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Join Date: May 2004
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This rod as it stands now weights approx 100 grams less than the typical aftermarket version. The next versions that will be sold are losing another 20 grams.

Old 12-12-2019, 02:16 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #41 (permalink)
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In our quest to lower component weights, we are about to test titanium bolts in these new lightweight rods. This is not something new. Pankl fitted to bolts in their rods back in the 80ís used in 24 hr turbo engines. Engineered correctly it poses no issues.

If we can lower the Rotating and reciprocating weights we can help with the crank harmonic movement. I am confident this will help in the life of the magnesium cases a lot.

Getting back into the air cooled world, we wish to offer a modern twist on these older engines. It seems to me that this is an area that has been forgotten about. I have studied what others are offering and in most cases the same historic parts are used.

I know this technology is more expensive so not for all, but my intention is not to compete against the common parts but to offer a modern up to date alternative.
Old 12-13-2019, 09:16 AM
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Titanium bolts

They were used on all RSR engines that had steel rods in the 70,s.They were reusable which was nice.
Old 12-13-2019, 09:26 AM
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Before my time but yes , the use of titanium rod bolts is nothing new. There is a terror in the minds of many about using titanium but when engineered correctly it adds huge advantages. We are making our new exhaust studs with titanium and the new head studs use titanium washers and nuts.
Old 12-13-2019, 10:48 AM
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HI Neil,
I love what you are doing with these new parts. It makes so much sense to design for the application and not just make new parts based on how the old parts were designed.
In on of your earlier post you show a rocker.

This looks to me to be a later 993 rocker that has been modified to accept the a screw type adjustment. Is this a service you offer? are these bushed to use standard rocker shafts or are they intended to use 993 cam housings and shafts?


Old 12-14-2019, 12:37 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #45 (permalink)
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Yes, these are 993 rocker arms. We use these for adjustable types as they are stronger and lighter than 911 types. 911 rocker arms are cast and 993 arms are forged.

The arms are purchased new, undergo a ratio check, pad check, crack checking, machining for the threaded bushing, additional modification if used for 911 cam housings, and finally after ultrasonic cleaning, sent out for DLC coating. Upon return, the shaft bores are honed for the clearance we specify and finally get assembled with the bushing. We use new rockers only if they are to be DLC coated as there is minimal contamination prior to DLC coating. Used rocker arms have too much embedded trash which makes the adhesion of the DCL too difficult to be certain of.

We offer non adjustable types made in Germany but these are not intended for street engines. They require lash caps to be used for adjustment and stock valves are too long.

Everything we have developed is intended to be used as matched parts. Camshafts, Rocker arms, valve springs etc are all designed to be used as solutions for those wanting something more engineered.

The "new" A symmetrical 964 replacement cam just completed, is designed to be used with the new valve springs we have had wound, or the 964 and 993 springs. We have extensively tested the 964 valve spring and it is a very good spring made from very good material. The wire stress numbers are at its limit but as the spring is wound from superior steel, the stress numbers are ok. The same cannot be said for some of the aftermarket springs currently sold.

The new 964 cam will take the place of our existing 964 1/2 step version. We now have cam designs for engine up to 2.8L, 2.9L up to 3.2L, 3.6L up to 4.0L and another for engines above 4.0L. There is currently a cam design underway for engines 3.2L up to 3.6L.

Last edited by Neil Harvey; 12-15-2019 at 03:36 PM..
Old 12-15-2019, 03:33 PM
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It has been a crazy time lately. Indianapolis for PRI, then to Detroit, now in Florida for a break and back to LA just after new year. In the next few days I hope to post some photos of the parts we are continuing to develop for these air cooled engines.

All new valve train parts both steel and titanium have been made which we spent a lot of time testing, testing with new and some existing valve springs. We found some of the existing valve springs are very good when used in certain applications. Unfortunately these are typically over sprung.

Cylinder heads are subjective, which size is better, what porting is better etc. I have left this area to each engine, not saying you need this amount of air. It's not always about the airflow through the head. It has to be measured from the entry of the intake system to the back of the valve.

There is a development 2V cylinder head underway for these engines, but to redevelop something similar to what already exists is pointless. Bill @ Xtreme offers an excellent alternative to the stock heads. There is no point in spending time and money to come up with something similar.

The current 2V heads have just about reached their max flow, so managing the flow per crank position is an area that can be influenced.

Two new camshaft designs have just finished testing. One is the new "964" design to take the place of our 964 1/2 step. The other is for 4.0L+ engine sizes. As I have stated in past posts, all the new cam designs are "solid A symmetrical" and will be available only on new billets. The lobe designs are set but the LSA's can be changed when required.

The 2.9L engine that has just had all of the parts completed will soon be assembled and tested. I will hopefully be able to give some updates that project soon too. This engine uses the new lightweight rods, Piston design, camshaft, 993 adjustable rocker arms and the cylinders have the
softer seat pressures. The rest of the engine is pretty much "stock" using twin heads with typical port sizes, valve sizes, stock intake system and the mech fuel system.

Its important to me that we develop parts that can be used across a wide range of engine spec's.
Old 12-27-2019, 03:17 PM
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Those combustion chambers are pretty impressive.
Patrick E. Keefe
78 SC
Old 12-27-2019, 03:48 PM
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This year my intention is to bring to this community more basic info on rebuilding these engines. Hopefully it will be of help, lowering the fear that some often have when starting this journey. I wont give away any secrets or modifications that are proprietary, rather focus on the best ways to tackle some of the required work.

I also will go deeper into the machining of the parts so you can have a greater knowledge of what is required, when and what in my opinion is the right way. Recently, a shop I am currently working with in the supply of custom parts had the engine case machined by a well known Porsche machine shop. The result was extremely poor with out of round main housing bores giving bearing clearances over spec of 0.004" in one direction. Mistakes can happen, we are all human, but the mistake was found after checking, not assuming it was done correctly.

Simple changes in certain areas of these engines can make a dramatic difference in the engines performance. An area I keep going on about is the over springing of the valve train. Some of these smaller engines produce less than 200 BHP, so any power regained is a huge plus. My beef is with companies that sell aftermarket valve springs without asking of giving any sort of data and reasons why you need them. Often fear of valve float is used as a selling point. BEWARE of salesmen who sell you stuff without having any reason for you using whatever they are selling.

We have conducted a lot of testing recently on valve springs and were pleasantly surprised just how good one of Porsche's stock springs performed. I intend to write a paper showing the results and giving an overall spring doc for many of the different engines. I cannot know every camshaft out there and how it works, but this should also give you an understanding of what goes on at 6000+ RPM, what questions to ask your cam supplier and what not to do when building your engine.

I have written a draft paper on the case assembly and what to do and look for. I will post this in the next couple of days. Then I will cover many of the areas often questioned. Head studs and their installation, Cylinders, measuring and the repair work, what to ask for and who best to be use in having your cylinders repaired. This is an area when knowing what to ask for will eliminate many of the poor results I have read about.

Cylinder heads and what to ask for, what info you should give the repair shop and what to look for when receiving them back. There are some really good shops doing this work and some others who are regarded as the go to places. This is not the place to compare or trash others work, rather to educate you on what to expect as rebuilt correctly.

The main thought process here is to educate, lower the fear level and show that there are many ways to do this work. Books that have been written often give no lea way or alternatives. You do have some tolerances in rebuilding these engines other than just the measurement tolerances. Hopefully understanding these will help and make this journey more enjoyable and rewarding.

Last edited by Neil Harvey; 01-05-2020 at 11:19 AM..
Old 01-05-2020, 11:17 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #49 (permalink)
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Interesting that the Porsche valvespring was developed by an American company back when they couldn’t keep them from breaking on the 356. The vacuum used during the making process was key to keeping occlusions/voids to a minimum.
74 911, #3
I do not disbelieve in anything. I start from the premise that everything is true until proved false. Everything is possible.
Old 01-08-2020, 08:48 PM
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Originally Posted by patkeefe View Post
Those combustion chambers are pretty impressive.
Shiny and clean maybe but very much old tech.

If Porsche designed them again today, they'd likely have:
Tighter valve angles reduce the surface area of the chamber,
Twin plugs to speed combustion,
Shorter exhaust ports to reduce head temperatures,
More squish area to speed combustion,
No or little piston dome to speed combustion and reduce piston temperature
Extra care in inlet port alignment (extra "sidedraft" and less downdraft for our flat 6!) to give greater swirl and tumble to speed combustion

When you consider how much money is often spent on these Mezger engines, I find it surprising no one has offered a modern design head with the above features. Not impossible as these features are readily seen on modern Ducati 2 valve aircooled engines for example.

Last edited by Peter M; 01-16-2020 at 11:04 PM..
Old 01-09-2020, 12:32 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #51 (permalink)

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