Seized engine '50 Panhead

[loch]

I don't know. How would the crank shaft/flywheel/connecting rods seize and suddenly seem to free itself? I mean after taking off the heads and doing the rock it in gear thing again it started moving with some effort. Once it started to cycle fully it was if there were nothing wrong with it all. When cycling the kicker the pistons move quite smoothly in the barrels.

I think if it were a bearing issue in the lower end I would at least hear some remnants of that issue even though the pistons were moving freely. Likewise with a bent or broken connecting rod. Both pistons appear to travel their full range inside the cylinder.

I'm grabbing at straws here because I've been lucky so far - never had to deal with this sort of problem before. Never had an engine disassembled to this point either.

That said, I pulled the pan cover off the rear head this morning. With the nipples leaking so badly I wonder if there's any point in doing a pressure test on the valve stems? I did discover that the head is set up for the hydraulic lifters (see pics), but I've known since I purchased this bike that it had solid lifters. Not sure if this is a problem or not. And I'm also not sure why someone would do that. If the lifter doesn't allow oil to flow out of the port in the rocker then it has to go somewhere. The manual talks about checking for a welch plug at either end of the rocker arm. Now this is in the section for Servicing 1948 OVH Engines For Best Oil Control... There is a hole at the opposite end of where the rocker meets the push rod. The exhaust arm seems like it's gunked-up with carbon when comparing it to the intake arm. But then entire exhaust valve assembly has carbon buildup. I don't know what's normal here so any comments or suggestions are welcome.


RearCylinderHead.jpg



ExhaustRear.jpg


IntakeRear.jpg

[duffeycycles]

With nothing obvious in the cylinders,was it the crank assy that seized ?

[PaulCDF]

Looking GOOD!!!

[loch]

Thanks Paul, no I did not look closely, but I have seen cylinders that were scored. There was no obvious scoring. I will take a closer today with a proper inspection light.

Update: Pics of the cylinders. Nice reflection on the cylinder walls. I still need to clean them up and take another look-loo. But the cross-hatch is still visible. Not as though it was just honed yesterday. Nevertheless, no obvious scratching. The first pic is the front cylinder the second, the rear cylinder.


CrossHatchFrontCylinder2.jpg

CrossHatchFront.jpg

[PaulCDF]

GREAT News!!!!!!
It was hard for me to tell from the video; Any scoring of the front cylinder wall?

[loch]

Eureka! No longer seized!

After removing the heads, shooting some happy-snaps for your viewing pleasure - I look at these photos so much my wife says, "Why couldn't it have been porn." I decided to give the rock back-and-forth another try. At least now I thought, I can see the pistons. First attempt the front piston moved a minor amount. The rear piston didn't move at all, or maybe I missed it. I recall getting worried that one was moving and the other not. So I put it back in gear, this time I slipped with the shift linkage and accidentally put it in 4th. Eh, what the heck. Engaged the clutch and thought of that bully in 5th grade who pushed me down the hill between second and third period. Yah, it moved. This time in full strokes. I put it back in neutral, cycled the engine several times with kicker and was happier than Jed Clampett when I saw oil spewing forth from the cylinder ports. I'm pretty sure I released some expletives. But this time in ecstatic elation. No longer seized. I need to do some more exploration with the heads. Research the fix for the nipples that are leaking so badly it's a wonder it ran at all.

Video link for piston movement:

https://www.youtube.com/shorts/QG4S2lcYZTs


RearHead.jpg



FrontHead.jpg


InsideofFrontCylinderSeized.jpg


FrontHead.jpg

[T. Cotten]

A Schrader valve is fine, if you remove the core, Loch!

The gap between valvestems and guides alone are orders of magnitude larger than the leaks we must find.
So it constantly leaks down, and must be replenished by a constant, regulated air supply. Handpumps, air mattress inflators, shop vacs, etc., are a recipe for exasperating false-negative results.

(And you want to hold the differential for at least a half a minute, for microleaks to present themselves as blisters of microbubbles.)

If you get big bubbles with intermittent pressure, they are big leaks no doubt.

....Cotten

[loch]

Thank you Otis. I'm hopeful. Hope for the best, prepare for the worst. And max flex.

For the life of me I could not figure out why the pressure gage would bounce up and down every time I squeezed the pump. The air was escaping from somewhere. Then it occurred to me that I was supposed to be testing the mating between the cylinder head and the nipple. Squirt, squirt, a few drops of the sudsy solution at the top of the nipple-casting junction. Alas! The second picture shows the front cylinder nipple junction leaking air like a hyperventilating deep sea diver. The rear cylinder is leaking in exactly the same manner.

A word on my setup (first picture) since there seems to be as many ways to skin this cat (no animals harmed in this production) as there are people on this site. I opted for a pipe pressure-test plug for 1.5 inch fittings. It has the aforementioned and very much shunned Schrader valve (oh for shame!). But viola, it works most excellently with the handy bicycle pump. My pump is of the foot pump variety has a gauge on it. It was dutifully collecting dust in the corner. No more. And no need for cursing every time the plug pops out because you failed to gorilla-grip it into the hole. With the test plug, just press it in with a bit of force and turn the wing nut until the rubber deforms to your own satisfaction. And if it pops out, do it again, but with more testosterone than the previous attempt. Since we aren't trying to inflate the Hindenburg, the bicycle serves this application very well.

Note I decided to show the rear cylinder as well. After-thoughts can be troublesome. So it's the first pic, the setup is the second pic and the front cylinder is the last pic. Some readers might be unfamiliar with this cycle.

More on this process and progress later.


RearCylinder.jpg





PressureTestSetup.jpg


FrontCylinder.jpg

[otis71]

I seized a pressure washer once and nothing seemed to free it up until I soaked it with marvel mystery oil. Still runs today!

[T. Cotten]

Two and an eighth, Loch!

Its best to get a farm-supply wrench and carve it narrower, and even whack it in half to fit a tool bag.
Got fancy with one of mine...

MANWRNCH.jpg
(For Chiefs, specifically,...)

Commercial catalog wrenches are stamped junk.

.....Cotten
PS: Just now collected another Patron cork from the dumpster if you need it!

[loch]

Yes those are bubbles coming from both nuts.

I'm headed to the hardware store for a plug and an appropriated sized wrench. Any chance you know what size nuts those are?

[T. Cotten]

I take it those are bubbles hanging from both nus, Loch?

Your next step is to remove the manifold, and test the inlet nipples (rivets, etc.) separately.

In order to observe the seam between nipples and the castings, a large rubber stopper can be used, but it takes strong hands:

NPPLTSTR.jpg
In the absence of a proper stopper, just improvise!

PATRON.jpg

If the nipples test bubble-free, then reconditioning the manifold is an easy cure.

....Cotten

[loch]

No cheap regulator kits required!

Just a cheaper blanking plate and an even cheaper airline fitting to jam into the air port. Not to be confused with the air port found on a ship or the airport wherein planes create a lot of noise to move a lot of humans to and fro. Pics included see attachments please.

The bubble test was an eye popping, complete and utter failure! My Panhead blows bubbles better than the most ardent 4-year-olds at day-camp. I'm certain when I saw them I expressed more expletives. Positive in fact, that I'm sure they began with some adjective of religious origin.

So, without looking any further, I can assume the inside of the cylinders are probably caked with a thick wall of carbon. This is my guess because I would have had to increase the fuel input quite dramatically to equal the amount of air going in through the manifold.





Panhead_Manifold_Leak_Test_Results.png



Panhead_Manifold_Leak_Test_Setup.png

[T. Cotten]

Thanks and no worries about the kit. I need to wait for the blanking plate to arrive before I can go to the hardware store. I ordered a Linkert test plate from one of the online stores. It has a through fitting that the manifold connects to (that will have to be tested as well). I thought it came yesterday but those were parts for the shovel.

I was thinking I could just run the test with the manifold on air compressor but that would mean having to sit right next to the compressor while doing the test. I've had enough time working around loud equipment while I was in the Nav. So I'll get another manifold and do the test in relative comfort.

Beware Loch,...

Of testplates with cumbersome fittings, airhoses, and hardware that can weigh enough to make the manifold move before it is secure.
Light and long vinyl tubing and plastic nipples are easiest to keep out of the way, and those shirt-pocket air nozzles make great valve/adapters to the tubing.

Most folks carve their plates themselves, and one fellow just crammed a plastic pen barrel through his pet's rubber ball.
(I cut mine from scrap ABS, and gasket them with solenoid foam seals.)

Commercial testplates with Schrader valves are silly. (Late edit: stupid.)

....Cotten
PS: And oh yeah, you can bump up the pressure (and kick the motor through) to then snoop the sparkplugs, headgaskets, etc.

Diagnostics. Its all about diagnostics.

[loch]

Thanks and no worries about the kit. I need to wait for the blanking plate to arrive before I can go to the hardware store. I ordered a Linkert test plate from one of the online stores. It has a through fitting that the manifold connects to (that will have to be tested as well). I thought it came yesterday but those were parts for the shovel.

I was thinking I could just run the test with the manifold on air compressor but that would mean having to sit right next to the compressor while doing the test. I've had enough time working around loud equipment while I was in the Nav. So I'll get another manifold and do the test in relative comfort.