Truck bought for parts, got it running, but…

[T9000]

I will look and see if I can find the specs, on "regular" steel steel connections you can look up the fastener specification, thread size/count/grade.
This would be OK for the exhaust elbow.
IIRC it is an M8 bolt.
View attachment 890227
Very good guide for items that the specs are hard to find.

Yes, thanks for bringing that table up, I have those spcs in the H1 manual, I presume those bolts are GR8.
My elbow bolts were so tight or stuck that the C side of the wrench would open and slip before the bolt would move, that's how I rounded one somewhat, after which I used the closed ring side, with a wooden block pressed in to stop the wrench it from slipping out due to the wrench's ring angle and opened the screws using a breaker bar (large steel tube from the 4 ton floor jack inserted over the wrench).

 

[Mogman]

Yes, thanks for bringing that table up, I have those spcs in the H1 manual, I presume those bolts are GR8.
My elbow bolts were so tight or stuck that the C side of the wrench would open and slip before the bolt would move, that's how I rounded one somewhat, after which I used the closed ring side, with a wooden block pressed in to stop the wrench it from slipping out due to the wrench's ring angle and opened the screws using a breaker bar (large steel tube from the 4 ton floor jack inserted over the wrench).

You of course want to replace all those bolts.

 

[T9000]

You of course want to replace all those bolts.

Absolutely! I want to use all brand new, like I already ordered the ones that I had part numbers for even before I was thinking to open the turbo! I am now working to find the part number or size for the Torx, the hex heads are M8, like you said, will use GR8 for those.

 

[Mogman]

Absolutely! I want to use all brand new, like I already ordered the ones that I had part numbers for even before I was thinking to open the turbo! I am now working to find the part number or size for the Torx, the hex heads are M8, like you said, will use GR8 for those.

As long as you do not have issues with the compressor screws there is no real need to replace them.

 

[T9000]

I am back in the trenches and getting ready for the new cartridge…and after removing the multiple layers of gunk I found more marking that maybe mean something?

In the engine valley, next to the oil pressure sensor there is circle of dots…



and on the passenger side under the turbo exhaust side it’s very hard to see and it looks like:

11 22 V or M or U or?










Are any of these indicating anything in terms of the engine block type (GEP?) and/ or manufacturing time frame/ date?

 

[T9000]

The waste gate is super simple, it is just a spring pushing against the "valve" in the turbo, when the back pressure gets to the point it overcomes the spring pressure it bypasses the exhaust turbine, as long as the valve is not stuck in the exhaust elbow it will work.
Here is a link to modifying the waste gate so it can be adjusted

Turbo waste gate conversion to adjustable

I was asked to make this its own thread. I converted the stock waste gate controller to make it adjustable, was really easy, just grind off the crimp in the middle of the "can" until it gives up the "cover", then carefully grind the end of the rod (spring end) until the spring cap is free...

www.steelsoldiers.com

I did cut the wastegate can, oiled it from both sides and cleaned the paint (from the rebuild ) of the arm. Now it’s moving smoothly being pulled by the spring where before it was totally stuck.

 

[Maxjeep1]

I did cut the wastegate can, oiled it from both sides and cleaned the paint (from the rebuild ) of the arm. Now it’s moving smoothly being pulled by the spring where before it was totally stuck.

View attachment 890665

You might want to make it adjustable while you are in there..

 

[T9000]

You might want to make it adjustable while you are in there..View attachment 890671

Yes, that’s the next step after I install the boost sensor. Actually I am putting together a basic data acquisition to capture boost, egt and maybe iat just to get my mind around the engine…I am thinking to add an intercooler and water-methanol injection combined with increased fuel supply, but that’s down the road, first I have to bring the engine to its operational baseline. I will run all these by you guys as I am still learning the engine details.

 

[Mogman]

The

Yes, that’s the next step after I install the boost sensor. Actually I am putting together a basic data acquisition to capture boost, egt and maybe iat just to get my mind around the engine…I am thinking to add an intercooler and water-methanol injection combined with increased fuel supply, but that’s down the road, first I have to bring the engine to its operational baseline. I will run all these by you guys as I am still learning the engine details.

That engine is a turd, while you may get a minimal power gain without spending tons of money it's just not worth the effort, in the end a turd is a turd, many before you have figured this out, some the hard way.
At the end of its civilian production that GM engine had a total of 4% of the light duty diesel market as the whole world knew it was a turd.
But of course you could be the "one" out of the countless number of folks thinking they could improve performance, keep us posted.
One thing, this turbo cannot produce enough boost to make an intercooler a worthwhile addition.

 

[T9000]

The

That engine is a turd, while you may get a minimal power gain without spending tons of money it's just not worth the effort, in the end a turd is a turd, many before you have figured this out, some the hard way.
At the end of its civilian production that GM engine had a total of 4% of the light duty diesel market as the whole world knew it was a turd.
But of course you could be the "one" out of the countless number of folks thinking they could improve performance, keep us posted.

You are 100% correct about the engine being a turd . I am just experimenting and don’t expect any huge gains, it’s a learning exercise and it’s relatively easy to modify. I plan to dyno it once it’s baseline operational and again after the mods to get some objective data points.
The one thing I like about the engine is the sound And it’s not because I like loud things, it’s quite the opposite, like I love the quietness of my 6.7 Cummins CGI, but that particular sound does something for me

 

[T9000]

One thing, this turbo cannot produce enough boost to make an intercooler a worthwhile addition.

I am glad you said that because that’s one of the questions, what turbo would be required and would fit? HX40? Or? I think the intercooler requires at least an additional 4-5psi to be compensated for.

Also the intercooler would be the last step, maybe I don’t even have to do it as the water-methanol injection may be enough and I appreciate your feedback.

 

[T9000]

One thing, this turbo cannot produce enough boost to make an intercooler a worthwhile addition.

I saw that Leroy makes a plate to close the oil ports so a different turbo could be installed, maybe just another option.

 

[Mogman]

I saw that Leroy makes a plate to close the oil ports so a different turbo could be installed, maybe just another option.

The engine will not take more boost, this is an indirectly injected high compression engine that was very poorly designed from stem to stern.
it has a 22:1 compression ratio, the Duramax only 16:1, The basic engine pattern is of a gas engine, cranks break, blocks break, heads crack
If you get over 15-20lb of boost you will lift the heads, then you put in studs and something else will fail, it will never make dependable HP
There are a few folks that have coaxed 300 or more HP out of them for short term with a ton of money in custom made parts. but for much less money you can drop in a 400+ HP duramax and it will run for 3-500 thousand miles easy.
Otherwise You can simply turn the pump up a little bit, clean up the exhaust, maybe get 215-220 HP and be happy with that.

 

[T9000]

The engine will not take more boost, this is an indirectly injected high compression engine that was very poorly designed from stem to stern.
it has a 22:1 compression ratio, the Duramax only 16:1, The basic engine pattern is of a gas engine, cranks break, blocks break, heads crack
If you get over 15-20lb of boost you will lift the heads, then you put in studs and something else will fail, it will never make dependable HP
There are a few folks that have coaxed 300 or more HP out of them for short term with a ton of money in custom made parts. but for much less money you can drop in a 400+ HP duramax and it will run for 3-500 thousand miles easy.
Otherwise You can simply turn the pump up a little bit, clean up the exhaust, maybe get 215-220 HP and be happy with that.

That info it’s a huge time saver as I am not looking to reinvent the wheel and yes, clearly DMAX is the way to go, which I would do on another truck.
I was hoping to maybe get around 250+ HP without pulling the engine to do arp studs and all that.
Couldn’t I get there by just increasing the fuel supply, reducing the intake temp while keeping the boost in the existing operating range of 15psi and further reducing EGT by doing water methanol injection?
In terms of return on effort it sounds like the intercooler would be the bottom of the list.
Thank you for sharing your knowledge!

EDIT: I meant ARP studs, not heads.

 

[Mogman]

That info it’s a huge time saver as I am not looking to reinvent the wheel and yes, clearly DMAX is the way to go, which I would do on another truck.
I was hoping to maybe get around 250+ HP without pulling the engine to do arp heads and all that.
Couldn’t I get there by just increasing the fuel supply, reducing the intake temp while keeping the boost in the existing operating range of 15psi and further reducing EGT by doing water methanol injection?
In terms of return on effort it sounds like the intercooler would be the bottom of the list.
Thank you for sharing your knowledge!

15 lb of boost does not significantly raise the intake temp, why an intercooler is not beneficial.

 

[Mogman]

GEP built a 240-250HP 6.5L(EDIT P400) it was spacial built, even with all of the improvements GEP made to the 6.5L IIRC it required special pistons/rods and a big girdle bolted to the bottom of the block to keep the crankshaft in the motor, and likely studded heads, AND again IIRC it required an electronically controlled injection pump.
they were high dollar and are no longer made

 

[T9000]

15 lb of boost does not significantly raise the intake temp, why an intercooler is not beneficial.

How about the heat coming from the oil fill port via the cdr valve? I presume with that much oil present in the turbo there must be even more hot air. And even if there is no oil, there would still be the hotter air which would increase the intake air temperature?
Additionally, I presume the exhaust temperature would be another added thermal factor. Even if the turbo shaft is perfectly isolated and no hot gases leak into the intake, there is still a lot of heat being transmitted via the metal cartridge to the turbo housing. Of course, I may be missing some other details.
By what percentage would you say these two higher temperature streams contribute to increase the IAT?

EDIT: It is my understanding that for about each 6 degrees increase in IAT there is about 1% decrease in HP and vice-versa.

 

[T9000]

deleted

 

[T9000]

Ok, so I finally got around to install the new turbo cartridge, new gaskets, new turbo bolts, unblocked the wastegate (it is moving smoothly now), but there is not much change. The blow-by is the same and it still leaks oil at the turbo base, maybe less than before.
I tightened the two turbo bolts little by little alternating from each side to about 30 ft-lbs as there is no torque info in the manual.
In one GM manual I found it says 33 to 44 ft-lb and on the flashoffroad site it says "Turbocharger Mount Bolts 43 ft-lb".
I have another set of bolts and another seal to try, has anyone dealt with a similar oil leak like this before?

 

[T9000]

I will look and see if I can find the specs, on "regular" steel steel connections you can look up the fastener specification, thread size/count/grade.
This would be OK for the exhaust elbow.
IIRC it is an M8 bolt.
View attachment 890227
Very good guide for items that the specs are hard to find.
EDIT, you would reduce the torque by 10% because you would definitely want to use never seize

Any other words of wisdom for turbo oil leak at the base?
Have you seen this issue before?
Is the torque maybe too much or too low?