RPM question

[Steven]

What RPM does the patrol run at 60mph? Trying to figure the best ring and pinions to get for my dana 44s. Thanks in advance.

[RiverPatrol]

As I recall it is around 3500.

[Steven]

That is high! I was thinking around 2500.

[RiverPatrol]

Well, the Patrol is running 4:10's front and rear behind a very high torque engine. Tire size will make a difference too. But the motor is really winding out at 60 MPH, and is really being pushed much beyond that.

I have a tach in one Patrol but it (the tach) isn't working right now. But I do remember thinking the RPM's were pretty high also. You can watch the video that Bosque just posted in his '67 Patrol thread and hear how the engine is really screaming at 70 MPH. 70 MPH is pretty much their max, and I can guarantee if you keep that speed for very long you will be burning bearings up.

[Steven]

Yea, I know it's a torque monster and I don't want to burn the engine up. Now that I have dana 44s the ring and pinion options are almost endless. I want to get it at a safe rpm when cruising at 60. I figured around 2500 would be safe.

[bosque]

I've said it before but I think my 67 purrs at 50, likes to cruises at 55., is okay at 60, and I just have a feeling is better off doing hwys at 55. No tach so just guessing.
Keep things in perspective though....like Ferdy mentioned to me about obtaining a Marks 5 speed....basically said,..... yeah nice but really, the vehicle is so mechanical and basic and was designed to 4x/rally on dirt...speed not the issue ever. This does resonate logic here so I just drive slower automatically in the Patrol.
What'd we say during the gas crunch of the 80's? "55 save lives"! ,,,,and gas too.

[RiverPatrol]

Yea, I know it's a torque monster and I don't want to burn the engine up. Now that I have dana 44s the ring and pinion options are almost endless. I want to get it at a safe rpm when cruising at 60. I figured around 2500 would be safe.

You're right; 2500 would be very safe and comfortable. So, getting it down to 2500 would be a good thing.

And, welcome to 60Patrol! You've got your first 3 posts taken care of so post away!

[Esteban]

I'm always keeping an eye on these issues, and years ago, I even went to the trouble of checking my tachometer with a precision mechanical one, and it's right on the spot. The Patrol can push to 3800 rpm anytime, although not recommended on these old engines. But I can assure you, that I've done that. By the way, the '68 owner's manual that's posted on the Patrolabilia section, list the top speed of 78mph (125 kmh) at 3800 rpm, with the 6.50-16 tires.

These are the theoretical speeds with the stock 6.50-16 tire, at approx. 28.5 inches in diameter (724mm)

RPM - MPH
500 - 10
1000 - 21
1200 - 25
1800 - 37
3000 - 62
3600 - 74
3800 - 79

I've always thought that the Patrol gearbox could use an overdrive. Can't understand why Nissan kept the original transmission for so long with a final 1:1 ratio, even when they change the model to the G61, and later the 160 or MQ model, until 1983.

[RiverPatrol]

Thank you Esteban! That's what we were waiting for! I had not yet had the inclination to record the RPM's, and it doesn't seem to be documented anywhere.

[bosque]

Thank you Esteban! That's what we were waiting for! I had not yet had the inclination to record the RPM's, and it doesn't seem to be documented anywhere.

2x. Man, I'm glad you joined here Mr.!!!