Bought the Comanche! what do I do with a seized engine?

[sevenn07]

You keep referring to it "off the chassis"... You do know that the frame and the body are one piece on the Comanche, right?

 

Rob L. :dunno:

 

And yes it is half unibody half frame. I may be using the wrong term. That was just the first word that came to mind.

[Eagle]

Do you think it would be better to just get the truck running without pulling the engine and such? I mean it is not an I have to. But if it would be in my best interest to just leave it in the bay and work from there I am game.

Only you can answer this question. It all depends on what YOUR goals and priorities are. If you want to learn how to rebuild an engine, then go ahead take it out and rebuild it. It's heavy and awkward. You'll be disassembling a significant portion of the front of the truck, and you'll need an engine hoist and an engine stand. You'll also be looking at several hundred dollars (minimum) between parts and machine shop work to do even a half-assed rebuild. You'll be disconnecting a lot of lines and wires -- you'll have to be very careful to take a lot of "before" photos and tag every single line and wire you disconnect or you'll never get it together again.

 

If your intention is to have a driveable MJ, it is possible that you can get it running by just removing the head and freeing up the pistons, as we have been discussing. It's a LOT less work to R&R (Remove & Replace) a head than it is to pull the entire engine and driveline. If you can get it running by just pulling the head, that makes good sense. If you pull the head and find something seriously broken inside -- you're just a little closer to pulling the engine because you will already have disconnected some of the things that would need to be disconnected anyway.

 

It all comes down to what YOU hope to accomplish.

[sevenn07]

Do you think it would be better to just get the truck running without pulling the engine and such? I mean it is not an I have to. But if it would be in my best interest to just leave it in the bay and work from there I am game.

Only you can answer this question. It all depends on what YOUR goals and priorities are. If you want to learn how to rebuild an engine, then go ahead take it out and rebuild it. It's heavy and awkward. You'll be disassembling a significant portion of the front of the truck, and you'll need an engine hoist and an engine stand. You'll also be looking at several hundred dollars (minimum) between parts and machine shop work to do even a half-assed rebuild. You'll be disconnecting a lot of lines and wires -- you'll have to be very careful to take a lot of "before" photos and tag every single line and wire you disconnect or you'll never get it together again.

 

If your intention is to have a driveable MJ, it is possible that you can get it running by just removing the head and freeing up the pistons, as we have been discussing. It's a LOT less work to R&R (Remove & Replace) a head than it is to pull the entire engine and driveline. If you can get it running by just pulling the head, that makes good sense. If you pull the head and find something seriously broken inside -- you're just a little closer to pulling the engine because you will already have disconnected some of the things that would need to be disconnected anyway.

 

It all comes down to what YOU hope to accomplish.

 

I like this point. I believe getting it running will be my priority.

 

A couple more questions.

1) Can you clean most of the engine with it still in the bay? (most of the pumps and such removed)

2) Do I have to retime the engine after pulling the head and such if I leave it in the bay?

3) Other than seals, if there is no major damage, is it ok just to clean and put it back together without rings and such?

 

I pulled the valve cover off today and the sludge in there was up to a half inch thick in places. Is this a bad sign?

[Eagle]

A couple more questions.

1) Can you clean most of the engine with it still in the bay? (most of the pumps and such removed)

Yes, but work carefully. Be sure you wash the gunk out and down on the ground, not into any part of the engine. Seal up or otherwise protect ALL orifices and sensors.

 

2) Do I have to retime the engine after pulling the head and such if I leave it in the bay?

No. The Jeep engines are not overhead cam, so removing the head doesn't affect timimg in any way if you don't disturb the distributor.

 

BTW -- this isn't a timing issue, but be sure you keep each set of valve components (valve, spring, keepers/locks, pushrods, etc) together and in order so that when you put the head back on every valve and associated parts goes back exactly where it started out.

 

3) Other than seals, if there is no major damage, is it ok just to clean and put it back together without rings and such?

Impossible to predict. I've done it. In my case, I reamed out the carbon ridge and honed the cylinder walls, but I left the pistons and rings in place and just buttoned it up again. Not high tech, but it ran fine.

 

I pulled the valve cover off today and the sludge in there was up to a half inch thick in places. Is this a bad sign?

Yupp.

[sevenn07]

Ok I got the head off yesterday and took a gander inside. I can't do to awfully much because nose got broke and I can't climb around the engine. I am out for today pretty much because it was put back. Why they couldn't do it at the ER is a mystery to me. I guess they just want more money.

 

But back to topic. I have taken a block of wood and small sledge hammer and hit on every cylinder with no luck moving. There is not a lost of rust or anything which surprises me. A little grit around some of them but that can be cleaned.

 

My questions for now are

What would be a good place to go from here?

Can the head and valve train be washed with a pressure washer to remove oil and sludge?

 

Oh and I have kept PB blaster in the cylinders the past two days on top of what was put in there when I started the project. The help will be greatly appreciated.

[Automan2164]

Ever thought about pulling the distributor, and priming the pump? Maybe getting a bit of oil going through the bearings would be a good idea.

 

Rob L.

[terrawombat]

I'd pull the oil pan and take a peek around the bottom and see if there isn't anything blatantly obvious causing the whole assembly to be jammed up.

[Automan2164]

I'd pull the oil pan and take a peek around the bottom and see if there isn't anything blatantly obvious causing the whole assembly to be jammed up.

 

Thats a good idea too.

 

Rob L.

[sevenn07]

I'd pull the oil pan and take a peek around the bottom and see if there isn't anything blatantly obvious causing the whole assembly to be jammed up.

 

Thats a good idea too.

 

Rob L.

I believe I will try that as my next step. When I pull the distributor don't I have to adjust it back? If so how hard is this?

[Automan2164]

I'd pull the oil pan and take a peek around the bottom and see if there isn't anything blatantly obvious causing the whole assembly to be jammed up.

 

Thats a good idea too.

 

Rob L.

I believe I will try that as my next step. When I pull the distributor don't I have to adjust it back? If so how hard is this?

 

If you are new to this, put get the engine to No. 1, TDC. Mark the location of the rotor, and make sure you put it back just the way you took it out. The gears are helical, or slanted, so it will rotate a bit while taking it out, and while putting it in. The oil pump drive looks like a flat head screw at the bottom of where the dist was. You can take a long screwdriver and cut it off, and chuck it up in a drill to prime the oil pump. Once that is done, you may have some difficulty putting the dist back in, as it rotates with the helical cut of the gears a tad, and has to drop into the pump drive at the same time. I just did this and took pics for a write up on Tuesday. I don't have time to upload, otherwise I would. It took me about 10 minutes of turning the pump drive a hair and dropping the distributor in a few times to get it to line up right. BE SURE NOT TO ROTATE THE ENGINE WITH THE DIST OUT UNLESS YOU WANT MORE HEADACHES!

 

Rob L. :thumbsup:

[sevenn07]

I'd pull the oil pan and take a peek around the bottom and see if there isn't anything blatantly obvious causing the whole assembly to be jammed up.

 

Thats a good idea too.

 

Rob L.

I believe I will try that as my next step. When I pull the distributor don't I have to adjust it back? If so how hard is this?

 

If you are new to this, put get the engine to No. 1, TDC. Mark the location of the rotor, and make sure you put it back just the way you took it out. The gears are helical, or slanted, so it will rotate a bit while taking it out, and while putting it in. The oil pump drive looks like a flat head screw at the bottom of where the dist was. You can take a long screwdriver and cut it off, and chuck it up in a drill to prime the oil pump. Once that is done, you may have some difficulty putting the dist back in, as it rotates with the helical cut of the gears a tad, and has to drop into the pump drive at the same time. I just did this and took pics for a write up on Tuesday. I don't have time to upload, otherwise I would. It took me about 10 minutes of turning the pump drive a hair and dropping the distributor in a few times to get it to line up right. BE SURE NOT TO ROTATE THE ENGINE WITH THE DIST OUT UNLESS YOU WANT MORE HEADACHES!

 

Rob L. :thumbsup:

OK thank you so much. It sounds like I need to get the motor to rotate first. That is my problem. It is siezed so no TDC until it moves :(

[Automan2164]

Sorry, forgot about that part. You can do it, but just make DARN sure, that the engine doesn't move until you put the dist back in. I just suggested that, because I was thinking that maybe a little oil to the bearings throughout the engine might free it up for ya.

 

Rob L.

[sevenn07]

Sorry, forgot about that part. You can do it, but just make DARN sure, that the engine doesn't move until you put the dist back in. I just suggested that, because I was thinking that maybe a little oil to the bearings throughout the engine might free it up for ya.

 

Rob L.

And I appreciate it. I am sure you are right that that will help quite a bit. I need to shoot some pics then post a few for yall too see. I really hope by some odd chance this sucker will break free! What if I pulled the oil pan and shot those bearings up with some PB Blaster?

[terrawombat]

Sorry, forgot about that part. You can do it, but just make DARN sure, that the engine doesn't move until you put the dist back in. I just suggested that, because I was thinking that maybe a little oil to the bearings throughout the engine might free it up for ya.

 

Rob L.

And I appreciate it. I am sure you are right that that will help quite a bit. I need to shoot some pics then post a few for yall too see. I really hope by some odd chance this sucker will break free! What if I pulled the oil pan and shot those bearings up with some PB Blaster?

 

No PB blaster in there. If you pull the pan and everything looks normal, I would start pulling bearing caps off - one at a time. Inspect the bearing. If there are marks all over it and it is scored, chances are the engine was either run without oil or the pump failed. If everything looks okay, reinstall the bearing cap to the proper torque (I don't know what that is, but it'll be different for the rod bearing caps vs. the main bearing caps). Continue down the line and keep inspecting the bearings. Take pictures and post them up here and we can tell you if they look okay or not - just make sure the pictures are CLEAR as it'll be near impossible to determine if anything is wrong with the bearing from a BLURRY picture.

 

I suspect you're going to find something very obviously wrong when you pull the pan.

[Geonovast]

Main bearing cap torque spec is 50, then 70, then 80. Do all to 50, then all to 70, then all to 80.

[terrawombat]

Main bearing cap torque spec is 50, then 70, then 80. Do all to 50, then all to 70, then all to 80.

 

Also, before re installation of the bearings, slather them with oil or get some engine assembly lube from your auto parts store and apply that. It's an oil-soluble grease that will save the bearings on a 'dry' startup.

[sevenn07]

Ok I got the pan pulled today. I have some news. Now I need you help deciding if it is good or bad. The problem is that the culprit was rust. The top of the cylinders are good and rust free. The bottoms of the cylinders are rusted. Now most of the rust is in piston 3 and 4 which are the two stuck in the highest position. The others are relatively rust free to what I could see. The rust in these two pistons is not just really light surface rust. I really need a pic to show you but it's not completely rusted around but it has quite a bit of rust on them. Could it be sanded down with say steel wool then left for the rings to do the rest or is this gonna ruin the engine?

[streetjeep2.5]

My initial thought is if those two next to each other are obviously worse than the others could it be a water jacket crack in the block? Or, is it just coincidental, like those just being higher up in the cyl's than the others the rust gathered there???? Guys, your thoughts????

[sevenn07]

My initial thought is if those two next to each other are obviously worse than the others could it be a water jacket crack in the block? Or, is it just coincidental, like those just being higher up in the cyl's than the others the rust gathered there???? Guys, your thoughts????

I don't believe they are cracked because the others are not completely rust free. I think these just happened to be highest up and since only the bottom side rusted then they got the worst of it. I could be totally wrong. But I really hope that I can get this thing to turn and possibly running. What would make only the bottom side rust though?

[Eagle]

My initial thought is if those two next to each other are obviously worse than the others could it be a water jacket crack in the block? Or, is it just coincidental, like those just being higher up in the cyl's than the others the rust gathered there???? Guys, your thoughts????

I don't believe they are cracked because the others are not completely rust free. I think these just happened to be highest up and since only the bottom side rusted then they got the worst of it. I could be totally wrong. But I really hope that I can get this thing to turn and possibly running. What would make only the bottom side rust though?

Condensation?

 

Question -- from where the other (lower) pistons are, can you tell if the rust extends as high as the portion of the bore where the rings operate? If you have heavy rust where the rings slide, you're going to have to tear it down, have it bored oversize, and buy new pistons as well as new rings. At that point, a junkyard engine is cheaper. However, if the rust is only at the bottoms of the bores, below the lowest point where the rings go in operation, the cylinders still might clean up and the engine might be usable.

 

Have you had the head off yet? How are the bores above the pistons?

[Automan2164]

Ok I got the head off yesterday and took a gander inside. I can't do to awfully much because nose got broke and I can't climb around the engine. I am out for today pretty much because it was put back. Why they couldn't do it at the ER is a mystery to me. I guess they just want more money.

 

But back to topic. I have taken a block of wood and small sledge hammer and hit on every cylinder with no luck moving. There is not a lost of rust or anything which surprises me. A little grit around some of them but that can be cleaned.

 

My questions for now are

What would be a good place to go from here?

Can the head and valve train be washed with a pressure washer to remove oil and sludge?

 

Oh and I have kept PB blaster in the cylinders the past two days on top of what was put in there when I started the project. The help will be greatly appreciated.

 

 

There be your answer to the question you posed Eagle. Don't tell me your going old on me!

Rob L.

[sevenn07]

My initial thought is if those two next to each other are obviously worse than the others could it be a water jacket crack in the block? Or, is it just coincidental, like those just being higher up in the cyl's than the others the rust gathered there???? Guys, your thoughts????

I don't believe they are cracked because the others are not completely rust free. I think these just happened to be highest up and since only the bottom side rusted then they got the worst of it. I could be totally wrong. But I really hope that I can get this thing to turn and possibly running. What would make only the bottom side rust though?

Condensation?

 

Question -- from where the other (lower) pistons are, can you tell if the rust extends as high as the portion of the bore where the rings operate? If you have heavy rust where the rings slide, you're going to have to tear it down, have it bored oversize, and buy new pistons as well as new rings. At that point, a junkyard engine is cheaper. However, if the rust is only at the bottoms of the bores, below the lowest point where the rings go in operation, the cylinders still might clean up and the engine might be usable.

 

Have you had the head off yet? How are the bores above the pistons?

The heads were off yes and no rust in there. all good. Now for the bottom side. Yes I do believe some of the rust did extend up into where the rings sit. I don't know how much though. If I just tried to clean it up and sand down what I could and such would it hurt to run the engine. I mean honestly all I have to lose is a trash engine anyways right? I don't really wanna put all the money into a new engine but I guess if it had to be done I could. The truck being wrecked just isn't worth all that much. (when I say wrecked I don't mean in bad condition wrecked, still very safe to drive and what not) One of the biggest things that scare me as well is why the engine got rust. Why didn't they run it every once in a while to keep that out. Or was there more to it that caused them to sit the truck up. I know yall don't know but I am starting to wonder a lot of things.

[streetjeep2.5]

:popcorn: