Cheburator

For a change I would disagree... I only have empirical evidence from about 6 engines - two Euro S2, a GT and three GTS. All were raced as hard as you would dare. The S2s were in a championship winning car, one of the GTSs is on here and has won many races, the GT and the GTS were mine, and the other GTS was also raced hard in England and Europe before getting a stroker.

Starting with my engines: the GT got pulled out because of oil control rings failure. I showed pics of the 2/6 bearing after 2 full seasons at the Nurburgring and the UK. It looked brand new. The timing on the engine was as advanced as you could get with EZK/LH combo - even JDS could not belive how much we added and the thing just run, sweet as a nut. The GTS engine survived a full season of racing only to fail as it lost all oil due to catastrophic leakage from the block to oil cooler hose coupling. While the 2/6 was ground to fine powder and the associated rods were bent, the rest of the bearings were as good as new, both mains and crank. And here we are talking about the inferior, plastigauged, GLYCO OEM STD bearings that I put in when I had the engine restored from the fire that it had been in its previous life, not some genuine Porsche branded bearings.

The S2s - one of them had 160k miles on the original short block when it was dropped in at short notice. It only failed as it overheated due to waterpump failure after a season of hard racing. It had accusump, but that's about it. The other S2 engine that failed was due to lack of limiter and owner experimenting in his last race of the season, which he already won the Championship.

All of the rod bearings that have failed here have happened either due to catastrophic loss of oil or lack of dry sump. The dry sumped cars are all alive and well...

Porsche did built 928s for racing, in fact one just surfaced in France, with the associated work by the factory to make it competitive. They just kept quiet about it...

Perhaps we don't drive our cars in Europe hard enough...

Iwanna928

5.4L 16v Euro singing over 7000 rpms

Maybe in a year or two! Put me on a list!

Always need a new goal and now I found one!

Awesome work Greg!

Rick Carter

Thanks for your dedication Greg.

GlenL

Will you complete the 928 **** with pics of exotic pistons?

hans14914

Greg,

Kudos on the new crank design, and pricepoint. I personally find it quite attractive, and may have to start my 5.4l crank savings fund. Can you please explain the 5.4L program in a bit more detail? Since these cranks are "smaller" in the counterweight department, and you have also shrunk the big-end of the rods, will the 5.4L crank work in a stock 87-91 "S4" block with S4 pistons, or will the clearanced GTS block and shorter skirted pistons be needed?

Very exciting times to be a 928 owner.

Thanks again,
Hans

Ducman82

5.4 L hybrid.... yummmm

GregBBRD

That's an idea I haven't seen....

Perhaps the point should be: It's really hard to see what is actually going on, inside an engine. Figuring out how the leading and trailing edges of a crankshaft should be shaped like is tough. However, its doubtful that the big "square" counterweights of the past are helping windage.

Jim Devine

These are the cranks Rousch Yates use in Nascar.
Click to enlarge photo to see counterweight detail.
Probably a lot of R&D to arrive at this.

http://www.roushyatesparts.com/parts...1000u-1157.htm

GregBBRD

So, perhaps we should suggest to Porsche that they wasted their time and efforts making different cranks, rods, and harder bearings for their Cup Cars and they should have stuck with the bearings from the street car?

That would be an interesting conversation. Short, but interesting.

You may not be aware of it, however, I just didn't start racing Porsche engines a couple of years ago. The things I am doing are responses to problems I've seen, for years and years.

I'm just trying to provide 928 owners with a better crank, rods, and bearings design for high performance use. Just like the Factory did for the Cup Car engines. Plus trying to provide a "bottom end" that is "more evolved" that 20 year old designs. Plus trying to "move" the RPM range up 800-1000 rpms, in these engines. Plus trying to make the crank stiffer, to not "beat" on the block so hard.

Certainly, there will be exceptions to every type of failure. There were 1998 water cooled Cup Cars that had no engine failures....and the factory took those engines back, at the end of the season, and rebuilt them with the new cranks rods, and bearings...at no charge. I know this, because I bought two of them and had to wait for the factory to rebuild the engines.

From racing the air cooled RSRs, just before the introduction of the water cooled cup cars, I can tell you this....if the engine had more than 75 knocks in a 10,000 count, the rod bearings would get pounded and fail at 6-8 hours. Without exception. I did the "post mortem" on several of these engines. Rod bearing failure, due to pounding the soft bearings.

We knew this. Porsche knew this. The crank, rods, and bearings that "magically appeared" in the middle of the 1998 Cup Car race season didn't happen overnight. It takes months to make a new crankshaft....not days. These pieces were designed in response to a major, well known problem and were on the path to being built, long before the first of the Cup Cars spewed their first connecting rods.

I'm just following down the path, trying to make the "majority" of the people that use 928 engines for high performance use have a "better" experience. Actually, my profit margin is way less that half of what I'd make selling a Moldex stroker. Way less. There's not even a 10% profit margin in these cranks, at this price. So I'm sure not doing this to make more money!

I'm just trying to build (provide the pieces for people to build) better engines.

dcrasta

Yes extreme Yum!
+1 on the details of the 5.4 build . I have been know to own very fast cars with terribad paint jobs.. (speed over beauty any day)..

BC

So somewhat in a round-logic fashion - with no detonation, engines can be made much more long-lasting.

GregBBRD

When Mark Anderson used factory bearings, with dry sump and stock ignition timing, we changed the bearings about once a year...and prayed when they went any longer.

I got that thing back, more than once, when it took a really long breaker bar to turn the engine....

GregBBRD

When Porsche designed the 5.4 engine, they moved the piston pin up 3.5mm to compensate for the change in stroke and left the rod the same length.

The rods that I have ready for release are built to this configuration.

Since good 5.4 cranks and 5.4 connecting rods have been very rare, not many have thought about building a 5.4 mini stroker.

However, with these new cranks, the ability to build a 5.4 liter for either a 2 valve application or a 4 valve application was obviously going to be possible and I've spent considerable time looking at this possibility.

I've looked very closely at making a slightly shorter rod and modifing a "stock" 5.0 piston for use in this application. Certainly looks like it will work.

I have drawings and actually have modified a 5.0 piston, for this application. I need to do some further "mocking" up of an actual engine and do some compression ratio calculations to move this forward.

brutus

I can not imagine how many hours you have spent working on all these things. What a great time to own a 928 !! So many possibilities.

GregBBRD

Wow, look at the Mallory in that Crankshaft! They elected to cut down the counterweights and add gobs of Mallory. Wow! And the center counterweights, hollow rod journals, and leading/trailing edges of the counterweights! That's a huge dollar piece of metal, for very cheap! Hell I'd bet the Mallory is worth $600.00.

I was just talking to Andy, about Nascar pieces, on another thread.

The Nascar "world" is so competative and involves so much money that they do not to "release" pieces that work, until the technology is replaced by something else. It's far better for them to destroy it, or to put it "on a shelf" for a few years.

However, they "test" boat loads of things, day in and day out....in order to find just a couple more horsepower or to make an engine live a few more hours. Their budgets for toilet paper are bigger than my entire engine development program! Of course, that "last" ten horsepower isn't goiing to cost any of my customers a championship...so I can settle for very good.

You can be almost certain, when you see something for sale that came from a "Nascar" program that there is something that wasn't quite right about the piece that is being sold...or it is old technology. There's got to be great stories about everything they sell!