Pa to Denver 454

turbojimmy wrote:

Gale Hawkins wrote:
By the way the 3500 RPM when climbing will help insure the 454 engine and transmission stay cool. When dragging out that Old Priest Run the engine temp gauge kissed the Red zone but did not enter it. I do not even remember looking that the transmission temp gauge.

I learned this last year during my first season with my 454. It's an '84 and only has a 3-speed TH400, but when it started to get warm on long grades I instinctively slowed down and it got even hotter. One day it was getting warm again, but I need to get around a slow-moving truck in order to get to a left-side exit. I sped up to about 70-75 MPH and the coolant temp dropped like a rock! Now I've learned to keep the RPMs up when it starts to get warm. I have a trans temp gauge, too, but curiously it was never hooked up. No wires to the lights or the sender. It's on the to-do list.

TurboJimmy that was interesting how you discovered how to keep a 454 engine cool in a MH. It was like on our 3 day of our 31 day trip in 2011 and we got off the Interstate and headed up to Mount Rushmore. I was pulling those first grades in 3rd as it dropped out of OD/4th on its own but the engine temp kept rising and I got very concerned knowing we were going to CA and back to KY.

I got on the gas harder and it down shifted to 2nd and very quickly the engine temp not only dropped back to normal range but even a few degrees below normal. Clearly gas engines do not like to be lugged down on the hills. :)

At Wide Open Throttle (WOT) ours will up shift at 4000 RPM. That is at 35 MPH from 1st to 2nd and about 58 MPH for the 2nd to 3rd automatic shift point at WOT. Not having an OD gear as in your case has almost not negative effect in a MH. We did a lot of miles in 2nd and 3rd gear on that 8000 mile trip to the Pacific Ocean.

Mentally I use 4000 RPM as the red line since that was GM's programmed WOT shift point but from the best I could find GM actually considered 4500 RPM as the official red line in big trucks. Now we have the Ford 429 (same block at 460 in many MH's) and the red line is more like 5000 RPM it seems. It is in a 1989 Ford F700 truck with a 16' flat dump bed.

Many complain that the big block V-8 engines are bad about running hot. Short of a bad radiator and/or fan clutch from my personal experience over heating is due to operator error of running them at low RPM's when under heavy load is is the case 100% of the time in a MH. :)