Everything Wrong With the 4BT Cummins (It's OVERRATED)

Because of it's versatility, reliability, performance, and mostly importantly, it's size, the 4BT Cummins has become pretty popular in the automotive world as an engine swap for Jeeps, trucks, buggies, rock crawlers, and even the occasional little sporty car.

That being said, no engine is perfect, and while the 4BT Cummins is a very reliable engine, it's been put on pedestal by Cummins fans much like like the 12V and 24V Cummins. So, it's time we ignore all the good things about this little engine and instead look at everything wrong with it.

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[Dustrunnersauto]

What do you think? Is the 4BT overrated or not?

[speed]

4BT is underpowered and overpriced imo, id rather swap an OM606 because just as reliable and much more power.

[bqbfevv]

One thing that you did not mention is that the fuel mileage is really good even in a full sized truck and it is small in size which makes it easy to work on.

[JrsGaragePa]

One thing people miss on the old diesels, there's no ecm, little to no electronics and full mechanical control. It's far easier to adapt those engines to any application than an ecm engine. There's also the difference in mechanics, old school loves being able to diagnose without a scan tool, were as newer mechanics don't know anything without the tool. I prefer old mechanical injection for It's simplicity, I don't want to spend thousands for all the electronic gadgets when it's overly complicating the situation.

[sammysamsam]

I’m a 30 year veteran mechanic and I daily drive an old Ford with a p-pump 4bt. Best engine I’ve ever owned. I run the piss out of it in a 1 ton 4wd truck and it always starts and delivers as much torque as the 460 it replaced with more than double the fuel economy. Need I say more? The shortcomings are only realized by people who are used to living in a bubble. I’ll probably have this rig going till the end of fossil fuels and you’ll probably have owned 4 trucks by then 😝

[rubenvor]

Great video, al so true. The 4bt is great and does great mpg, but its popularity has made it irrationally expensive.

[thecaptain]

I've never seen anyone buy a 4bt for 16k, maybe 1 to 2 k for a decent block and a few hundred more for a rebuild kit.

[davidmattice]

the best Engine Cummins ever built was a N14. hands down! and I am a diesel mechanic now for 30years ++++

[sebastiant]

You can get a 1.9L or 2.0L VW TDI engine weighs about half costs less then $1000 and you can just program the software to have more power then the 4BT.

[tacotimeracing]

My 4bt is out to go into another project but what started out as a get good fuel mileage project turned into one hell of a daily driver/toy (as most projects with good intentions do) The last dyno pull it made at an event was 525HP/936TQ with a little over 100lbs of boost with compounds. I love the little motors, but I will say it will shakes like a paint shaker! Besides all the trans parts I went through, I had several front covers crack, broken motor mounts, and the truck just was much looser after several years of driving. I have always told everyone afterwards that if a 6BT will fit do it... Love them 4Bs though!

[cnf]

They are very good little engines…but they’re so damn expensive now, I don’t believe it’s worth it. To give an example, people have been swapping 4BT’s and 6BT’s into Jeep’s for a long time. To swap a 6BT into a jeep, you have to stretch the engine bay by 4 or 5 inches I believe, which is obviously expensive and time consuming…a 4BT on the other hand fits great…but, because of how much the 4BT’s cost, I believe it winds up costing about the same to swap a 6BT in, and then you’ve got 6BT horsepower and torque.

Basically, if it weren’t so damn expensive, every ‘what engine should I swap into my car?’ Conversation would go ‘what engine should I swap into ___’ ‘a 6BT.’ ‘It won’t fit’ ‘a 4BT.’ Left stock, they’re a bit gutless, but bombproof, and you can turn them up to the moon just like a 6BT if you want to.

[jbmorris]

One more thing… the R2.8 crate for about the same price (or a little less) comes with a fuel pump, fuel filter, oil filter, vacuum pump, alternator and other accessories helpful for a swap. It’s essentially almost a drop in with the exception of dealing with motor mounts (and obviously engine bay and chassis clearances), especially if it were to be a daily driver. The R2.8 is also >200 lbs. *lighter* than a 4BT.

That just something I felt was helpful to state. Take that how you will folks.

[nexxtgenfarms]

The 4bt and 6th were designed to be cheap, but due to popularity it has become more expensive than it’s worth

[fastback]

Back in the days we bought bread delivery trucks from auctions for $3k and took the 4BTs out. Cut up the truck for scrap aluminum and got our $3k back 👍

[jameseroh]

My family has diesel powered Ram pickups. Both 1500 & 2500. To bad that when common rail technology was introduced with the increased power. That a 4cyl diesel was not a factory option. If a medium duty ZF-8 speed had been used, besides the G56 transmission. The fuel economy would have been awesome. And the power would have been fine, since a mechanical injected 5.9 put out less power than the 3.0L Ecodiesel.

[MrYahoo]

I have a 4bta in a piece of logging equipment, that thing is extremely reliable, starts 1/4 turn wether it’s zero or 90 out, good on fuel etc

[Freddie]

I'm sure with the P pump you can get some decent power figures if you really wanted especially when throwing a larger turbo at it but these engines honestly don't really have a place outside utility and equipment applications. That being said, I have always wanted to throw one in a half ton truck just to see what I could do to it.

[worldssickestmedia]

I own an engine shop. And all engine fan boys do this. Cummins guys. LS guys. K24 guys. 2JZ guys. All of them. They pick and attain the engine that they oh so desire. Then they talk about those engines like they are the end all be all of the entire universe. Like the engine they love is the baddest shit ever created in the history of the world. And of course any car will instantly and magically be transformed to the best car imaginable if you do that kinda engine swap. What follows is a bunch of fairytales and folklore about their engine, like even with a stock bottom end and 250k miles out of a junkyard that engine will make a million "reliable" horsepower. And every race engine in the world is designed after that engine. And if you mention any of the short comings that engine might have it's just absolute blasphemy. Like you insulted their mother. They just absolutely can't believe you would say such things. Cummins guys definitely fit that bill.

[miketee]

As a life long Jeep lover, RPMs and weight reduction are our friend. I would consider the 4BT a downgrade from the Jeep 4.0. The LS is probably making people tired of hearing about it but there is good reason. When you can't even spin your 42s fast enough to clean the tread out you may wish you had went for a gas motor.

[joeyscleaninglady]

most reliable engine in the world. Drive mine daily no issues at all plus with timing gears vs belt/chain it is basically a no maintenance engine (other than oil changes). I guess the 345 IH engine is similar but that is a gas hog and requires a carb or electronics to make it FI. Name another engine with no electronics (3 wire start) that only requires oil changes and can be run on road and make good power?