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whats the max rev for hydraulic roller lifters without a rev kit?
to pre-empt some of your questions, here are some answers:
all 4340 forged internals, balanced, splayed 4-bolt, 226@.050/.560 lift cam, 130# seat/400#open valve springs, titanium retainers
vader, leave it to you to come up with questions like those. i'll do my best to answer with the info i have and let you fill in the rest with your best guess. thanks for the help.
Just looking at some quick/dirty calculations, and making soem presumtions about the valve train, the valves may go into float at 6,300 RPM.
Assuming that the SS valves are about 105/100g each, and the retainers and locks are going at about 22g, and half the spring mass is about 60g, plus the push rods and lifters at about 45 and 100g respectively, and that the reciprocating mass of the rockers is about 50g (for a total just over 380g/.842 lb.), coupled with an acceleration rate of over 0.004"/° rotation due to the increased rocker ratio, the apparent mass at 6300 RPM is 22#/°. That doesn't take into consideration the oil present in the lifter and push rod which may tend to dampen the motion and also create further mass on reversion.
Further presuming that the lobe design lifts the valve to near peak within 45°, and using the inverse time derived from the RPM of the camshaft (not the crankshaft), spring presure required to control it at that RPM would theoretically be 246#. Given your installed height and the spring rate, you should be just getting into POTENTIAL valve float at that linear valve speed.
Granted, it's a guess based on a lot of presumtions, but it should be relatively close.
Frankly, I'd be more concerned about running 3/8" studs with no girdles with those kinds of forces.
Sorry if that seems a bit confusing, but engineering calculations from memory, on my first cup of coffee, and on my day off are confusing enough for me. You should be able to find enough reference material from any number of sources to derive a clean calculation and plug in your numbers and get a more accurate theoretical number for your exact circumstances and conditions.
A pretty safe bet will be right about 6000rpm +/- a bit.
Nice thing about hydraulic lifters is they will let you know by killing the power and pumping up when valve float gets severe enough. Just don't rev it that high.
You should not have to rev that motor more than 6000rpm to get best performance out of it anyways.
Go the track and try different shift points to see what the car likes best . Don't be suprised if its a lot less than you think.
Seat of the pants impresion can be deceiving.
Working off of F-BIRD, why do you want to go that high? Is that where your power is made? Or you just want a high revving engine? (Sorry, i don't know the nature of that cam).
stekman i've heard that rev kits are not really necessary and might only be good for 200-300 rpms at best and only if lifters are whats holding you back. my machininst says most people dont bother with them. as far as revving high, im most concerned because im running a 700r4 which has a big jump from 1st to 2nd and im afraid it will put me out of my powerband. the zz-409 cam is single pattern 226 deg and the superram still pulls to 6500 and beyond with a good cam from what dynos ive seen.
Originally posted by cormyr stekman i've heard that rev kits are not really necessary and might only be good for 200-300 rpms at best and only if lifters are whats holding you back. my machininst says most people dont bother with them. as far as revving high, im most concerned because im running a 700r4 which has a big jump from 1st to 2nd and im afraid it will put me out of my powerband. the zz-409 cam is single pattern 226 deg and the superram still pulls to 6500 and beyond with a good cam from what dynos ive seen.
Forget what ya seen and go to the track and try different shift points. believe the time slips.
i dont belive 6500 is too high if thats what wins races as long as your engine is built for it. the guys running minirams with long duration cams and high revs are just plain faster. i decided to keep my setup very streetable but i did build the bottom end to handle high revs. i am looking to maximize power and in order to do that you simply have to go into the higher rpm band as long as your cam and intake like that.
Originally posted by cormyr i dont belive 6500 is too high if thats what wins races as long as your engine is built for it. the guys running minirams with long duration cams and high revs are just plain faster. i decided to keep my setup very streetable but i did build the bottom end to handle high revs. i am looking to maximize power and in order to do that you simply have to go into the higher rpm band as long as your cam and intake like that.
But you don;t have a miniram or a big cam. All you're likely to do is put undue stress on the motor by reving the *** out of it.
Go to the track and run *your car*... forget what guys with mini rams etc are doing.
Many, most automatic cars actually will et best by "Short shifting first gear" try it.
its all forged internals with splayed billet mains, arp studs everywhere and h-bearings. im not too worried about a measly 6500rpms. just trying to nail down my valvetrain and a solid redline.
