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New Camshaft choices

After reading another post asking about camshafts, I have decided to offer our designs to the public along with some brand-new designs in the works. We have never been in the camshaft business, but recent inquires about our custom designs has shown me there is a demand for high quality camshafts. Our core discipline is the design of custom parts and engines, so we are well positioned to offer quality cams and their associated parts.

For many years we have focused on the later water engines. We recently completed the upgrade to the 991 engines with our version of solid finger followers. Now our attention is equally focused on the earlier air-cooled engines. We have many new parts in design for these engines, including a 2V 4 cam version with variable cam control on both cams using finger followers and not rocker arms.

Many of our water-cooled parts do carry over to the air-cooled engines. Crankshafts, connecting rods, some piston designs that will allow more dome volume to be added can all be used right now. We designed the crankshaft damper many have used for the water engines and these have proven to be very successful on the air engines.

All our cam designs have always been custom profiles which have been simple improved designs over the many stock profiles or all out custom designs. We have always out performed anything else that we could have bought from the well-known suppliers.

Our recent design for the early 911 engine we did for Jeff in Australia is an example of our current designs. We have many NA and Turbo designs that were done over the years but many of these need to be upgraded. Over the years we have become a lot more aggressive on the Intake side and less on the exhaust side. These newer designs have proved to make more torque. Technology marches on.

Many cams that are currently sold are copies and some are really bad. A cut and paste exercise at best. The lobe centers are moved around some to make them different, but the results usually come up short.

We are going to offer a higher-level camshaft for the Porsche market, cams CNC on brand new billets cut on both 47mm and 49mm shafts. Making them on a CNC grinder controls the final product ensuring each lobe is the same and allowing custom designs to be had without the need for masters.

We are currently testing a brand-new high-quality Valve spring that is hoped to be a good replacement for the 911 2V application. The specification was for a spring to have the control needed but with lower seat pressures. High seat pressures are often required to mask the poor cam designs seen in many in the aftermarket. So far it is performing above expectations and hopefully will be available before we can offer cams. Our intention is to offer a lightweight tool steel retainer to go with these. I’m not a huge fan of Titanium retainers in anything but race engines. Titanium wears and these often fail if not given close inspection on a regular basis.

These parts are directed towards the customer that wants quality over cost. There are many cheap cams and springs available, we do not need to add our name to these. Our parts are for those that want quality and engineering over cost.

Today I directed all our custom designs to be upgraded along with many of the latest designs to be added to the inventory. It is hoped to have cams and the springs available in the coming weeks. Retainers may take a little while longer as we cannot finalize the diameters until we finish the spring tests. I will put more info about each product up on our web site shortly.

Last edited by Neil Harvey; 08-21-2018 at 06:19 PM..
Old 08-21-2018, 06:06 PM
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Will you ever post specs? I know you’ve said that lobe design/profile is more important than the all out specs when it comes to harmonics.

Dougherty posts all of his, and it’s nice to compare.
Old 08-21-2018, 07:08 PM
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Absolutely.

We will make the basic specs available, but remember a good camshaft is not just about lift, duration and lobe center sep.

Our model here is to supply well engineered and designed cams as an alternative, to those that value quality. With the Landis up and running soon, we will be able to build a camshaft to each customers needs.

In the next week or so we will put up on our web site the specs of the cams we have to date. As I stated earlier many of these are going to be modernized to bring them up to current spec's.
Old 08-21-2018, 09:21 PM
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Are we leaning toward beehive springs in our 2V aircooled world?
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Old 08-22-2018, 12:32 AM
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Neat. Would really enjoy seeing the 4 cam and finger follower arrangement you have for air cooled setup. Suzuki I believe started the production of the intermediate shaft mounted finger follower setup some ~20 years ago and several parties really ran with it. Porsche used it first with the 991 GT3 engine. Previous to that though, Maserati of all places in the mid 80s made a 6v (yes, 6!) head with an interesting and very similar finger follower setup as an experiment which was fascinating.

About a year ago now my company completed a significant study and small production run of 911 valve springs, which a few sets I believe are still around. The short of it was that the entire industry sans Porsche stock valve springs are running far too much seat and nose pressure. Even extreme cam ramp speeds don't warrant usually more than around 65-70lbs of seat pressure and some 210-220 over the nose. A very well known Porsche engine builder, who is not a mechanical engineer and who will remain nameless, called my engineer who does have a masters in mechanical engineering and has been designing many components including valve springs for decades, 'crazy'. That's the thing about weights and math, it can only be objective. Nice to see things are waking up.
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Old 08-22-2018, 05:39 AM
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Yes, there is no need for all of that pressure when it's virtually only closing the valve and rocker arm. Very little mass compared to a pushrod, lifter, valve, and rocker, that some folks use spring pressures rated for on the 911.

Accelerated rocker and cam lobe wear, plus parasitic losses. Double-whammy!
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Old 08-22-2018, 07:30 AM
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Quote:
Originally Posted by Tippy View Post
Yes, there is no need for all of that pressure when it's virtually only closing the valve and rocker arm. Very little mass compared to a pushrod, lifter, valve, and rocker, that some folks use spring pressures rated for on the 911.

Accelerated rocker and cam lobe wear, plus parasitic losses. Double-whammy!
We found Porsche's spring needs when using the stock rocker held by intermediate shaft are slightly less than that of similar year Ferrari engines which use similar size/weight valves but with flat tappets with shims on top. The rocker shaft is calculated at half it's overall weight due to it being held by an intermediate shaft at its center balance point. The rocker curve on the actuating surface also presents a softer opening (can't phrase it any other way) than a flat tappet config, which by comparison is slightly heavier (as it must be calculated at 100% of its weight) and requires a bit more spring to control the abrupt opening of the valve which was found to easily 'loft' (valve moves forward without contact with shim bucket) with cam ramps with high acceleration rates.
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Old 08-22-2018, 07:48 AM
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Glad to read that I’m not the only one that believes most Porsche engines are over sprung.

I read ad’s for “high performance” springs sold that will give over 100lbs on the seat! Add in the same kit a set of Titanium retainers and you have a race set. Titanium Retainers should not be anywhere near a street engine if you want not to have problems. Most are cheaply made, full of sharp edges and uncoated. Jack up the spring pressure and ever wonder why they have so much wear showing.

We have inspected many cams supplied by well known suppliers to the Porsche aftermarket and all are “head scratches”, how do they get away with this. Jack up the seat pressures and cover up the bad design.

Many are copies, cut and pasted from other designs, with lobe centers narrowed or widened to obtain something to sell. The unsuspecting customer thinks they are getting something special. The engine runs “fine”, but the devil is always in the details.

All too often we complicate matters and engine talk is no different. It’s about pumping air in the most efficient manner. Having control over each component in the engine. If the engine internals that are tasked to suck and squeeze are doing their job, then steering the air around the valve stem and guide boss, making sure the valves are going up and down in time with the piston motion is essentially what we are trying to achieve. What challenges this simple explanation is friction, stresses and forces that are often a consequence of poor engineering.

Cam design and spring forces play a huge role in an engines performance or lack of it. Controlling the valve train at RPM and freeing up some of the unneeded forces due to spring pressures will do wonders for an engine. But there are other factors that need to be considered here. Engine speed, component weights, seat widths, seat angles, turbo or normally aspirated, all play a role on the choice of spring pressures.

The point is, it needs to be engineered, not guess at. The difference between that car that just went by you on the straight might just be the difference between having its engine engineered and yours being guessed at.
Old 08-22-2018, 10:11 AM
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Good stuff lvporschepilot! Thanks for the info.
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Old 08-22-2018, 12:33 PM
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Ok, so what's the hot ticket for a street driven mild turbo build. I bought a set of SC cams and had them reground by Dougherty, bought a set of stock valve springs from Eibach, and a set of hard coated titanium retainers from Chris Flavel at Finn Lane Motorsport. This is the first I have heard that Titanium retainers are bad in a street engine.
Old 08-22-2018, 01:52 PM
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Quote:
Originally Posted by Neil Harvey View Post
Glad to read that I’m not the only one that believes most Porsche engines are over sprung.

I read ad’s for “high performance” springs sold that will give over 100lbs on the seat! Add in the same kit a set of Titanium retainers and you have a race set. Titanium Retainers should not be anywhere near a street engine if you want not to have problems. Most are cheaply made, full of sharp edges and uncoated. Jack up the spring pressure and ever wonder why they have so much wear showing.
I'm sort of confused by this....

You might as well say that custom cams should not be anywhere near a street engine if you want not to have problems.
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Old 08-22-2018, 02:25 PM
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Fascinating thread!

Neil, can I suggest that when you release the specs of your cam designs on your website, you add also the intended application and target engine for each cam?
Old 08-22-2018, 06:36 PM
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Yes Neil I would also like to know what options you have on offer, perhaps a brief explanation of their strengths and best uses, for future builds.
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Old 08-23-2018, 07:20 AM
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Having been in the back round for many years , Neil I concur with your thoughts . Too much guessing . A sweet engine has been developed . They are reliable and have great presence .
I am Happy to see your post about bringing cam tech to the fore, and not just a secret .
I commend you
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Old 08-23-2018, 05:27 PM
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Neil,

Do you have cams for M96/97 motors? We have been using Shrick cams in these motors with good results but wondering if you have other options. Feel free to email me, we have a steady diet of these motors we build.

Cheers
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Old 08-23-2018, 06:44 PM
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Neil,

Do you have cams for M96/97 motors? We have been using Shrick cams in these motors with good results but wondering if you have other options. Feel free to email me, we have a steady diet of these motors we build.

Cheers
This the water Boxster engine? No, we have never worked on these and do not see ever starting.


It just not an engine we feel we can add any value to.
Old 08-23-2018, 11:30 PM
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Originally Posted by lvporschepilot View Post
Yes Neil I would also like to know what options you have on offer, perhaps a brief explanation of their strengths and best uses, for future builds.
This is our intention. We have all of the stock grinds on masters back as far as some 356 profiles. We hope to offer these "stock" grinds in an improved version along with all out custom profile designs.

Choosing a cam needs to be based on your engines internals, its use and what performance expectations you have.
Old 08-23-2018, 11:34 PM
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I'm sort of confused by this....

You might as well say that custom cams should not be anywhere near a street engine if you want not to have problems.
Kind of, in a manner of speaking. Its the unknowns that are sold that concern me.

Many have bought Titanium Retainers with springs a that give more force, but many probably have not opened up their engine to check the wear rate on the face between the retainer and spring.

Race engine get opened up on a regular basis and these parts are inspected and or replaced where required. Street engine are not. Are they really worth the trouble? In some minds they are. But often they are paired with the wrong spring for the application and poor cam profile design resulting in net zero advantage.
Old 08-23-2018, 11:40 PM
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Here is something I wrote tonight before closing for the day. Its a simple round about explanation of what I am trying to suggest with designed cams and well matched springs.

The last couple of days I have received many phones calls asking about valve springs and why I said many Porsche engines are over sprung. Someone here even mentioned about my comment regarding the use of Titanium Retainers in street engines and questioned “maybe we should not even use custom cams in street engines”. Good point and somewhat correct in my opinion if the custom cam is poorly designed. The same can be said for stock cam, if they are poorly made.

There is a lot to cam design that may be above or not important to many here, but the effects of poor cam design and poor Valve springs should be in everyone’s wheel house. One very important fact that should always be considered, the cam profile designs and the valve springs used together, need to be chosen as a compatible pair. Buying valve springs just because they have more spring force without knowing if you need them is foolish and could cause issues.

Staring with some cam terms, we have cam lift, cam velocity, cam acceleration and jerk. Without boring everyone here are some basic musts and must nots when considering a cam and its profile design. A plus here in the 911 air-cooled engine, is that the valve train is very stiff. One of the main reasons why Porsche built 47.00mm and 49.00mm journal shafts running in a big sturdy housing.

Too much acceleration can induce high shock waves into the valve train. These pulses can be very high and narrow and the higher and narrower these pulses are the higher the harmonic magnitudes become requiring a higher frequency Valve spring to counter these forces. This all come about by poor profile design typically when one profile design is married into another to create a custom grind”. These designs often have very high velocities and on the closing side, if the spring force is not increased the valve will bounce on and off the seat, lowering the engines VE. These are just some examples of why the cam profile and the springs need to be a matched pair.

When a 911 engine is running there are two parts of a engine that create these harmonic vibration issues. The crankshaft and the cam profile. The noise generated by the torque pulses twisting the crankshaft back and forth at very high frequencies, gets transferred to the 1st motion shaft and up through the timing chains into the valve train. This is the reason why we developed the crankshaft damper for the water engines and have used it with success on the air-cooled engines. The other is from poor profile designs creating the pulses or shock waves and transferring them into the valve train.

These harmonic numbers can decrease with engine speed and increase as the engine speed de creases. But what you do not want is a high harmonic number at your maximum engine speed, as parts will break, you end up with massive spring surge to name a couple of dreaded results. This is where you need to choose the valve spring with a higher natural frequency. Maybe this should be reason not to buy a set of “high performance” valve springs off the internet just because they say, “high performance”.

When it comes to choosing a good or bad spring without getting too deep into its engineering here are a few things to look for. These are things every DIY engine person can check.

Look at the springs free length. This is the spring sitting on a flat surface not installed in an engine. Before checking the free lengths, compress the spring close to coil bind 6 or 7 times. This relaxes the spring and sheds it of some of its manufacturing stresses. The spring will in most case shrink a little in free length. Now check each spring free length. Be careful here as I have seen springs sets with upwards of 0.050” difference. I have seen springs when sat on a flat surface look like the leaning tower of Pisa. When springs of different lengths are compressed by the cam, they can push out or bulge in one direction which loads up the valve with high side loadings increasing guide wear.

Its impossible for the DIY engine builder to measure a springs natural frequency, but before you buy any, this should be a question ask of the salesperson. If they are having them made, this would be a design parameter. As you increase the engines RPM, the springs harmonic number will de crease. What you do not want is to have the spring approach it’s natural number. As you lower the harmonic number the spring goes nuts and gets into what is called surge. But here is the catch. This is again why I suggest that choosing a cam and a valve spring should be engineered and not guessed. Some cam profiles with the same spring can operate in lower frequency ranges, and the same spring with another cam could run at a higher frequency. Cam profiles do determine the level at which a springs frequency can change, up or down. Get below certain numbers and the spring control is lost and the engines VE drops dramatically

There is a whole lot more to springs other than length, number of coils, wire diameter, number of active coils, lift, installed height, stress values, contact stress levels, etc, etc, etc. I touch on some simple matters in a very broad and simple manner, but to get my point across, this is a very important part of engine building. One that is often if not always not even considered until something breaks. My hope is that with some engineering input and basic knowledge by the DIY builder, you will have some questions to ask the supplier.
Old 08-23-2018, 11:45 PM
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technical capability of salesperson

It used to be your best salesperson was a mechanic who did not want to turn wrenches anymore.In this day you do not get that much anymore.These guys are just looking at numbers on a computer screen.This makes it very hard for a DIY person to make a rational decision on engine building choices.Del West used to make Ti valves with the 3 groove keeper but the wear there was accelerated by too much spring pressure.Hopefully with the help of people like Neil and others who chime in it will help to clarify some of these matters.With some of the spring choices like Aasco the effort to turn the motor over with just a wrench for cam timing is noticeable in the increased effort it takes.Some other choices have the outer of the inner spring already rubbing the inner of the outer spring in a resting situation.Not cool for a stress free environment that the spring needs to live in.The quality of the heads makes the motor.Fred
Old 08-24-2018, 04:47 AM
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