What's new
By:
Filters

4.7 opinions

Projectjunkie

Whatever
Joined
May 19, 2020
Member Number
306
Messages
2,866
Loc
Tucson Az
I've got somebody with a 06 commander 4.7, looking like a blown head gasket, #8 misfire, bubbles in radiator, etc
137k miles,

debating between:

1) slamming gaskets in it, or
2) reman heads
3) junkyard engine with 6mo warranty
4) reman engine

Thoughts and opinions? Do these heads survive an overheat? Also seeing some online chatter about cams failing, I'd rather not pull the heads off then have a can of worms when they could have just bought an engine... But then, is another 140k engine going to be on borrowed time anyways?
 
#2 or #4, if it doesn't have the PI heads (power improved IIRC) I'm pretty sure you can update it and get a little more power out of it.
If you could find a wreck with a 5.7 and get everything out of it that's the best way to go, my wife has a 2010 Commander with a 5.7 and it runs real nice.
 
My research has been for the sake of the closely related 3.7L v6.

The heads are sensitive to warping or cracking from heat. The head nor the block can be decked because its OHC and it affects the timing.

Not maintaining the cooling system, running too long with a cooling problem, and/or operating the auto trans so it pukes heat at the engine with the former circumstances..... You get the picture :homer:

If I was hunting for a used engine, I'd want one from a manual trans. It's been driven at a better rpm for cooling/oiling and not had to deal with extra trans heat. The auto trans does not use the powerband of these engines well.
 
I'd go for reman heads or engine. I wouldn't expect the heads to be good after getting that hot, and I've seen too many late model MOPARs go dropping valve seats after they get hot to trust just slamming the heads back on. Junkyard 4.7s are surprisingly expensive (usually around $1500 here) and you're buying an unknown, nothing sucks more than having to do the job twice, warranty on the engine or not.
 
I have a 4.7 Commander, that I think has suffered the same fate (got too hot when the Chin-lee made Advance Auto water pump shit the bed after only one year :mad3:). I'd like to keep it, because it's running fine otherwise - 5.7 swap sounds MUCH more appealing!
 
FWIW we have had multiple 4.7 that were fantastic. one 200k on it the other 160, Ive got a co-worker with 310k on his 4.7 dakota.. it sounds horrible but still rolls
 
I’ve got a set of reman heads on my workbench with about 2 miles and 30 minutes of runtime on them. I bought them from Clearwater Cylinder heads IIRC. They were for my 2008 Dakota. PM if interested.
 
u2slow said:
The head nor the block can be decked because its OHC and it affects the timing.
Click to expand...
Citation please.

Tons of OHC stuff gets decked no problem. A few thou of travel at the OD of a cam sprocket is a less than negligible amount of advance/retard.
 
I had a 4.7 briefly and I liked the motor. I ended up redoing everything and dumped it after a year, only because I was looking to build for more power.

But I do know that if don't see consistent oil changes over their life, they get sludgy and have big problems. Heard about coolant issues, too.
 
arse_sidewards said:
Citation please.

Tons of OHC stuff gets decked no problem. A few thou of travel at the OD of a cam sprocket is a less than negligible amount of advance/retard.
Click to expand...
I will dig up my 2005 chrysler manual later today. I believe there was a rejection spec for warpage - replace.

I failed to record the conversation I had with a dodge dealer mechanic I had approx 3 years ago on the matter. The short version, IIRC, was that most heads they encountered were too far warped to re-use or machine out.

Also, what is a minimum cut on such a head; can you reliably start with a 3 thou cut and feather it to zero? Or do you have to plan on a full pass removal say 5-6 thou on one end finishing with 2 thou on the other?
 
u2slow said:
Also, what is a minimum cut on such a head; can you reliably start with a 3 thou cut and feather it to zero? Or do you have to plan on a full pass removal say 5-6 thou on one end finishing with 2 thou on the other?
Click to expand...
When heads warp they generally wind up cupped or at least low on the ends and high in the middle. If you're just using lapping/abrasive methods you should be able to get a thou or less in the lowest spot. This is one of those areas where a home machinist who's dragging something back and forth on a piece of plate glass has a big advantage over a professional who's just setting up pass with a face mill and letting it rip.
 
Big thing is what shape rest of vehicle is in before you go spending big money on reman engine. If its available locally a used motor with warranty can be a good option for way less but I know there are risks there. Really up to how much you want to put into it money and time wise. I've had good luck with LKQ
 
Yeah, this was a non starter, I bid it high, I didn't want to put heads on it, ill slam a reman or used in, but don't want to open up a known problem engine and stand behind it
 
You must log in or register to reply here.
Top Back Refresh