Do jake brakes damage the engine?

I don't disagree except for one little thing. After the piston starts back down, there's a vacuum in that cylinder. In a diesel, that only happens when the Jake is on. Of course, it happens in gas engines every time the throttle is closed, but it's unique to Jake operations in diesels. (Well, I guess Volvos do have that intake restrictor valve for low idle temp control.)
And I'm sure the ring packs are designed with it in mind.

 

Listening to Bozo one night, years ago. Fuel mileage was the topic. Better than half the idiots that called in during the few minutes I could stand were doing the lunch counter echo chamber, because one driver who sounded authoritative said so at the beginning of the discussion.

"Everybody knows the Jake brakes use too much fuel to use..."

No, you mental midgets, the way you drive with a Jake uses more fuel, but the fuel is cut off (on electronic engines) when the Jake is engaged! And Bozo was just "yeah, yeah" because he didn't know enough to say anything.

Probably the last time I ever listened to his show.

 

I think you’ve just solved my understanding.

It’s the vacuum that slows the engine - right?

Nobody could ever explain that part to me.

 

Partly. It's also the lost energy of the compression that normally acts as a spring to push the piston back down. That energy would normally be returned to the crankshaft instead of being dumped out the exhaust.

 

So, what creates the excessive noise when jakes are engaged- is it the sudden release of compressed air?

Did mechanical engines also dump injected diesel with the operation of the jakes?

 

Yes, the noise is the release of the pressure. It's noisier than the normal exhaust because the normal power stroke extracts as much energy as possible before the exhaust valve opens.

And yes, basically the mechanicals dumped idle levels of fuel when on the Jake. Back then, the Jake had a microswitch on the pump to only allow operation at idle.

 

Thank you.

 

I drive a 2012 Mack with mp8 engine. The Jake is very quiet so I run it a lot. I will run it next to cops in town, it’s so quiet. But I’ve often wondered if it put more wear and tear on the hardware that comprises the jake( solenoid, springs, cam lobe, or whatever magic stuff is in there). Also, I wonder if it crams up the DPF faster. I realize it has a tendency to be rough on the whole vehicle, and load, in the lower gears so I try to be old-man smooth with it.
My brake shoes look the same as they did 150,000 miles ( mostly in town driving) ago. So I imagine that outweighs the potential costs of more frequent overheads. Right?

 

I'm not a mechanic. I make no claims at being an expert on Jakes. All I can report is something a shop boss told me once. An engine regardless of type every time a part moves causes wear. Very tiny pieces of metal so small you have to have a very high powered microscope to see get mixed into the oil. This is why the engine oil and filter MUST be changed by schedule. This is caused by friction. So, yes a Jake will cause extra wear, BUT that extra wear adds so little to the life of the engine it's not worth worry. Throughout the life of an engine, it is MUCH better to use the Jake than the brakes. That salesman is wrong. To disable a Jake is simply dumb in my opinion.

While I am on the subject I would love to interject something that has bothered me a bit of late. When you want information about things like this, the FIRST place in my opinion to go is an Owner Operator that does their own maintenance. Most of the time you are going to get good information that might save you some $$$ over time. Salesmen, even at parts warehouse locations I recommend getting a 2nd on whatever they tell you! These forums have a good OO forum I highly recommend going to for these types of questions.

 

Actually the harder thing on the engine is to idle it. To run a engine around 1200-1500 rpm is best for the engine. Jake's? Nope not hard at all.