304 cooling

im new to the community so i would like to say hello to everyone. i own a 1977 cj5 w/ a 304. this was a long project and its still going. i did some mods on the jeep (rebuilt the engine but its mostly stock except for summit cam and headers) my question is, has anyone experienced hot engine temp at freeway speeds of about 60 mph? my jeep has a 3 sp tranny and at that speed, im taching close to 5k. the jeep has 33's so its probably going a bit faster than what the speedo says. if i drop the speed to about 50 mph (about 4k on tach) the temp returns to norm. are these rpm's and temp norm? this is my first cj so im not familiar with it, althou i've had 2 wranglers in the past. i am running an electric fan and it cools jsut fine in city driving. im thinking the fan isnt suffient but the ram air should have. or maybe the 3 sp really works the engine ?anyway, any info would help

 

Glenn's correct, something is really wrong about this story. The two possible gear ratios are 4.10 and 3.54, so with 33s at 5000 RPM, you are traveling 119.4 or 138.7 mph respectively. The only way you could be getting these RPMs with the speeds you claim are if you are in low range (2.03:1 reduction) or if you have your tach connected as a 4 cylinder and not a V8.

 

i really havnt looked at the gear ratio....ill get my butt underneath the jeep later and look, this is something i should know as a jeep owner. as far as the fan, its mounted inside the radiator. thanks for the reply

 

thanks ill check the tach setting again but im pretty sure i set it at the 8 cyl mode.

 

thanks for the info, ill double check my tach and gear ratio. ill also double check my temp sending unit for accuracy. (this is sorta funny because when i ordered some parts online, a temp sending unit was in my box, i figured it was new, looked the same as the oem so i installed it even thou i didnt order it.)

 

thank you all for the reply...i let you know what i find.

 

I don't see in your post what temp the Jeep is running at. My '75 runs all day long at around 210 withut a lick of trouble. I rencently changed the t-stat from the original 195 to a 180, and no difference, but it stopped bubbling over when I parked it. (bad stat I think) I may go back to a 195 though because I need all the heat I can get in the winter!

 

Find out what core radiator you have. If it is a two core and your jeep will accept a three core switch to a three core. It holds more water and I guaranty your jeep will run cooler. That is what I did. A three core isn't very expensive either unless you get an aluminum radiator.

 

Has he got it in 4Low???

High5

 

sorry for not responding to this post for awhile, anyway the problem was fixed since i went with a bigger diameter electric fan. as far as the tach, you guys were right, it was just set wrong. thanks for all the input