The original 7FB engine cam had a really sharp ramp and was known to eat lifter rollers. With the 4MG came the 3013 cam it had less of a ramp so that problem sorta disappeared.
As far as the rotating assembly up to the 5KJ they all had narrow rod journals with V style rods that had to go 1 way. In 1990 the 5YG PEEC was introduced at 460Hp. It had a larger rod journal with a rod that will work either way. That said dowel pins go to the front. The wrist pin stayed the same and in my mind this is the strongest combination. With the 3ZJ came the 12 point head bolts and the larger wrist pin. To expand on why I like the smaller pin both rods are marked 9Y-6048 but the larger pin is bored out and has less meat around the pin, same as the piston. As far as 1 any better than the other…..I have seen early JWAC 400 B models with a 14613 trans and 3.70’s run 2250 all night long night after night keeping up with a long legged E model and 15. I have seen a few with crank trouble but never had any myself. I think preventive maintenance and timing are the life of one. That advance em half a hole #### is just that ####. The early motors were 24 degrees and the last ones were 9.5. Nothing replaces a meter know where you’re at.
I run a large pin rod now only because the piston and nozzle I chose to use that’s the only way to get it. Your nozzle has to match your piston crown and your pump has to match the nozzle pressure. If you’re running a nozzle and piston that was at 18 degrees factory and you advance a 9.5 degree pump cam it will work……but not like an 18 degree pump cam. the pump cam I run they do not make any more. It mirrors the 4 MG in all aspects but is a C model so it uses dual scroll plungers and barrels which have a higher crack pressure. In turn better atomization. That rumor that a B pump flows more fuel is only that a rumor. With 2200 psi the fuel is in much more liquid form or bigger droplets the bigger the drop the bigger fire it makes but not power it’s a negative effect and more likely to make trouble. The right pieces a C pump will circle a B. My C is flowing enough fuel that a 78/1.45 housing will not clean it up. My compound set up does. Many see my hood up and immediately tell me how stupid I am. I’m sure I do look that way.
I run my factory 5YG cam with a couple put back for hard times. The 7048 is about the only cam left that CAT offers and it’s not bad. The other is for an 8PN and while I can’t remember its number I remember you do not want it.
I don’t mean to take anything from the B. There is nothing better. I know people that stress over their 3ZJ being a b or C. In reality there are differences but the main difference they all stress over is rod journals and all the 3ZJ were large. The B 3ZJ were 11 degrees timing and 15.2 compression the C was 9.5 and 16.4. Even those numbers are generally speaking as it was a change over motor and anything goes there. I don’t think a narrow journal is anything less than a wide. The reason I run what I do is again I wanted to use a certain piston and nozzle combo. Im sure you can look back and todays opinion will vary from 2 years ago. I keep an open mind and like to think im always learning. Also trial and error. Formal education is pretty slim for me. The school of hard knocks has been very informative however lol. No matter what you do or how you slice it a B will never be an E, C15, or Acert. They are #### good engines though. The C model is also the only engine known to be out of production for 20 years only to be brought back because newer tech wasn’t as good. Not sold in North America of course but still pretty bad ### I think.
Many make general statements of BS about which is best or worst. I think they are like a Swiss watch and very particular. However getting one right you won’t find anything better. I know very little in the grand scheme of things. I do know that mine gets 5mpg pulling a pot in the Midwest. Has no trouble on 80 in the wind. Maintains 200 or less on extended pulls at 85 and 90 gross in this heat with what I do that’s rare. It’s proven dependable thus far once I got past the hump of CAC hoses. That was a challenge for another conversation. However I was trying to do something that was not ever intended to be done. Not saying it hadn’t been just CAT never meant for it.
I was asked a lot as a kid “Son you know the difference in a white CAT and a yellow one?”
I always replied no to which I was told “You can make that white CAT run”
That is something I will believe till they put dirt in my face. Nothing like a white B model. Just doesn’t get any better.
3406B turbo upgrade
Discussion in 'Heavy Duty Diesel Truck Mechanics Forum' started by mile marker 27, Jun 12, 2023.
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spsauerland, Feedman, Flint1 and 2 others Thank this.
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Preciate the read. I’m gonna have to try and screen shot all that. I want mine to be reliable, run but not race. I’m getting burned out on working on my FIL’s Cummins so, getting an education on a cat is more interesting. What driving me nuts, is the fact I’m sure there’s been someone in the pump of this truck and the baws I bought it from said, the guy who they bought it from put a new head on it, different nozzles during a rebuild. The truck was a local truck and they bought it for a backup, to some newer E7 Mack’s. It was a crying #### shame a couple of Kansas red legs thought so little of it. So, some chits been tinkered with I think but I don’t necessarily know how to find out. That engine tag basically tells me that, the valve cover came from a 4MG.
Was cat painting those engines white for Pete, or was Pete painting them white after they received them? What time frame were engines getting this paint job? -
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I had a 7fb that was white. I think the 7fb were the last. Which is what he means. -
Jubal Early Times, wore out and Oxbow Thank this.
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CAT sent a few of the 3408’s with chrome covers from the factory, muffler style heat shields on the manifold.Feedman, Jubal Early Times and Oxbow Thank this. -
Friend of mine in Norwood Mo, has an ‘80 model “A” with this in it.
Diesel Dave, Jubal Early Times, Feedman and 2 others Thank this. -
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Here’s some numbers on my existing turbo. Not sure if you can make anything out of it but there’s no tag on it. IMO, this turbo has quite abit of lag particularly once I get up on 13, 14 and 15th gears. That said it’s a dump truck, with a 15 OD and 3:55 rears. Probably the only dump truck in these parts with this combination.
Attached Files:
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