Continued from https://www.evolutionm.net/forums/sh...=164119&page=3 . I do not think I should continue to take the thread further off topic. Thanks for the reminder, Zeus.

Thanks very much. I PMed you. I need an email address to send scans of appropriate pages to so both of you will know which areas of the paper I'm referring to.

It must be amazing having someone with his depth of knowledge and experience as a personal friend. Everything I've ever read by him, and every presentation I've ever seen him give, is incredibly succint, insightful, unpretentious, and still very practical. Please tell him he HAS to write a book sometime, I know lots of people in the industry would pay good money just to learn a little of what he knows. Perhaps something like Blair's 4st design and simulation book, but on engine design, more practical, less modelling? Mr Hermann could probably supply many specific case studies of a good range of past engines.

I think your company's motivation is admirable.

I read in some old Revolver thread, how you guys strive to save mass in the spring as well as the retainers. From the few pictures I've seen of your product it appears to run a retainer as large or larger than the spring OD. Is there a reason why you don't reduce retainer OD by the diameter of one full coil, such that the edge of the retainer sits at or just beyond half a coil? This is common practice in drag, sprint, endurance racing engines, both multivalve OHC and 2V pushrod engines.

Ryan, by lowly I meant in terms of lower stress, lower inertia load, much lower cycle rate, vs racing engines. There's nothing wrong with being an import enthusiast I can be classified as an import enthusiast.
It is only the ICE, and detailing/fashion people that irritate me. The street racing crowd makes me angry.

Hi ogvw,

As mentioned I was referring to the lower stress, lower inertia load, lower cycle rate of upper assembly in street cars.

I think there are two ways to look at the street vs race valvetrain comparison. The closest analogy (maybe not so close) that I can think of is roadrace cars vs oval cars. Many people see the roadrace cars as superior because of the mixture of braking, turning, acceleration, that they have to do, across a wide range of turn radii, course gradients, speeds (hence aero loads), etc.

A less held view is that what hurts the road race car in some areas, can aid in other areas. For example, if the car has a tendency to rotate easily, the driver will struggle with the high speed sweepers and segment time will suffer, however on the very tight turns that lead onto long straights, the car will readily rotate, allowing early throttle, hence segment time there will be helped.

Following the same train of though, an oval car may only turn left, but it drives in much narrower speed range and has to negotiate only 4 turns that are much more similar (say Indy) vs the large range of types of turns at a road course. There are hardly any tradeoffs to be made. The setup has to be on kill in order to be competitive.

I see street vs race valvetrain the same way. Multitude of low stress factors compromising each other with no real objective comparison (wins, losses) vs fewer factors, much narrower objective with attendant higher stress, ending with affirmation of quality of job carried out (win or loss).

In a street specification multivalve OHC engine, the lower assembly will fail long before the upper assembly does. In a race engine the lower assembly is designed for much higher engine speed and suddenly the valvetrain is much more of a consideration as both lower and upper assembly begin to push the limits - more or less at the same time.


Best regards to all.

Shaun

 

Shaun,

E-mail address sent. As far as the retainer design goes, yes, it is equal to the OD of the spring. And while we strive to make the assembly lightweight we also need to have some balance as the majority of the engines that are receiving our spring kits are street engines. And your points are very valid, I have seen many racing retainers who's OD's are sitting in the mean of the wire diameter but for the street, we would rather "leave a little on the table".

Yes, it is pretty cool having a close friend who has an enormous amount of knowledge and great stories of years past. Jason (aka ogvw) and I are very fortunate to be involved with Hans. I spoke with him this morning about your request, and he was very excited to answer any questions that you have.

Take care,

Beau

 

Now this is what Evom is all about... enthusiasts sharing knowledge/having discussions without side note distraction!

...subscribed!

 

I'm interested. I will not pretend to understand every single bit of it, but I am interested...

 

Thanks, scans and questions have been sent.

Are you saying that turning down the retainers compromises their structural integrity? If not, what is there to lose by turning them down?

Thank you both very much for the time and sharing.


Cheers

 

Sorry Joey, but what is it you are interested in?

 

mttam -

is this Hans Hermann that started his career with Porsche in the early 50's, or his son?

If Sr., must be getting up there - as am I! and, for the edumacation of the younger folks, he has probably forgotten more about engines and motorsports than the collective knowledge of everyone who has ever or will ever post to this sight.


an older newbie

 

I guess the whole discussion, I was following from a distance in the other thread and if someone who is pretty renound in the automotive world is in on this, then it intrests me. I could care less about the back and forth arguments, but anything that is somewhat in depth, and especially if it involves a pioneer in the automotive world, is worth reading! And if he did have a hand in the design of the revolver cams, well then they may be something to look at. I have what in this crowd may be termed a basic idea of camshaft operation, but there may be some good information that comes out of this discussion...

 

Beau, are you?

 

Here is our stance on the subject. There are really two different markets here, consumer and race. Both of those markets share the same goal - more power, faster, lighter etc. The difference is that for a street car we overbuild everything because even one freak failure (even if it were from installer neglect) could ruin our business. If a race customer is looking for that last tenth of a horsepower its no problem - they understand and accept the possibility that when pushing the design limits of a part something will eventually break. In racing that is education.... now you KNOW exactly what the limit of your parts is. In aftermarket performance/streetcars if we broke a retainer because of excessive lightening it would be seriously detrimental to sales.

So while we have the FEA data on the retainer and we could lighten it up a bit we feel that we must find that middle ground for our customers - the ideal balance of lightweight robustness that works in these high performance road/race cars.

That being said - we are also interested in engineering solutions for full race builds and single purpose customers. If you need something special dont be afraid to ask.......

 

Thanks Jason.

I understand the point about potential installer error, although I can't think up very many ways at all to put a retainer on wrong, especially if it is part of a spring package. Most errors are from mismatching retainer to spring number esp if involving wrong placement of flat damper, or lack of proper spring location or prep to match a retainer.

I don't see how a retainer turned down to mean wire diameter in a 4V DOHC application (low spring pressure, low mass) is close to the limit. Unless of course Revolver retainers are unusually thin? I will have to take a look sometime. I have turned down Del West and Xceldyne retainers and they are perhaps some of the best stuff around and still take to it in extreme load and mileage applications. I can see how ICD retainers might be pushing it in extreme applications (Cup - DEI blowups), but turning down to mean wire diameter is far from ICD.

Don't mean to be a pain, just am curious. If you have any high resolution pictures of your retainers alone from different angles, can you perhaps email them to me? I realize you guys are busy, so thanks for taking the time to reply and TIA if you send pics.


Best regards