John H's 80% theory, debunked for all.

[jmbrodsky@domain.elided]

John,

        When I was in Tulare, I got the original owners' manual for my 75 
travelall 4x4.  In this book, it specifically recommends that you routinely 
drive the engine at redline, but never to exceed it.  It sounds like IH designed
their redlines, to be the maximum operating range, and not the maximum yield for
engine internals.  From reading a manual from a '73 it said the same thing.  Of 
course, they recommend the 'maximum operating speed' of the 392 as 3400 rpm, far
lower than the 4000 for the 304.  I imagine it's like tractors, made to run at 
full throttle all day, but WOT on a tractor engine is certainly not anything 
very fast.  I'll check the manual again, but I'm pretty sure that it says to run
the engine at max range on a regular basis, as these engines are designed to run
like that.

     -Joel Brodsky

         '76 IHC Scout II 345/tf727 RE8000, Cibie40s, custom 
                rear tire rack, 6 different color body panels.
                Not much sport, all utility.
         '75 IHC Travelall 150 4wd 392/tf727 Hummer brush guard, 
                3/4T rear springs, Hella Rallye 2000s, Con-Ferr 5x7,
                Class IV hitches front and rear, 3" Exhaust.
                1st Place, Rocky Mountain IH Rendezvous,
                3rd Place, Tulare IH Western Regionals.
         '74 IHC Travelall 150? 2wd 392/tf727 "The 'new' one"
                Factory AM/FM, Cruise, Tilt, AC, Captains Chairs.

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Date: Mon, 7 Sep 98 10:09:22 -0700
From: John Hofstetter <hofs@domain.elided>
Subject: Max RPM

Sorry Digesters, 
I hit the wrong button so send my last post without any message. Might be 
the best one I've sent all morning.

What I wanted to say was that a long time ago, I read in an IHC manual in 
which they recommended that the owner not exceed 80% of the maximum rpm 
of the engine as rated by the manufacturer. Consequently, I've always run 
my IHC's at lower maximum RPM's than most other drivers. I've almost 
always had a tach, and I very seldom ever exceed 3800 RPM on any of my 
345's. Maybe a bigger reason than the logic that I just tried to advance, 
is the fact that they sound like they're screaming at 4000. Another 
important reason is where the torque occurs in these V8's. When pulling a 
trailer, my Scout and my former Travelall were very happy at 1800 RPM, 
and the V8 in my Grand Cherokee is not happy at all going up hill with 
the trailer at 1800 RPM. 

Did you have a point to make, John?
No, I guess I really didn't, except I wanted everyone to think that I'm a 
very logical driver, which I'm not.

John H. 

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