3406B/C Frankenstein

Ok the timing by the spray pattern is not great. But sorta not that far I don’t think. Have those nozzles pop tested so you know if 1,2&5 had holes that are pissing not spraying. The thing is those holes are from extreme heat in the cylinder. Large droplets of fuel hit that piston crown when it’s right at the bubbling stage and start a “spot” . From there it just keeps digging. It could be from rack postition just easy as anything. More rack causes bigger droplets Notice that your holes are at different stages of development. See how the surface is really rough? That means it’s from multiple get warms. That roughness is how they dig. The little pieces burn off under normal combustion. Timing usually has more cracks across the crown and the spray pattern will be up the cone or outside the bowl depending on which way you’re out. The bottoms of those pistons are burnt so she’s had a big #### fire in the cylinders at one time or another. One piston had contact damage so get a turbo. That one is shot. Most likely you can’t see it without taking it apart. Also the start screw on the nose cone of advance needs to be around 1.1 inches as a starting reference. That truck come outta Arkansas. Now my competition i won’t say names believes in pin timing a C then backing the start screw way out where they start advancing immediately. Now there is an art to that to keep from breaking the cover. I’ll post a couple pics to show you where your contact damage on exhaust wheel is going to be and how the tape sits on cone to get 1.1 all CAT says is from back of nut. Well depending on interpretation that can truly be either side. And if you put it on wrong side you’ll crack your cover putting it on.


The C pumps don’t change the feel of the seat of your pants like the B pumps do by backing screws out. Some say they need a B govnor housing which is a wives tale doesn’t help. Others say they don’t flow as much which is farce as well. Now I can’t explain why the B yiu can feel difference in on 3 rounds and a C you sorta can’t. This is an older 7FB nose cone so it looks different but the principal is same

 

Need to check with @wore out on the turbo, but unless you are running local stop and go, I wouldn't go with the 177148 waste gate. That 78 mm 1.45 might be just a touch laggy but it sure seems to me like the best choice out on the road, and mine doesn't cavitate when you lift quickly to downshift.
I got this one from Momentum Werx.

 

I personally am a fan of a 78 1.45. I sometimes think the 177148 would be good for dump work. Short stuff stop and go but I’ve never run one cause I’m hard headed. @Oxbow has run the 177148, the 78 1.45 and the switchblade. He is a lot like me in the peculiar about his truck and the way it performs. Doesn’t let any Jack keg under the wheel. As a contractor he does a little of all of it. Real world experience is worth way more than me looking at a turbo map. So if he says run the 78 1.45 non gated that’s exactly what you need. I will say also that’s always been my go to.

 

Since he’s local, wouldn’t the 1.32 spool up quicker ? It worked fantastic on my 5Ek. Never created any heat. Hence, I don’t know how it would work on his set up.

 

I used to think that the 1.32 created heat, till I seen a dyno comparison of the exact same motor pulled 2 hours apart with the only change being exhaust housing. The temps, were really close, however the 1.45 did make about 10 more horsepower over all. Not enough to write home about or even notice in my opinion. The 1.32 does spool a bit faster.

This comparison was on a 2WS E model done In Arizona. So today my only reason for recommending the 1.45 over the 1.32 is the 1.45 doesn’t stall the compressor wheel when you let up on it. A B does seem more moody about that being honest and that could strictly be in my head.

 

So, I remember distinctly about 15 years ago when my stock turbo on one of our B Models began slobbering oil, and I purchased the 177148. Wow, what a difference in spool up and reduction of smoke! At the time I thought that was the greatest improvement for a B model ever! Since then we have tried different things on one or the other truck with a B model.

It is interesting the comparison that @wore out mentioned between the 1.32 and 1.45 didn't produce much more heat. Was the 1.32 waste gated? Anyway, our expereince in having swapped turbos on a truck with no other changes is that, at least with the wastegated 1.32, we did build heat more than the 1.45. The difference being that on the 1.32 on a warm day we could get over 900 degrees pretty easily, but on the 1.45 we can't get it to 900. The actual temperature may not be very accurate, but the comparison should be good as it was the same pyrometer and thermocoupler on each turbo. I suspect that the elevation that we run in exacerbates the problem compared to testing near(er) to sea level. Other differences may be that when we are pulling heavy on a long hill we will usually choose a gear that puts us near 1700 or more rpm. The 177148 seemed to really shine at lower rpms, especially below 1500, so that might be a part of the difference in results. The 177148 always felt like it died out above 1800. Watching the boost and pyrometer it would seem like when the wastegate opened the boost would top out at ~26 or so, and the exhast temp would act different than the old days, where pulling at too low of rpm is when we would typically see higher temps. I'm just talking out my ### as to the "why" of all of this, but that has been my experience. The Switchblade was the worst of all three. I thought it was a great idea, but it sure didn't work well for us at all. I think the problem was mostly related to their gate hanging up one way or the other, but I wasn't happy with it.

We did have to replace the turbo on our 6NZ (@475) in the dump truck, which I assume is just about identical to the 177148, and left that as is because of not knowing if tuning would be required to change it out. To be honest, the dump truck feels like a sports car when you compare throttle response, but loaded at full throttle I'm not sure that it pulls much if any better than our B models. Kind of like the difference in driving a Big Cam to a B model. The Big Cam feels way sporty, but get on a long pull and the difference shows itself pretty quickly.

Anyway, for local dump truck work I would still go with the 177148 if it were me. I would be concerned about disconnecting the wastegate and would leave it functional. It seems to me that the risk of overspeeding it isn't worth the gain, if there is any gain. Even though you may get more boost, if the air temp goes way up for that extra boost you may not be actually getting anymore oxygen? I don't know - beyond my pay grade. On that note, the wastegate mechanism on our 177148 rusted off last year, so we replaced it with another 1.45. The turbo part of it is fine if anyone wants it.