Yeah I know, I have a copy, but the .904 lobe section is really limited from Comp. I would hope they have a lot more .904 lobes numbers than what is in the catalog but you probably have to call to get them.comp cams has a master catalog lobe profile too
Well, they've been making them since the early 60's (factory and all), so I reckon the problem isn't "lobes that were designedI was wondering how reliable flat tappet lobes that were designed for the .904 Mopar lifters are and if people have experience with them?
I'm sure that is sound advice, and what has been said for some time now and something that has worked - for the most part, FT cam failures still seem to happen regardless of oil, correct break in etc.Break-in of flat tappet engines require LOTS (over 2000ppm) of zinc and accompanying additives.
After break-in, you still need to use oil that provides over 1000ppm ZDDP for the life of the engine.
Those lobe profiles are fine with the standard precautions for flat tappet cams.I have been considering cams for my upcoming build. I am likely to go with a flat tappet due to the cost of a roller. I was wondering how reliable flat tappet lobes that were designed for the .904 Mopar lifters are and if people have experience with them? I dont see a lot of people suggesting them on threads.
The companies I see with mopar lobes are Hughes and Comp Cam's Extreme Energy HL series
For example these are basically the same duration but different lift accelerations and max lifts. I dont know why you would ever use the regular ramp rate unless there was a durability issue.
Regular ramp rate
Mopar .904 tappet ramp rate
Nothing says using a synthetic with proper amounts of zinc and phosphorus made into the formula is necessarilyI'm sure that is sound advice, and what has been said for some time now and something that has worked - for the most part, FT cam failures still seem to happen regardless of oil, correct break in etc.
I could offer up examples of opinions in favor of synthetics, one from David Vizard, renowned automotive writer and all round petrolhead who is in favor of synthetics with FT cams but are these comments fact or advertising. Based on my experience I don't see that the use of a synthetic will deal a death blow to your engine and that a high zinc oil is the only way to go - although I have also use those oils (Brad Penn, Joe Gibbs) with good success.
The reason I tried a synthetic was I had too much oil pressure and wanted to switch to a thinner grade of oil. It has worked for me only thing I will say is it didn't help my rear main leak, but that may be contributed to the thinner oil.
I will be running spring pressures of 135/360 shortly with a SFT cam, hopefully all will be good.
I don't know of any synthetics that have a high content of zinc and phosphorus, maybe there is but I haven't seen or used one. From what I have seen synthetics use other products such as moly and calcium in their HP package, mainly I imagine as high levels of zinc is not compatible with catalytic converters. What I am saying is ZDDP is not the only game in town as to protection for FT cams.Nothing says using a synthetic with proper amounts of zinc and phosphorus made into the formula is necessarily
a bad thing here....
The two are not mutually exclusive.