine related.

The new engine has 170 T-stats, N65 injectors and advanced timing. That alone may cause it to run a bit warmer.

Tom'w is 300 miles!

Mark

[bkelly1011]

Good news, Mark - enjoy the drive, stay safe! - Brad

[OneLapper]

Good news, Mark - enjoy the drive, stay safe! - Brad

Thanks Brad!

Today we put 250 miles on the bus.  It was 95 degrees.  Engine temps were ok, oil pressure was good, but it was hot inside with just one AC working.  The 2000 watt inverter hooked up to 4 T105s and the D50 would not keep the Dometic Penguin 13,500 running.  The Xantrex was pulling 250 DC amps. Fortunately the 13 year old Coleman Mach 3 unit ran perfectly (and much more quietly) at 175 amps DC, but the temps inside while driving were still 85 degrees.  No one was comfortable.

We were planning on leaving on Friday but if it's too hot we'll leave Thursday night instead.

BTW, the inverter was not the planned solution for OTR AC.  I ran out of time and was not able to get the Westerbeke diesel generator installed before this camping trip.

Mark

[fortyniner]

Hey Mark, Ive been thinking about something similar with A/C but using a 24 volt D50 alternator/batteries in place of the 12volt one. A modern inverter minisplit seems to pull less power per btu too. I figured the old OTR unit would probably cost nearly as much to refurbish and requires the engine to be running to boot.

-TomP.