It would be nice to hear from Buschur, AMS, Turbotrix and Vishnu. I'm sure these guys have had plenty of these motors apart already

 

Pics?

 

Wonder if this might be a marketing ploy???

 

the "interference" in question is not a catastrophic failure type of interference. What happens is the bottom of the retainer comes in contact with the top of the valve stem seal every time the cam makes a full revolution ( idle, cruise, max rpm ) with any aftermarket camshaft running a larger lift.

What will happen if I dont replace the retainers? you might ask.... we really dont know yet - at the very least you will probably increase oil consumption and valve stem seal wear. In an extreme case you may break a seal or the small spring on the top of the seal that could pass through your motor somewhere.

As to all the others who are running without changing the retainers - I can tell you this ........ it was VERY hard to see. We werent looking for it but during testing stumbled upon the interference.

The bottom line is this - when I am building a motor I do not want interference ANYWHERE. Even the small pressure from the seal to retainer contact will prematurely wear the lifters/cams/bearing surfaces and add a bit more parasitic drag.

As an added benefit with our kit you get a CUSTOM VALVESPRING designed specifically for the evo. This spring will allow you to run much higher revs and up to 14.0+mm of lift Our retainers are 100% chrome moly steel ( SUPER durable ) and only fit with our springs. I know what you're thinking.... "Steel??? why not Ti ??" Well after getting samples machined in Ti and weighing other Ti retainers out there we found them to be heavier than the OEM aluminum retainers. So we took a different approach - since we design our own springs we were able to design a "package" that has less unsprung weight than ANY other spring /retainer combo available. As we learned with suspension unsprung weight is the enemy of all things performance! Think of how many times, and how quickly a retainer and spring changes direction - its STAGGERING! At Revolver we can calculate just how much of the springs mass is unsprung. So while others might have a lighter retainer than ours but a bulky, poorly designed spring ruins it as a package. So with the Revolver spring/retainer combo you get the durability that you need in a daily driven street car with the lightweight rotating mass of a racing valvetrain.

We'll offer an additional 5% off to evolutionm.net members. Just shoot me an e-mail to jason@revolvercams.com for details

Let me know if you have any questions

 

The Revolver cam set gives 11.4-11.5mm lift, which ranges between 0.6-1.3mm greater than the HKS sets. Therefore, what causes contact with the Revolver set does not necessarily cause the same with a cam set of lesser lift, unless clearly demonstrated otherwise.

 

Actually we tested this with a set of HKS 264's.....

like I said in my post above, if you are running a performance camshaft (regardless of brand) that has larger then stock lift you will see contact between the retainer and valvestem seal

 

Perhaps, but with the lift differences between the factory and HKS sets amounting to only a fraction of a mm, coupled with several EVOs running 30k miles or more on the cams without any discernable adverse effects, I would not be inclined to ring the alarm bell just yet.

We all appreciate the FYI nonetheless.

 

I agree with Ted on that, the lobes of the cams are stilll the same shape with close to the same lift. If there was a problem with clearence you would of had problems arriving within a short period of time. I have had these for more than a yr with no problem. If there was going to be any problems it would have happened within the thousand miles. I also checked my retainers and the clips about 1k miles after the cams where installed to place in some ARP headstuds. I didnt mic anything but from a visual inspect I am sure I would have seen buring or any type of blemish, but I didnt. I now have many more miles without any problems If the seals had any type of damage I am sure I would have seem oil consumption by now because I drive my car like I stole it all the time.

 

All it takes is a fraction of a millimeter....

not trying to ring the alarm so to speak - just want to keep everyone informed.

 

If the retainer is making contact while the engine is in a static state (not running), think about what is happening, when the engine is @ 7800+ RPM....even the best valve springs have a slight amount of "surge", for this reason we designed a spring with a high natural frequency....one thing to remember here is that this is a single spring system and there is no damper to assist the spring in controllingl the valve. The valve spring serves as the spring and damper. And while the interference has not proven to be catastrophic, we felt that it was worth addressing....obviously we we forced to, due to our lift values, but we designed a really good valve spring/retainer combo......and for the record...Revolver Cams did not start this post.
Please find the attached photos depicting the interference in deformed valve seal and polished circles and semi circles on the retainers.




Again, just sharing our findings with the rest of the community. Safe journeys!

 

Thanks for the pictures. That helps a lot to understand the issue.

Does anyone make a shorter valveseal? That would be the best solution to this for those with HKS cams -- not a new set of springs and retainers.

I ran into a problem on my Camaro running dual valvesprings (stock valvesprings were singles) and having sufficent inner clearance for the seals. I found that there were a lot of alternate seals on the market -- some were smaller exterior diameter, others were shorter, etc. Valveseals are fairly easy to replace and a lot less expensive than a set of springs and retainers.

If the stock wimpy springs do the job otherwise, "upgrading" to a stiffer set that will have more parasitic HP loss and wear the valvetrain more (which is what stiffer springs will do over time) doesn't make sense just to solve a valveseal clearance issue.

 

thats a good question

 

So if you measure the distance between the retainer and the stem seal with no spring on it how much lift can you have before the retainer contacts the seal?

 

the contact happens at about 10.2mm of lift +/-

every car we have looked at with cams installed has had this contact.

good question, one problem though - it is very difficult to remove andinstall valvestem seals while the head is on the car AND you have to remove the springs and retainers anyway to get to the seals.

to clear things up we did not design our springs and retainers to solve this issue, we designed them to handle huge lifts,high RPM's, and survive the lifetime of your engine - but we did find the interferance while testing so..... naturally our findings influenced our design.

in reference to "stiffer valvesprings losing power" well, there is more to it than just that....... let me quote a wise man for a quick rundown on valvespring design........

"As far as valve springs go....think of the camshaft as a bump in the road. With a suspension system, you have the spring, damper and tire. This system has a natural frequency (number of cycles before the object comes to rest in a static or steady state). The spring stores the energy and releases it, the damper helps control this released energy among many other things (but for this we'll keep it simple), and the tire also acts as a spring and damper within the sidewall and it too has a natural frequency (again another topic). Back to the bump, the damper slows the number of oscillations that would occur after the bump. Adding performace dampers increases the natural frequency, which to most everyone on this site, is a good thing.

The valve spring does not have the luxury of a separate damper to increase its natural frequency. This is what separates a good valve spring from a piece of coiled steel. When designing a spring to suit a system (camshaft and RPM range), generally a spring with a high natural frequecy is very desireable. The cam profile has everything to do with how the valve spring needs to be designed. The spring needs to have enough travel: Sc, to keep it from coil binding at max lift. The more radical the profile, the higher the frequency spring you want to allow itself to recover fully (not overshooting) so the valve is not floating or surging - losing contact with the cam. Seat pressure is also important, as too much is not a good thing. Too much spring rate can actaually rob power. Think about it....the engine has to work that much harder to overcome the additional force that opposes its direction of rotation. Yep, this is getting out there, but it is totally valid.

Tensile strength of the wire that is used allows you to optimize the valve spring design by using a smaller wire diameter (reducing valve train mass and allowing more travel) yet still mainting enough of a safety margin so that you are not overstressing the spring in it's designed environment. The grain structure aslo plays a major role in valve spring wire quality (another time on that one...this is long enough). An overstressed spring (i.e. poor design and/or poor materials and/or manufacturing methods and/or over rev) can lead to catastrophic failure in either buckling or breakage.....which usually leads to ventilated pistons........ "

 

Actually what I was wondering is exactly how far is the retainer from the stem sea? If 10.2 was true then they would hit on a stock motor because the the rocker has a leverage ratio.