Thread: Exhaust Brakes

It's not just modern engines that an exhaust brake can damage, the original Perkins Phaser 4 cylinder diesel in our Oka was fitted with an exhaust brake before it went into service with the RAAF, very shortly the head was off after the back pressure caused a few valves to stay open and they got smacked by the pistons!
The note in the service records stated that the exhaust brake had then been rendered inoperative and was not to be reconnected or used.
Before I fitted the Cummins 6BT we swapped over the standard valve springs to HD units to prevent the same thing happening to it.

So after having a quick look at the Sport owners manual looks like you can have engine braking in "Sports Mode" or on a long down hill the ASL might be your friend.

Originally Posted by oka374

It's not just modern engines that an exhaust brake can damage, the original Perkins Phaser 4 cylinder diesel in our Oka was fitted with an exhaust brake before it went into service with the RAAF, very shortly the head was off after the back pressure caused a few valves to stay open and they got smacked by the pistons!
The note in the service records stated that the exhaust brake had then been rendered inoperative and was not to be reconnected or used.
Before I fitted the Cummins 6BT we swapped over the standard valve springs to HD units to prevent the same thing happening to it.

Agreed - we used to fit butterfly style units to smaller trucks and had issues with some engines. The 6B and the later ISBe were prone to damage without other mods due to valve issues as well as turbo damage due to the back pressure - this was particularly bad on garbage trucks that were either 100% throttle or 0% throttle for most of their life. We used to make the customers sign an extensive waiver before we'd fit one to any vehicle.

Use the paddles

Originally Posted by Pedro_The_Swift

After a lifetime of excellent engine braking, this new " lift off equals neutral" is hard to get used too!!

Mine only disengages if it was just above idle at slow speeds but a slight increase in revs quickly locks the drive again. I find the drive disconnecting when the throttle is lifted off while creeping around shopping centre carparks is somewhat annoying.

Originally Posted by Tombie

Use the paddles

apart from the extra friction of faster moving parts.. it make no difference, diesels dont do engine braking.

How An Exhaust Brake Works | Banks Power

Originally Posted by Pedro_The_Swift

... diesels dont do engine braking.

How An Exhaust Brake Works | Banks Power

I never realised that. I just assumed they did as there was great (what I thought was engine) braking in a SIII farm diesel and, of course, in the D4. But having read through the link I see that in both cases it was the low gearing that provided the retardation in the SIII and locked torque converter/gear selection in the D4. Thanks for the post and link.

The first time I took my POS for a shakedown in the Grampians after fitting the automatic I was very pleased to find it would crawl downhill in 1 or 2 lo range without touching the brakes.

Cruising around tracks in 1 or 2 hi range has good engine braking as well.

In D for drive............. runaway train.

It's amazing how many people driving automatics don't know this.

DL