Gets hot after long, high RPM drive

[89 MJ]

I always thought that the electric fan kicked on at 235

[cruiser54]

2 hours ago, 89 MJ said:

I always thought that the electric fan kicked on at 235

208 or 218.

[87MJTIM]

My efan kicks on when the REM registers 219*.  (I don't trust the dash gauge.)

[89 MJ]

I’ll have to run it with the REM then. Thank you. 

[Eagle]

On 8/9/2022 at 6:14 PM, lejeune981 said:

So my jeep with a combo of 5.13 gears and 31 inch tires… spinning at 3000 to do 70mph isn’t spinning her too fast? 
think 75 mph is around 3200

it will deff go faster but I get worried running her above 3k
 

mine heats up too so I’ve gotta run the aux fan to keep her around 210 while cruzing these Florida’s highways 

 

Generation gap, Cruiser.

 

Most (if not all) you guys are too young to remember when cars all came with "three on the tree" -- a 3-speed manual transmission, shifter on the steering column, with no overdrive. The engine that became the Jeep 4.0L was introduced by AMC in 1964 as a 232 cubic inch (3.8L) carburetted engine that was, at the time, fairly revolutionary. In 1966 AMC followed with a de-stroked version displacing 199 cubic inches. The factory axle ratio was 3.08. On the standard tires, the final drive ratio worked out to 24 MPH per 1,000 RPM. That's also what my 1968 Javelin V8 had for a final drive ratio. That happened to equate to exactly 2500 RPM at 60 MPH. 3000 RPM was 72 MPH, and both the sixes and the V8s would cruise happily at 3200 RPM all day long. Redline for both engines was 5,000 RPM -- most wouldn't go much over that anyway because of valve float, but heavy duty, dual-coil valve springs took care of that.

 

3,000 RPM is definitely NOT "spinning her too fast." It's not even working hard yet. That's right where the engine was originally designed to run.

[cruiser54]

True stuff^^^

[lejeune981]

On 8/13/2022 at 1:37 PM, Eagle said:

 

Generation gap, Cruiser.

 

Most (if not all) you guys are too young to remember when cars all came with "three on the tree" -- a 3-speed manual transmission, shifter on the steering column, with no overdrive. The engine that became the Jeep 4.0L was introduced by AMC in 1964 as a 232 cubic inch (3.8L) carburetted engine that was, at the time, fairly revolutionary. In 1966 AMC followed with a de-stroked version displacing 199 cubic inches. The factory axle ratio was 3.08. On the standard tires, the final drive ratio worked out to 24 MPH per 1,000 RPM. That's also what my 1968 Javelin V8 had for a final drive ratio. That happened to equate to exactly 2500 RPM at 60 MPH. 3000 RPM was 72 MPH, and both the sixes and the V8s would cruise happily at 3200 RPM all day long. Redline for both engines was 5,000 RPM -- most wouldn't go much over that anyway because of valve float, but heavy duty, dual-coil valve springs took care of that.

 

3,000 RPM is definitely NOT "spinning her too fast." It's not even working hard yet. That's right where the engine was originally designed to run.

I learned to drive in a 65 Chevy truck with a 3 on the tree

but most the vehicles I had back then didn’t have a rpm guage and I was just a youngin without a care in the world for an engine lol. Sent many a piston or connecting rod into low earth orbit

now I’m 40 and worry bout sending a piston to the moon in my daily driver lol 

 

but yesterday I took a trip to the gulf and decided to let er rip.. cruised the 60 mile trip at 80 mph at roughly 3400 rpm the whole way.. it felt good to be the one passing people vs me getting passed in the slow lane like normal !!

[cruiser54]

Good for you!!!!