Pushrod engine without lifters

[hardingfv32]

I just saw plans for a prototype diesel military tank engine, about 850 HP.

It was a push rod operated splayed valve head much like the Mercedes Indy push rod engine, but there were no lifters. That cam is located in the normal pushrod engine location in the block. The pushrods sat on top of cam operated fingers, similar to the fingers that you see operating the valves in an overhead cam engine.

Brian

[flynfrog]

ok??

[PhillipM]

Is there an ending to this fascinating tale?

[hardingfv32]

You mean like the lack of $25m to fund the first two prototypes. Just seemed an interesting way to eliminate lifter bores.

Brian

[aleks_ader]

Brian could you that make quick draw??? I dont get it what is so differend in convetional "pushrod" engine design? THX

But overrall in f1 that engine will be a lit bit "useless", beacuse the "spring" efect of the bars cause big energy absorbions!! And consequence is "unsteady" or more unaccurete valve timing! Even more 17000 rpm make difference... But i will do little researc on that beacuse me also bothered wigh engine CofG!

[hardingfv32]

Quick draw is not in my skill set.

This design is just like the current overhead cam designs that use a cam driven rocker to push on the valve stems. I the case of this pushrod engine, a push rod is being pushed instead of a valve stem. Absolutely no value to F1, but still interesting if you have ever struggled with lifter alignment and friction losses.

Brian

[marcush.]

brian,fascinating ,very fascinating that finger follower thing.
I actually did something like that a long time ago with an A-series Austin Engine -1275cc which happened to have two apertures at the back of the block to accomodate the finger type followers .
Unfortunatelly I ceased all my work with A-Series engines to become involved into Ferraris and Porsches ..maybe sometime i find new motivation touching engines again after working in the automotive industry these days..
In those days I had my lifters made from a ceramic material which really worked very well in eliminating the most of the friction in that area and making camshafts survive a whole season when usually after a race weekend you could throw away both lifters and camshaft...
the finger type solution would have reduced mass even more ..I regret to not have pushed it along back then (2000)