2350 fuel pump tappets

[simon999]

I removed head of fuel pump . My engine which was assembled april 2014 already had steel plungers. But since I opened head ai put new plungers and barrels.
When I took old tappets they had brass pins and they pressed inside
   
The new tappets are different they have black hardened steel pin. That pin is not pressed in so I can push out with my fingers.

   
Question is when tappets move in the pump that pin slide and do any damage in the pump? Cause it is not pressed in or have a snap ring on the side

[Hammerhead]

I have no experience with them, and I agree that a hardened steel floating pin with no form of containment does not sound like a long term solution.
Are the ends of the pins "blunt"?
Or are they "domed" to relieve hard corner surface contact?
The picture doesn't provide clear detail

[simon999]

(06-09-2017 )Hammerhead Wrote:  I have no experience with them, and I agree that a hardened steel floating pin with no form of containment does not sound like a long term solution.
Are the ends of the pins "blunt"?
Or are they "domed" to relieve hard corner surface contact?
The picture doesn't provide clear detail

   
The new ones blunt, the old ones pressed in flat.

[Nilao]

Kind of reminds me of the old days of free floating wrist pins in Oldsmobile engines. But even those had retaining clips.

[Hammerhead]

(06-09-2017 )simon999 Wrote:  The new ones blunt, the old ones pressed in flat.

Ok with that pic I can see that the outside circumference is chamfered, and probably conforms to the pump bore. Also the recessed ring that looks like an O-ring groove is actually an oil retaining channel that should hold more than sufficient amounts of oil to prevent hard contact scoring of the bore.
I agree that this would not be my preference, and definitaly not how I'd design it...which is why I'm not an engineer. I agree with Nalio that free floating pins should have some form of "capture" system to eliminate the risk of bore damage. My personal preference is teflon buttons. They don't fail, they don't come out accidentally or from vibration, and they don't contaminate anything. Every hot rod or dragster motor I've built, that's all I use. Unlike snap rings or circlips, I've never had or seen one fail yet.