Hi guys,

I have an 02 Dakota Sport with the 4.7 Magnum. Long story short, the engine sludged up on me resulting in loss of the right timing chain hydraulic adjuster, a few of the hydraulic adjusters in the heads failed, and melted the connecting rod bearings on cylinders 6, 7, and 8. Yes I changed the oil every 3000 miles with full synthetic (as did the original owner). From what I've read, this happens because of the engine running hot and/or a venting problem of which both appear to be a common issues.

I love the truck and would like to keep it for a long time. What I'm trying to decide is what to do at this point. The current engine is past being rebuilt so I'd be looking at either a long block or a used engine. My problem with that is that if I put another magnum in the truck its probably just going to sludge up eventually unless the underlying issues are addressed. Maybe an oil cooler? After seeing some threads on here and some other sites, I'm also considering putting in a 5.7 hemi. I see them on ebay for $2000-3000 but they are from newer vehicles, mostly Durangos. Any ideas on this? Should I take my chances on another 4.7? Or go for a "better" engine such as the hemi?

Thanks in advance.

 

If you're up for it, I would do a Hemi swap. If you aren't, I'd put a 4.7 back in. What was your oil change interval? Mileage?

 

How's the block?

I just had the 4.7 HO in my Grand Cherokee go BOOM thanks to a dropped valve seat, common with an overheat but mine had never run any hotter than 215* the whole six years I've owned it. Meticulous care the whole time.

I decided to rebuild because the block was fine - one small scratch in the cylinder wall in the cylinder that the seat dropped, just barely detectable and was easy to hone out with just a light hone. My heads were toast as the valve seat obliterated and took out that head, then debris from it went up through the intake manifold and over to the other head.

Carnage:

IMG239.jpg

After contemplating parting the thing out, which I decided against as even though the engine had 102k miles on it - the vehicle is in MINT condition.
New engine is pretty much out in my case because it's the Overland edition which means HO version of the 4.7, plus a complete different PCM tune. Try finding a low mileage HO out there!!!

So I'm in the middle of rebuilding it. Heads are at a shop with a great reputation and yes - they will be peening EVERY valve seat. Quoted $380 for rebuild of both heads.

Found full engine overhaul/rebuild kit for under $700 - and I mean FULL! Everything needed if starting from a bare block and having two good heads save the water & oil pumps. Components look good - mainly DJN and PCI parts and almost all domestic except the gaskets. Pistons are cast (as the stock ones are) but are teflon coated (the stock Mopars aren't).

So after the head rebuild (rounded to $400) and the overhaul kit ($700) I just really need to do plugs, filters and fluids plus I'm gonna do water and oil pumps even though I could re-use these. So I figure I'll have about $1500 in the rebuild and should be done within the next two or three weeks...

 

HammerZ71- Wow, thats awesome, great deal. I think the block is the only good part left. Pretty sure the heads warped, the hydraulic adjusters for the rockers are shot, not sure about the cams, rockers, or valves, the bearing surfaces on the crank shaft are scratched up from the bearings failing, the connecting rods are scratched up as well, pistons may be ok but not sure, need new chains, oil pump, gears and everything else. I was told the block could be warped as well though. I'll try to post some pics.

MadisonDakota- Do you know what it takes for the swap? I can do most of it I think, and if I can't do something, I know a few people that can help if I need it. I know I'd have to make new engine mounts. Does the exhaust tie in the same? What about wiring? Do the dash instruments tie in the same or would that need to be rewired? I'd need a new computer and get it flashed... I currently have 4WD, would I have to make new mounts for the tranny? Drive lines?

I'm very mechanically inclined, I just don't know what I need parts wise or what needs to me modified to make it work. If I know what needs to be done I can do it, but I'm not the kind of person to go buy a bunch of stuff not knowing what I need and screw myself over.

 

Strip it down and pull the engine, I mean if you were gonna go get an engine you'd need to pull that one anyway.

Have a machine shop look at the block, probably the only thing I should have done was to pull the block and have a shop steam it - it'll open up all those channels for coolant and make for a 10-15* cooler running engine. But if the block is good or salvageable (might have to hone the cylinders out, but then you just get oversized pistons or at least larger rings). But if the block is good, trust me, you can rebuild it cheaper than buying an engine - and thisaway you come away with all new parts rather than buying an engine with 100k+ miles on it that's going to give you trouble before too long.

If the heads are warped, 4.7 re-manned heads are out there, new springs, valves, seats, seals, etc. from a variety of places for around $300 a side.

I've never rebuilt a modular, OHC engine before. Actually I've only ever done a 4.0 I6 which is child's play compared to this monstrosity, but it can be done, done probably better than it came off the assembly line and done comparatively inexpensively.

I mean, if I parted mine out, what the hell could I replace it with for the $1500-2000 topps it's gonna cost me to rebuild with all new, and in many cases upgraded parts?

When I'm done, I've got a near mint condition Grand Cherokee with in essence a brand new engine except the block, ready for breakin' in. Least that's the way I choose to look at it...

 

I'm not really sure I want the 4.7 back in my rig with the known overheating issues and the venting problems. I'm afraid I might end up with this same issue so thats part of why I kinda want to throw the hemi in there instead. But it WOULD be much easier to go the rebuild route since I can drop that straight in. BUT then again, the hemi would be a lot more powerful have a little more "cool factor". I don't know.... Heres some pics.

 

what is the second picture of?^^^

 

Thats the oil fill tube. It was mostly clogged with sludge. I had more pics but the site wont let me post any more.

 

Damn!!! Mine was clean as hell inside. No signs of sludge at all, anywhere and my timing set looked shiny and basically new...

 

Thats what's weird... I see posts from so many people saying that their engines are spotless, yet I see so many people (like me) that swear on their life that they changed the oil every time it was supposed to be yet theirs sludged up and blew. I don't get it.