Lost almost all engine compression overnight?!
03-05-2017, 11:42 PM
#11
Great info! Over the next few days I am going to spend a lot of time on everything that should be upgraded in the motor due to factory defects or errors. This was the first time I heard about the oil squirters being installed towards the wrong side. Is this why spun rod bearings are so common in these engines?
Just curious, you planning to go with stock replacement parts or aftermarket instead on the piston rings for example?
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03-06-2017, 11:49 AM
#12
JK Newbie
Thread Starter
That's part of what I'm researching. I'm really not sure what parts I'll keep OEM and what parts I'll go aftermarket. Part of me wants OEM but at the same time, they failed in the first place. My exhaust manifolds are cracked and those are OEM... so I'm thinking I won't stay OEM on those. I don't wanna put parts in that are gonna run into the same problems. Piston rings are a different story... once I get to them and see if they were installed correctly will determine if I go OEM or aftermarket. I'd love to hear from anyone that has an opinion on OEM vs aftermarket parts.
03-09-2017, 06:28 AM
#13
JK Super Freak
Since there are so many "Factory Defects" possible with this engine, would it pay to go to a later engine, say from a shop that has take outs from installing Hemis, or a commercial rebuilder ? Bores out of round ? Oil jets , you gotta be kidding
03-09-2017, 09:59 AM
#14
JK Newbie
Thread Starter
I've really considered it. Once I get inside the engine is when I'll really make my decision. I'll check the cylinders and also check the oil holes. I've started the tear down on it today. I'm hoping by the end of today I'll have both heads off of it and will start having a better idea of what I'm dealing with. I've been recording all of it for anyone in the future needing to do the same project.
03-13-2017, 07:49 AM
#15
JK Newbie
Thread Starter
Well, I've made it to the pistons and it's no surprise that the rings were seized/stuck. All 6 pistons looked identical and none of them were trying to "push" against the cylinder walls at all. There was gobs of oil/carbon on top of the pistons and most of the oil deposits were not that old. Here's the kicker.... after removing the rings, we discovered that all the rings appeared to be installed correctly! There were no stamped markings on the rings so I can't confirm whether or not they were even installed correctly but I know the 2nd compression ring had the "lip" pointed down. It's my understanding this would be correct as it helps "scrape" the oil down into the oil control ring. So my only question is, what would cause the pre-mature ring failure? Brand new, this Jeep was used as a rental car so maybe it wasn't broken in properly, or maybe at one point the engine was over-heated. Could the oil control ring just simply not be large enough? I've searching for answers but coming up short. Also, I'm ordering new connecting rod bolts (since they're TTY bolts) and I can't seem to get the bolt out of the connecting rod cap. They appear to be designed to not allow for removal but even in the shop manual it says they must be removed. Is there a certain method for doing this easily? Thanks! I will post more updated as I continue into the build.
03-13-2017, 08:27 AM
#16
JK Jedi Master
I wonder if low engine rpm and possible borderline lugging might have something to do with the rings sticking with carbon buildup.
I keep O/D off for anything below 55 mph. That keeps the engine in the 2,000 to 2,500 rpm range.
I keep O/D off for anything below 55 mph. That keeps the engine in the 2,000 to 2,500 rpm range.
03-13-2017, 07:17 PM
#18
JK Newbie
Thread Starter
Ronjenx, I think it's very possible you're right about lugging the engine. For a while the Jeep has been losing power. We have the 6 speed manual and I know own there's been times we've lugged the engine. It was so powerless it was almost impossible not to cause the second you hit a hill you have to downshift 2 gears. Good news is that the oil squirter holes were all facing the correct direction, thanks for pointing that out ronjenx. I figured out how to remove the bolts from the rod caps. There are ferrules holding them in and you just gotta pull the bolts super hard until you feel like you're about to s*** yourself, and then they'll release. I had an exhaust bolt snap off when trying to release the manifold but by the grace of God I was able to use an extractor and get it out. I'm using chem dip to clean valves and pistons. There's a lot of carbon on the valves as well. Tomorrow I'm lapping valves and putting in new valve seals. I'll update more as I move on.
03-13-2017, 07:43 PM
#19
Super Moderator
Subscribed! The original 3.8 owners that plan to keep them seem to be dwindling so any info is good info, thank you 
