Valve Springs

[chris_seven]

there has been some debate about valve springs recently and I am not sure if there are any 'hard' conclusions. I am particularly interested in springs for high lift cams

Eibach Springs seem popular but have been hard to find in the UK as stocks seem very limited although pricing looks good. I have recently been quoted 6-8 weeks for delivery

The difference between the two parts available is significant and I was a bit confused about the change in OD when used in a standard spring cup.

Does anyone have any experience with the 'High Lift' sets?

I have looked at AASCO and they seem much more expensive than Eibach.

JB Racing offer a Race Spring but these springs need a different cup to stock.

I have also been looking at Schrick springs and they offer a part for cams up to 13.2mm lift but I am finding it hard to find any other data about these springs.

Does anyone have any clear views on a reliable option.

Thanks

[Henry Schmidt]

Hi Chris
We are using the Eibach racing spring (20444.212) almost exclusively. I like the over the nose vs seat pressure as compared to many of the options.
We also make a titanium retainer for these springs.
We encountered the supply issue through Eibach as well so we generally have 10- to 15 sets in stock at all times.

[chris_seven]

Henry, thanks

Is the retainer different to stock?

We have been making our own retainers in Ti for about a year now as the number we have used increased quite steeply but they are for stock springs/keepers.

We have completed our adjustable forged rocker development and just ordered tooling for the '906' style Rockers so I am keen to find a complete solution for high lift cams.

[Henry Schmidt]

Originally Posted by chris_seven

Henry, thanks

Is the retainer different to stock?

We have been making our own retainers in Ti for about a year now as the number we have used increased quite steeply but they are for stock springs/keepers.

We have completed our adjustable forged rocker development and just ordered tooling for the '906' style Rockers so I am keen to find a complete solution for high lift cams.

The retainers weigh 12.5 grams vs 17 grams and fits the ID of the outer spring more precisely in an attempt to reduce vibration. Beyond that they are pretty much stock in design.
In the past we experimented with flat top retainers (IMSA GTP technology) in an attempt to reduce weight further but the net result was very little savings and the need for a special perch We built six or seven engines with this design but abandoned it for the more conventional design..






I look forward to seeing your new rockers, sound very cool.
Cheers

[JohnJL]

Henry is enough weight, but I will add I have them in 2 motors with high lift cams, one supercharged and the other NA and no issues with either other than, as Henry said, delivery time. Dont trust summitracing...

[chris_seven]

Ti Retainers - 11.5 gms - Black Titanium Carbide Coated to prevent galling/fretting.

please don't think this is a contest - just to show what we are doing.



This is the adjustable rocker - it has been forged from 4340VAR - hardened, double tempered and shot peened. They are DCT Treated and then machined followed by Isotropic Superfinishing

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and then finished with a PVD process that is a modified version of Plasma Nitriding.

We fit a genuine Glyco Rocker Arm Bush and then diamond hone to size.

The pad length has been increased from the standard length to be the same as a '906' Rocker to allow them a bit more tolerance with high lift cams.



We also make a surface hardened Rocker Shaft to match. The shafts have a surface of about 1000Hv which should mean they will work with the 906 rocker that doesn't have a bush.

The 906 Rocker is modelled and the die is being 'sunk' now . We will use the same 4340VAR steel and heat treatment.



We are also making the full range of lash caps for 9mm dia valves but have added a small feature to the ID to prevent air being trapped.

Drilling a hole through the cap is bad idea as the rocker 'nose' is so small.

[Henry Schmidt]

Those are some very nice looking parts....
Do you have any test engines running the rockers?

[racing97]

Hey Chris I noticed that you did not mention Schmidthelm from Heidelberg they produced many Cosworth and Porsche racing valve springs at least during the Porsche Schrick time frame, would it be worth your while to manufacture a batch. I think they were involved with some NASCAR teams in the last few years. Also have you found it quite remarkable that a conservative group such as Porsche would use the progressive winding for linearity of rate back in 65 with the yearly 911 models.
reagards

[chris_seven]

Originally Posted by Henry Schmidt

Those are some very nice looking parts....
Do you have any test engines running the rockers?

We have 20 engine sets running and as you say its like falling off a building - so far so good.

The oldest have been run in an FIA 2.0 litre motor with 906 cams for jus over 12 months.

[chris_seven]

Originally Posted by racing97

Hey Chris I noticed that you did not mention Schmidthelm from Heidelberg they produced many Cosworth and Porsche racing valve springs at least during the Porsche Schrick time frame, would it be worth your while to manufacture a batch. I think they were involved with some NASCAR teams in the last few years. Also have you found it quite remarkable that a conservative group such as Porsche would use the progressive winding for linearity of rate back in 65 with the yearly 911 models.
reagards

Schmitthelm moved from Hidelberg to Bueren in 2011 and I am not sure if they are still trading as their website no longer works.

I would have thought progressively wound springs would have a non-linear rate but no eigen resonance?

[Henry Schmidt]

Originally Posted by chris_seven

We have 20 engine sets running and as you say it like falling off a building - so far so good.

The oldest have been run in an FIA 2.0 litre motor with 906 cams for jus over 12 months.

Perfect.
I look forward to trying a set when they become available... are they?
Cheers

[chris_seven]

I have sold all of the first batch and the second batch are being machined now and should be 2-3 weeks.

I will let you know as soon as they are ready.

[Flieger]

Originally Posted by chris_seven

Schmitthelm moved from Hidelberg to Bueren in 2011 and I am not sure if they are still trading as their website no longer works.

I would have thought progressively wound springs would have a non-linear rate but no eigen resonance?

Hi Chris,

Can you expand on the resonance issue, are progressively wound springs better than the dual spring setups which use the light interference for damping? Do they still have a type of resonance?

[racing97]

Chris you are quite right my friend they are non liner my mistake, I believe they did this to reduce the number of active coils as the closer coils are active first then stop moving, thus altering the natural frequency. Anyway that would be difficult to manufacture at that time and I find it quite remarkable that they would choose that design initially for their six cylinder engine.

regards

[gtc]

I am building my motor with the Eibach racing springs and Aasco's HP-109 Ti retainers. They seem to fit together fine, and the price was unbeatable. ($70 for a set of Eibach springs, vs over $500 for Aascos!)
The springs were in stock at Summit when I ordered, but it looks like they're out of stock at the moment.

Have you guys seen the new Pauter rocker arms? They look pretty slick:
Porsche Rockers - Pauter

[chris_seven]

I an not sure when the progressively wound spring was first introduced but I am not surprised that they were used in a German engine.

I think that in the fifties and sixties Germany developed a hugely successful 'spring' industry and the manner in which German Automotive manufacturers set and test all valve springs is very impressive.

I would believe that eliminating Eigen resonances in valve springs is very important but I am not sure how many modes are likely to be excited in practice.

Clearly the damping used by the second spring can be a benefit but you can also use dual springs without damping.

I am sure I have seen articles in the past about tapered valve springs which have a non-linear rate but no Eigen resonance.

I like to idea of a beehive spring with a single coil but am not sure if there is enough space available.

CNC machined Rockers have been available in the UK for some time now but they are not well liked for use in FIA -Appendix K Race Engines. I am sure that they will be good for other uses.

In certain categories the 906 type rocker has been banned and this is the reason why we have produced a forged adjustable rocker.

906 rockers currently sell at 720 Euros per rocker which is why we have started a manufacturing programme and plan to be much more cost effective.


Rose Passion - P111785 - 90110530800 - RSR ROCKER ARM WITH PADS - Porsche 911 65-73 1968 2.0L COUPE MANUAL GEARBOX, 5 SPEED > ENGINE AND FUEL FEED > PARTS FOR RSR 906 ETC

[racing97]

I believe the 996 uses a conical spring which has its weight advantage and claims of surge resistance if the pitch is consistant which the Porsche spring also has. In the States here some Pro Stock teams claim they use Titanium and wind it in their own shop with a hand made fixture, and they were only good to a few runs as you can imagine.
I seam to recollect the 935 using progressive wound and tapered damper springs in the 70's

regards