Save your brakes but destroy your engine

[Full-Timers]

I just went back and re-read the Workhorse Technical Report, “Mountain driving: let your engine do the work”. I have a real problem with the last part titled, “An example of brake-friendly driving technique in Death Valley”. The driver, Mike, says he would allow the engine speed to vary between 4000 and 5200 rpms. At 5200 rpms the transmission would force an upshift and only then Mike would apply the brakes. I don’t know about all of you but my tach’s redline is 4000 rpms and 5200 rpms is way over redline. I am surprised Workhorse publishes a report stating it is acceptable to risk damage to your engine to save your under rated brakes. I fully understand that a $10,000+ engine replacement is a whole lot better than loosing your brakes and killing you, your friends and family but why not run between 3000 and 4000 and save the engine also.

[DriVer]

Originally Posted by Full-Timers

I don’t know about all of you but my tach’s redline is 4000 RPMs and 5200 RPMs is way over redline.

FT, We spoke about this very issue a number of times and generated a lot of bad ink along the way. This was a technology demonstration that presented the working limits of the engine. The engine is up to reving up to 5200 RPM in compression. In acceleration you will probably never see those types of revs. My engine's red line is > than 4000 RPM.

I have an Allison UP Grade Brake now and coming down off of Sam's Gap in NC put up a lot of revs but it was all good!

The entire lesson learned in this article is that it's preferred to "Select Shift" and or use of the "TGB" if one is available to slow the vehicle and convince owners that staying off the brakes is how you should set yourself up to negotiate down hill grades.

You would be amazed how frightened some people are to yank that shifter down because they fear blowing up the engine and transmission so they get on the brakes and cook their rotors.....

I am in disagreement with the title you've assigned this post because you can effectively manage your engine and your brakes ... without destroying anything.

[max49]

Mine has no 'Red Line', but it shuts down at 5000 RPM. Of course going downhill it will continue to rev , til it blows I guess. I also thought that was a bad judgement call of WH to use that example od "good driving technique'
I had a 454 that was red lined at 4500 RPM. My 8.1 has seen 5000RPM several times but now that it's out of warranty, I try to keep it @ 4600 or less. The 8.1 needs high revs in the high mountain states.

[Davel]

I am surprised Workhorse publishes a report stating it is acceptable to risk damage to your engine to save your under rated brakes.

The problems with Workhorse brakes is not because they are "under rated". It is one of application in vehicles that are used irregularly that also have piston-bore clearances on the tight side of the spec. I have had my W-22 in the Rockies, the Smokies and maybe the steepest road of all, US 30 going into Gettysberg, PA, and have not found them to be lacking in capacity in any way. I have also had to stand the coach on it's nose a few times when people pulled in front of me. While I did re-arrainge the cabinets, the coach stopped perfectly in a very short distance. I know there is a problem with the brakes, but it is not one of stopping capacity.

I gear down aggressively on hills and I'm not worried about spinning the 8.1 to over 4,ooo rpm. As I've mentioned here before, I had two solid lifter big blocks that I drove to work in the 60's and they went 7,000 rpm every day I drove them. And they were not built near as well as our engines are. Metalergy, specs and oil are all much better now than they were then.

Keep on truckin',
Dave

[az bound]

I must have missed it somewhere. Where did it say that it would damage the engine if allowed to exceed 4000 rpms on a downgrade? I also could not find where it stated the brakes were under rated for the application. I am sure the government would have never approved them if this were the case. This brake issue has me so worried that I decided to purchase a new coach with a 2008 W-22 chassis.
The way I read the notice from Workhorse about the inspection is that if the calipers are found defective by the service center, Workhorse/Bosch will replace all defective parts along with repairing any damage resulting from the defect, ie. rotors and pads. If there are no defects found with the caliper then there will be a $250.00 inspection fee and the owner will be responsible for any costs for repairs. Sounds totally fair to me.

[wa8yxm]

What you may or may not know is that the Allison transmission has a brain, A very good brain, and that brain knows well the limits of the engine.

On a very very long downgrade in either Tenesee or Georgia (I forget which) I engaged the grade brake and used it to down-shift the Allison a gear or two.. As I continued down the hill the rig slowly picked up speed.. Well before the point where the engine was in danger the transmission up-shifted again to protect the engine.. I then braked it down again and we started all over.. A couple of hills took as many as 3-4 cycles before I got to the bottom.

But the Grade Brake on an allison will not blow the engine, it will upshift first

Now the UP version of the grade brake I can not post about,, But I can say this about UP in general... From everything I have read about them.. I suspect they know what they are doing too and their product will work like the genuine Allison version.

[Stubborn]

az bound wrote "If there are no defects found with the caliper then there will be a $250.00 inspection fee and the owner will be responsible for any costs for repairs. Sounds totally fair to me." I was under the impression that the calipers would be replaced regardless with new calipers not just if they found defects.

[DriVer]

Originally Posted by Stubborn

I was under the impression that the calipers would be replaced regardless with new calipers not just if they found defects.

Stubborn, Let there be no impression, calipers will be changed under the terms of campaign should they fall within the scope of the campaign.

The inspection fees being discussed here are incurred by some owners under the Interim phase of this campaign that present a NTF condition on their rigs.

[Stubborn]

Thanks Driver!

[Full-Timers]

When I see red, it indicated danger to me. I don’t like running my engine in the red rpm range just as I don’t like running my temp gauge in the red range.

[max49]

Originally Posted by az bound

I must have missed it somewhere. Where did it say that it would damage the engine if allowed to exceed 4000 rpms on a downgrade? I also could not find where it stated the brakes were under rated for the application. I am sure the government would have never approved them if this were the case. This brake issue has me so worried that I decided to purchase a new coach with a 2008 W-22 chassis.
The way I read the notice from Workhorse about the inspection is that if the calipers are found defective by the service center, Workhorse/Bosch will replace all defective parts along with repairing any damage resulting from the defect, ie. rotors and pads. If there are no defects found with the caliper then there will be a $250.00 inspection fee and the owner will be responsible for any costs for repairs. Sounds totally fair to me.

Now that's a funy post, at first I did'nt realize it must be 'in jest'. But it was 5200 RPM and it 'didn't say any where in there that if your 496 cu in engine blows, it will still be your engine.

[mfire1339]

sure.... Let her rev........19,000mi.

[az bound]

No jest ment at all. I can find no such reference to acceptable risk, nor one refering to the brakes as being underrated. I'm really interested in what you are refering to as I just invested over $1000,000.00 in coach on a W22 chassis.

[DriVer]

Originally Posted by mfire1339

sure.... Let her rev........19,000mi.

mfire1339, There nothing to suggest that that piston let go due to hi revs in a compression cycle. I have seen worse engines where the crank broke and came through the block. Unless there a verifiable mechanism of failure, a broken piston can be attributed to any number of conditions WHICH if in your case I hope was repaired under warranty.

Having spun over 85,000 miles and being a poster child for just about every conceivable gadget surely I would have thrown all 8 coffee cans out of the engine by now but that's not the case and my 496 keeps right on purrin'. I love this motor for that and its a BIG brute that takes a lickin' and keeps on tickin'

In regard to my engine, I can't allow it to live as if I were walking on egg shells, it needs to run and running it well doesn't hurt it at all.