So I just purchased an '08 Dakota for $1500 knowing that the motor had issues and probably needs a rebuild. Looks like the keepers on one of the valves, or a valve spring, broke, dropped the valve into the cylinder and on the up stroke, the valve stem broke and the valve itself was driven sideways up into the seat. This also caused a nice gouge in the piston.

Local shop gave me a wild *** guess in rebuild cost of $2800 to $3400 site unseen for the rebuild which would include boring the cylinders and putting in new pistons. I do understand that it could possibly go higher.

Reason I am here is to try and find out if a Mopar long block with a R8172486AC part number will fit this Dakota. The part number showing at Mopar parts is R8172486AA, but the AC says it supersedes the AA number. However, when I look at the AC fitment, it only shows as a 2011 RAM. I have tried search to figure out the difference but have yet to figure anything out.

If it does fit, I found a local shop with a R8172486AC long block directly from Mopar for $3,750. It is still in the original wrap with the Mopar number on it. The Mopar site says it doesn't fit a 2008 but does fit a 2011 Dakota.

Thoughts??

This is from the Mopar Parts Overstock site with the two part numbers in question in bold:

ENGINE. Long Block. Remanufactured.

Part Number: R8172486AC
Supersession(s): 68031382AA; 68031382AB; 53021213NA; R8172486AA; RL031382AA; 53021213MA; 68172486AA; R8172486AB; RL172486AA

 

there were no changes on the engine between 2008 and 2011. the long block should work on both.

 

Thanks. I was hoping that was the answer as all the research I tried to do didn't seem to mention any differences within the same generation.

 

even outside of the generation they are mainly the same. I think the shortblock is the same going right to the beginning of the 4.7. the main difference is that in 2008 they released the "ho" version or High Output which had 2 plugs per cylinders and some other changes on the cylinder head / camshafts, but the block, pistons, crankshaft stayed the same.

if my memory serves me right, between the one put in the full size RAM trucks, the dakotas, and the jeeps, the main difference was the accessory drive, intake manifold and exhaust manifolds.

 

Thanks for the additional info.. Just made me realize I should verify that this AC version has the dual plugs like mine.

Interesting that nothing on the truck mentions HO and only has the Magnum/FlexFuel designation.

 

Picked up the motor this morning. It had been sitting for 8 months in the original plastic and crate from Mopar. Used my camera to check inside the cylinders for any rust and they were all perfectly clean along with clean cam shafts. All the plug and injector holes still had the red caps in them.

Guy cut me a deal off the eBay advertised price so I ended up paying $3,250 for it. Told me that if I needed it, he had the matching transmission he would let go for $2,000.. Hoping I won't..