• Welcome to The Truck Stop! We see you haven't REGISTERED yet.

    Your truck knowledge is missing!
    • Registration is FREE , all we need is your birthday and email. (We don't share ANY data with ANYONE)
    • We have tons of knowledge here for your diesel truck!
    • Post your own topics and reply to existing threads to help others out!
    • NO ADS! The site is fully functional and ad free!
    CLICK HERE TO REGISTER!

    Problems registering? Click here to contact us!

    Already registered, but need a PASSWORD RESET? CLICK HERE TO RESET YOUR PASSWORD!

H1 Hummer Cummins Swapped

FellowTraveler

Well-Known Member
Messages
2,869
Reaction score
2,453
Location
Nature Coast
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

Well-Known Member
Messages
267
Reaction score
378
Location
Canada
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.

Well-Known Member
Messages
9,445
Reaction score
10,317
Location
Boulder City Nv
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
2,869
Reaction score
2,453
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.
 

Attachments

Last edited:

Sand

Well-Known Member
Messages
267
Reaction score
378
Location
Canada
Drive it daily. Its great. Keeps temp perfect. Tows what I need to. Still some relays and wiring to finish for my cold days intake heater etc. The pair of duramax intake heaters work great by the way below freezing. Trans controller feels settled. Oil analysis just came back clean and average.
Im looking at additional crank venting. Possibly through a CDR to the air cleaner from the oil filler neck.
I love the project. Might be time for z new one. Possibly superduty ford cummins...
My 05 duramax got rearended last week and they will write it off for sure.
 

FellowTraveler

Well-Known Member
Messages
2,869
Reaction score
2,453
Location
Nature Coast
Good to hear its working out for you.
You might want to look into the valve cover venting plumbed into the downpipe with a vortices tube and using a check valve the vacuum created will pull and incinerate whatever particles present.
 

Will L.

Well-Known Member
Messages
9,445
Reaction score
10,317
Location
Boulder City Nv
I would include a catch can. The more vacuum -the better.

But why just shove oil out the exhaust? Recover it in a catch can. I got a provent 200, but it isn’t the best choice for going under water due to the regulator in it.

You just run vent line through catch can into draft tube in exhaust.
33C7727D-4A95-4574-BC19-C5723901FE59.pngAE9FA70A-59F9-4D91-9DFC-CB6B76D11D77.png

 

FellowTraveler

Well-Known Member
Messages
2,869
Reaction score
2,453
Location
Nature Coast
YES! Provent is perhaps the best way.......the dowpipe setup will because of high EGT's under boost incinerate whatever escapes the catch can.
 
Last edited:

FellowTraveler

Well-Known Member
Messages
2,869
Reaction score
2,453
Location
Nature Coast
On another note the valve cover vents on the Cummins separates the oil allowing it to drain back into the diesel through the valve cover. I have quite a few miles on my conversion and the hose from the valve cover vent is dry & w/o oily residue.
 
Top