3406B/C Frankenstein

Yes they are exactly what you need. They come factory in a 4CK 460HP PEEC. With the 3590 nozzles. The 4CK was a C style pump at 10.3 degrees timing. Which should line right up the the C pump that you have. Essentially since you already had the C pump it made since to convert you on to a C model but with having the narrow rods we had to use an early style C setup with the small pins.

That extra above the ring lands is what made the early motors handle all that timing down low. I was thinking one was wider or deeper than the other possibly the center cone was different maybe not I do know that if you run 21 degrees initial timing on them this is what you get

I have pulled countless sets of the later piston design out of 7FB’s and 4MG’s that were bone stock driven by quality hands and never seen a set that wasn’t cracked to hell, if running the early nozzles on them. I ran the right nozzles in mine but wrong pump and she was cranked up. That piston was right at a year old. Notice that the top had very little carbon and the top isn’t blued? That means no heat. 1 thing caused that and 1 thing only. Too much timing too early. When I converted my original PEEC pump to mechanical and dropped that 1/4 hole advance philosophy my troubles magically disappeared.

You just witnessed what a later pump on early pistons will do. Something had to be changed one way or another and it still needed overhaul on top of that. That whole fuel system has to match rotating assembly is key to longevity. I have given bad advice to good friends of mine from not knowing better and listening to people that thought they did. The feedback I got from a couple that are sure enough top notch as well as my own experience led me down a long hard road of discovery. Funny thing is I ended up right back where my mentor the man I learned everything from was trying to take me. You gotta have fuel and air to get one to run. Fuel at the right time if you want it to perform.

 

I don’t blame ya a bit for double checking. Being observant and attention to detail is the difference in doing it once or who knows. You definitely are observant. It’s amazing how many Pete’s get ruined by the simple air filter change. It friggin nuts ain’t it? I see quite a bit of it. Got one in here now that a half hole advance was it’s downfall. Very nice 94 model clean as a whistle with only 500k on the clock. Guy that has it bought it in 98 and uses it very little. Got one coming soon as it’s out the door that was got by wrong filters only they were to short and didn’t notice they weren’t touching the top. Then one after that that was worn out as a road truck 5 times then had the bunk knocked off and made it a quad. When I was young the guy that owned it at the time had a pump up sprayer by the seat with an electric solenoid out on hose in front of air to air he’d pump that up then flip it on to help keep it cool. (So he thought anyway lol)

You should have a helluva motor there you get it done. Catching them little details most won’t ever see. Again I don’t mind a guy being double sure. I just sorta typed out why I thought the way you’re going was the way to go. A guy can see the reason behind it that way and it sure beats following advice blindly so to speak.

Hey I also forgot to caution you it’s best to use the clamp together ring compressor. The tapered one piece is bad to bust the oil ring land. With plenty of caution the old expansion style will work just be sure it’s square and doesn’t drop in the liner on 1 corner. Any resistance pull it out and start over.

 

Bro, I've been reading your posts for years. Would you mind if I drive my Pete over and pick your brain?

 

Might be sorta like pickin your nose but if that’s what you want do……I reckon We be around

 

@wore out I recently bought a 91 378 Peterbilt 3406B with Engine serial number: 5KJ05173. This is the first semi we have bought/used on our farm so I know there not going to run like the new pickups. So we haul hay grossing around 55,000 Lbs. and to me the truck seem weak, if it had 80,000 I feel like it would be a turd. But this is what I don't understand the truck is making 35psi boost on hard pulls everybody has told me that is real good, exhaust temps will get up to around 900.
Does this sound right or I'm I just spooled from these 400hp 1200tq pickup trucks

 

Boost is just a number, you could have a boost leak….it could have a fuel issue just a multitude of things. Low power has a check list you go down. I will say if you expect it to move like a later model diesel pickup you have high expectations. I have a 5KJ in my 91…….bone ### stock other than a 178063 turbo which isn’t the best but it come with it. It only makes 24psi that’s it. It steps off with a cattle pot at 90k gross like it should. But it right.


I also want to say you can witch hunt your power problem till your blue in the face run it on a dyno see the numbers then go from there. If you don’t know what to expect or even if it has anything wrong……how do you make it right?
I also want to say at its age the amount of ####ery that some misinformed Jack ### could have done is unreal. I have also never not 1 time helped with a power problem that when I tell them what’s wrong they say haven’t said checked that helped a guy not not long ago that argued with me till the end and finally put a turbo on (32psi that can’t be it) that fixed it haven’t heard from him since. Possibly I’m becoming a butt hole possibility I’ve always been one but the first rule to fix anything is verify complaint.

 

Ok I will start off and look for boost leaks, Also I'm sure someone has messed with it in the past because is has a Cummins turbo not sure the size but says Cummins on it. Also if you was loosing boost from a leak would it not smoke more. On a hard pull around 1700 RPM and 35psi boost it has just a slight haze that's with the pedal to the floor all its got

 

I didn’t say it had boost leak I said it could. Cummins turbo well I’ll leave that alone too take it to a dyno and a good B model man I don’t want to hurt your feelings but that’s a can of worms without having here in person I’m not touching

A boost leak won’t necessarily cause excessive smoke, there is only one way to know that’s bock off the air inlet and air them up.