How high can the 420A engine rev safely on stock springs and retainers without worrying about valves floating or what not? Also, what is needed to get rid of the rev limiters ? (7200 and 7800 fuel/ignition cuts) would a msd ignition work? just wondering. Im rebuilding my engine and Im trying to decide what to do head wise. Originally i was going to get stainless valves, crower springs, retainers, pt cruiser lifters, rockers but someone said I should get cams and get port work done instead of getting the wprings, retainers and lifters since the stock ones are fine. anyone know?

i figure i may do rt2 since i can always get springs, retainers, lifter and such later on and the head would not have to be removed (at least i dont think it would) to put those in, where as getting it ported and polished would.

7200k
I would get the springs, retainers, etc. if you want to rev higher.

7200 is the rev limiter. I have heard people saying the stock valvetrain can rev up to 8200-8500 safely. thats the part im wondering about.

The rocker arms can go up to 7200 rpms with no problems, any higher and they have the potential to break. Upgraded rockers from a PT cruiser (or blackdog racing rocker arms) solve that problem.

The stock valve springs and retainers can reportedly handle 8200 rpms on stock cams or mild cams, but I don't know if they can do that with the increased lift on agressive cams. I think the retainers would, but I'm not sure about teh springs.

Lifters should be fine to 8200 rpms as well. Lifters from a PT criuser have improved oiling, which is always better, but I don't remember anyone having problems with stock lifters. (it's not like the 4g63 lifters :) )

>Also, what is needed to get rid of the rev limiters ? (7200
>and 7800 fuel/ignition cuts) would a msd ignition work? just
>wondering.

there is no way to defeat the stock rev limiter without buying the AF/X computer or having a full standalone. although the MSD and the Crain units are highly effective, they are sitll just piggy-backs to the stock ECU.

in addition to everything else that has been said... unless you are turbocharged, you'd need some insane cams to make any real power up that high. something like the crane #18's, or in other words, the most aggressive and non-streetable camshaft that you can buy.

Does the AFX ecu handle the 7200 fuel cut problem? I remember it pushing the ingition limit to 7800 but you still can't get that high without hitting fuel cut (7200). To my knowledge there is not anyone who yet has the ability to rev past the 7200 fuel cut, am I correct?

yeah. supposely you can rev to 8200, according to what's written on Howell's site. but you're right, i haven't heard of anyone here who has actually done it.

How about the guyyys who tested it? It was on a couple different cars, and anybody who buys it gets a true 8200rpm redline.



15.9 @ 86.7mph

Smooth idle? We don't need no stinking smooth idle.

Mods List:
http://highlander.dsmpower.com/sig.htm

I remember Dino saying that the redline was 8200 but you still can't get there because of the fuel cut, so nobody will ever know till we find a way to beat the fuel cut.

i heard u can rev to 9000 like a s2000 if u take out your ecu and put in a s2000 ecu, aka toaster oven, they sell wiring kits at www.imfullofshit.com

part number : 420
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96 talon esi-t
san clemente, ca

I've hit 7500 before. Ill try 8200 when i get my lifters,rockers, and springs installed..ill let everyone know then

I went 1st,2nd,3rd,2nd today by accident and thought the rev limiter would kick in....I was wrong! Since I have the A/T Tach in there still I can only guess how much past 8000 it went I'm thinking 8300 or 8400 and no damage at all but I wouldn't want to do that all the time.