5.7 vs 6.4

[rzr6-4]

Neither have a ton of tire tread, and I don't like the wheels on either, so either way I'd be looking for a new wheel and tire combo regardless.

'13
60k on the motor is good, but as others have pointed out 240k on the rest of the chassis is getting up there. Rebuilt front end is good-ish, but factory track bar and steering box/shaft are known week points, so I'd want to know if it was a OEM spec refresh or aftermarket upgrade. Pinstriping from bushes is very unfortunate. And of course, still the 5.7

'14
I know I'm the odd one out here, but I like the blue and graphics. The obvious concern is the locker. He says it's just the actuator, I'd do some prodding to find out how he knows that that's all it is. I know you need bags, looks like a set can be had for around $500, leaving you $900 to fix the locker and you would be at the same overall price. 140k is no spring chicken, but if I were to be in the market right now, that's where I would be looking as well due to price point. Not optimal but nothing crazy.

If you can get it for $8,500, I'd be favoring the blue one.

 

[olyelr]

The ‘13 has 4.56 gears, while the ‘14 has 4.10’s. Also, the ‘13 has a 5 link front suspension and leaf springs out back, while the ‘14 has radius arms up front and coils out back.

Not sure if any of that matters to you, but something for your consideration.

And as far as the locker goes, its very possible it works just fine…they are very finicky and difficult to get to engage, even when they do work.

 

[DILLIGAF]

What if I go to Costco and my groceries are really heavy?

That's why I put Airlift 5000 and a cam in mine. Because it can't handle a bit of light work without looking squatted .

 

[ramffml]

No, they're not. 6.4 has forged steel crank, sodium filled exhaust valves, EGR (as I found out when trying to source replacement exhaust manifolds) to reduce in cylinder temps to increase durability, and of course more displacement. I think the torque curve tuning is different too - faster torque rise for towing heavy loads.

If you're interested in every detail, ask Rick. lol
Or google.

I haven't seen any reports of the 5.7 being worked to death in the 2500. I know you 6.4 guys prefer it over the 5.7, but neither of these engines are first class and neither of them are trash, I wouldn't get lost in the weeds trying to classify one as "car" and "truck" and just rubber stamping an engine based on that criteria.

The proof is in the pudding, how does it hold up in real life? The 5.7 was used for years as the base engine in the 2500, I wouldn't lose sleep over it if I wasn't towing max loads often.

 

[HEMIMANN]

I haven't seen any reports of the 5.7 being worked to death in the 2500. I know you 6.4 guys prefer it over the 5.7, but neither of these engines are first class and neither of them are trash, I wouldn't get lost in the weeds trying to classify one as "car" and "truck" and just rubber stamping an engine based on that criteria.

The proof is in the pudding, how does it hold up in real life? The 5.7 was used for years as the base engine in the 2500, I wouldn't lose sleep over it if I wasn't towing max loads often.

They would not have added more expensive truck features for no reason.
It does matter. Do you have a database for Hemi engine longevity vs. duty cycles? Me neither.

So I trust the engineer on this design aspects.

 

[Docwagon1776]

I haven't seen any reports of the 5.7 being worked to death in the 2500. I know you 6.4 guys prefer it over the 5.7, but neither of these engines are first class and neither of them are trash, I wouldn't get lost in the weeds trying to classify one as "car" and "truck" and just rubber stamping an engine based on that criteria.

The proof is in the pudding, how does it hold up in real life? The 5.7 was used for years as the base engine in the 2500, I wouldn't lose sleep over it if I wasn't towing max loads often.

The 5.7L is a general purpose motor and a quite good one. The 6.4 BGE is designed specifically as a truck motor with fleet sales in mind, though, with the 6.4 Apache being for the cars.

I wish I had an honest fleet rep to talk to, still, I'm curious if I could get expected lifespan differences. I know they have the data internally. I have some informational handouts (in .pdf) on my work computer, but while they talk about all the longevity upgrades and TCO differences, they held anticipated service life closer to the vest.

 

[ramffml]

They would not have added more expensive truck features for no reason.
It does matter. Do you have a database for Hemi engine longevity vs. duty cycles? Me neither.

We have forum reports. When's the last time you saw a dead hemi here on the forum that wasn't lifter failure? Lets be honest; this is the same engine (or "family of engine" if you prefer), with the same flaws... hemi tick. If I had to bet on what takes out a hemi, regardless of how its being used, I'd pick "munching lifters" every time regardless of 5.7 or 6.4, or even 6.2 for that matter.

So I trust the engineer on this design aspects.

Yes, the engineers designed the 2500 to have high max tow ratings that can only be achieved with the extra power of the 6.4. That doesn't mean the 5.7 is going to explode, they also designed the same 2500 to use the 5.7. Do you trust that decision, or only the decision that put the 6.4 in it?

Remember also this is a power wagon, with OP's requirement of towing 6000 lbs or less. 1500's can tow more than that thing due to suspension. The 5.7 will do just fine there.

 

[ramffml]

The 5.7L is a general purpose motor and a quite good one. The 6.4 BGE is designed specifically as a truck motor with fleet sales in mind, though, with the 6.4 Apache being for the cars.

There are slight differences in the 2500 5.7 vs the 1500 5.7 as well. Possibly different cam, definitely different tuning as its down on power. So in the 2500 the 5.7 was tweaked for more severe duty cycle, that is for certain.

Lets define "truck engine". Because there are no set in stone requirements. Looking at the other brands though, one thing they all have in common is iron block NA v8, just like the 5.7. The GM 1500 v8s are aluminum block, the 2500 v8 6.0 and 6.6 is basically "same engine" (or "engine family") as their 5.3 and 6.2, but with iron block instead. So for GM, "iron block" is a pretty good criterion. But neither GMs 6.0/6.6 nor Fords 7.3/6.8 have a displacement on demand system like MDS, which is a fuel saving thing; maybe those guys look at the 6.4 and say "lol, MDS, that belongs in a car".

Where do we draw the lines here?

Do we get the warm and fuzzies first for an engine, and then make the rules to include/exclude what we want? Or do we look at the last 10 years of actual history and use in the real world and realize that the 5.7 does very well from a longevity standpoint, though obviously down on horsepower vs something like the 6.6 and 7.3.

 

[Docwagon1776]

Where do we draw the lines here?

For me, it's pretty simple. The OEM says "we designed this for trucks". How they get there is largely irrelevant to me, nor do I poo-poo trucks with a general purpose motor or a GP motor modified for truck use. GM/Chevy's 350 was the epitome of a general purpose motor, it got tweaked and put in everything from sports cars to RVs.

I like the 5.7 and the 6.4, but I'd rather have the 6.4. However, of the two trucks the OP is looking at (while I'd honestly choose neither) if I had to pick one or the other I'd go with the 5.7 in this instance.

 

[Redthies]

No way I'd get a 5.7 in a 2500 (owned a PW), in fact I probably wouldn't even do a 6.4 unless it had the 8 speed. Also if you plan to daily drive, plan on stoping at every gas station along the way, I'm sure you are not concerned about mpg but constantly having to stop and fill up gets old quick, the range is terrible.

I know you don't want to hear it but but ignoring the reality of the situation isn't going to make it go away. A slide in is a Bad idea in a 2500 and an even worse idea in a PW. That high center of gravity is going to cause way too much body roll with the PW's soft suspension. This is coming from a former PW owner so not making this up.

.

You’re right on all accounts. While I appreciate your input, you (as you know) failed to heed my caveats of A, I don’t give any chits about fuel economy, and B, I know far more about campers in trucks than a huge percentage of the population. I have a set of brand new 2013 3500 leaf packs (complete suspension actually ) sitting in my shop. I’ve owned about 22 Dodge or Ram HD trucks. 998% of them have been diesel though, so that’s why I’m here asking if the 6.4 is that much better than the 5.7 for my future hunting beater.

 

[Wild one]

The truck 6.4 is alot more engine then the 5.7 is.It uses the same basic heads as the Hellcats use ,that are far superior to the eagle heads on the 5.7,and as stated has a forged crank,while all 5.7's use a cast crank. It's also designed to run on 87 octane at full load for 12 minutes with out self destructing. Out of all the NA later model VVT Hemi's it has the most robust pistons,and valves. On paper it's 410hp doesn't seem like much more then the 5.7's 395hp,but it's torque under the curve blows the 5.7 into the weeds.
Both are N/A hemi's but by no stretch are they comparable.I wouldn't buy either one as the PW isn't much more truck then the 1500 is as far as payload goes,but if i had to choose one or the other,i'd spring for the one with the 6.4,as it'll probably hold it's value better then the other one will

 

[Redthies]

Was the 5.7 in 2500s ever an MDS engine? I’m told the ‘13 engine is not an MDS one. Is the 6.4 an MDS engine?

The owner of the ugly blue truck also states he was “going to re-seal the diff when he changed the actuator, but then bought a different truck”. This statement does not give me the warm fuzzies.

 

[Redthies]

Neither have a ton of tire tread, and I don't like the wheels on either, so either way I'd be looking for a new wheel and tire combo regardless.

'13
60k on the motor is good, but as others have pointed out 240k on the rest of the chassis is getting up there. Rebuilt front end is good-ish, but factory track bar and steering box/shaft are known week points, so I'd want to know if it was a OEM spec refresh or aftermarket upgrade. Pinstriping from bushes is very unfortunate. And of course, still the 5.7

'14
I know I'm the odd one out here, but I like the blue and graphics. The obvious concern is the locker. He says it's just the actuator, I'd do some prodding to find out how he knows that that's all it is. I know you need bags, looks like a set can be had for around $500, leaving you $900 to fix the locker and you would be at the same overall price. 140k is no spring chicken, but if I were to be in the market right now, that's where I would be looking as well due to price point. Not optimal but nothing crazy.

If you can get it for $8,500, I'd be favoring the blue.

I agree on the tires and wheels. The 20s on the black one are actually at about 85-90% tread. I’m sure I can trade them off / sell them for something better. They are hideous and I want to run 35x12.50R17 and probably on a factory Dodge wheel. I’ve seen a few sets of the newer PW wheels with new 35s on them for good prices.

As much as I hate that blue, if I could get rid of the graphics it would be a bit more tolerable.

 

[Redthies]

Remember also this is a power wagon, with OP's requirement of towing 6000 lbs or less. 1500's can tow more than that thing due to suspension. The 5.7 will do just fine there.

And remember, the OP also has a complete brand new suspension out of a ‘13 3500 ccsb so he can turn the 13 PW into essentially a one ton by swapping out the leaves and putting load range E tires on it.

 

[mtnrider]

And remember, the OP also has a complete brand new suspension out of a ‘13 3500 ccsb so he can turn the 13 PW into essentially a one ton by swapping out the leaves and putting load range E tires on it.

Then why are you even asking about a 6.4? Your leaf spring idea will limit you to the 13 only.

.

 

[Redthies]

Then why are you even asking about a 6.4? Your leaf spring idea will limit you to the 13 only.

.

I don’t have to use the 3500 stuff, just saying I have it. I said in the first post or two that I didn’t want to take this to payload or fuel economy, yet that’s where other posters continue to take it.

It sounds to me like it’s 50/50 on whether the 6.4 is significantly better than a 2022 era 5.7 crate engine. I mention the fact that it was purchased from Ram and installed in ‘22 so it’s understood that the engine has all the updated parts in it, vs a low mileage used engine from 10 years ago that may not have all up to date internals.

Does the 6.4 have any “known” issues? Or more specifically, any that aren’t shared with the later 5.7s?

 

[HEMIMANN]

If I needed a grocery-getter, I'd get a Tesla "truck" 'cause they can barbeque ribs in the store parking lot.

 

[Wild one]

I don’t have to use the 3500 stuff, just saying I have it. I said in the first post or two that I didn’t want to take this to payload or fuel economy, yet that’s where other posters continue to take it.

It sounds to me like it’s 50/50 on whether the 6.4 is significantly better than a 2022 era 5.7 crate engine. I mention the fact that it was purchased from Ram and installed in ‘22 so it’s understood that the engine has all the updated parts in it, vs a low mileage used engine from 10 years ago that may not have all up to date internals.

Does the 6.4 have any “known” issues? Or more specifically, any that aren’t shared with the later 5.7s?

The 6.4 will get better milege,and will blow the 5.7 into the weeds as far as power goes.You're very gullible if you think MDS has anything to do with engine longevity.Sounds like you've made up your mind already,so why are you asking for our opinions

 

[Docwagon1776]

It sounds to me like it’s 50/50 on whether the 6.4 is significantly better than a 2022 era 5.7 crate engine.

I think if had that conversation in a vacuum, you'd find a stronger siding for the 6.4L. In this case, the other variables in the two trucks you presented are muddying the waters on the advantages of the 6.4, especially with your use case not being particularly demanding. I'd rather be down on HP and the durability difference is weighed against a much lower mileage 5.7L.

That's why I said I'd actually not buy either of those, but if they were the last two trucks in existence I'd go for the 5.7L one and budget for a transmission. Previous owner seems less sketchy and it's better maintained than a golf balled PW with unknown axle issues and a retarded PO.

 

[Ritchie_Rich]

Hard pass on both trucks for me.