Exhaust brake warm up question

[RSchwarzli]

Question. You are not to biuld boost on a cold motor or head gasket issues could develop, nor does it do any good for anything for that matter!



Yet we are told to use our e brakes (Pacbrake etc) for motor warm up in cold weather.



My question: How long should one wait before engaging the exhaust brake?



I just started my truck to warm up. Its 18 F outside. My e brake (PRXB) runs 41 psi backpressure at idle. I have a gauge so I know exacly. If I wait a minute or two, flick it on, my coolant is still like 50 F and it is running 40 psi boost or the equivelant thereof.



So how long does one wait to engage the brake to aid warm up?



Thanks!



Robert

 

[blacksheepdiesel]

Good question. While you may be building back pressure you are not adding extra fuel and actually building boost which is what puts the most pressure on the head gasket. On my '01 I would start the truck cold, let the oil pressure build for a few seconds, and then engage the Jacobs exhaust brake. Never found that it damaged the head gasket.

Godspeed,
Trent

 

[RSchwarzli]

That makes sense. So the 600 F pyro is just reading pent up exhaust heat trying to get out not actual fuel.

I guess to further that, it can't be extra fuel as my boost is zilch. If boost is also what controls the afc, then no extra fuel is being injected.

Makes sense. Thanks!

 

[Bob Beauchaine]

Robert



You might want to try this little trick. Activate your exhaust brake at say 60 mph for about 5-10 seconds then hammer the go pedal. You will, or should I say, should see more black smoke coming out of your exhaust. Black smoke is unburnt fuel. That being said I have done oil analysis on all my oil changes and have never seen excessive fuel dilution in my oil. That would have been my bigest concern from using my exhaust brake. I do use mine daily and it has tripled the life of my brakes so that's a plus. Right now I've got over 100k on my exhaust brake with no known ill effects so I would not worry about adverse effects if you use the exhaust brake properly, including warming up your truck.



BTW I think you truck looks awsome!



Bob

 

[Mikey-KE7LBB]

I usually wait about a minute or so before I push the EB button. I just have a problem knowing that the turbo is forced to spin faster when the oil is thick.

At 32* it starts and idles around 750 rpm which is ok in my book. The thing that concerns me the most is at -30* it will start and idle at 1000 rpm + when the oil is dang near the viscosity of molasses!!

I think that the EB is far less an issue than the high rpm when starting in extreme cold.

 

[NIsaacs]

I agree with Trent, the back pressure is not the same as boost pressure as far as the head gasket goes. Boost includes the explosion that occurs also the timing that it occurs.



I use all mine for warm up as soon as I get oil pressure. The '01 idles at 40 psi and 700* post.



Nick

 

[CKelley1]

this question is loaded with myths. the turbo turns slower at idle with the eb on than off. at highway speed the eb does not increase head pressure and does not produce smoke. at idle the eb does not increase head pressure by even one pound. it does produce carbon at idle but the exhaust heats up the engine faster. cummins recommends turning the eb on shortly after starting and only run for about 4 or 5 minutes, start driving, and then do not load the engine hard until the temp is up to normal. use of the eb on heavy tow loads is actually good for the engine, it keeps the block from cooling off as fast.

 

[RSchwarzli]

Wow! Thanks for all the good info folks! Oo.

Robert



You might want to try this little trick. Activate your exhaust brake at say 60 mph for about 5-10 seconds then hammer the go pedal. You will, or should I say, should see more black smoke coming out of your exhaust. Black smoke is unburnt fuel. That being said I have done oil analysis on all my oil changes and have never seen excessive fuel dilution in my oil. That would have been my bigest concern from using my exhaust brake. I do use mine daily and it has tripled the life of my brakes so that's a plus. Right now I've got over 100k on my exhaust brake with no known ill effects so I would not worry about adverse effects if you use the exhaust brake properly, including warming up your truck.



BTW I think you truck looks awsome!



Bob

Bob,



Yes, I know the smoke ball you speak of well!



I also run a oil analysis and have no traces of fuel.



Thanks as well for the compliment!