5.0 Coyote Valve Spring Upgrade: Brands, size, and price

Eric@jpc

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If you are talking very high hp the major issue is having a cam, valve, and follower strong enough to open the exhaust valve against ultra high combustion pressures. Many a valve stem buckled and rocker arms destroyed trying to open the exhaust valve too soon.

Also some talk about seat pressure. The spring only implies a force. Pressure in this case would be on the contact area between edge of valve and seat? Others talk of back pressure on the valve back face that can reduce closing pressure.

Which one is it? Seat force exerted by the spring? Pressure on the back face? Pressure on the combustion face?

Ps remember when jpc changed over to studs on the cam holders? Is that still an issue?

Great thread op, this is enlightening.

We have not used those studs in some time now.

i think all your questions play a role in to what spring to use



For a 500-600whp NA build that's stable to 8000+ RPM, preferably retaining full VCT operation range, would the Trickflow #1 or the Livernois be the best option?

Either one will work :rockon:
 

DSG2003SVT

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I'm not looking to spray, just NA. If there is a better spring for that app than those two, let me know. I was just assuming that those would be the best.
 

AssPikle

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This explains your point better. Thanks for clarifying.

Yes what im saying is if you're building an engine and installing springs i would not purchase Boss Springs. I would BUY something better.

A real Boss has a larger exhaust cam which can make the valve float issue come sooner then if you have stock GT cams.

If you have an aluminator (comes with boss springs) and its already in the car and running i wouldn't change springs just because.

There are some guys making 1000 on boss springs in their Aluminator how ever its not an ideal setup IMO.

All my comments are more for the guys that are building a short block and looking for a replacement spring.

Every combo will be a bit different so there is not real answer to when you should change. How ever if you have plans on 800 plus my suggestion would be livernoise or trickflow "1". if you have some big cams i would suggest a swap

there are many variables to this question. IF you want any specific answers you can email me [email protected] i would be more then happy to help you with your specific combo.

:beer:
 

JP0814GT

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Has any one tested the single coil Ferrea springs with fully functional VCT? Only curious due to their rates seem to be in the ball park of the Livernois & TFlow 1's Ferrea is typically good quality parts.
So on a Turbo car if your trying to keep full VCT is getting the highest spring rate possible without VCT being effected the goal?
I also seen Ferrea has a higher lbs rating dbl coil spring available other than the one spring listed here. Logically I can see where a very stiff high lbs springs could cause inconsistencies in Valve control when retaining full VCT and could require lock outs example trick flow 2's.

Livernois= 70lbs to 190lbs

Trick Flow 1 = 80lbs to 180lbs

Ferrea = 90lbs to 190lbs
 
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SteveG@Lethal

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Has any one tested the single coil Ferrea springs with fully functional VCT? Only curious due to their rates seem to be in the ball park of the Livernois & TFlow 1's Ferrea is typically good quality parts.
So on a Turbo car if your trying to keep full VCT is getting the highest spring rate possible without VCT being effected the goal?
I also seen Ferrea has a higher lbs rating dbl coil spring available other than the one spring listed here. Logically I can see where a very stiff high lbs springs could cause inconsistencies in Valve control when retaining full VCT and could require lock outs example trick flow 2's.

Livernois= 70lbs to 190lbs

Trick Flow 1 = 80lbs to 180lbs

Ferrea = 90lbs to 190lbs

We have used them and they do work nice. You will have to use their Titanium Retainers and Spring Seat/lock as well which add ups.

The most used ones are the Trick Flow 1 & 2. You can re-use all your factory parts with them.
 

Gpcalero

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Okay, so I am going to open up this can of worms again....

Which valve springs do you guys suggest for a full bolt-on 5.0 with stage 3 N/A comp cams running 7,700 rpm? I'm just trying to get a few different opinions on the matter before I send the car off for the cam install and aed tune. Are they necessary and how much extra should a shop charge me on the cam install? I heard the valve springs were a PITA to change.
 

kcsvt94l

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I love how people didn't take the time to read Shaun's clear explanation of the information which was spot on.

How does pressure differential effect an all but closed valve? That is his point. Essentially the only point where you'll have a pressure differential occur on valves due to "BOOST" is in certain turbo applications with excess back pressure due to the additional pressure stored on the exhaust side (hot side) of the turbo.

What JPC is saying in regards to the the Boss exhaust cams contributing more so to the issue as opposed to a different cam is because the the bigger(more aggressive grind) exhaust cams in a Turbo boss 302 application magnifies what Shaun is referencing. pressure differential across the exhaust valve.

NTXRocker, your situation is no different because of how nitrous works which is simply compressing the amount of air that can be forced into the cylinders before the controlled explosion takes place. At the time of expansion of that compressed air the Intake valve is closed thus not creating any pressure differential across the intake valves.

Gpcalero, You would be perfectly ok on a max effort N/A Setup going with the boss 302 springs and valves.
 
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twistedneck

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Gpcalero, You would be perfectly ok on a max effort N/A Setup going with the boss 302 springs and valves.

even with the heavy factory valve? I thought boss NA were designed only to work with the lighter hollow stem ex. valve?

Have you heard about the fracturing exhaust valves mentioned earlier in this thread? that scares me..:uh oh:

i'm on cobra jet cams, NA, with boss heads and springs.. what rpm do you think that's good for? I ask because Ford racing swapped to Livernois springs using those same cams on the 2013 cobra jet cars.
 

RSKtakR

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Time to bring this up again sort of.. lots of good info here. I am about to have a 5.2 short block built for my 2013 GT, I bought a set of new OEM Gen2 heads with OEM valves and springs installed that will just get my current stock gen1 cams. The shop that is going to assemble the motor and install it for me asked me about valve springs and mentioned running Pac 1234x's. Right now, I have a 11:1 rods/pistons short block and stock gen1 heads/cams VMP Gen3r blower making 930whp at 19lbs through the built 6r80. The 5.2 will be 12:1, and get the same blower but with a 69mm upper vs the 72mm that is on it now so whp would go up to 1100ish at 21-22psi maybe. I don't have a problem swapping up to the Pac 1234x springs while everything is apart as its just cheap insurance and the $600 cost of springs is minimal compared to overall cost here and at that boost level and hp level, the springs are probably needed. But what about the valves themselves? Will the stock gen2 valves hold up to the added pressure of those Pac springs? I had a pushrod motor at one time that had stronger springs and Manley valves and one day the damn valve broke off the stem and fell into the cylinder, and I don't want that shit happening again. If new valves are suggested, what's a good dependable replacement?
 
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