What PSI until i start floating valves?
4th Gear Member
Joined: Sep 2009
Posts: 1,481
From: NC
The stock Valvetrain is good to 8k+ rpm. Anyone has anything to say that says otherwise is a noob and needs to go back to pushrod motors.
OP, clarify what you're talking about if you're not talking about valves & cam followers. The cast crank is good up til around 750hp maybe more but I don't know anyone that has went through all the trouble of building an engine and kept the cast crank. the Rods are good till about 450rw and the pistons are good right up until you detonate.
OP, clarify what you're talking about if you're not talking about valves & cam followers. The cast crank is good up til around 750hp maybe more but I don't know anyone that has went through all the trouble of building an engine and kept the cast crank. the Rods are good till about 450rw and the pistons are good right up until you detonate.
Anyone else support the claim that the stock valve train is safe for sustained 6500rpms? Note: I am running StageII cams with increased lift.
Go Texas!!!
Joined: Jul 2009
Posts: 4,613
From: Lincoln, NE
Anything over 6500 rpm and or .550" lift I would upgrade valve springs. It has been done many times spinning to 6500 rpm and not have valve float so long as your cams lift stay under .550". This of course is with a N/A motor, not forced induction.
4th Gear Member
Joined: Sep 2009
Posts: 1,481
From: NC
That is pretty much what I was thinking too. To be safe I am planning to drop back to 3.73 gears to keep my sustained(several seconds) rpms below 6400.
My dumb noob self wasn't willing to risk rpms over ~6200.
My dumb noob self wasn't willing to risk rpms over ~6200.
6th Gear Member
Joined: May 2006
Posts: 10,357
From: earleville md
yes boost will aid in valve float, but its more about rpm... honda guys run stronger springs on big boost set ups, but thats because then run ****in 28psi on 9500rpms... your going to be working with 15(thats MORE then you should be, if u have a stock valve train/cam, you should be smart enough to keep the boost in ur range, untill you have the full, proper set up) and what... 7k tops? no... stock cams so 6250 red line.... i would be more concerned with the exhaust guides then the valves floating due to boost if i were you.... but hey, im just the guy who works on heads... wtf do i know lol
Thread Starter
4th Gear Member
Joined: Apr 2008
Posts: 1,086
From: mi
so if i only go say 11-12psi to be safe for now then maybe in the summer throw some valve springs in there and bump it up to 14-15 psi what do i have to do next winter to do stuff right and be able to run the boost?
and what happends to the valve guides and how do u prevent it?
and what happends to the valve guides and how do u prevent it?
4.6L Section Moderator
Joined: Nov 2007
Posts: 10,286
From: South Central PA
Do it once. Run it until you start to get valve float. Then back it off slightly. Upgrade everything all at once. Dont just do something to get by. Thats wasted money. Wait til winter then buy TFS heads and cams from nick. Badass!!!
6th Gear Member
Joined: Jan 2007
Posts: 5,884
From: MI
I've had my cams in for over a year now, and continually spin 6200-6300 (6400-6500 in 1st) on the stock valve springs. On the nitrous i only go to 5800-6000.
I think this is totally acceptable n/a, but would not continually do it with some sort of boost.
I think this is totally acceptable n/a, but would not continually do it with some sort of boost.
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zanemoseley
2005-2014 Mustangs
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Sep 6, 2015 12:58 PM
