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Originally Posted by David Kirkham
I believe the ribs in the valley are moon glow--so do all of the engine builders I have spoken to. The Merlin didn't have them in WWII. F1 blocks don't have them either--if anyone needs strength it is the F1 guys. Do you know of ANY modern production V8s that have them? I just checked our Copper 40 GT we made and it doesn't have them. As you know, people are now putting over 700 hp to the rear wheels in their Ford GT's with the new blowers.
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David
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Originally Posted by David Kirkham
Well, I base that on the observations of many, many motors. As I mentioned, the latest Ford 5.4 doesn't have ribs and is capable of 1000 horsepower (more than I need). Perhaps Ford put ribs in later blocks (I don't know, but you mentioned they did) because people were intending to blow them to ridiculous horsepower figures I simply don't intend to achieve. 700 horsepower is enough; 800 horsepower would thrill me as it is a wide margin of safety. (I am not sure why you mentioned I was only interested in 600 horsepower.) I am sorry if you understood me that way--I should have explained things better.
But, the list of engines without ribs is much longer. The Rolls Royce Merlin, and all radial engines of WWII didn't have ribs. Before anyone says that radial engines are a different monster because all pistons push on the same crank journal, remember there are several radial engines that had multiple cylinders in line (albeit twisted to put the other jugs into the air stream.) Finally, one of the greatest race engines of all time, the Porsche 917, produced 1200 horsepower--and it had no ribs...it is a flat (opposed) engine.
After taking all of those things into consideration, I decided the ribs were insignificant in the overall strength of what I wanted to achieve. the length of the water jacket had nothing to do with the decision. I could have made individual plates between the ribs had I been so inclined. See the picture of the latest DART billet block with ribs and bolt on water jackets. (It made me smile to see both of us come up with the bolt on water jacket independently.)
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OK, see here's the problem: I remember the issues with your differential design. I now see you saying "I decided the ribs were insignificant"; while I personally know of many many examples from actual block manufacturers with much more experience and many more engineers on staff that ribs are (just a little?) significant.
Me implying you didn't want to be bothered with individual valley cover plates is not me saying it's not possible, because as you've so clearly posted, it IS possible.
Here's the thing. You're producing a billet block. Other manufacturers are producing billet blocks. In the same price range. You're competing with them. They have features you don't, you have features they don't. You might want to study some of their features with the knowledge of their more extensive experience in block design and production. All that'll happen is you'll have a better block, maybe. Or not.
At this point, let the dyno tell its tale. It just seems such a jeckyl and hyde design: soooo strong on the bottom end, and just so-so up top. How is the bottom end interface with the rest of the block? Is it something that could be grafted onto the bottom of a Shelby/Pond/Gensis aluminum block?