Thanks for all the information. It's of great value, I am still on the fence with the roller cam vs HFT cam myself. You are absolutely right, lots of $$$ to put out for hydraulic roller. I suppose part of the allure was the ease of drop in, no break-in, etc. Like you said, there are so many differing opinions out there as to what to use. Lots of guys saying go HFT cam, lots of guys saying, 'I don't like HFT cams in BBCs..'' Lots of stories about wiped out lobes on break in, etc. It can be overwhelming.
My car will never see the strip, it's purely for cruising, putting nasty black stripes on neighborhood streets and making babies cry. I think somewhere between your street cruisers and street beast that is an absolute ball to drive is accurate. I will never take the engine to 6000.
There is a scat assembly I'm considering, cast crank, forged rods and a choice of either KB hyper pistons or a forged piston. My question is... If I get the internally balanced assembly from Scat, does this mean I can run a neutral flywheel and neutral balancer? Scat says it's ready to drop in, and of course other engine builders say the opposite.
Off to Wallace racing for some reading on DCR... Thanks for all the help.
It's my pleasure to help.
About losing a cam lobe, yes, it *does* happen... Only once for me, about 12 years ago. Nowadays, when I change the oil, I throw a bottle of the cam break-in additive in with the new oil; the main ingredient is the zinc additive they used to have in standard oil formulas. It's worked well for me (knockin' on wood, here!).
With regard to your rotating assembly, this (again) isn't quite as simple as some might make it out to be... As I'd mentioned before, RPMs increase the stress as a square of the function, rather than a direct linear correlation. This also comes into play on your rotating assembly; as the stroke increases, the distance that the piston must travel per revolution logically requires the piston to have a higher rate of acceleration. So an engine with a 3" stroke will actually move up and down more slowly than a similar engine with a 4" stroke. It's referred to as "critical piston speed,' and it relates to the entire bottom end assembly. From http://www.strokerengine.com/RodStroke.html
, the calculation for mean piston speed is as follows:
Piston Speed in Feet per Minute = (stroke x 2 x rpm)/12. With a 4.25" stroke, if we assume 5500RPM, this works out to 3896 fpm.
From the same website, they list the aftermarket cast crankshaft limit as 3750 fpm, but a forged one at 4500 fpm. Reverse-engineering the RPM limit (using your crankshaft as the limitation (3750 fpm), the red-line becomes ~5300RPM.
Doing some snooping around along this vein, I've not found any manufacturer say "my hypereutectic pistons will live to xxxx feet per minute." Most statements are rather vague, though they indicate between 3500 and 4000 feet per minute... which puts you right back at the same range. I'd simply run with your current plan, and call 5500RPM as "the redline."
Now... it sounds like that's all in line with your expectation for an engine that'll be "making babies cry." Going back to the camshaft selection, I'd suggest looking at the "Thumpr" by Comp Cams, at http://www.speedwaymotors.com/COMP-C...FZF7Qgod_WgAgg
Hydraulic flat-tappet, and the RPM range matches up to the rest of the package (off-idle to 5600 RPM). If you want to get a good idea of what it sounds like, do a youtube search of thumpr cam and 454, and you'll hear what it sounds like... The good news about the cam is that it sounds racy and should pull hard, and the lobe separation is narrow, so you get that loping idle. Other good news that actual valve lift and duration numbers for the intake side are very mild, so no "sexy" work needs to be done on the valve-train.
The price has come down a lot... when I was building my latest 454 (2 years ago) I went with the Summit cam because I was trying my damnedest to hide the costs... from my wife!
Anyway, glad I could help... I think sitting around, trying to crunch the numbers is just one of those fun things about building engines... and when you've put together the perfect recipe, getting in and DRIVING it... Ain't NUTHIN' better!