Quote:
Originally Posted by Ol' Ron
Grancor made some heads with Harley combustion chambers?? Had a set that had a pop up design for a 3 3/4 stroke piston on a 4' crank. Heads are now in a junk yard in Yuba city Ca. With the rest of my engine.
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The Navarro 'Hi-Dome' heads are a half-copy of the Harley KR design (in the valve area) - but not down in the combustion chamber area (or the pistons). I talked to Barney at length about doing the whole KR design back in the 80's - but he only wanted to make a certain amount of changes to his regular core boxes - so he made it about 1/2 way there.
On the Flathead Cadillac blown/injected engine that we built for Bonneville (the 'FlatCad'), I adapted the KR design to our head designs (we made them out of billet aluminum) as well as our pistons. My neighbor and I talked at length about whether to go pop-up with a flat-top or domed chamber. He said that Harley came out with a domed pop-up very late in the development, but that it really didn't run any better than the flat-tops (as a matter of fact a bit slower and everybody panicked) - so I went with flat-tops in my 3D CAD designs. Was a lot easier to machine the heads/pistons with a flattop and get the exact quench I wanted.
We've made 650 HP on alky on the engine dyno - our challenge is keeping the head gaskets in it - as the decks are 'thin', just like our Fords.
Here are some pictures:
Head1_ChambersHandPolished.jpg
Chamber_HandPolishedAndORinged.jpg
PistonPopUp.1.jpg
EngineBlowerDriveMockup101.jpg