Why does does the Hemi 6.4L have to be replaced when cam/lifter fails?

[camM]

Hello,
I was wondering if anyone knows exactly why the whole engine needs to be replaced if there is a cam/lifter failure and there are deposits in oil control valve. The 5.7 just asks for the pan to be dropped. I know that tolerances are tighter on a 6.4L, but I cant see what specific tolerances they are speaking about.

I would think that a full rebuild would allow everything to be cleaned sufficiently. Rebuild kit, new lifters and cam, new oil pump, new control valve, and a new intake it seems like every would be good to go. I get parts for these are super hard to find, but I still think you would fork over a lot less money going the rebuild route then full engine replacement.

Just wondering what I am missing. Been looking at a couple 6.4L threads where they are dropping 15K plus on a new engine and it just doesnt make sense to me.

Thanks!
Cam

 

[ClawSS]

Labor on a new longblock has already been booked at Saltillo Engine plant and can be shipped in so that the dealer just swaps out the accessories and installs into the engine bay. Labor for a rebuild would be an "external" expense to potentially somewhere outside of the dealership plus incremental parts. Not many dealerships can hot-tank a block, etc.

 

[H3LZSN1P3R]

Simply convienece as the dealers are not setup for full rebuilds its not cost efficient for them

 

[pizzatots]

how often is this happening? I thought this was a big issue on the 5.7 and hopefully resolved on the 6.4?

 

[Gatorm]

Real common issue…..I’ve had probably a half dozen of them done. We swap cam and lifters and check for metal in the pan. Only one had a metal issue and had to rebuild the engine.

 

[jetrinka]

How many miles are usually on the engines that experience this failure?

Are the engines being serviced properly prior to the failure?

My thoughts exactly

 

[WXman]

What I would love to know is this: out of all 6.4L engines that fail, what percentage of those engines were being run with 0W20 or 5W20 engine oil?

On my 5.7 that I bought new last year, it sounded like dog crap from day 1. Lifters ticking, lots of valvetrain noise, especially upon a cold start. Couldn't believe a new engine sounded like that. Just shy of 5,000 miles I dumped the oil and put 5W30 full synthetic in and immediately ALL valvetrain noise disappeared. At 12,000 miles now and engine is still dead silent. Recently I have begun to only use the truck primarily for towing a 20' enclosed trailer around and it performs great with zero valvetrain noise.

 

[NC Rebel]

6.4 hemi V8 uses 0W-40

 

[WXman]

So it sounded like a farm engine - you know, the hundred-year-old ones that fire right up after they have been sitting in a field for the past few decades. But according to your calibrated ear you have improved something?

No calibrated ear needed. The ticking in these engines is so bad that it has earned it's own nickname. They call it the "Hemi Tick". Mine was pretty bad. From inside the cab, a cold start was horrible. Sounded like a dry start condition every morning. And then when it was warm the valvetrain was loud. Since I dumped the 0W20 water oil there has been zero ticking or knocking on cold starts, and it purrs like a kitten at operating temp even on the hottest days. Makes perfect sense when you consider that a 20 is lower viscosity and is going to drain off the cam lobes, etc. faster and when it gets hot it's going to thin out more. Also makes perfect sense that they're specifying 40 in the HD trucks sense they know those will be worked hard. We even see this in the car world. Mustang 5.0 V8 uses 5W20 unless you get the Track Pack which spec'd 5W50....hmmmm... same engine, different oil spec when they know the car is likely to be driven hard. Why not just spec the better viscosity to start with and protect ALL of the engines you sell?