Pulling my hair out over this misfire

[dmsfrr]

Originally Posted by runmikeyrun

I could see the top, I’m thinking more if it’s broken in the middle. I might pick up one of those boroscopes regardless, I’ve got a bunch of old bikes that could an inspection haha

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The rest of the lifter is inside it's bore and can't be seen from the top.
Look at the first photo back in comment #32.

[runmikeyrun]

Originally Posted by dmsfrr

The rest of the lifter is inside it's bore and can't be seen from the top.
Look at the first photo back in comment #32.

Ah, nuts! Thanks for pointing that out. I was thinking of the picture from the service manual, which showed a cutaway, but only for visualization purposes.


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[KULTULZ]

OEM HARDENED TAPPETS

[runmikeyrun]

A couple days soaking with MMO didn’t unstick that lifter (I simply cranked the engine over a few times and watched). At this point I have two choices:

1. Put the valve cover back on and run the truck for a while, hoping the lifter frees up.

(Subquestion: can I run the truck with the valve cover off? Or will I get oil running all over?)

2. Put the #4 cylinder to TDC and pull that valve spring and check to make sure that valve isn’t bent/sticking.

Part of me wants to check the valve as long as I already have the valve cover off; the other part says the valve isn’t the problem, it’s the lifter so I shouldn’t waste the time taking it apart.

I have to run out of town for the night, I’ll be back working at it tomorrow evening (Tuesday).

Thanks!


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[Daves55Sedan]

Ummm...if the engine isn't totally gunked up inside, I would not run the engine with the valve cover off. It will look like a waterfall of oil sprayed all over everything, particularly exhaust manifold (smoke, smelly oil burning).
I would NOT attempt to remove a valve spring with the head installed on the engine. If the spring is removed and the valve is not stuck, the valve will slide down inside the cylinder and it will be impaled by the piston possibly causing damage.
Furthermore, I don't know of a way to make removal of the spring possible when the head is still mounted on the engine. To my knowledge, the head must be removed so that a valve spring compressor can be employed. It is not possible to use it when the head is mounted on the engine.

[Lanny]

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QUOTE----Put the #4 cylinder to TDC and pull that valve spring and check to make sure that valve isn’t bent/sticking.

================================================== ===



I removed the valve springs on a 289 Ford, so I could replace valve seals, and
that was with the heads in place on a runnable 289 engine.
I did it by putting the piston all the way up on each cylinder that I was working on.

I made a simple tool, many years ago, when I did that job. You should
be able to find a tool, or make one that will pry the spring down to
remove the keepers.









.

[runmikeyrun]

Originally Posted by Lanny

QUOTE----Put the #4 cylinder to TDC and pull that valve spring and check to make sure that valve isn’t bent/sticking.

================================================== ===



I removed the valve springs on a 289 Ford, so I could replace valve seals, and
that was with the heads in place on a runnable 289 engine.
I did it by putting the piston all the way up on each cylinder that I was working on.

I made a simple tool, many years ago, when I did that job. You should
be able to find a tool, or make one that will pry the spring down to
remove the keepers.









.

I was going to say- piston to TDC and/or stuff the cylinder with rope and it won’t fall in.

Thanks for the tip about not running with the cover off. I did see a video with one cut open and peeled back, but not off, that’s why I asked.

We’ll see how it goes...

Thanks again!



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[40cpe]

If the lifter was not stuck you could push the push-rod end of the rocker arm down when the #4 cylinder is at TDC compression stroke. Save yourself the effort. Tapping on the push rod end of the rocker arm with the piston at TDC compression stroke is your only hope short of a teardown.

[56sedandelivery]

I have used compressed air to keep the valve up while on the engine. You need a adapter to the spark plug hole and be sure both valves are closed.

[dmsfrr]

Originally Posted by runmikeyrun

A couple days soaking with MMO didn’t unstick that lifter . . . .

If the lifter can't move on its own it's got to come out to see if it's cracked or there's something wrong with that lifter bore. There's only one way I know to do that.....


.

[runmikeyrun]

Diagnosis made: it’s the valve sticking. Lifter is ok.

I turned the motor over by hand until the valve opened fully. I propped the rocker arm in place on the pushrod side so it stayed up, then turned the motor over to TDC and I was able to push the pushrod down with relative ease. So it’s not a stuck lifter.

In this video you can see when I turn the motor over the valve is slow to close (the other valves sprung right back) because the stem is dragging in the guide.

https://youtu.be/ScOWoeKBFCU

On top of that, you can (sort of) see in the photo that the valve seal is pushed up to the top of the stem, I’m assuming it’s being caught and moved up by the bent part of the stem. I pushed it back down where it belongs and turned the engine over some more. When the valve opened and closed again the seal rode right back up.



I buttoned up the motor and I’m exploring options. One is to have the local shop handle it. If it’s a straightforward repair it wouldnt be too expensive. If bolts start breaking (or if something else lets go in 6 months) it might be cheaper to do an engine swap. Since this originally had a flathead but has been modified to accept the Y block, I’m wondering if another motor would use the same mounting points?

Thanks a ton to everyone for all your help, you really made my diagnosis easier and faster.


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[runmikeyrun]

So on a whim I took her outside and dribbled a whole bottle of MMO down the carb while an assistant kept the revs up. It’s definitely running much better. Idles much better. Still burning oil but I’m going to replace that valve seal and see what happens.


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[40cpe]

I was told that those seals are designed to ride on the valve stem. When the valve is closed, it allows oil mist to lube the stem. When the valve opens the seal rides down on the guide to help prevent the intake valve sucking oil by the guide.

[runmikeyrun]

Originally Posted by 40cpe

I was told that those seals are designed to ride on the valve stem. When the valve is closed, it allows oil mist to lube the stem. When the valve opens the seal rides down on the guide to help prevent the intake valve sucking oil by the guide.

Interesting. That’s the only one of the valves that I saw the seals moving though.


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[KULTULZ]

Originally Posted by 40cpe

I was told that those seals are designed to ride on the valve stem. When the valve is closed, it allows oil mist to lube the stem. When the valve opens the seal rides down on the guide to help prevent the intake valve sucking oil by the guide.

That's correct, an umbrella seal.

[runmikeyrun]

Hmm. I wonder why I’m still burning so much oil on that side.


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[KULTULZ]

Originally Posted by runmikeyrun

Hmm. I wonder why I’m still burning so much oil on that side.

1) A cylinder can show good compression and stil have a defective oil ring.

2) Valve guide(s) and/or defective seal(s)

3) Poor crankcase ventilation

4) Blocked oil drainage

5) Did you ever read the spark plugs?

You said previously this engine had been rebuilt?

Something ain't right ...

[Daves55Sedan]

So I guess we have a valve sticking within the valve stem guide on a recently rebuilt engine, right?
I do not think this can be attributed to improper valve lash adjustment. A bent push rod, definitely would cause me to suspect having the adjustment screw down too far. All I can offer to that is....There is an excellent text is the shop manual that tells you how to do a proper valve lash adjustment.
We once had one engine builder in this town. The guy was absolutely a perfectionist. He would never have finished any engine without having checked the tolerances of the valve stem guides. The tinyest flaw, and he would have replaced the guides. But shoot, I don't know how they do 'em now. Maybe they don't even consider checking the valve guides now?

[runmikeyrun]

Originally Posted by Daves55Sedan

So I guess we have a valve sticking within the valve stem guide on a recently rebuilt engine, right?
I do not think this can be attributed to improper valve lash adjustment. A bent push rod, definitely would cause me to suspect having the adjustment screw down too far. All I can offer to that is....There is an excellent text is the shop manual that tells you how to do a proper valve lash adjustment.
We once had one engine builder in this town. The guy was absolutely a perfectionist. He would never have finished any engine without having checked the tolerances of the valve stem guides. The tinyest flaw, and he would have replaced the guides. But shoot, I don't know how they do 'em now. Maybe they don't even consider checking the valve guides now?

It was rebuilt in the early 80s, and not sure to what extent. It is surprisingly clean on the inside though.

I’m going to replace the seals on that cylinder with either positive or the seals with the spring. It didn’t start burning oil like that before the valve started sticking.

The plug for that cylinder has wet oil down inside the insulator. It’s possible a ring went bad when the valve was sticking but I see that as plausible since compression was actually lower. On motorcycles (where the majority of my experience lies) the compression actually helps expand the ring so if that’s the case it makes sense why a ring wouldn’t be sealing well.

We will see when I replace the seals, which will hopefully be Sunday.


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[KULTULZ]

Just read an old FORD SERVICE LETTER I came across notifying dealers about the Y throwing push-rods. It is (was) attributed to too loose valve-guide/valve stem clearance(s).

Now throw into this the different push-rod lengths used and their ability to be assembled into the wrong engine. Think VALVE-TRAIN GEOMETRY.

The FE and MEL had similar maladies.