Greetings. I usually just read topics but today is my first post requesting practical advice and experience concerning my recent overheating and subsequent diagnosis that ive got 2 dead cylinders (#2 and 8) and the remaining 6 holding at 90psi...I have gathered that my best action is to have it rebuilt.
Here is my question. Are there any internals that i should upgrade while i am at this? any weak links that should be looked at other than a new oil and water pump? I'd love to get "better" mileage and towing capacity and am looking for upgrades that would have positive cost vs benefit ratio over the life of the new engine.
Also are there any "performance" chips that can be recommended? As a curiosity, why do these engines cost soo much more to replace than a 5.9?

Many Thanks

 

Newer technology makes them more expensive. If you want performance now's the time to get it if you want to rebuild the engine. If you are just looking to make your engine strong put stock back in. The 4.7 is a solid engine and typically won't give you problems. The transmission will die long before the engine will typically and if you do rebuild the engine look into a shift kit for the trans and an oversized tq converter. That would be a good investment while the trans is out of the D. As a side note, your dead holes are probably just a blown head gasket. Tere's no way to tell of course until you get the head off.

 

+1 on what mean green said, all of it

 

Quote:

Originally Posted by Mean Green

Newer technology makes them more expensive. If you want performance now's the time to get it if you want to rebuild the engine. If you are just looking to make your engine strong put stock back in. The 4.7 is a solid engine and typically won't give you problems. The transmission will die long before the engine will typically and if you do rebuild the engine look into a shift kit for the trans and an oversized tq converter. That would be a good investment while the trans is out of the D. As a side note, your dead holes are probably just a blown head gasket. Tere's no way to tell of course until you get the head off.

Actually there is a little trick in helping you know what the issue is.

First do a compression test on each cylinder and write down your findings on each. Next pour about 2-3 cap full’s of clean oil through the spark plug holes directly into the cylinder. Now do a second compression test and write down that PSI measurement to the right of your first measurement. Do each cylinder one at a time (only pour the oil when you are ready to measure that particular cylinder).

Now if your measurement increases with the oil in the cylinder then you have bad piston rings and the motor must be rebuilt. If they stay the same then most likely the head gasket is bad.

Now this isn't necessarily the last word, but it will help you diagnose all of your cylinders.

One thing that gets me is that you only have about 90 psi?????? That doesn't sound right and in fact is very low. On a new rebuilt motor you should be around 150 psi and down to maybe 125 on the low side. If you are getting continuous readings of 90 then I would look more at the head gasket then anything.

If you do rebuild the engine, bore it out about 30 over and Port and polish the heads. Replace the oil pump as well. I would put in a really good head gasket like Mopar Performance when you rebuild over OEM.