David,

I am not sure why you are getting a measurement of .471" (11.96 mm). Aside from the heads that we checked, we also bought brand new valves from and all of them were the same measurement-wise. The valve that is shown in the picture is a "brand-new" OE piece that we purchased at the dealer (PN: MD184078) this was an exhaust valve. And this valve measured exactly the same as all of the other valves we checked.

Anyway, the OE retainer measures @.383" (9.728 mm), with the OE retainer in place on the valve there is .178" (4.54 mm) of exposed stem from the top of the retainer to the tip of the valve...add those number and you get .561" (14.27 mm).

Our retainer installed on the valve measures .447" (11.36mm), and measures .269" (6.83 mm) and sits in the exact same position as the OE retainer. There is no way to safely make the profile of this retainer any thinner.

Again, thank you for the intellingent posts.


-Beau

 

Due to it's technical merit, a lot of WORKS customers have asked us to look into this thread and comment.

We have several stock motors on stands right now getting ready for stroker kits so we will check the valvetrain for interference. For those of you who have already installed our spring/retainer kit, don't worry because in the beginning we designed the WORKS Ti retainers to be much shorter than the OEM retainers anticipating high lift cams.


We should have some info by the beginning of next week.

 

Bump. Hoping that the factual disagreement can be reconciled here.

 

I'm concerned enough to just go ahead and get a spring/retainer set. I'll need the extra headroom in the rev range anyway.

 

For a little over $200 I decided this was probably a wise investment. I DO NOT want to have my valves tap dance with the pistions.

 

we are not talking about valve to piston contact - we are talking about valve stem seal to valvespring retainer contact, not as catastrophic but concerning none the less.

 

I feel like a newbe! I knew that.. Really I did!

How the hell that thought slipped out excapes me.. Never the less, you are correct. I still think the springs/retainer package is a wise investment.

 

I wouldn't necessarily feel 100% safe using aftermarket springs, retainers and locks since, while they may not have the valveseal problem, they are not "proven" in the same way as the stock stuff. I worry about valvespring rates that might be too high for the stock lifters (causing slight loss of valve lift), too high for the quality of the cam (from a metallurgy standpoint, possibly leading to failure of the cam hardening and metal in the oil system), etc.

If there's no interference with the stock valvesprings (the Buschur assertion), then I'd rather stay stock. It's not just a matter of a couple hundred dollars.

 

The EVO uses the same valvetrain (aftermarket) as the older 4G63's (DSM's). There is plenty of feedback from those applications you can cross reference. I see no reason to worry. We even use the same lifters as they do.

 

no need to worry - we used CAD to design our retainers and tested them using FEA and also bench tested them to forces beyond what ANY spring could apply.

a hydraulic lifter does not exert any force on the valvetrain - its sole purpose is to take up any "lash" between (in the case of the 4G63) the rocker arm assembly and the camshaft. This is accomplished with oil pressure - so as long as you have oil pressure no need to worry


on the EVO the valvetrain is operated by roller rocker arms (from the factory) so there is very little "sliding motion" on the cam lobes, that is what wears out a camshaft. Again - we use different surface treatment for different cars (bucket lifter, roller rocker, solid tappet) just like the OEM's to ensure factory like durability.


There is interference when running a bigger set of cams - and Im sure Dave Buschur will agree that the OEM springs leave a little to be desired for anything more than stock RPM's

 

Incorrect - the springs and retainers that come on the EVO are very different from the previous DSM models.

 

Actually the valvetrain has some differences since the DSM days. The springs have less strength for one. The cams are hollow, making a lighter valvetrain assembly lighter. The retainers are lighter as well. The exhaust valves are hollow and filled with Natrium? This makes a lighter rotating mass in general, thus robbing less power. You don't want a heavy valvtrain and overly strong springs. This robs power and creates more wear on many vital components.

 

^truth

 

Agreed. But there isn't anything you can use (that I'm aware of) that matches the weight of the stock tapered spring. Even Ti retainers won't cut it. This is one of those things that sacrifice will have to be made.

Same thing with using an aftermarket camshaft. You're going to lose the lightweight hollow shafts for the solid shafts found on the aftermarket. What happens when a user decides to replace his valves (for whatever reason)?

Point being, pretty much whatever we do to the valvetrain, we're likely going to give up something in return. Would you not agree?

 

I've compared the part numbers pretty extensively.

Stock springs work best with stock camshafts