AMC 360 rebuild ideas

[Rinkle_Stinkle]

So I drove by an experienced engine shop this morning and he definitely said its top driver side under the valve cover. He said he suspects a possible loose rocker (which would be best scenario) but he really wouldn't be 100% sure unless he was to open the valve cover.

I proceeded to tell him this was something I was going to attempt to fix as that was the entire point of me purchasing this jeep was to learn and grow with it yada yada...
He said he 100% supports that and said that if I pull the cover and get stumped to call his cell phone and he would be more than happy to drive by the house and take a look for free! That simply amazed me he even offered that because in my experience most shops could care less about your education and would rather you know less than more.

So in two weeks I will pull the valve cover off in the driveway (weather dependent) and I will take pics of what I find.


EVEN if I find its a simple fix I still want to plan out a possible rebuild, even if its further in the future verses closer.
I am definitely going to upgrade to the TFI ignition I think. the cost of the upgrade is minimal and from what I've read its pretty straight forward and will add better spark.

[letank]

Don't tear it apart until you at least check the compression. A leak-down test would be even better. The running engine will tell you things that the torn-down engine can not.

If you have an exhaust leak and it's hard to find, it's not doing much harm. Never tried it, but I recall you can connect the shop vac to the tailpipe, pressurize the exhaust, and look for places where air is coming out. Lots of tests to do before you tear into the engine.

I'd suggest you do this interactively, using the forum as your sounding board. Do the easy stuff first - remove the valve covers and look for a broken rocker bridge or a bent pushrod. Rotate the engine to each cylinder's TDC and examine how much slack is in the rockers. You can even put the valve covers back with the old gaskets and some silicone, if you need to run it temporarily.

x2,
166Kmiles is not too much if the engine was taken care of. Pict of engine bay and inside state of cleanliness can give a few clues on maintenance.
Remember that nobody can do a rebuilt as good as the way it was done at the factory. The 74 started to have visible blow by at 330kmiles.

[Rinkle_Stinkle]

Don't tear it apart until you at least check the compression. A leak-down test would be even better. The running engine will tell you things that the torn-down engine can not.

If you have an exhaust leak and it's hard to find, it's not doing much harm. Never tried it, but I recall you can connect the shop vac to the tailpipe, pressurize the exhaust, and look for places where air is coming out. Lots of tests to do before you tear into the engine.

I'd suggest you do this interactively, using the forum as your sounding board. Do the easy stuff first - remove the valve covers and look for a broken rocker bridge or a bent pushrod. Rotate the engine to each cylinder's TDC and examine how much slack is in the rockers. You can even put the valve covers back with the old gaskets and some silicone, if you need to run it temporarily.

x2,
166Kmiles is not too much if the engine was taken care of. Pict of engine bay and inside state of cleanliness can give a few clues on maintenance.
Remember that nobody can do a rebuilt as good as the way it was done at the factory. The 74 started to have visible blow by at 330kmiles.

that's the plan! I will be doing that this weekend more than likely.

[Fast Eddie]

I have a 79 J20 with iron manifolds and the air pump fittings. Looking at Hedman Street Headers #99240! Anyone used these or have any experience with these headers or others, on a SJ? Thought would be greatly appreciated BEFORE I spend the time and money to install!!

THANKS!

[MadMax78]

I have a 78 Cherokee with hedman headers. Where on it when I bought it. Other than tightening the header bolts a few times no issues so far.

[Rinkle_Stinkle]

Ok so update.

I pulled the valve cover. Everything is Olof, no weird rubs or wear marks, no broken spring, bent rods, etc.

As I was moving down the engine and just checking over everything I knock the spark plug and it moved.... so I put my hand on it and sure enough I was able to take it off by hand. I’m thinking this was my problem. Go figure, 2 mechanics completely over looked it. I should have gotten my hands dirty sooner it looks like...

This was late last night. I put the valve cover back on with a new gasket and will tighten it up today. I’m going to switch to a TFI ignition today as well so I’m removing it all spark plugs.

I did however find a small amount of oil in the air hood. It wasn’t a lot but it was enough to cause slight worry...

After doing the ignition I will do a compression test. I will post results once done.

[440sixpack]

Normally you can screw a spark plug in a few turns and it will run fine and make no noise at all. I hope that was your problem but I wouldn't bet on it.

[Rinkle_Stinkle]

Yeah... not looking good. I have not gotten to the compression test, hoping tomorrow.
But, the side the was making the tap has oil on every spark plug. They aren’t soaked but they do have some oil on them. I know that could be a few things but I also know that with an older engine it could and most likely are the piston rings. Combine that with the oil I found in the air hood it’s starting to look like a rebuild or swap again.
Hoping to know more tomorrow

Also: and I’m sure you get this a lot but I am at a loss as to how to post pics. I take it that it has to be from a desktop computer?

[440sixpack]

Oil on the plugs can be several things including rings . but on a worn engine loose guides and crunchy valve seals are the most common cause.

What is an air hood ?

[Rinkle_Stinkle]

Oil on the plugs can be several things including rings . but on a worn engine loose guides and crunchy valve seals are the most common cause.

What is an air hood ?

Air cleaner housing I guess it the term.

[440sixpack]

Okay. oil in the air cleaner is from blow by . a tiny bit is normal for an older engine if it soggy you have lots of wear. add that to probable worn guides and you have a tired engine.

[Rinkle_Stinkle]

I think I figured out how to post pics... I don't have any of the spark plugs yet but will get those today.

air handler .jpg

air handler 2.jpg

engine bay 1.jpg

makeshift garage.jpg

makeshift heat.jpg

[Rinkle_Stinkle]

rocker arms cylinder 1.jpg

full left rockers.jpg

[Rinkle_Stinkle]

So with that said, if I run this into the ground what kind of possible timeline am I looking at? I’ll post the spark plug pic tomorrow. The air filter definitely isn’t soggy, it is dirty but the oil was mainly in the air cleaner housing.

[tgreese]

So with that said, if I run this into the ground what kind of possible timeline am I looking at? I’ll post the spark plug pic tomorrow. The air filter definitely isn’t soggy, it is dirty but the oil was mainly in the air cleaner housing.

Your oil filler cap is supposed to have a foam insert to block the oil mist from the crankcase. Turn the filler cap over and if there is no foam, get a new one. Easy to find aftermarket part.

[Rinkle_Stinkle]

So with that said, if I run this into the ground what kind of possible timeline am I looking at? I’ll post the spark plug pic tomorrow. The air filter definitely isn’t soggy, it is dirty but the oil was mainly in the air cleaner housing.

Your oil filler cap is supposed to have a foam insert to block the oil mist from the crankcase. Turn the filler cap over and if there is no foam, get a new one. Easy to find aftermarket part.

the oil filler cap has foam inside of it so I don't think that's the issue.

[Rinkle_Stinkle]

Well I got it up and running again. I drained the coolant to check that and it had some rust color so I flushed the radiator and switched out the ThermaStat because the jeep had been running cold and the upper radiator hose was bloated and needed replacing so I figured why not.... had to replace the petcock valve because the original one was clogged and didn't drain.

Upgraded to the TFI ignition, added a new Ford F350 coil, 8mm wires and champion plugs gapped at .045.

started her up and still here the tap... so I'm guessing it internal at this point. I thought it was a lifter but there was zero play in the rockers. I know its cylinder 1 and its in the head but short of taking off the head, rebuilding and or replacing it there is not much more I know I can do.

I ran out of time to do the compression test. (it got real cold last night and that plastic tarped garage was feeling more like a freezer.)

I'm going to try and find time to do the compression test in the next two weeks.

Recap of what I found..

I found oil the in the Air filter housing and the air filter definitely needs replacing, i'll be getting one tomorrow. the air filter wasn't soggy but it was dirty and the oil I found was in the housing itself not in the filter.

I found oil on the spark plugs... I know this means more than likely those piston rings have worn away which is the main cause for this and the combined Blow by I'm seeing confirms this. I've attached the pic of the plugs. They look fairly old.

All spark plugs.jpg

Left driver side.jpg

Right pessanger side.jpg

I am at a cross roads now.... do I drive this thing till it can't drive anymore or do I need to plan to replace this engine sooner over later.

This is where I need help... from more experienced owners. I know that nothing is certain, but is this something I can nurse along for awhile? I'm going to change the oil in the next two weeks and replace with heavier weighted oil and Lucas heavy oil stabilizer to see if I can reduce the tapping sound.

[440sixpack]

The plugs don't really look that bad. serious oil burning will turn them black and crusty.

No slack in the rocker doesn't mean much unless you're turning the engine to get each one on the base circle of the cam.

In my opinion if you plan on keeping this rig you need to figure a rebuild is something you must do. and after all that's just part of running old rigs it comes with the territory. as far as how long you can run it like it is that's totally up to you, if it's not getting 4 MPG and burning a quart of oil per 100 miles run it as long as you want. best case scenario you run it until you're ready to pull it and it's fine, worst case scenario you trash a $250 core engine so you just buy another.

[Rinkle_Stinkle]

The plugs don't really look that bad. serious oil burning will turn them black and crusty.

No slack in the rocker doesn't mean much unless you're turning the engine to get each one on the base circle of the cam.

In my opinion if you plan on keeping this rig you need to figure a rebuild is something you must do. and after all that's just part of running old rigs it comes with the territory. as far as how long you can run it like it is that's totally up to you, if it's not getting 4 MPG and burning a quart of oil per 100 miles run it as long as you want. best case scenario you run it until you're ready to pull it and it's fine, worst case scenario you trash a $250 core engine so you just buy another.

That's exactly what I wanted to hear. I think I'm going to run this thing as far as it will go or until I actually have the funds in the account to swap for a new engine. The original plan was to try and keep the original engine to do a rebuild but honestly I just don't have the tools, space and knowledge to do a full rebuild. This last weekend taught me a lot about my current limits and a makeshift garage and my limited tool selection is telling me that its a little over my head at this stage in my life.

I may look into replacing the heads this summer. I do think I can manage that but would need to wait for it to warm up some.

[letank]

Reading again your posts, as said by 440sixpack, the plugs look really good.

did you try to run the engine with the valve cover off on the noisy side to see if all rockers are moving and the oil is flowing?