Engine/Transmission (1994 - 1998) 60 lb Exhaust Springs

[Grinder1]

Getting ready to install a Pacbrake. Is it worth the extra time and $$ to install the 60lb springs? How much extra braking power do you really feel, esp. running an auto transmission? (yes I have a TC lock-up switch). What is the best valve spring compressor tool to use?

 

[HBarlow]

I have never owned a 12 valve and know very little about them but no one has answered.

From what I have read and heard the 60psi valve springs are required in order to use an exhaust brake in a 12 valve. I believe that without an exhaust brake your exhaust valves will not completely close against the back pressure created by the exhaust brake.

An exhaust brake provides excellent braking to slow from highway cruise speed saving your service brakes. The exhaust brake will also allow you to hold speed in check on a long mountain descent with a trailer behind without applying and overheating the service brakes.

Earlier trucks with front discs and rear drums didn't have great brakes but they will perform much better and last longer with the exhaust brake.

 

[Bill Stockard]

Getting ready to install a Pacbrake. Is it worth the extra time and $$ to install the 60lb springs? How much extra braking power do you really feel, esp. running an auto transmission? (yes I have a TC lock-up switch). What is the best valve spring compressor tool to use?

I previously owned a '97 3500 dually with an automatic transmission (4. 10 ratio) and had a torque converter lockup switch. When I installed a PacBrake, I didn't install 60-lb exhaust valve springs and could not install the plug in the butterfly (old style PacBrake). The PacBrake wasn't very effective. Later, I had the 60-lb springs installed and I could install the plug in the PacBrake butterfly and it made a world of difference. I could travel down a 6% grade towing our 29-ft Hitchhiker II 5th wheel with the torque converter locked in 3rd gear and never touch the brake pedal. Either install the 60-lb exhaust valve springs or don't spend your money on an exhaust brake.



I cannot recommend a spring compressor tool since I had the local Cummins distributor, Cummins Southern Plains in Fort Worth, TX do the job for me and have no recollection of the cost.



Bill

 

[GAmes]

I recommend the NAPA p/n 3271.

 

[Grinder1]

Harvey, thanks for your input. Yup, the earlier trucks like mine don't have the greatest stopping power.

 

[Grinder1]

Bill, that's exactly the info I was looking for. Ok... ..... sounds like a no brainer that I need the 60lb kit with the plug. Thanks
Still looking for anyone's thoughts on a good valve spring compressor.

 

[Cosmo]

Are you not going to get a PRXB? If so, it's not the fixed orifice that he's talking about that the plug closes it off to increase braking power.


I've got a PXRB on my 12-valve, with the 60 lb springs, however I don't feel like it does Jack to help with slowing down. On long grades it did OK at helping to maintain speed, 6% downgrade while towing a ~12k pound trailer, however while running around empty it feels as if there is literally zero difference between brake on and brake off while coasting.

I do, however, feel that something isn't right with the install.

I bought the cheaper valve spring compressor from Genos, but in hindsight I should have opted for one of the more expensive ones that does both springs at the same time (I was putting intake springs in too).

 

[BigPapa]

I've used the KD tool with quite a bit of frustration. It had a lot of wear on it, though. According to a friend, this one is supposed to be the shiznit:



Valve Spring Compressor for the Cummins 12 Valve. PN CVSC020 - Tork Teknology

 

[Grinder1]

Cosmo, what year was the truck that had the PRXB? If the install isn't right, then that's a real problem for sure. I'm going to install the older C14000AT PacBrake. I know it's not as powerful at low RPMs as the PRXB but it's a much simpler piece of equipment. I got it for $380, new in the box. There are two small holes in the butterfly plate, the 60# kit will plug one. I'm just messing around with some simple upgrades, as I'm not sure how long I'll keep this truck. Most guys are telling me to hang on to it, as it's got low miles and is "unmolested". Of course the paint falling off is a real pisser, thanks EPA.

Has anyone out there had the older PacBrake, then gone with the PRXB unit?

Hey Big Papa, thanks for the Tork Tek info. Anybody else have a Spring Compressor story?

 

[RustyJC]

Forgive me for stating the obvious, but if you have an automatic transmission, are complaining about poor exhaust brake results and don't have a torque converter lockup device, without some mechanism to lock up the torque converter when the exhaust brake is in use, the exhaust brake will develop very little braking power but will develop a LOT of heat in the transmission fluid due to torque converter slippage and fluid shear.



Rusty

 

[CKelley1]

you have to use the 60 lb springs or you will cause damage to valves and pistons. you only need to change the exhaust valve springs. the K&D tool works great. a hint mark the harmonic ballancer with soap stone at 120* from tdc and 240* from tdc. set to tdc and do #1 and the 4th in firing order next turn 120* and do the 2ond and 5th in firing order last turn to the 270* mark and do 3 and 6 in firing order

 

[Bill Stockard]

Rusty is correct. Without a manual torque converter lockup switch, the exhaust brake is useless except for heating transmission fluid.



Grinder,



If your early style PacBrake is vacuum operated you will need to look up the instructions for cleaning the electric/vacuum valve in the TDR archives when the exhaust brake sticks. Carbon will eventually build up in the little valve and cause the exhaust brake butterfly to stick in one position. The valve can be disassembled and cleaned in spray brake cleaner, lubricated, and reassembled and it will work again like new.



If your PacBrake is air operated, you won't encounter this problem. The air cylinder operates the butterfly faster and with more force.



I kept mentioning 60-lb exhaust valve springs, but I don't remember since Cummins did the job. Cummins Southern Plains may have replaced both the intake and exhaust valve springs. They were selling/installing PacBrake exhaust brakes at the time which was several years before Cummins introduced their E-brake.



Bill

 

[CKelley1]

re read your sig i hate autos, would never own one or drive one but in reading post on them and exhaust brakes i think i would contact bd and get the springs, brake and there lock up kit as a package. bd and pac are equal and the best. i just know from reading bd makes a lock up for the pos auto

 

[jtwcummins]

When I installed the exhaust brake on my 97 I replaced both intake & exhaust springs because I was going to do 3g or 4g gov springs and wanted to be sure valves wouldn't 'float'. I installed the Banks brake and it came with a controller and vac actuator for the trans throttle valve. The throttle valve is on drivers side of trans and increases fluid flow as accel pedal is depressed. When the EB was on the throttle valve was turned on full and TC locked down to about 18 mph.



I never turned the brake off and ran for 8 yrs on stock 47re trans w/o any problem. You get around 180 HP of braking and it really worked great, would slow down when towing down I 80 from Reno to Sac. If traffic was not bad would never need to use service brakes.

 

[Cosmo]

The PRXB is installed in my 98 12-valve, and it's perhaps a month old now. Pacbrake's kit comes with a black control box that gets wired in and automatically locks the torque converter up.

Or I should say it keeps the converter locked IF it was already locked. So if I hit the OD off button to drop down to 3rd and raise RPMs, the brake won't engage unless I then step on the throttle to get the converter to lock up, and then let off to get the brake to engage.

It also means I have to be in 3rd or 4th with the converter locked if I want to manually downshift to 2nd or 1st and keep the converter locked for the brake - if I'm just cruising in 2nd the converter doesn't lock and the brake doesn't engage.

I'm also on the 2nd little black control box, as the original one was bad out of the box. It had an intermittent engagement signal to the air solenoid. The black box I'm running is actually out of a 48re truck, and apparently it's backward compatible according to the guy who designed it.

My trans temps are quite cool usually. In 90 degree weather, towing a 12k+ pound load, the trans would stabilize at about 150 degrees rolling down the highway. In town with the TC not locking up it got warmer, 190 degrees is about all the hotter I saw. Unloaded and in 40-60 degree weather here it usually doesn't get any warmer than 125 degrees. The 6% downgrades didn't raise trans temps at all, so I know the converter isn't cooking my fluid.

 

[Grinder1]

Forgive me for stating the obvious, but if you have an automatic transmission, are complaining about poor exhaust brake results and don't have a torque converter lockup device, without some mechanism to lock up the torque converter when the exhaust brake is in use, the exhaust brake will develop very little braking power but will develop a LOT of heat in the transmission fluid due to torque converter slippage and fluid shear.



Rusty

I installed a TCC switch on my truck years ago, and yep, you gotta have that for an Ex Brake to be effective at all.

 

[Grinder1]

Rusty is correct. Without a manual torque converter lockup switch, the exhaust brake is useless except for heating transmission fluid.



Grinder,



If your early style PacBrake is vacuum operated you will need to look up the instructions for cleaning the electric/vacuum valve in the TDR archives when the exhaust brake sticks. Carbon will eventually build up in the little valve and cause the exhaust brake butterfly to stick in one position. The valve can be disassembled and cleaned in spray brake cleaner, lubricated, and reassembled and it will work again like new.



If your PacBrake is air operated, you won't encounter this problem. The air cylinder operates the butterfly faster and with more force.



I kept mentioning 60-lb exhaust valve springs, but I don't remember since Cummins did the job. Cummins Southern Plains may have replaced both the intake and exhaust valve springs. They were selling/installing PacBrake exhaust brakes at the time which was several years before Cummins introduced their E-brake.



Bill

Bill, which EB did your 97 have in it? The C14000AT or the PRXB?

 

[Bill Stockard]

You get around 180 HP of braking and it really worked great, would slow down when towing down I 80 from Reno to Sac. If traffic was not bad would never need to use service brakes.

Yep, I made that down hill run a couple of times with my '97 towing... sat back enjoyed the ride and read the helpful signs for the truckers.



Bill

 

[sstefanini]

I have the old style brake, w/o a mystery switch. It's pretty disappointing the amount of braking effect I get out of it, and am considering yanking it. Thanks for all the great posts in this thread.

 

[HBarlow]

I have the old style brake, w/o a mystery switch. It's pretty disappointing the amount of braking effect I get out of it, and am considering yanking it. Thanks for all the great posts in this thread.

Instead of giving up on your exhaust brake why not install a torque converter lock-up switch? Without it you are trashing your transmission and not benefitting from the brake at all.