30 year old motor, stuck valves or rings

[markstrimaran]

Hi
It's a 360 AMC V8. It is my snow plow jeep , and boat transporter. It gets driven about 6 miles at a time maybe 20 times a year.
Any sea foam or marvel mystery oil? Thinking of filling the crank up with diesel fuel, and letting it sit until November.
It will start up, and idles rouph when cool. When hot it only will run at 1500 rpm.

 

[gonzo]

How did you determine the valves or rings are stuck?

 

[Mr Efficiency]

Find the troubleshooting script for that engine, and follow it.

 

[upchurchmr]

Do a compression test first.
Look at the plugs when you do it to see if there is one cylinder that's really different.

 

[PAR]

The AMC 360 was the last V8 produced by AMC, before being bought by Chrysler, who continued it's production run for a while in Jeeps. It's a tall deck block and has some potential, but not a lot. The best thing for a tied one, is as a boat mooring weight, frankly. This is given its value, potential, parts availability, replacement part costs, etc. There are a lot of engines you can use that'll bolt up, that are a lot easier to find parts for and a lot cheaper to repair too.

You can try "pickling" the engine (filling it with oil) and hoping for the best, but it sounds like it was in crap shape before this latest issue cropped up. Even if you do free 'her up, it's still an engine with issues. How much do you want to put into an engine like this.

 

[markstrimaran]

Thanks for the response.
I am going to pressure test the cylinder tomorrow. Just hoping the boat experts would have some secret tricks, on the low budget side.

I will pull the valve covers and look, but for an old motor that gets 6 mpg at 70 mph. I will spend about 20 bucks to fix.
As a Cummins 4bta swap out. Is on the back burner. Just trying to delay the process until the kids are off to collage.

 

[markstrimaran]

How did you determine the valves or rings are stuck?

Just a guess, as pulling plug wire from distributor has no response.

 

[markstrimaran]

The motor has 78,000 miles. It had 67,000 in 2006. It has always ran very smooth.
A couple of weeks ago, it lost all spark, and coasted to stop. It had a coil wire to ground break on a soldered end. It was running a little rouph but would idle.
So far I pulled the exhaust to check for a bad catyalic converter. The smog pump has not been in operation since 2007.
I replaced the fuel filter, and fuel pump, as the pump had minor fuel leak.
I have not changed the oil very often, 3000 miles or every 2 years.
I pulled all the 2011 installed Bosch platinum spit fire plugs. All black and dry.

I added some engine flush, idle for 5 minutes, then drain and changed the oil.
I got a can of sea foam, but it does not run, idle well, I don't want to smoke out the nieborhood.
The vacuum advance, has been re worked into the 1979 configuration. The chokes, egr, might not work as intended.
It has a very primitive "electronic Ecu, The engine will run with out them.

starting the engine requires pumping the fuel peddle 5 times fast when cranking. Then holding to the floor. It will flood easily.

 

[Angélique]

. . . . I added some engine flush, idle for 5 minutes, then drain and changed the oil. I got a can of sea foam . . . .

Foamy oil could be an indication of water in the oil. If it smokes white (steam in smoke) then this is often an indication of water entering a cylinder first, however this also gives some discoloration of the spark plug of that cylinder, which you don't seem to have.

Water in the oil often comes from a leak head gasket, water entering a cylinder almost always comes from a leak head gasket, other possible causes for water in the oil are a crack in a head or in the block, or a cylinder bush fits loose in the block, etc...

If you have a water entering the oil issue, then of course the coolant level drops too, because the water in the oil and/or cylinders has to come from somewhere.

 

[Angélique]

↕ I've split up my previous post, and have added a bit to the below part . . .​

. . . . pulling plug wire from distributor has no response.

Then best check the inside of the distributor cap, and also the rotor, see the info below . . .

And when old, also check the spark plug wires, and the high voltage wire from the ignition coil to the distributor cap, as they can have internal breaks and/or current leaking issues, which all is easily solved by replacement of these relatively cheap items, that often are ignored.

↓ Work Smart - Not Hard - Know How Now ---> Signs of Worn Distributor Cap and Rotor

↓ Joe Pool ---> JP 2 Code ---> Old Distributor Cap and Rotor ---> The Three Billy Goats Gruff (to keep the (grand)children occupied while checking the Jeep)

↑ The production code right of the center contact terminal there ‘‘ 1↑0 ’’ and the numbers ‘‘ 1 to 12 ’’ around it means . . .

Production Year = 2010, for the center ‘‘ 10 ’’
Production Month = September, as the center arrow points to the outside ‘‘ 9 ’’ for the month.​

- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

1997 Volvo 850 Wagon Project ---> #47 Ignition Wires, Distributor Cap & Rotor

Volvo 5 cyl - ‘‘ - $ 48.44 → 6 high voltage wires; - $ 29.65 → distributor cap; - $ 20.65 → rotor; - $ 1.00 → dielectric grease - ’’

↑ The terminal current transfer surfaces inside the cap (to spark plug wires) are very crusty = no good current transfer there !​

↑ Old ← Rotor → New ↑​

↑ Rotor old; notice the crack in the arm, plus the bad center and end current transfer surfaces = no good current transfer there !​

↑ The date code stamped on these current wires means . . .

‘‘ 94 - 41 ’’ - Production Date: - Year 1994, in week #41.
‘‘ 94 - 43 ’’ - Production Date: - Year 1994, in week #43.​

‘‘ Wasn’t expecting much improvement since there were no real ignition issues, but the engine seems to idle and run a bit more smoothly. No apparent difference in power. ’’

So, the good thing is, it can be quite bad before you experience a real ignition problem, but now you do have a running problem, best check these parts !

Good luck -

 

[markstrimaran]

Thanks,
It is running on all 8 cylinder now. I think, when the coil wire broke and the engine quit running. I got two of the spark plug wires interchanged on the distributor.

 

[Angélique]

Thanks, It is running on all 8 cylinder now. I think, when the coil wire broke and the engine quit running. I got two of the spark plug wires interchanged on the distributor.

OK, ready for another 30 years then . . ​

Here's a picture of the firing order for the next time . . ​

AMC V8 Timing​

- ‘‘ - Firing Order AMC 360 cid : 1 - 8 - 4 - 3 - 6 - 5 - 7 - 2

Distributor Rotation : Clockwise​

(LHD) - Drivers Side cylinder numbering (front to back) : 1 - 3 - 5 - 7
(LHD) - Passenger Side cylinders numbering (front to back) : 2 - 4 - 6 - 8 - ’’

Below an animation showing the same firing order of the LA series small block Chrysler, 273, 318, 340, 360.

P.S. → How Stuff In My Car Works → Videos → TDC ↓ video ← is in text explained in this post's first link.

TDC = Top Dead Center = the top end of the compression stroke of cylinder #1 = also the ignition point of cylinder #1 on the distributor.

How to find TDC on a Chevy 350, when you remove and install a Distributor or unplug all the Spark Plug Wires.

Chevy 350 Small Block - - - - - Firing Order = 1 - 8 - 4 - 3 - 6 - 5 - 7 - 2​