Guys-- I would like to point out a few of my observations about the flat tappet cams in high strung engines-
I have run all versions of the FE engine and never had a cam problem--
I have run Top Fuel engines that we took roller cams out of and put flat tappet cams into because the rollers would come apart and scatter in the engine--we used the PROPER lifter for the type of CAM CORE and no problems
Now move forward several years-- modern engines and machining/blue printing methods have changed-- everybody is using aftermarket cranks and rods(what has that got to do with CAMS?) follow closely, no flames, we're thinking out loud here----
I believe that the cams aren't getting enough
oil--for many reasons--
1. all you guys want the FE block which in some cases doesn't have
oil to the likter galleys--no
oil drip onto cam, no oil around lifter, no lifter spin
2.not enough rod side clearance--so, reduced oil flow across rod journal and reduced oil fling upon the cam
3.no oil holes in side of aftermarket rods to squirt oil up onto cam and cylinder walls
4. scraper windage trays to reduce crankcase windage which reduces oil to cam
5. High pressure high volume oil pumps with accusumps, coolers , remote filters, excessive plumbing that combined with heavy weigh oil vis actually reduces the flow of oil to the engine. Most of you would benefit from the standard 6 quart pan and engine mounted filter for your street application, the oil would get to temperature and the flow would be better.
6. GET THE IDEA THAT MAYBE ALL THESE DIRECTIONS THAT WE HAVE DRIFTED MAYBE AREN"T GOOD FOR OUR CAMS??????????
The trend now is for oil squirters to oil the insde of the piston tops and drilled rods to carry more oil up to the pin area, which adds to the windage situation but helps upper crankcase oiling--
The other area is that everyone is looking for that big dyno number ,which probably will never get used, and the cam selection to build a high hp engine that will idle and still have high range power requires a cam profile that is marginal for the oil capibilities of that very same engine in the operating rpm range where it is utilized. The valve spring pressure required for these profiles are too severe for long life and will lead to nothing but increased wear in the valve train .
My suggestions?? Well we are in the woods, let's see if there are some trees
Consider detuning your mega HP engine to what you can drive and get live
a more moderate cam design that isn't more radical than the c3az6250d cam
A modern hydraulic roller lifter design-they now have profiles that make excellent power with moderate spring pressures--putting oil to the lifter bores for hydraulics will be necessary in some cases
Increase rod side clearance, rods that have squirt holes, piston sprayers,etc
Jerry
Threaded Mode
