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Engine help needed please!

I

Incredible Hulk

NAXJA Forum User
Location
Burnsville, Minnesota
So I was taking out my oil pan tonight to do my rear main seal, and as I took it out I found this little gem in there. (Out of a 97 4.0)
354f0f62.jpg

So, I am assuming that it wasnt born in there, and probably didnt find its way down there all the way from the top. I think I may have heard something by now. There are no metal shavings in the pan, its clean as a whistle. My engine has not been making any odd noises lately, and has been running smooth. So, I am confused.....
This nut is the same style as the set of 6 pairs that you see when you look at the bottom of the engine once the pan is off. I was hoping it was one of those, but no luck. It has three little sets of marks on the top of it.
SO, does anyone have any ideas of where to put this? I am just curious if anyone has thoughts on where to look.
Thanks for the help.....
josh
 
id say rod or oil pump! either way thats pretty scary, would suck to put it back together without knowing what it was and have the engine go boom!
 
Thanks for the vote of confidence caleb, you freakin douche-bag. Geez.
I am positive it is not one of the bottom rod bolts, but it could be something else. I am gonna dig around in there tomorrow morning and see what I can find. I will check the oil pump, but where on the oil pump would there be a nut like that? It has coarse threads by the way. Any other ideas?
josh
 
I beleive oil pump is bolted on,rod nut maybe or a little something extra when builder was cleaning up shop.I had a chevy that I dropped pan to change seals,I found a hydraulic lifter in bottom of pan,ran another 200,000 miles no problems.Probably just a little funny business at the old factory on a slow day ?
 
Hard to tell but is that nut the same size as the ones on the lower control arm bolts?
 
I find it hard to believe tht a nut that size could have worked loose without already causing a major problem before it even came off of the threads! Assuming that it came off while running, I find it even harder to believe that the loose nut wouldn't have have caused problems on it's way to the pan.
So I have to go with the guy who suggested it is an extra nut left in the pan at the factory. Stranger things have happened....
 
Incredible Hulk said:
Thanks for the vote of confidence caleb, you freakin douche-bag. Geez.
I am positive it is not one of the bottom rod bolts, but it could be something else. I am gonna dig around in there tomorrow morning and see what I can find. I will check the oil pump, but where on the oil pump would there be a nut like that? It has coarse threads by the way. Any other ideas?

josh
Click to expand...

I don't think anything down there uses coarse threads. Certainly not the rod nuts, and I doubt the oil pump nuts are coarse either. I think it either fell in and found its way down the oil galleys, or it was built in.
 
Could it have gotten in accidently by way of the timing cover? There is that decent size gap on the bottom. I had to fish out a woodruff key when I did my timing set the other week.
 
That's a flanged-head nut, and they aren't used everywhere. In '97 wasn't that the year Jeep started using the main bearing girdle to stiffen the lower engine assembly? If so, I think the main bearing cap bolts have studs on the lower ends, and perhaps use flange nuts to attach the girdle to the main bearing bolts? Dunno, because I haven't had onbe of the new engines with the girdle apart, but that's my guess. I'd guess the guy assembling the girdle dropped one, didn't bother to fish it out, and after the pan ws installed and the engine flipped over it dropped down into the pan.
 
More than likely it was left over from the build and it has been in the pan since the engine was built. Since you have checked out the rods and everything, I wouldn't worry too much. I found a socket in the bottom of an engine I overhauled about 25 years ago. The engine had gone 200k with no problems.
 
I should mention that I took out the oil pan and changed hte seal about 2 years ago. I dont specifically remember seeing anything in there then, but I dont remember really looking either. But I doubt I would just not look at all. I always look for shavings etc. I will keep digging today.... I'll let you know what I find.
josh
 
if it was a rod nut you would have had a catastrophic failure by now. if you have no engine problems, i would tend to believe it was something that was accidently dropped in when being built and filally made it to the pan.
 
I'm gonna go with those who said that it's an extra nut from the factory or some place. You would have too many things go wrong if it were something else.
 
Eagle said:
That's a flanged-head nut, and they aren't used everywhere. In '97 wasn't that the year Jeep started using the main bearing girdle to stiffen the lower engine assembly? If so, I think the main bearing cap bolts have studs on the lower ends, and perhaps use flange nuts to attach the girdle to the main bearing bolts? Dunno, because I haven't had onbe of the new engines with the girdle apart, but that's my guess. I'd guess the guy assembling the girdle dropped one, didn't bother to fish it out, and after the pan ws installed and the engine flipped over it dropped down into the pan.
Click to expand...

I'm with Eagle on the stud girdle nut. It looks just like the nut that was holding the stud girdle on my '01. If you had the pan off before and didn't notice anything in the pan it probably wasn't there. If you motor does indeed have the main girdle look at it closely.

B-loose
 
It bolts over the top (bottom) of the main caps to stiffen the engine assy. It is there to reduce NVH(noise,vibration,harshness). Check your post at mn-jeep. I was wondering what size the hex was on that nut?

Brian
 
Incredible Hulk said:
So I was taking out my oil pan tonight to do my rear main seal, and as I took it out I found this little gem in there. (Out of a 97 4.0)
......This nut is the same style as the set of 6 pairs that you see when you look at the bottom of the engine once the pan is off. I was hoping it was one of those, but no luck. It has three little sets of marks on the top of it.
SO, does anyone have any ideas of where to put this? I am just curious if anyone has thoughts on where to look.
Thanks for the help.....
josh
Click to expand...

That's one of the nuts that holds the main bearing cap girdle over the main cap studs. Just put it back where it came from (it'll be obvious which one's missing) and torque ALL of the nuts on the main cap studs to 35lbft. Here's a pic:
GIRDLE.jpg


The nuts are in the second from bottom row. Ignore the washers in the bottom row; I used those as spacers to clear the girdle from my stroker crank.
 
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