Learn me Chrysler's 3rd Gen HEMI engines

I'm planning for a new build to use a V8 for all the typical reasons, but I want to keep away from using an LS for the- admittedly poor- reason of "DURR ANOTHER LS SWAP DURR". I remembered that Chrysler has their 3rd gen HEMI engine that's roughly in every local bro-dozer and challenger here in the Midwest, but I realized that I know next to nothing about this engine or it's aftermarket. Can canyone fill me in? And is there any appriciable reason to use one over a different engine for a turbocharged/boosted build?

Well for the starters it’s really a hemi in name only unlike the previous two generations it doesn’t have true hemispherical combustion chambers.

Not a guru, two issues I have seen is the wiped cam / lifter failure (hit or miss) and broken exhaust manifold bolts in the trucks ( certain years) . Only thing I would recommend is changing the valve springs if you plan to wind it up a lot. Most seem to hit 200K without issue.

Paul B

When they first came out, engine management for swaps was an absolute bastard.

Appleseed said:

When they first came out, engine management for swaps was an absolute bastard.

That’s all Chrysler products.

For reasons I am not entirely clear on, they seem to hydrolock a lot due to a failed intake gasket.

I'm working from very faulty memory but I think the magazine "Mopar Action" had an article about this a few years ago.  You might try their website.

i 'think' the cam wipe/lifter issue was on the later engines that had some displacement-on-demand type deal, or i could be totally wrong on that.

They seem to be pretty stout engines though. A cam swap is about as simple as doing it on an LS, can be done in the car and the only special tool needed is the valve spring compressor to help upgrade the springs. Headers are a little trickier as those hemi heads fit tight into the chassis but people say if you unbolt the mounts and raise/rotate the engine up on either side it frees up some room, so difficult but not impossible.

I have been very much looking into the LX platform cars as of late and engine-wise they seem like there isnt much to worry about.

This article is geared more towards muscle car/hot rod swaps but gives helpful info about transmission capability, swap bellhousings, etc. And gives some helpful dimensions. It also mentions that car Hemis run the starter on the passenger side, while truck Hemis run it on the driver's side. Might be something to consider for a swap.

This article from 2011 Hot Rod Magazine highlights the failure points of the the Hemis and where they break

https://www.hotrod.com/articles/hrdp-1105-what-breaks-on-2008-to-2011-dodges/

They also built a cheap turbo junkyard 5.7L Hemi that made some big power for very little scratch

https://www.hotrod.com/articles/hrdp-1106-turbocharged-hemi-engine/

As well as a 950whp stock block and crank 6.4L

https://www.hotrod.com/articles/build-practical-bomb-proof-6-4l-hemi/

I know they are drive by wire as far back as 2004 but finding the pedal position sensor for a 2004 1500 was slightly difficult last time I looked. What might be helpful to know is that while drive by wire, it's a remote sensor with a cable going to it, so you can mount it anywhere the cable can reach and not have to worry about putting a new pedal in like you would on a drive by wire LS.

I'm lazy and cheap so even though I'm a closet Mopar guy I'd still lean towards an LS for something  I was putting together. 

Daylan C said:

I know they are drive by wire as far back as 2004 but finding the pedal position sensor for a 2004 1500 was slightly difficult last time I looked. What might be helpful to know is that while drive by wire, it's a remote sensor with a cable going to it, so you can mount it anywhere the cable can reach and not have to worry about putting a new pedal in like you would on a drive by wire LS.

Do what Car Craft did. Pop the side cover off, gut the actuator out of it and then add a roto-plate to mount a throttle cable to

Daylan C said:

I know they are drive by wire as far back as 2004 but finding the pedal position sensor for a 2004 1500 was slightly difficult last time I looked. What might be helpful to know is that while drive by wire, it's a remote sensor with a cable going to it, so you can mount it anywhere the cable can reach and not have to worry about putting a new pedal in like you would on a drive by wire LS.

I'm lazy and cheap so even though I'm a closet Mopar guy I'd still lean towards an LS for something  I was putting together. 

Actually, all Gen 3's have been DBW since introduction in '03. Now, back in '03, they had to do some funkiness for that year only. It's the only year with a separate trans control module to use the DBW. Siemens couldn't get the NGC to handle the TCM and DBW, internal to the PCM, in the timeframe needed with the launch of the new motor. So instead, you have a separate DBW module along with separate TCM.

Now, that we're a decade removed from introduction, the stock PCM has been broken fairly decently plus Haltech makes the Mopar stand alones. So there are options out there, just not either easy nor cheap.

NOHOME said:

For reasons I am not entirely clear on, they seem to hydrolock a lot due to a failed intake gasket.

Intake is dry just like a LS, so this is perplexing. Now I have seen some HG's fail which lead to hydrolocking on the two rear most cylinders, along with spun rod bearings on 7 and 8 because they are the hottest.. Additionally, valve seats drop more than rain drops in a thunderstorm. Valve springs are also underwhelming in stock applications and love to break to cause a valve float but not completely drop the valve.

As to some the other questions, any SBM trans will bolt up. There is even an adapter to allow the old TorqueFlite converter to the hemi crank. I have one. 

Manifolds can't be flipped without an adapter or redrill the heads.

2500 series trucks never came with EGR or cylinder deactivation. EGR ports are blocked in the passenger head. There are block off plugs for the solenoids in the block. *hint, hint*

LX body intakes do but don't work with the truck accessories. But changing back and forth is all a bolt on affair, but there is not an ability to mix and match.

Oil filters changed from the ran forever 090 filter to the 899 filter, 3/4" thread vs 22mm, but the block never changed thread pitch. You can get the truck 45 degree adapter if you run into clearance problems. I have no experience with the latest filter version.

Any version of the heads are perfect for boost. The "small" 5.7 versions still flow 350+cfm. The larger displacement heads flow even better but you then need the larger port intake which gets pricey.

Expect to have to spend more just because there is not a lot of people playing with them. if you want "uniqueness" or a die hard Chrysler fan, this is the swap for you.

Hope all of this helps.

I really didn't want to like the idea of messing with a Gen 3, but how close are the mounts to a Magnum small block? Asking for a friend...

Have a 5.7 in a 04 Ram 1500, it's been abused for 200k and still runs strong.

I've heard of HEMIs dropping valves if they overheat, had it happen to a co-worker. Not sure if it impacted certain years or was wide spread.

The 5.7 Hemis are frickin' expensive.  They have valvetrain problems.

Apparently, you cannot have a massively overhung exhaust valve and expect the valvetrain to live if you want to idle it around all the time.  Which is SOP for police cars and 99% of the trucks they were put in.  This was a common fault with the 354s/392s as well as the 426s.  Not enough oil flying around in the valve covers to get the job done unless you are winding them up on a regular basis.

Srsly.  I can identify all sorts of Chevy 5.3s for under $600 with warranty, but I can't touch a 5.7 Hemi for under $2000.  They are in demand because they fail a lot and they were not common to begin with.  (You'd think that Chryslers would rust faster than the engines failed, but somehow the beancounters made it closer to parity)

This sucks because I am a dork and I grew up in the 1980s when "Hemi" was a rarefied word and if I were to desecrate a car with a V8 swap, I'd rather it be a Hemi and not some Chebby thing (only little boys have bow ties, y'know)  but DAMN.  They are problematic and therefore expensive.

Good points on Chrysler for putting the camshaft so high that the valley is UNDER the cam.

In reply to Knurled. :

What usually gets destroyed from high idle time? Valvetrain? Cams? Both? 

In reply to Appleseed :

My understanding is that the tips of the exhaust valves/rockers get chewed up.

I want a Charger squad car, but things like that make me nervous. Wonder if it would be as simple as rehab the valvetrain.

In reply to Appleseed :

Just pull the heads and replace the valves and guides and rockers, no problem.

 Ya'll weren't kidding about the cost- Car-part has the cheapest for ~$4,000, though I'm gonna poke around my local yards just in case.

Ranger50 said:

Any version of the heads are perfect for boost. The "small" 5.7 versions still flow 350+cfm. The larger displacement heads flow even better but you then need the larger port intake which gets pricey.

Expect to have to spend more just because there is not a lot of people playing with them. if you want "uniqueness" or a die hard Chrysler fan, this is the swap for you.

Hope all of this helps.

That ~350cfm and the dual spark plug setups were the big reasons why I looked at them. I know dodge only did the latter to meet emissions, but dual plugs *should* help keep cylinder temps way down under boost- as far as my understanding goes.