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H1 Hummer Cummins Swapped

FellowTraveler

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I would be remix not to point out that the actual stall speed you will get from any converter always increases with modifications that raise peak torque and its rpm.

The converter was designed as a torque multiplier at speed which ceates lots of heat and increases your fuel consumption however; when dealing with the Cummins your peak torque comes in at lower rpm than say the 6.5td so it does not need much torque multiplication at the converter so a low stall makes for a much better DD diesel. Keep in mind if too low a stall it can overwhelm your breaks on stops.....so individuals who have the too low stall just put it in neutral at stops.
 

Sand

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Still looking good. My midrange drone was solved by bolting an exhaust flange back together that had come loose a foot before my muffler....happens.
And my engine started pushing a lot of oil out of the crankcase on one 3 hr drive. I suspected vacuume leak and plugged the vac pump, disconnecting the pac brake (which I had not wired to a switch for use yet anyway). Seemed to stop the puking oil situation.
2 weeks go by and I suffer a lack of boost, skyrocketing EGTs and massive blowby out the crank breather and oil fill cap. It gets progressivly worse. Im reduced to no power above 1100 rpm and the slightest application of throttle brings egts to 1000 deg. I limp home at 30kph idling the whole 5km.Im thinking slipped timimg gear or hole in piston etc. As im ready to pull injector lines and check compression -someone suggests I may have an exhaust brake issue. Sure enough. Its jiggled shut slowly and then pegged itself closed under pressure. I plugged the Vac back in and the brake opens and all is well.
Ill send oil out for analysis in a few weeks and see if I blew a head gasket.... oil got dirty fast lol.
Still unsure why I had the inital oil out the crankcase condition. Seems fine for the moment.
 

Will L.

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Still looking good. My midrange drone was solved by bolting an exhaust flange back together that had come loose a foot before my muffler....happens.
And my engine started pushing a lot of oil out of the crankcase on one 3 hr drive. I suspected vacuume leak and plugged the vac pump, disconnecting the pac brake (which I had not wired to a switch for use yet anyway). Seemed to stop the puking oil situation.
2 weeks go by and I suffer a lack of boost, skyrocketing EGTs and massive blowby out the crank breather and oil fill cap. It gets progressivly worse. Im reduced to no power above 1100 rpm and the slightest application of throttle brings egts to 1000 deg. I limp home at 30kph idling the whole 5km.Im thinking slipped timimg gear or hole in piston etc. As im ready to pull injector lines and check compression -someone suggests I may have an exhaust brake issue. Sure enough. Its jiggled shut slowly and then pegged itself closed under pressure. I plugged the Vac back in and the brake opens and all is well.
Ill send oil out for analysis in a few weeks and see if I blew a head gasket.... oil got dirty fast lol.
Still unsure why I had the inital oil out the crankcase condition. Seems fine for the moment.
Could the closed exhaust brake have created excess pressure in the crankcase? Is there a pass through egr that ties with cranckcase venting?
 

FellowTraveler

Well-Known Member
Messages
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2,310
Location
Nature Coast
Still looking good. My midrange drone was solved by bolting an exhaust flange back together that had come loose a foot before my muffler....happens.
And my engine started pushing a lot of oil out of the crankcase on one 3 hr drive. I suspected vacuume leak and plugged the vac pump, disconnecting the pac brake (which I had not wired to a switch for use yet anyway). Seemed to stop the puking oil situation.
2 weeks go by and I suffer a lack of boost, skyrocketing EGTs and massive blowby out the crank breather and oil fill cap. It gets progressivly worse. Im reduced to no power above 1100 rpm and the slightest application of throttle brings egts to 1000 deg. I limp home at 30kph idling the whole 5km.Im thinking slipped timimg gear or hole in piston etc. As im ready to pull injector lines and check compression -someone suggests I may have an exhaust brake issue. Sure enough. Its jiggled shut slowly and then pegged itself closed under pressure. I plugged the Vac back in and the brake opens and all is well.
Ill send oil out for analysis in a few weeks and see if I blew a head gasket.... oil got dirty fast lol.
Still unsure why I had the inital oil out the crankcase condition. Seems fine for the moment.
I forget what vac pump you are using. The 2nd Gen vac pump will pressurize the crankcase if there is any leak whatsoever. The Cummins is well known for excessive crankcase pressure so I went with extra venting "CASE tractor valve cover vent" it replaces two valve covers better yet two (2) valve cover vents for best results or go custom venting each valve cover to eliminate any future crankcase pressure period (on a good motor) "your oil should not get dirty fast."

You might figure a work around for that exhaust brake if it fails so you don't have a repeat of that issue.
 

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