911 aircooled developments

[Neil Harvey]

Some images of the new 92.00mm Piston and rod we did for Jeff and now used in both the 93.00mm kit, along with other kits.

[Helix8]

Very nice - what does the top of the piston look like?

[Walt Fricke]

What do you use to retain the wrist pin?

[mikedsilva]

Is Jeff's engine up and running yet?

[Trackrash]

Makes me wish I had't sold my old 2,2.....

[Neil Harvey]

Originally Posted by Walt Fricke

What do you use to retain the wrist pin?

Std type round wire lock.

[Neil Harvey]

These rods are currently available in all of the std sizes and lengths. There are two levels of rods dep[ending which material they are made of.

The "standard" grade is 34CrNiMo6 which is higher than 4340, commonly used in domestically made aftermarket rods. This has a tensile strength of 1400Mpa, where 4340 is 1200Mpa. The other material used is 35ncd16 which is higher than 300M. It has approx. 20% more fatigue strength over 300M. I'm not sure is anyone builds rods unless custom, with materials this higher grade.

These are offered as a alternative to the other well known aftermarket rods currently sold and used in these engines. The "35" versions are lighter than anything else sold currently unless you move into Titanium. They have added features including the relief shown above the BE so the compressive loads are transferred over a larger part of the upper bearing shell.

We are also making available these rods in some custom sizes and lengths along with custom Pistons. These kits will be available for all of the std air cooled rebuilds where the std deck heights are in play along with all of the std CR numbers. Top guided and longer CCL rods, shorter piston compression heights with smaller piston pins. giving better control of the piston, better gas exchange, and less weight over the pin will help these older engines that have been supplied with age old designs for years. We feel its about time someone offered something new.


We are currently in production with rods and Pistons, so initially there will be some lead times for these parts. Stock length rods are currently available now along with std pistons for those that are not inclined to wait.

Our customer base has taken us back into the air cooled world after many years not seeing one of these engines. Upon some research we found the same old parts designed back in the 70"s still been sold today. This gave us cause to re look at what is available and make new parts for these engines, including these Rods, Pistons, Camshafts, Intake systems, exhaust systems, etc.

[Neil Harvey]

Some more updates on some of the parts soon to be available.

2.8L upgrade.
The photos attached above are the parts available for the earlier 911 engines to upgrade to 2.8L. Included in the 2.8L kit is a new camshaft. The Rod is longer and lighter than any other currently available for a 2.8L upgrade. Same for the piston. The piston pictured is for a dual plug head. These are the parts we supplied to Jeff (home built) for his 73 911 engine.

2.9L upgrade.
These parts are currently in prototyping and we should see these in the next 2 weeks. A new longer, lighter rod, a new Piston for dual plug head, and a new camshaft are included in this upgrade kit.

3.4L kit
This upgrade kit includes a new rod, and a new Piston. We have also designed a new piston for single plug heads to be an alternative to the early wedge type piston design. A new camshaft design is in development for this kit. This engine upgrade has been lacking for modern components for years.

3.8L upgrade
This is currently in development and should be completed by months end. A new Rod, Piston and camshaft will be available.

964 Camshaft.
This camshaft will be our new version of the venerable 964 cam used in so many engine upgrades.

We felt that many of the current kits available for these engines have not kept up with the changes in modern design. Many of the substituted parts are copies of factory parts giving no increase in the engines efficiency. We have focused on component weight, friction reduction and air management to gain back some of the engines performance lost in these air limited engines. Customers have been limited to choices with most engines built using the same parts. We felt its about time these earlier 911 air cooled engines had some new parts.

All of the kits can include upgraded cranks, cylinder heads and other options we currently offer.

[mepstein]

Originally Posted by Neil Harvey

Some more updates on some of the parts soon to be available.

2.8L upgrade.
The photos attached above are the parts available for the earlier 911 engines to upgrade to 2.8L. Included in the 2.8L kit is a new camshaft. The Rod is longer and lighter than any other currently available for a 2.8L upgrade. Same for the piston. The piston pictured is for a dual plug head. These are the parts we supplied to Jeff (home built) for his 73 911 engine.

2.9L upgrade.
These parts are currently in prototyping and we should see these in the next 2 weeks. A new longer, lighter rod, a new Piston for dual plug head, and a new camshaft are included in this upgrade kit.

3.4L kit
This upgrade kit includes a new rod, and a new Piston. We have also designed a new piston for single plug heads to be an alternative to the early wedge type piston design. A new camshaft design is in development for this kit. This engine upgrade has been lacking for modern components for years.

3.8L upgrade
This is currently in development and should be completed by months end. A new Rod, Piston and camshaft will be available.

964 Camshaft.
This camshaft will be our new version of the venerable 964 cam used in so many engine upgrades.

We felt that many of the current kits available for these engines have not kept up with the changes in modern design. Many of the substituted parts are copies of factory parts giving no increase in the engines efficiency. We have focused on component weight, friction reduction and air management to gain back some of the engines performance lost in these air limited engines. Customers have been limited to choices with most engines built using the same parts. We felt its about time these earlier 911 air cooled engines had some new parts.

All of the kits can include upgraded cranks, cylinder heads and other options we currently offer.

How does someone purchase from you? thanks

[75 911s]

Interested in the 3.4 pistons and rods.

[Neil Harvey]

Originally Posted by mepstein

How does someone purchase from you? thanks

Best to email me with what you need.

neil@performancedevelopments.com.

[Neil Harvey]

Originally Posted by 75 911s

Interested in the 3.4 pistons and rods.

same. Email with what you need.

Would need your cylinder head volume so we can establish the CR you need and the cylinder heights you have. These kits are "custom" to a point. Although most will end up the same, there is some leeway we have to obtain exactly what you need.

Neil

[Neil Harvey]

Some updates.

The 2.9L engine parts are almost completed. This engine config uses a different piston forging as the 93.00mm bore allows the use of the lighter bridged forging. This forging also allows for a much shorter compression height making the piston lighter as well.

The biggest gain had in this engine is the connecting rod. Its a lot longer than stock and lighter. They are coming in, sub 480 grams. The first prototypes are close to been finished and tested. Once we have this completed they will go into production.

There is only so much you can expect these small displacement engines to produce. Heads have limited port sizes, valves sizes are dictated by cylinder bore size etc, so component weight and friction are two areas that gains can be had. We know how much these engines can theoretically produce with the energy contained in the fuel, and by subtracting all of the loses known in 4 cycle engines we end up with a number between the actual measured BHP and what the calculated HP is. This amount of HP is what we can influence with component design, component weight and lowering parasitic losses.

Friction is a huge loss in small engines so anything that can be done to lower this is a huge help. Anything that slides against something creates friction and heat and this energy is lost is just turning the engine over.






The work involved and these parts come at a cost. They are not cheap and not intended to take the place of current parts sold by other vendors. They are intended for those that what a more modern interpretation of these earlier 911 engines with components that are engineered and designed to extract more performance.

There are new pistons in design for single plug versions of both these engines and as soon as they are completed I'll post photos. Included are pistons for the 98.00mm bore as the 3.4L conversion from 3.2L seems quite popular. The new design is a compete departure from the ancient wedge type sold currently for these engines.

[Neil Harvey]

Forgot to add, the new head studs we have in production go along with these upgrades as well.
I have included here a better photo of the camshaft and the stock cast rocker arms.

[Tippy]

Neil, excellent stuff!!

Not that I am in the market, but more of a curiosity question. Do you plan on boosted applications with flat top or slightly dished pistons with your connecting rods?

Just really curious what that combo would result for RPM wise on a 3.2 based 3.4? Redline basically.

[Taycan]

PM sent.

[Neil Harvey]

Never received any PM. Send it again and I will respond.

An update also.



An update also.

The cam inventory is getting larger. We now have non symmetrical cam designs for air cooled NA engines up to 2.8L, 2.9L to 3.4L, 3.4L to 3.6L and 3.6L to 3.8L. All these new designs will only be available on new billets, with DLC lobes. The existing 1/2 step designs and some of the older Turbo designs can be regrinds.

These designs are all matched to our new spring. This spring comes in two favors, each having a slightly different rate and installed seat pressure.

I'm happy to announce that Steve Becker, ex Andial race engine builder has joined PD, is up and running and will be taking care of the PD stock/upgraded engine rebuilds and also offering our Signature machining service including Cylinder head rebuilding service. In the past PD has not offered this service at the price of many other service suppliers. Our work was never intended for those customers requiring a cost based product, rather for the more exclusive customer wanting quality over cost. Steve is now able to offer a cost competitive service for those wanting a quick turnaround, quality work and will be selling our line of Connecting Rods, Pistons and Cylinders, Camshafts, Valve Springs, Head studs and fasteners.


Above is an example of what you will receive.

[Discseven]

Originally Posted by Neil Harvey

Neil... what's weight of that assembly? Very nice appearance.

[Neil Harvey]

Originally Posted by Discseven

Neil... what's weight of that assembly? Very nice appearance.

As pictured, Rod with bolts, Pistons and Pin, 914.50grams.

No clips or rings included in picture.

[Fly911]

Would it be possible to have the wrist pin even higher up in the piston? If you had a hole where I marked on the picture, and slid the wrist pin in, and then had a tight fitting plug that locked in place, with grooves for the piston rings, you would have a much better geometry. You would have to put the piston rings on after the rod was installed.

You would get less piston slap, a lighter piston, and a longer rod to stroke ratio. All making more HP... Or am I in the wilderness here?