Valve retainers

[crummasel]

Hi there,

does anyone know if there are different valve retainers and, if, which one is the lightest version fitting onto stock 2,2-2,7 valve spring packages. On all engines i found the same ones but i did not do all of the versions.

Thank you

Robert

[HawgRyder]

Dependine on the valve and retainer...you may have either 7deg or 10deg locks...they are NOT interchangeable!!
I believe the 7deg ones are stock...but I found some 10deg ones in a 2.2 one time...it had been worked on...and the replacement vavles/retainers/clips were of after-market design.
As to weight...Titanium is lightest...or Aluminum...but longevity becomes a problem.
Bob

[crummasel]

Clear.
But what are the stock options or are all the same?

Robert

[HawgRyder]

If you stick with stock vavles...that are listed as right for the year of your car/engine...you can't go wrong.
Bob

[chris_seven]

All standard retainers have a 14 degree included angle in the tapered seat.

With a 3 groove design I think this is described as unclamped.

I have seen some retainers with a 20 degree included angle and I think these are used with a single groove retainer and are a clamped design whichmay be better with Race cams.

[crummasel]

Thank you guys, but i think i created a misunderstanding:
I am looking for potentially different options in terms of weight of the valve spring retainers and not the small parts here on Pelican listed as valve keepers.
So what i am asking about is the "stepped" small disk on top of the springs and not the small half conicals.
Thanks
Robert

[HawgRyder]

You are referring to the retainers...and those MUST match the clips or locks (in degrees).
There are aluminum ones...Titanium...lightweight steel (trimmed down)...and probably more.
The problem will be in choosing ones that match the size of the coils they are going to retain.
In high performance engines this usually means multiple springs (2 coils..opposite winding....or 1 outer spring with a flat type spring that "rubs" on the inside of the outer one) ... what this does is reduce the bounce or 2nd order vibration when the valve closes.
Check out some hot rod mags...see what designs are the latest ones for todays engines.
Perhaps you might find retainers made by reputable makers that will fit the application...search the web.
Bob

[chris_seven]

We started making 6AL4V Titanium Retainers last year and the reduction in inertia is helpful in controlling the valve at high rpm.

At standard revs they are probably not needed.

We have chosen a standard angle so they work with the stock 3 groove keeper.

If you want to use a single groove clamped type Schrick make these for the 911 engine but they are quite expansive.

The choice of retainer material comes down to basic fatigue life which will be related to the level of alternating stress developed during operation.

it is well accepted that ferritic steels have an 'endurance limit' which is the stress at which the part will never suffer from a fatigue failure.

A good guess would be 50% of yield strength although this may be a little conservative.

Titanium and Aluminium were never considered to have had an 'Endurance Limit' but this has changed a little in recent years.

In the Seventies Ti alloys were fatigue qualified on a batch to batch basis as inconsistencies in manufacturing control measurably affected material properties.

The improvements made in the last 10-15 years seem to have eliminated most concerns and
6AL4V has a well established Endurance Limit that is well backed up with good data.

Aluminium is more difficult to quantify and the strongest alloys such as 7075-T6 do have quoted Endurance Limits and these are typically about 30% of yield strength BUT the values given are generally based on 500,000 fully reveresed load cycles which IMHO is a long way short of the 10^8 cycles that I would like to see.

Recent developments from Kaiser Aluminium has introduced a new and slightly stronger alloy 7068-T6 but there isn't much fatigue data available so I would worry about using this without some testing.

The other concern I would have with Aluminium is wear rates due to fretting. It is possible to reduce this by anodising the Aluminium but there is data to show that the fatigue limits of 7075-T6 can reduce by as much as 65% when anodised.

I came to the conclusion that 6AL4V Titanium was a good choice as there was significant data available and a huge number of retainers have been made using this material so as long as stress is within acceptable limits it should be OK.

I do worry about Titanium's resistance to galling, whch is not high and we have PVD coated our retainers in a black Titanium Carbide Coating to eliminate any potential for wear.

It has also been established that thin coatings of TiC (0.2 to 0.5 microns) produce an improvement in fatigue life and could be considered as an insurance policy.

[Sboxin]

IMHO you might want to call and talk to one of the Porsche race shops--
EBS in Reno helped us with a 964 rebuild -- Titanium retainers were provided
with an EBS designed valve spring for race duty.
This is their contact info:
Porsche Racing Parts : Engine Performance Parts : Brake Parts : Used Porsche 356 : 911 : 912 : 914 : 944 : Porsche Boxster Parts : EBS Racing Inc.
(800) 462-3774 : M-F 8am-5pm PST)

Be aware, there are differing opinions about Ti or not...if you plan to run the
engine for 10-20 years then you may want the heavier retainers.



Regards,

[Walt Fricke]

Titanium seems to be the material of choice for race motors, where you are running at 8,000 rpm or thereabouts, or higher.

Down at the stock range, where 7,000 rpm is well beyond the cam's breathing capacity, and (say in an SC) the optimum upshift point is about 6,250 rpm, there is little to be gained with lightening the valve train. A tad less parasitic drag? I suspect that would not be quantifiable.

I have a used set of titaniums. I replaced them because I could see the impression of the end of the spring (where it is cut off and ground flat) on its bearing surface. These are from maybe 15 years ago, so perhaps materials have improved.

Race springs often require that you machine the cup parts which sit under the springs at the other end. Or that you dispense with the cups entirely, and just add more spacer washers. That seemed to work for me on my first go around, but it seems like a good idea to have the cups there.

[crummasel]

Thank you, but i was just wondering if there are any differences in weight of std. OEM Porsche Parts during the evolution, NOT Porsche race engines or aftermarket parts.
Thank you,
Robert

[Sboxin]

Wow!!

What a unique question Robert!!

Has anyone ever asked this question before -- and who would have the answer...Porsche engineers . . . ?

Regards,

[Walt Fricke]

Robert - your question is a bit obscure (and thus was misunderstood), because only guys making race motors care about weight of this sort. It is unimportant in stock motors.

So much so that I believe at least the following valve train components are the same from 1966 (or soon thereafter) through 1989: The height shims (maybe the wider OD ones came later), the base cups, the inner and outer springs, the retainers, and the keepers. The seals have varied a bit, but since all these valves were 9mm stemmed, they interchange as well.

This is convenient if you are working on motors of this time frame. A keeper just jumped onto my floor, and I couldn't find it. Aaaaargh. But luckily I found one in my valve parts tray. I keep hoping I'll find the other one, so I can put it back in the tray and still have a spare.

[crummasel]

Thank you, that was the information i was looking for. Among lots of engines i made i found also interchangability, but i was just curious.
...and i was not saying i was looking for parts FOR stock engines, just looking FROM stock engines... ;-)
There are several motivations which make such a question not obscure, i think.
Again, thank you.