Case Half Right Nearly Complete

When figuring out how to properly machine these cases for repeatability, keep in mind that there are three main factors we have to contend with:

1. We need to preserve the fidelity of the feature in question. This means that if we are making a threaded hole, for example, that the dimensions of the hole, the thread pitch, and the location of the hole on the casting have to be perfect. Obviously.

2. We need to preserve the repeatability of this feature by accurately programming it into the machining model so it can be duplicated over and over again.

3. We need to accommodate the limitations of the machine. We are dealing here with an extremely high end 5 Axis mill, but it has dimensional limitations that have to be observed and accommodated.

These three items are what take so much time, and this process would be very different if we were using another machine, and would be different even if another type of 5 axis would be used. So we are tailoring the machine model to the machine we have.



A machined case half in four easy steps….

That is the goal, anyways. We are diligently working to machine each case half in FOUR operations. Two on the one side, two on the other side. You’re probably asking  – what about the ends?

Well, we have adapted our machining model such that it works on a 5 axis machine, therefore there are only four “setups” or operations. The ends get taken care of during one of the four operations.

As usual, tons of handwritten notes and measurements. To say this is a complicated job is an understatement, but we are getting there.

New Product – Billet oil filter console

Whether you’re running a engine mounted oil cooler or one of the factory oil filter consoles, you’ll want to take a look at my new billet oil filter console. For starters, it looks amazing, quite unlike the factory offerings.

From a function standpoint, I have a big problem with the existing solutions. Not only is the engine mounted oil cooler pretty ineffective at actually cooling the motor, it doesn’t exist in the 964 / 993 models, so what does that tell you about it’s usefulness.

Filter console options are also limited; there are unicorns like the 959 and 965 filter consoles which aren’t available, leaving you with the sole option of using the 993 console which leaves much to be desired.

For starters, the 993 console doesn’t include the return line in the same fitting; Porsche makes you buy a separate widget to attach the incoming line. Additionally, the 993 console places the filter hanging vertically down, which makes it a bear to actually replace the filter.

My console angles the filter like the unobtainum 965 console, but not only that, it includes a female connector for a -16AN line so that you don’t have to attach multiple pieces. You get a clean install, a beautiful looking product rendered in aircraft grade aluminum, and you get a filter that’s easy to change and access.

If you’re looking to add a filter to your pressure circuit like the later cars, this is the one you want.

Doesn’t require modification of your engine tin (or anything else for that matter). You will, however, need to do something with the early fan shroud which has a duct specifically for the engine mounted oil cooler. We suggest blocking it off, or switching to a late shroud.

Price – $395, available now:



Introducing my new Patent Pending Rebuildable piston squirter

What I have to show you is my rebuildable piston squirter – this model is for retrofit to existing Porsche 911 cases. One of my other patents integrates the squirter assembly right into the case itself, which is the ideal solution, but this one here works basically as good.

I have rebuilt many Porsche engines and I am convinced Porsche never really gave much thought to rebuilding the motors. They are a new car company; I get it. But how many of these squirters are inoperative when you go to rebuild? How many don’t really pass the compressed air test? How can you really know if the insides of the squirter barrels are clean, and free of any debris?

That’s a lot of questions. Too many for my liking. I got sick thinking of not being able to access the insides of the squirters when building a really expensive motor, so I decided to fix it.

My requirements were as follows:
1. I did not want to have to tap the case or modify the case in any way. Whereas I am very comfortable modifying the case, I wanted to cater to the lowest level of home mechanic.

2. I needed to get at the complete inside of the squirter barrel so I could visually see what was inside.

3. I wanted to be able to rebuild the squirter without removing the barrel from the case.

4. I wanted the same performance as stock – meaning, leave the check valve in there to preserve idle oil pressure.

What I achieved was a steel barrel which is a light press fit into the case. This barrel has a cap, and the insides of the barrel contain the spring and the ball, just like stock. [img][/img]

The advantages of my squirter over a stock one are:
– ability to change the orifice size on the cap on the fly for more or less flow
– completely rebuildable and inspectable
– much easier to install than a stock unit

Which brings me to my next point. What is holding this thing in the case. I already know I am going to get many people who doubt the adhesive, but I am 100% comfortable with it.

The adhesive in question is Loctite 640, and its properties for adhering cylindrical bodies together are legendary. Take a look at the spec sheet for this product and you’ll see that it was tested for over 1000 hours in a bath of engine oil at 250 degrees and it did not lose an iota of strength.

Staking these things is not necessary; the factory did it because they were paranoid. In fact, a press fit is not necessary either, but I recommend it as an added, if unneeded measure of safety.

Lastly, we come to orifice sizing. Stock sizes are as follows:

911 – 1.0mm
930 – 1.5mm
964 – 2.0mm

Because the internal dimensions of my squirters are different than stock, my orifice sizing needs to go up 1/2mm to ensure the same flow as stock. Don’t worry, this was all extensively tested.

So my recommended sizes are:

911 – 1.5mm
930 – 2.0mm
964 – 2.5mm

Also, note that there are two barrel diameters available, just like stock. 6.0mm is the one you want if your squirter bores are real nice. If you buggered up your squirter hole, we make a 6.6mm oversize just like the factory.

Prices are $45 each, which includes the barrel, cap, spring, and ball. You’ll be able to order them off my site soon, until then drop me a PM.

Oh, and here is a video that explains the installation much better than this wall of text!

Let me know what you guys think!

Well, we’re running behind….

It looks like we won’t be able to meet the schedule posted in the last post. Making the casting is one thing, but the machining is proving to be a major area of focus right now.

In some respects the casting is the easy part, although thus far nothing in this journey has been easy. The reason why I say the casting was the easy part is that there is a lot of extra meat on the casting, which of course needs to be machined off. This extra meat makes the casting somewhat more forgiving to make.

The machining, by contrast, has to be ultra precise. To that end, we have rejected many of the machining methods used to machine the case, and even rejected many of the machines themselves. Originally, we were going to machine the cases with a combination of vertical CNC mills and CNC lathes. That idea has proved itself to require too many setups, which affect the repeatability and the accuracy.

We have now realized that the machines we had access to won’t be appropriate for mass production, and so have decided to use a combination of large horizontal CNC mills and a 5 axis Vertical CNC mill.

These machines can machine our part with fewer setups, and less movement of the part than the machines we had access to, which will of course result in a more accurate part, and more importantly, a more consistent part.

Thanks for your patience as we endlessly fiddle with this, and rest easy in the thought that once we nail the routine down, the actual production of the cases will be elementary….



Machine model complete

Once again all of our hard work has paid off in the form of what is arguably the most accurate model of a flat 6 engine case out there. Recall that we started with a 50 micron scan of an actual Porsche case. From there, we developed a Solidworks model. But just having the model in Solidworks doesn’t really finish the job.

From there, we needed to take the original model and make a model suitable for creating a casting. A casting has draft, extra material, and all sorts of features that you won’t see on a finished case.

Of course, the casting model is of little use to the machinist, who has to create his own model that will be used to guide the tool path of the CNC machine which will remove all the metal that was added in the casting process. And in the end, it’s the machinist’s model that needs to be the most accurate, since there is essentially zero room for error.

It took us over 6 weeks to measure every last hole, nook and cranny on the case by hand and then compare it to the computer model to ensure accuracy. From there, a SurfCAM model was developed which gives us our tool paths for each case half.

This is also much harder than it would appear. Each case needs machining on all sides, and then both halves are bolted together and machined again where they need it, as well as line bored. This was an incredibly laborious process but I felt that being accurate was more important than being first to market. So thanks again for your patience.

From here, we are constructing the fixtures that will hold the case down for the various machining operations and text machine the first case halves. Tentative schedule is as follows:

November 1: both case halves machined on all sides. Create fixtures for gun drilling and line boring.

December 1: Produce a right and left case half capable of being built into a motor.

January 1, 2018: First Engine complete and operational. 

Beta testing and customer deliveries to follow. The picture you are seeing below is  of the SurfCAM machining model.




Check, Check, and Recheck

Although significant time (and money) was spent to create what is probably the world’s most complete solidworks model of a Mezger engine case, that is simply not good enough to machine off of without triple checking everything. Sure, the scan was to 50 microns, but we need to be sure….SURE…that the dimensions are perfect before we start destroying perfectly good castings.

To that end, The Machinist is diligently confirming every single last little dimension on the model to the factory 3.6 case. It begins with a perfectly flat slab of granite with which to measure from; from there, reliable and repeatable baseline dimensions are pulled of the case and double checked with the model.

We also use conventional 2D drawings to make our notes on, and these are printed 1:1 scale so we can set the case right on top of them and jot down everything we find to be of importance.

The whole point here, just as with the tooling, is to come up with a prototype case that is very close to where we want to be. I’m not going to exaggerate and tell you it will be perfect from the get go, but all of these steps help to ensure that we have an accurate case pretty much from the start.  Nothing is left to chance. Nothing is assumed just because it has been scanned at 50 microns beforehand. That is not the way we roll here….

First CNC machining pass will happen in the first week of October.


While I wait…..

While I wait for the machinist to finish constructing the fixtures that will hold the case in place for machining, I am putting my 3.2 short stroke motor back together. It started life as a 3.0 in my 1983 SC, and was just tired all the way around.

Although I had the case halves soda blasted and hot tanked, it is still very hard to clean out the oil galleries. It is clear to me that Porsche never paid any thought to rebuilding these motors whatsoever. Here is what you will NOT be doing on my cases:

1. Taking JB weld and coating the outsides of all the aluminum plugs so they don’t leak. Not only is this a totally hack solution to an easily solvable problem, it looks like crap. My case has hex head plugs that can be removed and replaced. A little loctite will keep them in place and leak free.

2. Want to clean out your piston squirters, or verify they work? You need a tool like the (excellent) one from Stomski racing that fits in the case through bolt hole and shoots a jet of air up into the squirter. Alternately, you can rig something up, but it is still a hassle. How about just using removable squirters that unscrew???? Yeah, that’s what I said too.

3. Regardless of what the case looks like from the outside, there is no good way of ensuring the oil galleries are clean and clear without removing the plugs, which is a hassle. Usually you wind up spraying a gallon of carb cleaner through every hole you can see, then say a little prayer, and hope for the best. See point #1.

Also working on a new feature that will make it easy to separate the case halves without hammering or prying. My case should last forever, but if you need to open the motor because you a) dropped something in there b) forgot an oil pump seal, c) forgot to put the chains on the lay shaft and don’t want to use a master link, you’ll be able to split the case easily.

Most of the ideas I came up with were directly borne from building a ton of these engines myself. I hope that shows through in the final product.

Prototype #1

What you’re looking at is the first non factory prototype casting. It’s not perfect, and we know that, but for a first try, it is a remarkably good casting. We have some gating fixes to do and some other tweaks, but this casting has a purpose – it will help us set up the CNC routine for the machining. Overall, a great start!