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Negoitiating hills with BB - Printable Version

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Negoitiating hills with BB - jburgessx2 - 05-12-2009 14:32

I'm getting ready to take my Bird on a trip from SoCal to Oregon. I haven't
really driven hills too much and was looking for some advice on how the coach
handles on hills and how to control the speed (if necessary). I have an 85 PT40
with the 6V92 and transmission retarder. Does down shifting help control the
speed going down hill without increasing the rpm's too much? Should the
retarder be used rather than down shifting?

I really don't want to over rev the engine or stress the retarder too much so I
need some tips on how best to control a BB on the hills.

Thanks.

Jerry
85 PT40

Negoitiating hills with BB - Curt Sprenger - 05-12-2009 14:54

Jerry,

Going UP hill or Down hill...The 92 series engine was designed to run all day at or near max RPMs.  Running at Detroit stated max RPMs will not hurt it. Just keep it at or just below max RPS and all should be fine. Watch the two trans. temp gauges. and do not exceed maximum operating temperature. Use the brakes in conjunction with the retarder and down shift as needed. It's a marital thing...got to spend time with the girl and get used to it while monitoring all this.


I leave the trans. Retarded in the "active" or "ON" position all the times.

Watch ythe engine temperature when climbing hills and turn on the Fan Override if the engine temperature is getting close to 190 degrees.


Other will chime in and provide more info.   

Enjoy your trip.

Curt Sprenger

1987 PT38 8V92 "MacAttack Racing"

Anaheim Hills, CA
Read all about Southwest Bluebirds and Friends (SWBB) at http://www.SOUTHWEST-BLUEBIRDS.ORG ...Then Join us.

"Host of

On Tue, May 12, 2009 at 7:32 PM, jburgessx2 <"jburgessx2@yahoo.com"> wrote:






I'm getting ready to take my Bird on a trip from SoCal to Oregon. I haven't really driven hills too much and was looking for some advice on how the coach handles on hills and how to control the speed (if necessary). I have an 85 PT40 with the 6V92 and transmission retarder. Does down shifting help control the speed going down hill without increasing the rpm's too much? Should the retarder be used rather than down shifting?



I really don't want to over rev the engine or stress the retarder too much so I need some tips on how best to control a BB on the hills.



Thanks.



Jerry

85 PT40





Negoitiating hills with BB - Wayne Kotila - 05-12-2009 15:02

Use a combination of the transmission retarder, downshifting a gear and the brakes.Remember to keep your speed down and to watch your tranny temp. guage, and turn of the retarder switch when the temp gets over maybe 250 deg. I was told by an Allison dealer it could handle short spurts over 300 deg and I went by that and it ended up burning up my tranny. I would call a reputable dealer service department like "Holland motor homes" and ask them the recomended max temp. to let the tranny hit. I have been down many steep mountain grades with a PT40 and it is no problem, you just have to use your service brakes to help keep your speed under control.
Wayne
1985PT40


From: jburgessx2
To: WanderlodgeForum@yahoogroups.com
Sent: Tuesday, May 12, 2009 9:32:35 PM
Subject: [WanderlodgeForum] Negoitiating hills with BB




I'm getting ready to take my Bird on a trip from SoCal to Oregon. I haven't really driven hills too much and was looking for some advice on how the coach handles on hills and how to control the speed (if necessary). I have an 85 PT40 with the 6V92 and transmission retarder. Does down shifting help control the speed going down hill without increasing the rpm's too much? Should the retarder be used rather than down shifting?

I really don't want to over rev the engine or stress the retarder too much so I need some tips on how best to control a BB on the hills.

Thanks.

Jerry
85 PT40



Negoitiating hills with BB - Pete Masterson - 05-12-2009 15:04

Perhaps someone with an 85 can address specifics about handling the retarder in your year coach. (I have an 'exhaust-based retarder' and it has different issues.)
In general, coming down grade, you do shift down to match your engine to the speed you're traveling -- but the retarder (electric or ??) may have specific instructions. The primary concern is heat build up in the retarder, so watch the appropriate gauges carefully. On the up grade, watch (1) oil temperature and (2) water temperature. If you approach the "red line" with either one, pull off and run at high idle until normal temperatures return (usually about 3 minutes).
Brakes should be used to bring the coach to about 5 mph below your target speed. Then roll under retarder control until your speed increases to the target or slightly above. Then use the service brakes to bring the coach speed bat to about 5 mph below the target speed.
Do keep an eye on the air in the system. If you seem to be running the air down faster than it recovers, then slow way down or stop until the air pressure builds up. (Shifting down should run the compressor faster to recover the air pressure.)
You absolutely do not want to overspeed the engine. Recheck your manual, as different engines have different specs. My S-60 has a 2100 RPM red line under power, but allows a maximum 2400 RPM while traveling under jake brake down grade. If things are getting "close" then use the service brakes.
Note, do not 'pump' the brakes (that just bleeds off excessive air), the brakes are designed to handle controlling the vehicle. The slow below and build up procedure gives time for the brakes to cool (somewhat) between applications.
If it seems like you're building excess speed too quickly, then set your target speed lower.
A rule of thumb is to go down hill at about the same speed you came up the hill. However, it's often OK to go down a little faster than the up hill run, if the highway conditions permit. Keep in mind, not all grades are the same on either side of the hill. Often, (in the western mountains) one side of a pass will have a steeper run than the other. For example, the downgrade from Donner Pass, west to the foot hills is about 40 miles. From Donner Pass, east to the Nevada border is more like 10 miles. The actual grade (e.g. 6%, 7% etc.) is about the same, but the "intensity" and curves are a different experience.
Enjoy your trip.
Pete Masterson
'95 Blue Bird Wanderlodge WBDA 42
El Sobrante CA
"aeonix1@mac.com"


On May 12, 2009, at 7:32 PM, jburgessx2 wrote:

I'm getting ready to take my Bird on a trip from SoCal to Oregon. I haven't really driven hills too much and was looking for some advice on how the coach handles on hills and how to control the speed (if necessary). I have an 85 PT40 with the 6V92 and transmission retarder. Does down shifting help control the speed going down hill without increasing the rpm's too much? Should the retarder be used rather than down shifting?

I really don't want to over rev the engine or stress the retarder too much so I need some tips on how best to control a BB on the hills.

Thanks.

Jerry
85 PT40



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Negoitiating hills with BB - Pete Masterson - 05-12-2009 15:08

I'd suggest 250... Oil starts breaking down rapidly above 250 (even the synthetic oils).
My DD S-60 manual suggests a "normal" engine oil range of 200-250 degrees. When climbing, I pull off to cool off if it gets above 230. Trans temp isn't an issue on the S-60 -- mine never gets above about 175 degrees no matter what.
Pete Masterson
'95 Blue Bird Wanderlodge WBDA 42
El Sobrante CA
"aeonix1@mac.com"


On May 12, 2009, at 8:02 PM, Wayne Kotila wrote:


Use a combination of the transmission retarder, downshifting a gear and the brakes.Remember to keep your speed down and to watch your tranny temp. guage, and turn of the retarder switch when the temp gets over maybe 250 deg. I was told by an Allison dealer it could handle short spurts over 300 deg and I went by that and it ended up burning up my tranny. I would call a reputable dealer service department like "Holland motor homes" and ask them the recomended max temp. to let the tranny hit. I have been down many steep mountain grades with a PT40 and it is no problem, you just have to use your service brakes to help keep your speed under control.
Wayne
1985PT40
From:jburgessx2 <"jburgessx2@yahoo.com">
To:"WanderlodgeForum@yahoogroups.com"
Sent:Tuesday, May 12, 2009 9:32:35 PM
Subject:[WanderlodgeForum] Negoitiating hills with BB


I'm getting ready to take my Bird on a trip from SoCal to Oregon. I haven't really driven hills too much and was looking for some advice on how the coach handles on hills and how to control the speed (if necessary). I have an 85 PT40 with the 6V92 and transmission retarder. Does down shifting help control the speed going down hill without increasing the rpm's too much? Should the retarder be used rather than down shifting?

I really don't want to over rev the engine or stress the retarder too much so I need some tips on how best to control a BB on the hills.

Thanks.

Jerry
85 PT40





Negoitiating hills with BB - Dan - 05-12-2009 15:23


I agree to go down at the same speed you go up but also be sure to select the right gear at the top of the hill because you might not be able to down shift if you are going too fast.
Dan Williams, 88wb38, Jackson, MS
----- Original Message -----
From: "jburgessx2@yahoo.com"
To: "WanderlodgeForum@yahoogroups.com"
Sent: Tuesday, May 12, 2009 9:32 PM
Subject: [WanderlodgeForum] Negoitiating hills with BB


I'm getting ready to take my Bird on a trip from SoCal to Oregon. I haven't really driven hills too much and was looking for some advice on how the coach handles on hills and how to control the speed (if necessary). I have an 85 PT40 with the 6V92 and transmission retarder. Does down shifting help control the speed going down hill without increasing the rpm's too much? Should the retarder be used rather than down shifting?

I really don't want to over rev the engine or stress the retarder too much so I need some tips on how best to control a BB on the hills.

Thanks.

Jerry
85 PT40






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Negoitiating hills with BB - jgarner @dslextreme.com - 05-12-2009 16:32

Here are some tips on driving the DD 2 stroke engines like you have...

http://tejascoach.com/tejasoil.html#Drive

HTH, Joe
'87 PT40
8v92