Pictures of cracks in 4.0L engineDoes anyone know of a site where there are pictures

[kastein]

He used photobucket, another image host. It's what basically everyone does to post pictures :dunno:

I mean, paid members here can post attached images, but that's not why anyone joins as a paid member, and it's a silly reason to do so IMO. I'd honestly suggest just using imgur.com or tinypic.com, you can use both without having an account there.

 

[oldbill]

Does anyone know of a site where there are pictures of the cracks that appear in some 4.0L heads that cause problems. Supposedly these cracks are the result of over heating. Cleaning up the surface of my 4.0 head while replacing piston I've noticed what might be a small mick, it is within the inside of the sealing ring on the head gasket. It almost appears to be just a surface scratch and doesn't appear to be seen of felt in the combustion area. At this point being retired I'm a little tight on money to have the head machined or buy a new one. If I can go as is I'd like to, but am looking to the experts for answers. If it would help I could try to post pictures tomorrow. I not the first owner of the Jeep but have had it for a couple of years and it has never over heated or lost coolant. Engine has around 190000 miles on it. Bearings and everything looked good. Put in a re manufactured crank due to the cost of the odd size main and rod bearings.
Thanks,
Bill

Picture hopefully

 

[Innojazz]

I use Photobucket for other things too so I just upload them to there and then copy the URL into the post using the

 

[Talyn]

Looks like a scratch. As long as it is not in the sealing area of the head gasket its fine. What did you clean it with?

 

[kastein]

Looks like a scratch to me too. Almost like a piece of sparkplug insulator got mashed into the head by the piston at some point in the past, is there a matching mark in the piston?

 

[winterbeater]

But it does show up at both #3 and #4 combustion chamber. The most likely place to crack. And you see it going all the way to the valve seat to the right. I'd clean the combustion chamber better. To me, it could easily be a crack.

 

[Talyn]

But it does show up at both #3 and #4 combustion chamber.

Typical place to crack is under the valve cover.

And you see it going all the way to the valve seat to the right. I'd clean the combustion chamber better.

Now I see that part. Hard call from just the pic. Looks too straight (or arc) to be a crack. A better pic wouldn't hurt too.

 

[5-90]

jeez, I am such a noob.. I am trying, honestly.

Ah - but you know and admit you are a noob - which really makes you an FNG, not a noob (and definitely not an FNK. FNKs usually can't be trained.)

And knowing is half the battle, no?

Just as an FYI, there was no production aluminum head for the 6-242 engine (or for the AMC six in general.) There is an aftermarket aluminum head (I'd still like to know if I had any - even tangential - role in bringing it to market, because it bears many of the hallmarks of a longish discussion we had on "strokers" some years back that I condensed and dropped off with Russ Flagle at Indy Cylinder Heads...)

About the only production aluminum parts found on the 6-242 were (I believe) the intake manifold, thermostat housing, water pump housing, and assorted accessory brackets. The AMC six is/was one of the last of the "all-iron" engines, as I recall...

 

[5-90]

Typical place to crack is under the valve cover.

From what I've been able to gather, it seems to most often crack right under the oil fill cap. Coincidentally, this is also where the TUPY foundry mark is usually found - so you're probably going to see one or the other.

The TUPY (revised) head is a direct bolt-in swap for the early #0331 head, so you can swap it over and go.

As far as the dye-check kits? I firmly recommend the Magnaflux-branded pocket kit, it works quite well and can save you taking home boned parts from the breaker's!

 

[Talyn]

From what I've been able to gather, it seems to most often crack right under the oil fill cap. Coincidentally, this is also where the TUPY foundry mark is usually found - so you're probably going to see one or the other.

That is correct.

The TUPY (revised) head is a direct bolt-in swap for the early #0331 head, so you can swap it over and go.

03+ (some say late 02, but 03 on the safe side) should all be TUPY heads. There is also a new strengthened head available.