So, the springs on a patriot head are inadequent with a .550 lift cam?? Or have they changed their spring pressure to accomedate higher than stock cam profiles? It seems to me that anyone going with better heads would have (or soon should have) a higher lift cam. Better heads should have better springs.

 

Most springs out there are about 240lbs of pressure full open to coil bind. Our spring isnt much different its 260. There is also a variety of different ways you can set the heads up depending on which spring you are using. Most companies have an installed height of 1.680" on our trucks. Some are 1.700" now coil bind is usually between 1.060" - 1.020" depending on the wire that is used to make the spring. An Ovate wire will allow you to have more clearance before coil bind. You can not run the springs at coil bind or they will break. We generally keep a .030"-.040" clearance before coil bind. Ford likes to see .090"-.120" clearance before coil bind. Now as for Ford springs they are a very good quality spring but they are not designed for what we are doing. Ford keeps as little spring pressure closed or open as possible. The reason being is durability and longevity also fuel economy. It takes less HP to open a valve with a small amount of seat pressure.

Jim@JDM

 

"I'm sorry but getting valvetrain advice from a small blower case manufacturer or a tuner is not the way to do it."


Charles from MP is an engineer and you could only dream of the days and nights this man has put into his blower.

Jim also is an X Ford Engineer and still has strong ties to Ford!

How do I know this I manage the 4.6L Cast Iron Block Dpt. for Ford Romeo Engine Plt.

God Bless,

Suavy

 

Yes, we have actually done tests here with 95lbs of seat pressure in a stock eaton truck, with stock longblock versus the stock valves springs. The stockers had about 65lbs of seat pressure. The 95 lb springs picked up nearly 30 HP and it started as early as 3200 RPMS. The nitrous is not so much a factor, but anything over 12 psi is too much for stock valve springs. If you look at dyno graphs out there its evident, you can actually test it yourself if you are willing to spend the day at a dyno shop. Make a dyno pull on factory stock valve spring truck at 12 psi and 16 psi, then you can see the difference. You will make more HP and torque at the beginning of the run by adding boost but will lose more HP and torque by the end of the pull than with less boost. So your peak power may be more but your top end where you need HP the most will be less.

Coild bind is always a concern, to acheive the spring pressures that we need you really cant run anything over a .550" lift cam. If you look at most flow sheets out there from different head porters, you will see at .550"-.600" lift there is usually about a 4-6% loss in cfm. That minut of a loss of CFM is about the same HP it costs you to go from a .550" lift to a .600"lift. The longer you keep a valve open with small CFM gains it will actually cost you HP. Our current cam selection ranges between .530" and .550" lift basically with a lower lift you just put a wider pattern on the lobes and you can acheive the same thing. And with lower lift you can add more spring pressure. Which optimum is 120# of seat pressure closed, after the spring has been destressed.

Jim@JDM

 

Coming from the perspective of a jaded getting-on-4-year reader of these boards, this whole valve spring issue is one of the more interesting discussions that I have read in years. A special thanks to the folks at JDM for continuing to share their insights with us.

It looks to me like valve springs have been discovered as a must-do mod for any overspun blower. This is risk-free HP. I am reading this data correctly?

BTW, let's try to keep things civil here. Comp Cams certainly knows valvetrains both in theory and practice, but the good folks at JDM have done substantial experimentation and shared the results, which appear to speak for themselves. Nicely done, Jim and crew.

 

Tim your not jaded, your just misunderstood

 

This seems intuitively correct, Jim. But I am having a hard time reconciling this with the statement quoted above from Crane:

"Many people mistakenly think that using higher seat pressures causes a reduction in the horsepower delivered to the flywheel because higher seat pressures (and also higher spring rates required for high performance) require horsepower to compress the springs. This thinking is simply incomplete! For every valve that is opening and its valve spring being compressed, another valve is closing and its valve spring is expanding. This expansion returns the energy to the valve train and the engine. This results in a net power loss of "0" hp. Many engineering texts refer to this as the "regenerative characteristic" of the valve train."

This also seems intuitively correct.

But, this principle is obviously NOT true when there is valve float (at least of the NA kind that I have studied in the past), as the valve is by definition losing contact with the cam lobe after it rolls over the lobe center and can't possibly be pushing the cam back down then. Taking this idea to a lesser extreme, could it be that since the cam is moving away from the valve after max lift, even when there is not any real float, that the push down on the cam as the spring closes cannot equal the force required to push the spring up? If so, then Crane seems to be wrong.

Help me out on this one, Jim.

 

why can every other blower/tubo make power with the exception of a magnum? theres dozens if not hundreds of stock block kenny bells making power where they should where dozens of mp owners have reported picking up power with an apten. whats more logical to beleive that the mp is just an overspun roots eaton that wont make power or the engine somehow knows that it has a mp and needs these valve springs.

jim@JDM - what valve springs are in say dons motor. i know hes made mention of it being old and he doesnt seem to make any less power than the so called new motors.

 

That has not been stated in this thread - and let's keep it that way. The research reported here is that any high-boost 5.4 (roots, twin screw, turbo, etc) can benefit from stiffer springs.

The last thing we need here is counterproductive sniping about irrelevant issues.

 

KB's are not running at there "potential"....I think thats the word your looking for.

I run my KB at 23 lbs boost with a 95 lb Crower spring for a short time, it also had solid adjusters. The thing would pull strong to 6000 rpm at that boost level but when I pulled it apart there were signs of valve float all over the place. So why did it run so good ??? It was the solid lifters. Solids don't pump up and hold the valves off there seats....sure the valves weren't under control but it didn't kill the power all that bad....but I now know that it wasn't near its full potential either.

There... that oughta confuse the hell outa everyone
Dale

 

This thread is definately one of the better I have read in a while. My hats off to Jim for sharing his knowledge on the subject.

 

Tim,

If we had a perfect valvetrain world we would all be running around with 16 selinoids under our valve covers instead of 16 valve springs. This however is obviously not the case. I believe Crane's statement is for a push rod engine. The overhead cam engine takes two and a half times the amount of energy to rotate the valve train because of the additional moving parts. You have 7 feet of timing chain, oil fed tensioners on both sides of the engine, twice the weight in timing gears, two camshafts instead of one, basically a whole lot more rotating mass. As for the OHC engines and valve spring tension, you have alot less cushion the way the cam follower enters and exits the ramp of the lobe. This is the reason less valve spring pressure is needed, therefore less resistance. Where as on a push rod engine all the excess cushion between the lifter and pushrod, rockerarm, and mainly the rocker stand, then you have the end of the rocker which sits on top of the valve. A higher spring pressure theoretically should cause no HP loss because if one valve is opening the other is closing, therefore accelorating down the backside of the cam and forcing the cam to rotate using less engergy to open the next valve.

What we see mostly with weak valve springs is alot of valve train vibration. Or as Ford would call it a noise or a frequencey. We as if you have boost holding the valve off the seat its not like it would hold it off .010" and stay there. It actually bounces back and forth. Even if you are on the backside of the cam or the ramp just before the valve is getting ready to open. Then if the valve is closing it is still trying to hold it off the seat. Which that pulsating action can continue through many cylces because the spring is storing its energy and will continue to bounce. You want just enough spring pressure to keep the valve from doing this on a overhead cam motor. Some of my best days at Ford, back when Toyota and Nissan where a big threat to them in the small car market, Ford used to actually go out to a dealership and buy a brand new production import car. The Engineering groups would get their section of that vehicle. The section I was most interested in was the induction system. That was part of my Job anywheres from the combustion chamber, to the valves, to the intake, right down to the air filter. In all their overhead cam motors we would see spring pressures so low we were suprised it could hold the valve up! Thats when Ford commisioned one of the most intellegent overhead cam designer company in the world to go to a full scale OHC engine. So I spent most of my days in the dyno cells watching cam followers fly off the backside of a cam and beat the death out of the valve covers. This was due to bad harmonics and too low of a valve spring pressure. Too much spring pressure caused loss of HP,alot of wear and tear on the extremley long timing chain guides, and the timing chains, also the gears for that matter. Some tests the spring pressures were as low as 30lbs and some where as high as 180. This is all closed seat pressures. 65lbs was found to be the optimum spring pressure on durability engines. Now remember Fords durability program is 150,000 miles. Where as running 120lbs of seat pressure Im only going to give a durability of about 65-75K miles before you will start to see pretty good wear on the timing chain guides. I guess this is the reason why ford didnt build 10 sec daily drivers. Sorry for rambling...


Jim@JDM

 

Thank you for sharing you experiences Jim. This kind of info for the gen2 community is helpful.

So... how do I know this floating of the valves is from intake PSI or from the intertia of a quicker accelerating motor? Or both?

Titanium keepers help to solve the intertia problem. (which I know is supplied on most aftermarket heads)

Regards, Rich

 

Excellent Post

All I can say is "I BELIEVE"

As Jim said there's more to his heads than most ported heads, but those 104lb springs are the icing on the cake and do make quite a diff, it can clearly be seen on a dyno. AS for what springs Don or V or other JDM older motors have, Jim has been aware of the Valve Spring issue for years, and I'm sure they all have the best Springs available in them at that time, I just looked in V's F-150 Gallery and see no sign of spring problems, my guess is we all have the same 104lb springs ???
https://www.f150online.com/galleries...2541&anum=1645

AS for why stock block KB's or Turbo's can put down high power on factory springs / aka weaker springs I can not answer , but one thing is for sure, the Mags can put down more power and benefit GREATLY with higher pressure springs. There's no doubt in my mind the weaker factory springs in my orig built Motor is why I chipped a Valve, (we already know it was hurting HP BIG TIME, we proved that many times on the Dyno)

Why I think it's been the topic of conversation lately is because now with these 104 springs (and soon to be 120's) these Mag's truly are now putting down what KB's were only a year or so back, and even more so than many out there today.

GREAT JOB CHARLES AND JIM

BTW
Another good article on Springs

http://www.circletrack.com/techartic...ech/index.html

 

I have been in and around L's for five years now and I have learned a great deal along the way. I have never made a purchase from JDM, I had basically come to the conclusion that they were just overpriced for what they sold compared to all the others. After reading and being involved in this thread I now realize that I have been very wrong in my thinking. It is so amazingly refreshing to see a vendor on one of these sites explaining not only his product but how he arrived at his products. Thanks for all the info and time Jim.