Looking for some advice. I have a 2006 HEMI with 55,000 miles or so that I recently picked up. I have since torn the engine down to find the following:









I purchased the vehicle as a project knowing full well it had mechanical problems, so I am not entirely surprised by what I found, but perhaps a little disappointed. My initial disagnosis was a bad head gasket, my reasons for which I'll explain below.

Supprisingly enough the truck ran and drove more or less fine. The engine was smooth under acceleration and made power. It occasionally would throw a P0300 code (multiple cylinder misfire) and the idle would sometimes be a little rough. I suspected the head gasket was bad though as there was coolant in the oil (the air filter was soaked in a weird coolant/oil mixture from the breather tube).

After taking off the heads the head gasket actually looked okay. I'm sure it was leaking somewhere, but there was no definite signs of damage. About six out of eight pistons have some degree of damage with the one pictured above having by far the worst (the picture above is, I believe, of cylinder #8 - passenger side closest to the radiator). As shown above the head also has some slight damage, however the valves all appear to be in good shape. The #8 cylinder wall is pictured above as well and it is the only cylinder with light scratching.

My initial thought was that something got in the cylinder and bounced around causing the damage. But I figured if that were the case it would have likely damaged the valves both on the way in and on the way out. I showed the pictures to a shop and they suspected that it was the coolant getting in there and deforming the piston (relatively cold coolant on hot metal). While that may explain the cylinder pitting, the wall damage would have had to been caused by something else. Also, the wall damage has me wondering if the rings are bad in that cylinder.

All this leads me to wonder what is the best repair for this damage? I am looking for the most cost effective regarding both time and money. The shop I mentioned above suggested just to hone the cylinder in place and smooth out the piston with a die grinder. Told me that I would never know the difference. To me it sounds a little sketchy, but I can see where they might be right. I am not looking for a maximum performance race motor here, just something that is reliable everyday.

Since this is getting kinda long, I will end there.

Thoughts and opinions are appreciated.

 

low grade fuel...87 octane is known for causing pre-detonation in the Hemi's.

Also, the ringlands on the piston skirts are extremely close to the top which causes a weak point for detonation to break away and throw metal chunks.

As far as fixing the damage?..the cylinder wall is pretty f'ed up and i dunno if they can bore it out large enough, plus you'd have to replace a piston or few??? $$$$

Your much better off saving time and money and purchasing a low mileage used one off Ebay or an online salvage yard that deals with engines. You can pick up a fairly low mileage (<40kmi) engine for $2k shipped for the hemi's.

 

Here ya go

 

well the only time i have ever seen something like that was when me and my buddy took apart the sameri cause it was running rough after we put it through the mud holes a million times... and i wouldnt grind anything, i would get new pistons and like the shop said get it honed or better yet get it bored out lol, or find another truck like that has been salvaged and get the motor from it if it hasnt been damaged... im sure there will be better ideas but thats what i have goodluck

 

if thats the worst of the cylinders, don't worry about it. new pistons and rings, get the heads scanned, they might need surfacing if they warped (or get new ones).

 

But ALL of that legwork, time and money spent will cost alomst as much as a used engine would, not to mention putting it back together!

 

i agree with dirty.. you can save a lot of time and money, well idk about a lot of money , but finding one in a salvage will probly be your best bet, hey maybe you will get lucky and find one with a few mods done already!!

 

I'm with feej.

The guy got it as a project, so I'm assuming he got it cheap. He could hone it himself, grind the piston head and replace the rings on the one cylinder for cheap. He'll be out a few hundred and some time, but that's what projects are all about.

 

he'd end up saving a grand but putting in much more labor if he were to rebuild it, but i definitely see your point. but rebuilding an engine ain't so bad once it's out, and he's gotta pull it either way.

 

Well since I am in Alaska, shipping is usually a big factor. However luckily enough I did manage to source an engine locally that's priced at $2,100. It has a claimed 29,000 miles (I'm always a little suspicious of used engines, but it is at a big well known salvage yard).

Any thoughts on whether it is possible to replace that cylinder with the engine still in the car? It looks like if you drop the oil pan you would have enough room, but I am not sure. That piston is by far the worst, the others have surface dings and a couple have no damage at all.

Also, would honing remove those scratches?