DT466E Max RPM

[Sleddgracer]

I can't leave town without going over a mountain pass ( unless I'm going south to the US ) - some of them are 6% to 8% grades 20 miles long - trucks with Jake brakes seldom have a problem, but it's not uncommon to see a truck from the prairies that isn't equipped with a manifold brake of some kind, lose control when their brakes start smoking - the lucky ones make it up a runaway lane ( where many still roll their truck ) or go over the side and down a few hundred feet - a big rig, or even a pickup hauling some hay, have to LOWER them selves down the hills - hit the down hills too fast to start with and you're literally not likely to survive to the bottom of the hill - and a reason that a non-locking transmission is a deal breaker on any bus I look at with the idea of buying

[o1marc]

Originally Posted by AaronTSchultz

I have an Allison md3060

Aaron, go to the UserCP in the upper left here and fill out your profile so we know a bit about you and your bus. Fill out as much detail in there that you can, it helps greatly in getting you proper advice.

[AaronTSchultz]

Sleddgracer, Was that supposed to be helpful in some way?

[AaronTSchultz]

Thanks o1marc.

[o1marc]

Originally Posted by AaronTSchultz

Thanks o1marc.

Is it a dog nose, FE, or RE?

[Sleddgracer]

Originally Posted by AaronTSchultz

Sleddgracer, Was that supposed to be helpful in some way?

l hope so - sharing what l know about navigating steep hills - personally I wouldn't attempt going down some of these steep hills with a transmission that doesn't lock up because just having brakes is not going to be good enough to get down safely

[AaronTSchultz]

RE. I'll update it.

[WARGEAR]

Originally Posted by Sleddgracer

l hope so - sharing what l know about navigating steep hills - personally I wouldn't attempt going down some of these steep hills with a transmission that doesn't lock up because just having brakes is not going to be good enough to get down safely

I find more of these types of comments than I’d expect in a forum like this. Saying that a heavy vehicle can not safely be driven down a hill because the trans doesn’t have a lock-up torque converter does nothing but scare novice people asking for help. The brakes stop the vehicle, the engine braking helps but should not be relied on over a properly functioning braking system in a vehicle driven by someone whose entire life is quite possibly on board (ie carefully).
Drive slowly, patiently, and deliberately.

[Sleddgracer]

Originally Posted by WARGEAR

I find more of these types of comments than I’d expect in a forum like this. Saying that a heavy vehicle can not safely be driven down a hill because the trans doesn’t have a lock-up torque converter does nothing but scare novice people asking for help. The brakes stop the vehicle, the engine braking helps but should not be relied on over a properly functioning braking system in a vehicle driven by someone whose entire life is quite possibly on board (ie carefully).
Drive slowly, patiently, and deliberately.

I'm only telling the truth - almost all of the trucks that lose control and go over the side, or roll their trucks on our local pass are trucks that are not equipped with Jake brakes or equivalent, were traveling too fast for the road and burnt their brakes out - it happens often enough ( several times each year ) that some serious thought was given to banning semis from using highway #3 through the mountains that weren't equipped with suitable manifold brakes - I think not having a lock up transmission when driving the mountains is a serious issue when driving something as large as a school bus, and would require careful attention even driving an empty pickup truck - if I'm scaring someone and they don't attempt these steep, longggggg, mountain pass hills with a non-lockup transmission, then I'm doing a good thing - maybe I'm saving lives

[PNW_Steve]

Engine braking and air brakes are "complimentary".

Using engine braking takes a fair bit of the load off of your service brakes reducing the likelihood of you being one of those rigs I saw regularly in the truck escape lanes or on fire at the bottom of the hill.

When I drove between Kingman AZ and Bullhead City I saw this often enough that it became a normal sight.

[Sleddgracer]

Originally Posted by PNW_Steve

Engine braking and air brakes are "complimentary".

Using engine braking takes a fair bit of the load off of your service brakes reducing the likelihood of you being one of those rigs I saw regularly in the truck escape lanes or on fire at the bottom of the hill.

When I drove between Kingman AZ and Bullhead City I saw this often enough that it became a normal sight.

I've been driving the passes around here for the last 52 years, sometimes in a car or empty pickup, sometimes in a 30000 gvw rig ( bucket truck ) that was overweight from the factory, sometimes driving an old B49(?) tandem Mac gas pot hauling timbers on a 20 ft deck, and I've seen a lot of nonsense on the roads - like the family that was having a tailgate picnic with their station wagon parked smack dab in the middle of a frequently used runaway lane - I took a chance of being rear ended to stop and warn them, and was told to 'f-off' for my concern - I've followed semis down the hill that had smoke billowing from several burning brakes at the same time - no idea if he made it safely to the bottom of the hill - I've had to re-route many times when the highway was closed by a truck accident ( going off the road or roll over ) - this is no figment of my imagination, it's real and it's serious - if gearing down doesn't slow you down, stay away from the steep mountain passes if you are driving a heavy vehicle

[PNW_Steve]

One of the most notable that I have seen was a brand new Peterbuilt with a condo sleeper reduced to an almost unrecognizable pile of rubish.

The tow truck driver told me that it had less than 20k miles on it.

[o1marc]

Originally Posted by WARGEAR

I find more of these types of comments than I’d expect in a forum like this. Saying that a heavy vehicle can not safely be driven down a hill because the trans doesn’t have a lock-up torque converter does nothing but scare novice people asking for help. The brakes stop the vehicle, the engine braking helps but should not be relied on over a properly functioning braking system in a vehicle driven by someone whose entire life is quite possibly on board (ie carefully).
Drive slowly, patiently, and deliberately.

Ya wanna know what's scarier? Finding yourself in that situation and not being educated or prepared for it.

[EastCoastCB]

Originally Posted by Sleddgracer

I'm only telling the truth - almost all of the trucks that lose control and go over the side, or roll their trucks on our local pass are trucks that are not equipped with Jake brakes or equivalent, were traveling too fast for the road and burnt their brakes out - it happens often enough ( several times each year ) that some serious thought was given to banning semis from using highway #3 through the mountains that weren't equipped with suitable manifold brakes - I think not having a lock up transmission when driving the mountains is a serious issue when driving something as large as a school bus, and would require careful attention even driving an empty pickup truck - if I'm scaring someone and they don't attempt these steep, longggggg, mountain pass hills with a non-lockup transmission, then I'm doing a good thing - maybe I'm saving lives

Originally Posted by PNW_Steve

Engine braking and air brakes are "complimentary".

Using engine braking takes a fair bit of the load off of your service brakes reducing the likelihood of you being one of those rigs I saw regularly in the truck escape lanes or on fire at the bottom of the hill.

When I drove between Kingman AZ and Bullhead City I saw this often enough that it became a normal sight.

Those runoff ramps in the steep grades are there for a reason.

[Sleddgracer]

Originally Posted by EastCoastCB

Those runoff ramps in the steep grades are there for a reason.

I was super impressed with the runoffs going down the hill to the Columbia gorge in Idaho - must of been an acre or two of kitty litter ( deep layer of crushed rock ) that would have safely stopped a rig with little or no damage to the rig - here we have escape lanes that divert from the highway with almost 90 degree corners - I guess Highways figure that rolling a truck is safer when it's done off the road - we have one escape, straight ahead, at the bottom of a long grade, but you have to run a stop sign to access it - sort of reminds me of figure 8 race tracks - lol

[AaronTSchultz]

We recently went on our shakedown trip into the Mountains of Colorado. (Instagram "Serendipitous_Bus") if you want to see pics of the conversion. The bus did fine other than a few issues with dry rot tires. We made it home and will get those fixed shortly.

I drove from 5,000ft to 9,500ft and then back down a week later. In about 1hr Drive. I was going about 25-35 most of the way. My coolant temp was about 215. but would quickly cool back to 190 when not on a steep grade.

On the way I started to notice a blueish smoke when I would hit the accelerator. Once we got there I noticed I was having a bit of blowby. Clear coming from the exhaust when at idle, but constant greyish from the blowby when at idle.

There is none when I start the bus, and it only starts the blowby smoke when the engine warms.

I was going to take it to the international dealer, but I wanted to get some opinions before taking it into them. I really hope to not have to do a rebuild. 238k Miles, and 12,000+ hours. from Arizona.

Any advice would be helpful. Thanks.

[cadillackid]

215 is good and warm but shouldn’t hurt the engine.. did you read that crown the dash gauge or from a diagnostic device like bluefire?

Things to watch would be your oil and coolant levels, you can also drain some oil and send it off to black stone for analysis. They will tell you if there’s excessive amounts of fuel or coolant in it. That’s a good first step as is watching your fluids for anything unusual.. ie black swirls in coolant, oil level increasing or changing color. Coolant loss, etc all things you can do yourself
I don’t mind a little smoke from a diesel if it’s not a high amount, not constant.. if you work it hard on the hills it’s possible your oil thinned from being hot and a bit hot by the rings. Would mean worn rings but not necessarily rebuild right away. If a black stoke test shows coolant in oil then things need to get deeper.( pressure test, ). fuel in oil thins it and can mean Injector issues.

[AaronTSchultz]

The oil is a bit too high. 1/4" past full on the dip when I measured the engine cold. I didn't see any thinning though and it was black. It smelled like burning coal from a bbq. But my smell isn't the best.

Coolant has dropped a bit from when I vac filled it. I figure it's just from working its way through and getting rid of all the air. Maybe 1" in the reservoir below where I had it filled. (I'll keep a closer eye on it though).

Being a new bus to me, I don't know what sluggish or weak acceleration would be.

The temp was measured at the dash, which I believe to be quite accurate as the thermostat which I checked opens at 190 degrees, and that's what the dash rises to before maintaining it's temp.

I did lower and take the side scoops off the engine bay air intake and the engine air intake, but because it's smoking at idle I don't think those are the problems.

In the next couple weeks I'll take it in to get a once over from the international dealer. And let you all know what is wrong with it.

[RomaniGypsy]

Originally Posted by geminusprime

So I've gone through this forum and schoolbusfleet and a few other diesel forums, and I can't seem to get a decent figure on the DT466E's max RPM's. I can find a lot of claims and comfort levels, but nobody seems to have an actual nameplate max RPM and I can't for the life of me find it through navistar.

The engine is a DT466E from a 1997 Vista.

From here, some very well regarded members have stated they wouldn't push it past 2600 or 2500, while others give 2700+. However I can't seem to find an actual nameplate figure on my engine block or online stating what the manufacturers max RPM is.



For a bit of additional clarification, I've got the AT545 Slip-o-matic and prefer a average speed of 45 MPH. Not trying to push the bus constantly, but just trying to see if I'd be able to travel at a decent speed on highway sections with 50-55MPH limits which would put me at 2550-2650 RPM.


Any advice? Is 2650RPM safe for several hours, or would that be not advised?

EDIT: Added threads that I've browsed. Maybe I'm missing a good one or something.

• https://www.skoolie.net/forums/f37/d...m-14686-2.html
• https://www.skoolie.net/forums/f37/t...eds-15419.html
• https://www.thedieselgarage.com/foru...rpm-dt466.html
• International DT466 Specs & History
• https://www.thedieselstop.com/archiv...o=&fpart=1.htm
• https://www.schoolbusfleet.com/forum...?TOPIC_ID=7126

I know the power after 2400 RPM goes right down, but just trying to get a feel of what I shouldn't push the engine to.

Mine would max out around 2700 under full throttle acceleration. I had the AD2000 and though it would cruise at its governed max of 65 mph with the engine turning 2150 rpm, going up hills would cause it to kick down and I never saw it go above 2700 no matter what I did.