DoubtingThomas86 Posted December 6, 2019 Share Posted December 6, 2019 Hey all, Thought I’d give some updates. My brother 500MJ picked this MJ up from Mkusmc. Thanks again. When I got my hands on it a number of parts had come along with the purchase of the truck. Gaskets, cap rotor, some sensors, etc. 500MJ also threw in some parts from the parts store that has become his garage. Installing these parts has mostly taken up my time working on this Turck up to this point. Long story short it was trailered home when deemed unable to make the journey from WI to MI. Getting the truck started was a bit of a challenge on the cold day we had BUT the old thing way able to make it onto the trailer under its own power, albeit only using 2-3 cylinders. Here’s the truck loaded up and ready for the ride back to MI After getting it home I started work on the motor, with 258k on the 2.5L I wanted to make sure it would run and run decent before sinking in time and $$. Messing around with sensors helped as did some seafoam in the oil before I changed it. I just wanted to get all the crud out of it. The thought was that I had a sticky valve and the seafoam would help free it up. With sensors changed, a new cap rotor and plugs, and new oil the Jeep ran much better BUT IT WAS STILL MISSING ON CYL 4! I decided after some convincing to go in for exploratory surgery and started pulling the valve cover and surprise surprise a pushrod on the misfiring cyl was bent. Now the big thing has been figuring what bent the rod. I take off the head to look further and clean up 30+ years of grease and grit. After a some trip to the local garage to borrow some tools. I disassemble the head and get everything else cleaned up and get some paint on the head. Will Hemi orange add 10 HP or it that just an urban myth? The cyl walls look good in the head, some minor striations but nothing deep and what is there is very minor. When testing compression before pulling the head I was reading 100-110 on all but the fouled up Cyl 4. So I feel comfortable that the rings are ok and will get me through. All the valves came out fine but I am going to double check them and the push rods to verify trueness before putting them back in. My thoughts on what bent my push rod: Low oil? Overheating? Valve adjustment that never happened thereby causing it to work it’s way loose? So far I’ve been chasing a reason as to what bent it. I thought the valve would be bent as well but it seems fine. Next steps: -Verify trueness on rods and valves. -Get some lapping compound and lap the old valves back in to the clean head. -reassemble and put back in the Jeep. -Bend another rod somehow, and join a hot rod club with the 2.5 L Sent from my iPhone using Tapatalk Link to comment Share on other sites More sharing options...
fiatslug87 Posted December 6, 2019 Share Posted December 6, 2019 Hemi Orange, at LEAST 10hp! Link to comment Share on other sites More sharing options...
500 MJ Posted December 7, 2019 Share Posted December 7, 2019 10 hours ago, DoubtingThomas86 said: 500MJ also graciously threw in some parts from his stash in his garage because he is my awesome Brother. Easy now... fixed this for ya. Link to comment Share on other sites More sharing options...
MiNi Beast Posted December 7, 2019 Share Posted December 7, 2019 What a good brother he is. He should get you a nice train horn to install in it as well. port and polish with some roller rockers and them squirrels be ready to run for a bit. looks like a decent MJ for sure. Link to comment Share on other sites More sharing options...
Jeep Driver Posted December 7, 2019 Share Posted December 7, 2019 The head needs to go to a machine shop. New seals, new springs. You need a valve job. Or you'll be chasing another bent push rod. Link to comment Share on other sites More sharing options...
DoubtingThomas86 Posted December 7, 2019 Author Share Posted December 7, 2019 What a good brother he is. He should get you a nice train horn to install in it as well. port and polish with some roller rockers and them squirrels be ready to run for a bit. looks like a decent MJ for sure. Sent from my iPhone using Tapatalk Link to comment Share on other sites More sharing options...
DoubtingThomas86 Posted December 7, 2019 Author Share Posted December 7, 2019 The head needs to go to a machine shop. New seals, new springs. You need a valve job. Or you'll be chasing another bent push rod. Got some experience with this huh? Sent from my iPhone using Tapatalk Link to comment Share on other sites More sharing options...
Jeep Driver Posted December 7, 2019 Share Posted December 7, 2019 4 hours ago, DoubtingThomas86 said: Got some experience with this huh? Sent from my iPhone using Tapatalk My guess is- Carbon build up on valve stem caused it to stick open. Push rod came up out of it's seat in the tappet and rode the tappet lip/barrel up causing it to strike the rocker and causing the bend....something is going to give and fortunately it was the rod. There is no valve adjustment on these engines. You will not be able to test the valve stem run out without the correct tools......IOWs unless it's clearly bent you will not know if it's bent by just looking at it. Seals and springs are cheap.........can't imagine you putting this head back together without replacing. You need to have the deck checked.....if planed, the valve stem length needs to be reduced accordingly. A head shop will do this as a matter of routine. Valve guides need to be inspected and refurbished if necessary. Your valves, chambers, deck have not been cleaned. That head is not ready to be reinstalled. I've built several engines and replaced/serviced several heads. Heads always go the machine shop. I'm not an expert, I'm not a machinist, I trust those who are. Link to comment Share on other sites More sharing options...
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