Technical What would have done this? .. broken valve

Not what but who. 8^) Jack E/NJ

 

Nice Guy wants to sell me a nice 8BA. This is kinda strange. He has new valves and guides, decided to go with a runner. No signs of cracks or abuse. What happened?

 

Some yahoo dropped a nut down the intake when he removed the Stromberg. And he never went back to find it. It jammed in the valve and broke the head off.

Or is that the exhaust?

 

Exhaust.

 

Late timing or leaky valve torched the stem.

 

There is foreign object damage on the valve seat right in the middle of my yellow circle.
It doesn't look like the drove it long after the valve broke though as the piston doesn't look beat up from what I can see.

 

missed it completely! ... engine is clean otherwise with seller having bought new valves, springs guides! I wanna stock, come to Papa! Thanks 48!

 

The existing owner acquired this with loose headbolts. I wonder if prior owner tried to pry a stuck one out?

 

Nope ... there is carbon over the marks. Spot on 48!

 

Bump

 

Tight guide? Lippy

 

Matt have you checked out the Ford Barn yet? That stuff you're looking at, reading both forums is good.

 

That’s what I would bet my $ on. Hence mark on seat. Get it apart have it shake n bake cleaned. Crack text & pressure test. You may have a good one. Enjoy mate.
Cheers
Tony
It also looks like someone beat on remaining valve stem with a punch. Could be Wong.

 

What does the combustion chamber in the head look like ?

 

It looks like the end of the broken valve stem may have pounded on the valve stem piece for a bit. Luckily there may not be clearance for a broken valve in a flathead to jump over on top of the piston and it just bounced up and down in the valve pocket. Look at the head above that valve to see if it is marked up.

 

Will do! Thank you!

 

I am with you on someone prying on a valve,,,,,that would mark the seat also .
And the stem end looks like it is mushroomed from being assaulted with a punch and hammer ?
You mentioned that the present owner received the engine in this condition,,,,,so he really has no factual history on this engine as far as running condition,,,,right ?

Tommy

 

So ... present owner bought it from previous who said “ it was running and made a lot of noise so we shut it off. “ head was loose when present owner got it. There is some carbon on the marks kinda supporting this story, no signs of abuse elsewhere. I have never seen or heard of a value just snapping but that sure seems what it looks like.

 

Maybe it stuck, they pulled the head and pried it. That seems to make the most sense.

 

In the picture, all three valves that can be seen seem to be fully open. I don't think that occurs in the normal scheme of things. I think there may have been more done to this engine than we know.

 

Either someone pried up on the valves or turned the engine over without first adding some cleaner to the system to help free up the sticking components.

When it comes to multiple previous hands, all sorts of strange and weird stuff can happen to engines. Especially when someone is unfamiliar with a particular engine, or engine type.

Ignorance and lack of patience creates all sorts of bizarre end results.

 

I was wondering about the condition of the head because I thought that, or the piston top might tell you whether the valve head had spent some time bouncing around in the cylinder......or if something had gotten between the valve and head that prevented it from opening and it broke. There really doesn't appear to be any damage from a tumbling part. It looks to me as if the valve was stuck, or rusted to the seat and someone inserted something to try to open it.....hence the small mark on the valve seat. It would also help if you have a picture of the valve itself. I'd drop the whole thing in a tub of citric acid/water and let it bathe for about a week.

 

Tubman , ( Denny) ,,is pretty familiar with these engines,,he’s had a bunch of them .
I think he is correct in looking at all of those valves open at once,,,,,,maybe several stuck in the guides .
This engine has been sitting for some time looking at the “patina “ on the deck surface .
I’m not running this engine down or trying to scare you off,,,,it is probably an excellent core to rebuild .
Just use good judgment,,,and ask questions like you are doing and it should be okay in the long run .
BTW,,,,,,you haven’t mentioned an asking price,,,,I hope it is within reason .
I am confident this engine has been sitting for some time,,,,,,is that sawdust in the cylinder ?
Look it over good ,,,it might be in great shape .

And yes,,,,,valve heads have been known to pop off,,,,,and bounce around in the chamber .

Tommy

 

Thanks all!

 

Stem corrosion at the weld. Gasoline used to have pretty high sulfur , along with high lead content. The sulphuric contributed to sulphuric acid buildup.

valves are generally manufactured from two pieces, the head and the stem, which are friction welded together to make what looks like a one piece valve. Eaton valves, in particular, have the friction weld below the guide, and the acid could attack the weld, and the head would pop off..

TRE valves had the weld farther up the stem, such that the weld didn’t see much exposure to the sulphuric acid.

I ran into this while trying to qualify alternative suppliers for a family of Diesel engines, probably 25 years age.

FWIW, I saw the same type of failure on a SBC that I bought as a non runner. It was locked up, and had a couple of valve heads popped off, with no evidence the failure happened while running.

 

Finn,

thank you so much. I worked in industrial chemistry and appreciate the accuracy of your answer. What type or grade of gas could have created this, or, was this damage caused prior to modern gas. Lastly, am I correct in assuming new valves and guides could save her?

 

i achieved this same break once when i had a flat head it had a stuck valve or two , i shot some WD 40 down the stem and tapped it with a hammer i had handy , heard the dreaded ping and the head of the valve was gone ooops , guess that s not going to work

 

Capt.

I think this is why God, in her fine glory, invented Marvel Mystery Oil. I have had friends long gone who always added a pint to a tank.

 

I was going to reply pretty much what Finn said but he beat me to it. This was a 2 piece valve that had popped off just from sitting. And all the replies about the other stuck valves seems accurate. And as desoto291 said I would consider this as a potential rebuildable core and would pay accordingly. I’m sure there are guys that would throw the new valves and guides in,slosh some marvel mystery in the cylinders and go. I don’t think I would do it if it were mine.


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