Stock Valve Springs?

[JDM Sam]

There are also 2 versions. single spring and dual spring.

This is the difference in the springs.
Factory springs have about 45 lbs of seat pressure (at closed valve)
Single: 58 lbs (+28%)
Dual : 85 lbs (+ 88%)

So depending on your build goals there are 2 choices to go with.

The dual is recommended for people who plan on getting aggressive cams, big boost, increased rpm.
The single is recommend for a more conservative build.

 

[mazdaspeedwerx]

http://www.nhra.com/dragster/1999/issue02/Tech_Speaking.html

"Several misconceptions about valve springs influence racers to make poor decisions. A customer who says, "I don't need good springs because I'm running stock valves," is badly mistaken. Steel valves are heavy, and adequate spring pressure is absolutely essential to control their motion. A valve's inertia increases with the square of the engine speed, so even a small increase in rpm requires significantly more spring pressure to maintain valvetrain stability.

In fact, too little spring pressure is almost always the root cause of valvetrain failures. We spent a year studying valve springs using an Optron, a sophisticated electronic device that can precisely record valve motion and reveal valve float. We learned some shocking truths about valvetrain behavior at high rpm. Even with a relatively mild camshaft profile, the valves bounce on their seats before they close. If the spring is too light, the valve bounces uncontrollably. The valve hits the seat, rebounds, hangs in the chamber a while, then bounces erratically several more times. Imagine how hard this is on the valve and the rest of the valvetrain!

Another excuse I've heard for not using stiff valve springs is that they take more horsepower to compress. My reply is that each spring stores energy, and for every valve that is opening, another one is closing. Anyone who has been whacked by a torque wrench while turning a crankshaft can testify that the valve springs exert considerable force on the closing ramps! I have never installed stiffer valve springs on an engine and lost power; the improvement in valvetrain dynamics more than offsets whatever additional power is required to overcome the springs' resistance."

so with pretty aggressive cam shafts and low hp would I need springs? I almost bought a set but decided against it.

 

[JDM Sam]

Yes, you should. The cam specs not hp dictate whether or not you need springs.
Other factors are boost, rpm.

You also get titanium retainers that reduce valvetrain mass.

"For every gram you can reduce from the valve area (valves, retainers, keepers), you will pick up on average of 35-40 more rpm in valve control."

By the way valve float kills power up at right before the redline.

 

[orng1]

By the way valve float kills power up at right before the redline.

And pistons...

 

[slomsprotege]

some else elaborated on this

 

[orng1]

some else elaborated on this

What exactly do you mean?

If the valve stays open it'll let out all the air that it's trying to compress, so no power.

If the valve clearences are tight against the piston, and the valve is open when the piston goes to compress it'll make contact and damage the valve and piston. This happened to me twice on my CRX so I learned my lesson and upgraded, too bad my friend had to find out what the redline was on a no rev limit ECU and blew the engine. But after those experiences I have learned my lesson and would rather be safe than sorry.

Oh yeah the motor blew because it ran lean, that time...

 

[shane02pro5]

I'd like to hear more elaboration on this from Kooldino!

My Long block should be done in a few weeks and now would be the time to change something. I am planning for just over 300whp daily with my IHI turbo and possibly upgrading to different setup using a gt28rs or similar.

 

[icespeed]

JDM Sam, where did you get those numbers on the spring ratings?

I recently lost the top end on my MSP, causing the whole engine to blow. I know 100% (and confirmed with my mechanic) that a valve was sticking for the better part of two weeks before the engine popped. We assume (yes I know, assume) that the valve floated, whilst sticking open, causing the big boom. So, to all those "nay-sayers", yeah, we can lose the top end, just like any other car. Oh, 90k miles @ 12lbs (ok fine 88k of the 90k on 12lbs ).

Anyways, I'd like to know more about those spring ratings, as I intend to not let the top end fail on me again (looking to get another 4 years out of the "new" engine). It seems to me that the higher spring ratings would allow higher rpm redlines. It also seems that normal rpm ranges would benefit from upgraded springs as well (closing quicker for more "ideal gas" combustion). I need concrete numbers for these springs, so I can calculate (unless info is already supplied) the max redline/lbf increase, lbf/time, % failure/lbf increase, expected longevity of springs, etc.

Can we get a poll on this? How many think performance springs would be bad for "normal" applications (i.e. not upgrading cams, redline 7k rpm, boosting < 15psi).

 

[NEBoosted]

I bought my Valve springs from Crossover auto. They are made by supertech. I bet if you call up Crossover they will be glad to give you all the specs. They recomended their single spring for 14psi or less. I got the dual springs since i will be doing 15+.

*************.com

 

[icespeed]

ty!

 

[JDM Sam]

Those are the numbers supplied directly to me. I work at Crossover and a few members worked with me to help get these valvetrain pieces made specifically for our car to finish the top end of this motor. The thing lacking performance/aftermarket wise on this engine is the cylinder head, besides the rods/pistons which are readily available.

Keep in mind the stock valvetrain was not made for a boosted car let alone performance. None of the stock engine components were made for a boosted car like the rods. Also, the factory redline is 6500 but the PCM lets you rev to 6950. Upgrading to higher performance springs and lighter retainers will improve performance and give you more peace of mind.

Also, I recently checked Eibach's online application catalog and it seems they have dropped their line of springs for this motor as well.

 

[icespeed]

awesome, thank you for the info!

 

[Maxx Mazda]

I took my engine up to just about 8,000RPM on the dyno and still hadn't floated the valves from what we heard, but the FS stops making power around 6500RPM anyway. There's no need to rev it that high. The being said, I'm going to be ordering all the head "goodies" from crossover in about a week.

 

[livelyjay]

Good info guys, I learn something new every day I read "useful" threads on the forum.

 

[shane02pro5]

I brought this back up to Dana from Speedcircuit and he still said that from what he has seen valve float has not been an issue on these cars and since I will be running stock cams and not upping my rev limiter I'll be fine.

 

[Maxx Mazda]

I took my engine up to just about 8,000RPM on the dyno and still hadn't floated the valves from what we heard, but the FS stops making power around 6500RPM anyway. There's no need to rev it that high. The being said, I'm going to be ordering all the head "goodies" from crossover in about a week.

 

[NEBoosted]

I brought this back up to Dana from Speedcircuit and he still said that from what he has seen valve float has not been an issue on these cars and since I will be running stock cams and not upping my rev limiter I'll be fine.

valve float may not happen for everyone. but for someone building the block there is no reason to not spend the extra 400 bucks on springs. all it takes is for you to be the one unlucky person to lift a vavle and destroy your entire motor. Kind of like when you gf says that shes on b/c and you still get her pregnet somehow. Might as well wear the condom too is all I'm saying.

 

[Maxx Mazda]

Condoms suck...

Before I get flamed, they really do if it's a steady girlfriend, I never use them, but by all means wrap it up for the randoms...

 

[AusOrion]

Can someone at CrossOver Auto please provide the following information on the single and dual valve springs that they have:
- Installed Height
- Seated Pressure
- Open Height
- Open Pressure
- Outside Diameter
- Inner Diameter
- Maximum lift

Btw, the latest Eibach application guide does not specifically mention having valve springs for the Protege. However, the specifications given for part no. 25100.01 are exactly the same specifications given in this thread for the Protege:
http://www.mazdas247.com/forum/showpost.php?p=692721&postcount=32