New J10 - Blown motor. Need advice

[bruegge]

Hi All,
Jeep newbie here, love the site. Thanks in advance for your time and help. Here goes...
My son and I have been watching the show Raodkill, and inspired by said show, I made a 90 mile trip to buy a 1974 J10 with a 401/TH400/Quadra-trac and little rust in Colorado terms. The truck was bought at an auction by a friend of mine, it was abandoned and sat for ~ 4 years. He could get it to start, but not much more.
I rode my motorcycle to Steamboat and spent the day working through a list that we put together in hopes of driving the jeep back 90 miles, bike in the bed. We changed plugs, wires and cap, changed the oil and filter, drained the gas, worked out a few wiring glitches and added copious amounts of MMO to both oil and gas. We noticed some of the plugs were bad, and decent compression in most cylinders, but three were low at 30, 60, 60. Oil pressure was non existent on the gauge, but didn't notice lifter noise, hoped is was a bad gauge or sender. We prayed an act of god would help the compression.
Around 10:30 at night I fired up the truck and started to drive home. While it was a long, slow trip, there were times I would have swore the engine was running stronger and I was sure the MMO was freeing up stuck rings and cleaning carb jets to like new. At 1:30 am, 10 miles from home it started to run poorly again, I was blaming a low gas tank (thinking I sucked some crap in the tank up) and begging the jeep fairies that I wouldn't have to wake up my wife to get a ride the rest of the way home.
In the end I made it home, went to bed late, but got up early, excited to work on the truck.
Day 2 involved pulling the valve covers off to find loose rockers, two missing push rods and a few bent rocker bridges. We pulled the intake, then the heads and found two broken push rods, one in the valley, the other pinched by it's lifter in the lifter hole. I've looked at the bottom of one lifter and found it well rounded out on the bottom.

I'm reaching out for advice on what I need and how deep down this rabbit hole I should go. In my current dream world, I would use plastigauge to check main and rod bearings. Hoping those look good, I would replace the cam, lifters, push rods, rockers, rocker bridges, timing gear and associated gaskets. Does this seem like a feasable solution? I know my way around tools and an engine pretty well, but I've never been cam deep before (I've pulled heads and timing gear before). I think this would run ~$1K, and I'm ok with that.

This truck won't be a DD, but I would like to do this right. In the end if I put 30-50K miles on it in my lifetime I will be surprised, so I don't want to sprint to a full rebuild unless it is strongly recommended.

Does anybody have better advice on a solution? Are there any "while you're in there" recommendations? I have found a Comp Cams Xtreme Energy cam that I like, #10-214-5. Any thoughts on it? Do I need the full kit (inc springs and holders) or could I just go with cam, lifters and timing set? Any guesses as to what happened in the first place? The low compression cylinders had the missing push rods, so I'm guessing the damage was done before I picked it up. Any thoughts on how much more damage I caused by driving it?

Thanks in advance guys, again I appreciate your thoughts and your time.
Ray

[tgreese]

Hi Ray - How loose is the timing chain? What would you like to do, fix the engine in the car or are you willing to remove it? I would look most critically at the top end of the engine - valve train and cam - considering the carnage found there. I would replace the broken and bent parts, button it up, and measure the oil pressure with a good aftermarket mechanical gauge. These engines are known for low hot idle oil pressure at high miles, which could be a worn oil pump, delaminating cam bearings, or just plain worn out. I'd want to know hot cruise and hot idle oil pressure, compression wet and dry, and go from there. A leak-down test might be next.

If it were for me, I would not modify it. A 401 has a lot of poop in stock form, and speed equipment will cost more than the factory parts.

[bruegge]

Thanks for the quick response Tim.

I would like to keep the engine in the truck if possible. I will pull the water pump and check on the timing gear. I'll also throw a new oil pump on the parts list.

Ray

[letank]

Welcome to the asylum Ray, it is always a trip to see how newby are fairing, you did well for a midnight run.

As far as timing, some of the timing sets are not up to specs, see the real issue here -oiling slots-

http://theamcforum.com/forum/edelbrock- ... page4.html

unfortunately photobuckets has gone belly up but I saved the picts, wait a little for the links to show up -cannot find them at the moment, but I am sure somebody will chime in with more precise description-

the slot has to match the side on the cam end



http://www.bulltear.com/forums/showthre ... 1aeda404c0

from this forum earlier this year, but picts gone

http://www.fsjnetwork.com/forum/viewtop ... 10&t=12192

Otherwise Ammeter bypass to do, and probably a dui or other ignition distributor to install

http://www.madelectrical.com/electrical ... uges.shtml

[RamJetFSJ]

Welcome Ray, and cheers to you for living the Roadkill dream! Good luck on your project. And remember, Dont get it right, just get it running!

The guys at Roadkill and DED really gave me the motivation and confidence to finally get my 15 year project Jeep driving daily, even if its not perfect.

[Nikkormat]

If this is meant to be a project pull it apart and see what you find. Then you will know how to proceed. Valvetrain problems can affect oil pressure and compression!

It pull the heads, cam, and then pull the pan off and take a peek at the bottom end. Worst case scenario if you decide you're in over your head at that point you could pull the short block and send it to a professional.

And welcome aboard! Sketchy FSJ road trips are the best!

[440sixpack]

What he said.

Just bite the bullet and fix it.

[bruegge]

Thanks for the help and the kind words guys. Letank, thanks for the links and pointing me in the right direction. Obviously I have more homework to do.
I'm hoping to order up parts tomorrow, I will keep you posted on my progress.
Ray

[Gumby]

I would actually hold the order until you figure out what the bottom looks like. Getting the full picture will keep you from banging your head ... wait, you still will. Welcome to the insanity of owning one of these. You are a true adventurer for going to pick your truck up on a bike. Total beast mode.

[letank]

Also check these posts, of course photocrooked is DOA, so no picts, but a wealth of reading

http://www.ifsja.org/forums/vb/showthread.php?t=176619

[REDONE]

I would actually hold the order until you figure out what the bottom looks like. Getting the full picture will keep you from banging your head ... wait, you still will. Welcome to the insanity of owning one of these. You are a true adventurer for going to pick your truck up on a bike. Total beast mode.

Completely agree with my good buddy Gumby here. You'll still be piecemealing this and that later, but the more you get at once, the more deals and breaks you can get from the vendors. Also, where's about in CO are you?

[will e]

You are a true adventurer for going to pick your truck up on a bike. Total beast mode.

Totally agree. A 9 out of 10 for beast mode. You would have got the extra point if you had sold the bike for gas when you picked up the Jeep.

I would just pull the motor. It's been through hell. And working on a motor all day in the truck sucks. By the time you pull the heads and front cover all you have left is a couple of motor mounts (which probably should be replaced) and the transmission bolts. Once you have the engine out you can do a really good inspection and clean up. You can pull the oil pan and pastiq gauge the bottom end. Probably just go ahead and replace the rear seal at the same time. If the bottom end looks good put the oil pan back on (again easier when out of the truck) and try it out.

I am a little concerned about the compression numbers you had. But with the push rod problems it may not be rings.

Frankly, if it was me, I would have it rebuilt. Get it done once and do it right and then move on to the next thing. If you end up fighting the engine for the next couple of months you might lose interest in the project.

[babywag]

agreed pull it. laying on your back trying to check bearing clearances?
everything is so much easier w/ engine on a stand.

[Nikkormat]

Engine stands are cheap at harbor freight! But, i wouldn't get the cheapest one.

I made the order parts before I knew what I needed mistake once already. Like others have said, take it apart. Make a list of what all you need first. It will save time and money on returns and re orders later. Plus, who doesn't like coming home from work and finding 4 big boxes from summit on the porch?

Also, you have a 401. The most sought after jeep motor, period. Be careful. Put the time in to make sure it will stay together. Only bore it if necessary, and only as far as necessary.

[bruegge]

Good advice guys. I got excited and ordered cam and head bolts already. I guess I'll need those no matter what, so no loss there. I will wait on the rest until I've pulled the engine. Hope to get this done by Saturday. Thanks again for all of the advice and encouragement, I will keep you posted.
If anybody can point me in the direction of picture posting, I'll get some up for you.
Redone - I'm up in Frisco.

Thanks again!
Ray

[az chip]

Hope to get this done by Saturday

That would be BEAST MODE El numero uno. I would get it done by Saturday. But in which month would be the question.

[KJ Ryu]

If anybody can point me in the direction of picture posting, I'll get some up for you.

Thanks again!
Ray

Upload the image(s) to a site that allows 3rd-party linking (not photobucket! I use postimage.org). Once it's uploaded, either right-click the image on whatever site you use and select "copy image address" or some sites will have a button to create an IMG link for you; if not: Come back here; on the advanced editor, click the "Img" button; paste the image address that you copied earlier. Repeat for each picture.

[letank]

oiling notch on the 74, in 2009



and the other side