2000 Dakota update and further advice (Head gasket)

It will matter a lot. You may need to remove the distributor to get everything lined up right.

It's an old engine, you don't need any assembly lube. Cleaning won't hurt anything, though.

The manual for the engine will tell you if you need to replace the head bolts or not. Some engines have bolts that are intended to expand when torqued by a controlled amount and the bolts cannot be reused. Some engines do not. I don't know about yours.

It wouldn't hurt to look at it. Move it back and make sure all the notches line up afterward, though. On the other hand, if you did see something wrong, could you do anything about it? If you can't do anything to fix it, why look for it?

It's not really bad but it's certainly not a sign of a happy engine. Try using dykes or horizontal cutters to try and get the pieces off.

It's not a sure sign of anything.

Ask the shop. Personally, if the engine has 151k on it, it's probably due for valve seals soon. But I'd be reluctant to do anything you don't have to do until you know the block is good.

You'll know soon enough.

--scott

How do I go about making sure this engine is timed right? The distributor has not been moved much.

How do I go about making sure this engine is timed right? The distributor has not been moved much.

Dont get upset about this. You have done nothing that cant be sorted out.

You can do a "static timing" to get you very near the right timing. To do this, you get the #1 cylinder piston to TOP DEAD CENTER (TDC) on the firing stroke.

Nota Bene: This piston will be at the top of the cylinder twice in each cycle, once on the power or firing stroke, and again on the intake stroke. --Both will show to be TDC on the crankshaft pulley marker so clearly that alone cannot be used.

Since you havent moved the distributor much, you can probably pull the piston to the top, and look at the inside of the distributor. The pointer should be pointing exactly toward the cable tower that services the #1 cylinder. If it is 180 degrees off, then you are not on TDC firing stroke. Rotate the crankshaft to the next occurance of the piston being at the top of the cylinder and see if that brings them into alignment.

Now, if you have gotten the camshaft out of time, you will also have to correct that. It probably wont apply to you, but it can if you have overhead camshafts, or a broken timing chain or belt, etc.

When you get the engine back together, you can finish up the ignition timing.

Can I bring the piston to TDC with the heads off? Then adjust the distributor so the rotor is pointing at number 1 cylinder?

Your half right. The other TDC is on the "Exhaust" stroke, not the "Intake" stroke. The other is called the "Compression" stroke. On the "Power" stroke, the piston is going down.

Can I bring the piston to TDC with the heads off? Then adjust the distributor so the rotor is pointing at number 1 cylinder?

What is the difference? You will have two configurations at which piston

So if you know for darn sure that the distributor has not been moved much at all, you can bring cylinder 1 to TDC and then open the distributor cap and see where it is pointing. If it is nearly on 1, you can assume that you are on the correct stroke.. However is you are pointing more toward cylinder 4, this would indicate you are on the wrong stroke, and you need to advance the engine until the piston once again rises to the top of the cylinder.

Your half right. The other TDC is on the "Exhaust" stroke, not the "Intake" stroke. The other is called the "Compression" stroke. On the "Power" stroke, the piston is going down.****

Maybe I botched that.. My intentions were honorable.

There are four strokes for this type of engine.

Intake Compression Power Exhaust.

The 1 TDC firing position is between the compression and power strokes. The wrong position is between the exhaust and the intake (for timing purposes).

At TDC you are maybe between strokes?

On the 3.9 "Magnum" the distributor does NOT control the timing. Just put it back near the mark so that the rotor is pointing to the correct plug tower and you'll be close. This is called the "phasing" of the distributor, and its not really a precision setting.

Put a straitedge along the threads and see of all the threads touch the straitedge. If the bolt is "necked" some threads won't touch, and replace it.

Also, the push rods had a clack coating on

Its up to you. If its a thin non-flaky coating, I'd just leave it alone.

Also, an old manual to another car

You can use a dab of assembly lube there (white lubriplate or similar) I wouldn't use a heavy chassis grease.

I sure as heck would! And see above- the timing is set by a cam position sensor on the passenger side of the transmission bellhousing. Bolt the distributor down before you turn it so that the rotor drive doesn't jump out of its slot and so the distributor housing doesn't rotate. That'll save you the hassle of re-phasing the distributor later.

I'd try to get them off... but its a rather bad sign. That thing got HOT. The piston rings may have little or no spring tension left and it may just swill the oil when you get it running :-( In fact, the very few 318-family engines I've heard of failing from overheating did just that- they lost all the ring tension and turned into oil hogs rather than breaking heads or blowing gaskets. of course since this one has coolant in the wrong places it obviously does have head damage.

It could still be a warped head.

I'd be very careful how much money I sunk into it... If it were mine, I'd ask them to check the heads for straightness and mill them if necessary. That usually doesn't require a hot-tanking. If they do tank them, they should be able to tell you if their process will damage the seals and guides.

I'd also check the block for straightness with a straightedge as well as I could. Its not going to be a machine-shop quality measurement, but you should be able to check for any sunken or raised spots yourself.

After what this engine has already been through, that won't be the deciding factor!

Not in this case, since the crank position sensor sets the timing, not the distributor ;-)

But you do have to get it phased right, and your procedure that you outlined should be plenty for that. To tell the difference between TDC on the exhaust stroke (not the one you want) and TDC on compression (the one you do want) with the heads off, look at the camshaft lobes for cylinder #1. TDC @ exhaust will have the exhaust valve just closing and the intake valve just opening. TDC on compression will have both cam lobes pointed generally away from the lifters and will have both valves closed.

This piston will be at the top of the cylinder twice in each cycle, once on the power or firing stroke, and again on the intake stroke. HLS. ____________________________________________________________________

Your (sic) half right. The other TDC is on the "Exhaust" stroke, not the "Intake" stroke. The other is called the "Compression" stroke. On the "Power" stroke, the piston is going down. thenitedude. ____________________________________________________________________

HLS was right. The piston is at TDC at the beginning of the power stroke, and again at the beginning of the intake stroke.

You're right too. The piston is at TDC at the end of the exhaust stroke, and again at the end of the compression stroke. It's the same information expressed in a different way. Rodan.

No. The beginning of "Power" stroke and the "Intake" stroke is ATDC. (After Top Dead Center)

The piston is at TDC at the beginning of the power stroke, and again at the beginning of the intake stroke.

Rodan. ___________________________________________________________________

No. The beginning of "Power" stroke and the "Intake" stroke is ATDC. (After Top Dead Center)

thenitedude. ____________________________________________________________________

You win, nit dude.

Rodan.

No. The beginning of "Power" stroke and the "Intake" stroke is ATDC. (After Top Dead Center)

At TDC, the piston is dead still between two strokes.

I would button it up and see how it runs. If it runs fine for a week, it should run fine indefinitely. My guess is that the nits at Midas didn't get the air out of the system and the engine probably had water in the block but mostly air in the heads. That *should* have protected the rings and lower block from disaster and would explain why the heads went first. My guess is that the heads warped from basically running dry and that's what let coolant in the combustion chamber and made the smoke cloud.

One thought, If I should not spend extra money on this, since I have the heads off would it be feasible to replace the valve stem seals myself? Is this a hard job? Also, should I lap the valves at home? Is there a chance of scrwing something up?

I have the stuff to lap valves. I did it on an old techumseh engine I rebuilt this winter. I would have to buy a valve spring compressor. I can get one cheaply at harbor freight.

I know have a picture of the head and gasket. Can I email to someone on here to give me threir opinion?

One thought, If I should not spend extra money on this, since I have the heads off would it be feasible to replace the valve stem seals myself? Is this a hard job? Also, should I lap the valves at home? Is there a chance of scrwing something up?

I have the stuff to lap valves. I did it on an old techumseh engine I rebuilt this winter. I would have to buy a valve spring compressor. I can get one cheaply at harbor freight.

If the valve or seat surfaces are deeply pitted or burned, then you are best off to let a machine shop do it. They usually cut the seats and faces with perhaps a half to 1 degree difference in angle so that the seal will be better and will last longer. If you are really tight on coins, you could try it yourself, but I dont really recommend it.

The valve stem seals are little rubber "umbrella" thingys that slide over the valve stem and sit down inside the valve spring. They deflect large drops of oil from hitting the top of the valve guides. In a new engine, the metal valve guides in the head themselves do *most* of the sealing, I've pulled non-oil-burning Mopars apart and found absolutely nothing left of the little rubber umbrellas. The guides were doing all the work.

They're not hard to replace, but you have to use a valve spring compressor to remove the keepers, retainer plate, and valve spring. Do one at a time and take your time. A new set of stem seals is pretty cheap (bottom of this page- 5/16" size, $15.95