Cummins 4BT & Diesel Conversions Forums banner
1 - 19 of 19 Posts

·
Premium Member
1972 F250 4x4, 78 d44, 3.55, np205, 200hp 4bt nv4500 in progress
Joined
·
62 Posts
Discussion Starter · #1 ·
In the process of getting a Bosch VE IP / 3200 spring / fuel pin from Badger Diesel. Fred has recommended marine injectors, saying there would be a restriction not running them (running stock injector). I remember reading stock injectors are fine for a 200hp build. This would be for a super hx30 intercooled. Needing reliability and was thinking marine running more fuel would heat things up and not be reliable and might reduce engine life.

Any reason I should go stock instead of marine?
Thanks!
Sam
 

·
Registered
Joined
·
2,418 Posts
I'm thinking that if it were ME I'd go with stock for where you want to be, but you are probably gonna be right at the point where it could go either way.
I'd lean towards stock because they are the right fit for 98% of your driving time larger might JUST be a better fit at WOT under full load but not so much from idle to peak torque,
as I see it you spend much more time there that at WOT under full load.
I try to play to a platforms strengths when building it and the b series strengths are the front side of the torque curve so mod for there to get the most out of it...$.02
 

·
Registered
Joined
·
75 Posts
In the process of getting a Bosch VE IP / 3200 spring / fuel pin from Badger Diesel. Fred has recommended marine injectors, saying there would be a restriction not running them (running stock injector). I remember reading stock injectors are fine for a 200hp build. This would be for a super hx30 intercooled. Needing reliability and was thinking marine running more fuel would heat things up and not be reliable and might reduce engine life.

Any reason I should go stock instead of marine?
Thanks!
Sam
If you’re not already set on that fuel pin, the one that the hungry diesel offers is great. I have one in my swapped van and in my 4bt boat. Lots of good info and support on the 1st gen Cummins Facebook group.

You have to wade through a bunch of idiots posting but there are several very knowledgeable guys chiming in there that might have some answers for you regarding injectors.

Are the marine injectors the right spray angle for your pistons?


Sent from my iPhone using Tapatalk
 

·
Premium Member
1972 F250 4x4, 78 d44, 3.55, np205, 200hp 4bt nv4500 in progress
Joined
·
62 Posts
Discussion Starter · #4 ·
Thanks Guys. Eggman when you say stock inj are good for front side of torque curve that’s the left side? This is all keyboard pounding for me at this point without any experience but that makes sense that a marine injector would be set in place for wot performance.

Are these 3908155 pistons big bowl?

Wheel Tire Automotive tire Crankset Bicycle part
 

·
Registered
Joined
·
75 Posts
Going off these photos. Looks like you have non IC pistons that utilize a 155* spray angle so the marine injectors will be compatible. pictures of 12v intercooled piston compared to nonintercooled piston - Competition Diesel.Com - Bringing The BEST Together

But honestly if you haven’t done many other mods, start with the fuel pin and free pump modifications and see how you like it before spending $$$ on injectors.

Funny this came up. I’m about to put my marine injectors back in the 6bt van today. Removed for testing when I thought I had a stuck one but it ended up being a failing fuel shut off solenoid.


Sent from my iPhone using Tapatalk
 

·
Registered
Joined
·
2,418 Posts
The "marine" injectors IIRC the next size up stock are 4x.012" and marine 5x.012", 4x.012" injectors were a good match for me at the 200HP+ level and more than capable of fueling to 30psi at the manifold without being hot/dirty off idle. I can not see any gain from going larger at that power level, however when I went to compounds on a fresh overhaul I did move up to 5x.012" but I'm now fueling to 45psi and never see below 20psi with even modest throttle input so they are clean and cool.
I do not "think" that with a single that is gonna be living in the real world which is 1,500 to 2,200 RPM would benefit from larger than stock injectors.
 

·
Registered
Joined
·
2,418 Posts
Studs, Cummins head gasket on freshly surfaced head and block I also run closer to stock injection timing that most do.
 

·
Registered
Joined
·
2,418 Posts
I went with ARP as they have a quality reputation and do not break the bank.
 
  • Like
Reactions: Justgosurfin

·
Registered
Joined
·
2,418 Posts
I didn't and so far so good, FWIW my engine machinist would not surface the head and block until he had the gasket I was gonna run in hand he had different finishes depending on the Mfgr.. I do not know if he was just blowing smoke but it really mattered to him seeing as it was gonna be running higher boost, now as a machinist of 40 years after talking to him at length and touring his shop I had decided he knew his $#!+ so I followed his guidance and that was ~ 75,000 miles ago.
 
  • Like
Reactions: Justgosurfin

·
Registered
Joined
·
12,542 Posts
Eggman, have to be careful using the term marine injectors. There are 2 types of the marine 4bt engines. One with the VE pump were only 150-160 HP and I don't think they had anything bigger than the 4x.012. Only the 250 HP engine with the P7100 got the 5x.012 and those would be the wrong pop pressure for a VE pump. You have those in your VE engine but those are made up using the correct pop pressure.

Stpackard, your pistons appear to be ones referred to as marine style bowls. One possible part number is 3802100 or 3907156 and there may be others. Those are often used in rebuilds because they are very cheap. True marine pistons are a bit different. First off, they have a lower compression ratio than regular ones. Second, they have 2 keystone rings instead of one on regular units. And some models come with coated skirts like the ones shown below. Also, they are a heck of lot more expensive. Unless you plan power going toward the 250 HP area you don't need bigger injectors than stock. If you plan to move up toward 250-300 HP then you will need them and they must be matched to the VE pump.
 

Attachments

·
Premium Member
1972 F250 4x4, 78 d44, 3.55, np205, 200hp 4bt nv4500 in progress
Joined
·
62 Posts
Discussion Starter · #14 ·
Thanks again everyone. I don’t think I’m going to need 250+, don’t even know if I’ll need 200hp for 72 f250 4x4 but then I have no clue, this project has been all conjecture up to the point it’s able to be fired up/driven with butt dyno. I want to get a feel for baseline with the super hx30w/IC/hvlp fuel pump then move up from there so I think stock injectors sounds right. Appreciate the advice from those who’ve been there/done that.

I just tightened up the carb bolts on the fe 390 and it runs smooth and quiet, butt dyno reads excellent power. This cummins/nv4500/3.55s is a gamble for me to be eventually swapping out a well running v8 390 11-12mpg to a 4cyl cummins, but it seems (hoping) the cummins will at least be at the same power levels and increased mileage at the specs I’m doing.

I haven’t been able to tell if guys in 3/4 and 1 tons run twin turbos or super hx30w out of necessity for baseline driveability or if they do it purely for towing, thrill, or performance level. At a time I was in a phase of running bias ply 35’s and now that that’s out of my system low rolling resistance AT 32’s run and look fine, keeping it simple. 5830 lbs on the drive up farm scale and I realize a 6bt would be the ticket but am turned off by the weight on the front end and. I like the 4cyl simplicity and compactness hoping it’ll measure up to the 390 and be reliable for a long time.
 

·
Registered
Joined
·
2,418 Posts
the 200HP 4BT was to me superior to the 390 that was built to tow in every way.
 
  • Like
Reactions: stpackard

·
Registered
‘97 F-250 4bt/ M5R2
Joined
·
19 Posts
Packard, I am most surprised that you are able to eek 11-12 mpg out of the 390! I believe you will be thrilled with the 4bt at 200hp. My project truck is using the 44mm hx30 and has plenty of power in my opinion, for what the truck was built to do. I think you’ll find that engine is not the weak link in your setup.
 

·
Premium Member
1972 F250 4x4, 78 d44, 3.55, np205, 200hp 4bt nv4500 in progress
Joined
·
62 Posts
Discussion Starter · #17 ·
Levis, Thanks for the encouragement. I grew up hearing my parents jokingly say a key to happiness is low expectations, so I think I will grimly set them accordingly running a 4cyl in a 3/4 ton and if it’s better than that, ok.

Were you able to decode your esn and are you running the csx IP that was on your engine?

Packard, I am most surprised that you are able to eek 11-12 mpg out of the 390! I believe you will be thrilled with the 4bt at 200hp. My project truck is using the 44mm hx30 and has plenty of power in my opinion, for what the truck was built to do. I think you’ll find that engine is not the weak link in your setup.
 

·
Registered
Joined
·
12,542 Posts
Your fuel mileage on the 390 sounds about right. I had a '73 F100 4x4 with the 360 and the best it would do was 13.7 MPG city or highway. If you tune a 4bt to 200 HP you will have more torque than that 390. Be more like you put in a 460 V8. A 4bt weighs about the same as a 460 too.
 

·
Registered
‘97 F-250 4bt/ M5R2
Joined
·
19 Posts
I ended up buying a new pump in order to have the aneroid, and the cold start. Pricey but worth it. I did not bother with the serial number since most everything has been changed by now.
 
1 - 19 of 19 Posts
Top