Engine 12
Is Now

Under New Ownership


Since Hurricane Michael in October 2018, Engine 12 now has a proud new owner.
It is now owned by David Jones in Texas and he will be

improving the running of it.
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15 November 2018:
Since Hurricane Michael more or less destroyed my home and shop, David Jones is now the new owner of the engine.

David has been busy and got it running again soon after getting it back to Texas.  He has been having the same timing and clag problems I was having due to the poor spray pattern and dribbling of the injector.  

Now, he is in the process of designing and building a new pintle type of injector.  I will try to keep you informed of his progress.

First, David came up with a preliminary sketch of an injector.

First sketch of pintle injector.
The new injector is designed to fit into the original opening in the cylinder head and should work much better than the poppet type I had been experimenting on before the storm.  David has better CAD capabilities and a better shop in which to make these precision parts.
   
First CAD drawing of pintle injector.

Inside view of pintle injector.
Here are a couple of views showing the inside of the injector.  Note the "O" ring near the top of the pintle.  This is to seal the pressure side of the pintle from the spring side.

3-D view of pintle injector.
This is how it should look when completed.


Parts made so far.
After some consideration, we've decided to try for a precision fit of the top of the pintle to the housig bore.  This is because the injection pressure may be so high as to blow out the "O" ring.  David is studying methods of getting the close fit needed to prevent excess leakage.

More later.
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5 December 2018:
In the last month, David has gotten some more done with the injector.  Shop time has been limited due to a new (first) grandchild and that pesky requirement of a job to put food on the table and a roof over his head.
 
Various parts, tools and trials.
Using engine studs as raw material, injector housings and drill guides are made.  Complicating the process is the size of the components that have to be made and the precision fit required for them to work.     
 
Getting close.
In order for a pintle to work properly, there must be an extremely close fit between the large diameter on the pin and the inner diameter of the body.  It is the differential pressure between the hydraulic pressure trying to hold the tiny valve at the end of the pin closed and the hydraulic pressure trying to lift the pintle against the spring and the valve pressure.

If the fit is too loose, there will be excessive leakage at the large diameter of the pintle and the injector will not work due to the pump not being able to provide the volume of fuel to allow the pressure to rise to the point of opening the pintle valve.  Also, without close alignment, the spray pattern will be compromised.    
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