rpm and speed

[jamesr]

What maximum, sustained, RPM do you guys run your engines?  I have been picking up my Grandson after school (13 miles down the road) and have been holding a steady 3000 rpm.   Now, I read that 3000 rpm is "redline", for the L134, yet max. horsepower is 60 at 4000 rpm.  What do you think?  Jim

[Carls_jeep]

I don't have a tach, I just stay at 45 mph or slower. What is your Jeep doing in MPH at 3000 rpm?

I will guess about 60 mph because I had mine to about 65+ once and it was screaming bloody murder.

[aboyandhisdog]

The Novak site has a pretty good gear chart.  Try this:   http://www.novak-adapt.com/knowledge/gearing.htm

I have a tach on my 3A.  I would never drive more than 3000, and it is straining at those RPM's.  That is about 45-50 on my speedo.  I could cruise all day at 35mph but the higher revs make me a little nervous on such an old design.

[jamesr]

Yes, with my tires that is about 50 MPH max.  It worried me.  I hold up traffic and pull over now and then, but I worried about the rpm also.  Guess I'll take the truck when I pick him up, and leave the Willys for the desert. Jim

[RussellL]

The military data plates list max speed as 60 mph.  If you calculate the gear ratios, 60 mph is very close to 4000rpm.  I've always assumed that the red line was probably 4000 rpm.  I never heard anyone say it was 3000 rpm, although that is about the fastest it is comfortable to run it.  

[Carls_jeep]

The M38's I drove in the NG had a stencil on the dash that said, Max. 45 MPH. In a convoy we maintained 45 MPH average but sometimes we went faster to catch up but the Officer in the right hand seat would get upset if I got over 50 MPH. He would radio to the lead vehicle to slow down so the column could close up. I was the XO's driver and many times we were at the tail of the convoy with a few Motor pool vehicles for emergencies.

The M38, CJ2 and CJ3 have the same engine and gear ratios and would do between 65 and 70 but they are screaming like a banshee at that speed and a little squirrelly.

[RussellL]

That plate is on my 52 M-38. �I certainly agree that taking it up to max speed would be very hard on the engine.  I never go faster than 45.  

[Carls_jeep]

Yep, that's what the tags said but the Army said otherwise. Their max was 45.