Two Stroke Detroits

[ameristar1]

What do you have to do to get more power out of the older 2 stroke Detroits? I have been out of the loop with them for a while, yet when I hear one run it gets the blood boiling. How fast can you spin them, and can compound turbos be used versus the more common parallel systems that I see.
Are there any resourses out there that show the proper way to rebuild one? It was an 8v-92TA with an Allison in a double wide, long wheelbase KW K100 that corrupted me bad that got me started into trucking.
Thanks in advance for the help.

 

[Smokey73]

most of the time, 12v's used bigger injectors than 6 and 8v's. I had a problem once when I sent a set of poppers, from a 12v-92 that I was rebuilding, out to an injection shop to get checked. I put everything back together and couldn't get enough power to hold RPM's, the engine was in a large gen set. Everything led back to the injectors. I pulled them out and sent them back to the injector shop. They then told me that the ones I had were from a 6v and that someone must have swapped them out ,last time i sent them in, for some smaller ones. Evidently they had run into this before, one of their techs "hooking" up a buddy of his with a dump truck. It's good to have friends in the right places.

 

[ameristar1]

I know that the numbers corespond with flow rate (like N35s are smaller than N50s), but since the injection system is a little different on these engines than say a Cummins, how do you tune it for more power, higher rpm, etc. Like can the timing be altered, or is it fixed and cannot be adjusted?

 

[NJKen]

Keept his post alive until GeoNC finds it. He is not on as much as he used to be but he is one of the 2 stroke detroit authorities around here.
Ken

 

[Smokey73]

I never really tried to tune 'em or anything, I just tore 'em apart and put 'em back together

 

[RustyRecycledT]

Haven't had to mess with mine as yet. I push the button, engine fires up before it even completes one revolution. Pretty sweet!

I'd like to know anything that I could do in the future to 'improve' things though.

 

[69dieselfreak]

http://www.freewebs.com/nevrenufhp/index.htm


Detroit V92's
Detroit 6&8V92:
This is a copy from Diesel Stop, I haven't done these mods.

Adjust the no load speed up.
Back out the buffer screw a few turns.
On the back side of the governor is the cap held in by 2 bolts, take that off and you have access to the idle control and the top no load setting.
Loosen the small 1/4" nut at the end pack and back out the idle speed screw about 4 turns.
Loosen the large clamp nut with the 4 notches in it on the other end of the pack. then screw in the entire assembly 3-5 turns. Tighten the large clamp nut.
Fire engine up and adjust the idle screw to just below the desired idle. Tighten the idle screw nut.
Adjust buffer screw to desired idle and so when you stab the throttle the gov doesn't search.
Put cap back on and run it around and adjust from there.
You can also get better response by running a tight rack but with you sand jockeys playing with that makes for a good runaway so just jack up your no load adjustment and try to keep it below 2600 rpms at top no load.


i got this off of a member on here but i cant rember his handle

 

[ameristar1]

Haven't had to mess with mine as yet. I push the button, engine fires up before it even completes one revolution. Pretty sweet!

I'd like to know anything that I could do in the future to 'improve' things though.

I was just looking at your truck Nameless; is that right? 318 Detroit getting 15mpg? How'd you pull that off? I thought these things were kind of thirsty.

 

[RustyRecycledT]

I was just looking at your truck Nameless; is that right? 318 Detroit getting 15mpg? How'd you pull that off? I thought these things were kind of thirsty.

It is only 'Nameless' because I have yet to come up with a name. In time (and miles) it will reveal its true nature to me and will be named. Make sense?

As for the 15mpg....I got lucky! Coming from Ohio to Arkansas, that was the fuel mileage it got coming home. I know a couple of other people with converted 4106s getting very similar mileage. In 'busworld' they refer to the 4106 as the 'sportscar of busses'. I'm pretty sure that with more experience with the 4sp tranny it could have done better. Shifting those things is NOTHING like shifting an 18 wheeler! I'm better now than I was, but there is still lots more room for improvement.

My father has a 4104 with a 671 in it. He's getting around 8-10mpg.

Here is 'Nameless'

 

[ameristar1]

I just saw what the 4106 looks like and the only thing I can come up with is the 6-71 has to work a little harder to push your dad's bus around. But still, 15mpg in a vehicle that big is impressive. And I bet you had to get used to the big pause between gears, like shifting a Mack 5 speed.
Is the engine in your unit fairly fresh, or do you have a lot of miles on it?

 

[DeepRoots]

you mostly need bigger injectors.

what kinda governor do you have? I'll email you some specs on them (and how to adjust them). I've got the manuals on cd.

 

[ameristar1]

you mostly need bigger injectors.

what kinda governor do you have? I'll email you some specs on them (and how to adjust them). I've got the manuals on cd.

I don't even know what the different governors are. This is my first trip into the innerworkings, and I need all the help I can get. Email the info to [email protected], and thanks DeepRoots.

 

[RustyRecycledT]

I just saw what the 4106 looks like and the only thing I can come up with is the 6-71 has to work a little harder to push your dad's bus around. But still, 15mpg in a vehicle that big is impressive. And I bet you had to get used to the big pause between gears, like shifting a Mack 5 speed.
Is the engine in your unit fairly fresh, or do you have a lot of miles on it?

That's what I figured too. The weight between the 2 busses is really close. Mine has the 8v71 and his the 6-71. My engine is not as worn as his either. Mine has a little over 60K on an out of frame rebuild.

As for the shifting, it seems like I could hard boil an egg between gears. Just seems like an eternity. I am getting better at doing it without the clutch though. That seems to make things happen a little quicker, but still nothing like any car I've ever driven.

I finally figured out how to post a picture, it's on the last post I made before this one. That is me, my boy, and 'Nameless'.

 

[ameristar1]

That's a good looking bus, and I figured that you probably have a fairly fresh motor in the old girl. No synchros in the trans just makes you more skilled, that's all. Before long you'll be short shifting that box with your eyes closed.
Maybe dad's unit needs a tuneup. Some things are universal like doing a compression and leak down on the cylinders, running an oil analysis just to see what the condition on the inside is.

 

[DeepRoots]

ok bro, well we're going offshore for 4-5 days and probably wont be in cell range.
I'll mail you a handful of pages on the governors, but it'll be big.... I've got the 71, 92, and 149 series detroit shop manuals on cd here on my boat if you ever need any pages/info.

Drew