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If you contact Mark at Hergesheimer he will sort you out. I had a quote from then....cant remember the cost now...but I ended up going with these guys. ..they were a little cheaper and still a nice item..
http://www.ebay.com/itm/192151572115
To say that work has been busy is an understatement. I have been waiting eagerly to find the time to do the install of my new Guard GT2 LSD. Not just a clockwork shop install but an install that lets me savor the moment, evaluate every single detail, and of course take plenty of photos! This can only be done as a mid-night op to dawn. And here we go!
With the OEM housing out of the gearbox, first order of business is to extract the bearings.
I randomly found a turbo wastegate flange tube as a press die. When using a hydraulic press at midnight you learn to use anything that's in sight!
The twain shall meet.
For the new LSD unit I opted to replace the stub axles to the earlier style(aka 996/Cup style). Many have kept their later(997) model stub axle with longer bolts and have been successful. Me? I just want to be different. The difference between the early and late model has been discussed in other threads but below an image for those not familiar.
Upper Left of image: Later style(997) LSD side gear with ~8mm step.
Upper Right of image: Later style(997) stub axle with hollow end to encapsulate the step.
Lower Left of image: Early style(996/Cup) LSD side gear with flat surface.
Lower Right of image: Early style(996/Cup) stub axle with flat end.
I am such a nerd to think a car part named Stub Axle is cool.
Here's the nerdiness again...on bolts...the early style is factory equipped with grade 8.8 tensile strength bolts, whereas the late style has grade 10.9...so let's mix it up and get some 10.9's to the early style.
Think of all the things I could have accomplished if not for obsessing about bolts. Just FYI, these bolts are only to keep the stub axles from lateral movement, the engine torque is transmitted through the stub axle splines, and not these bolts.
Haven't had time to write up a post so just some teaser pics for now. This project is sending me to the poor house...
More to come. Enjoy. Happy Thanksgiving.
Where to start...a lot of events has transpired in my professional life since the last post; From working entire weeks setting up and exhibiting at SEMA and PRI trade shows to supporting customer's cars between the shows to developing new products to shaping up 2018 plans. All of this leaves me no time to work on my car lately. Which is okay, because the past 6 weeks was consumed by curating ingredients for a recipe I'm cooking up. Let me tell ya, some of the ingredients for this recipe just aren't easy to come by so not being in a time crunch is nice. If you haven't guessed by the photos in the previous post the recipe is for a factory 4.0 engine build! Well, not exactly a complete factory MY2011 997.2 RS 4.0-spec build since factory 4.0 has VarioCam on the intake and exhaust camshafts, my MY2007 997.1 has VarioCam only on the intake. It'll be impractical (at this time) to replace the ECU, which has extra drivers for exhaust VarioCam, and the wiring harness, and make the .2 ECU compatible with .1 ABS and other modules. So for this build it is proper to say its a factory RS 4.0 engine "rotating assembly"(same as PMNA 4.0 Grand Am spec).
Engine Rotating Assembly:
Porsche 997 RSR/GT3R/4.0 street car 80.4mm stroke crankshaft
Porsche 997 4.0 street car titanium connecting rods
Porsche 997 3.8 & 4.0 street/Cup 102.7mm pistons and cylinders
Porsche 997 3.8 & 4.0 street crank pulley
Porsche 997 4.0 street oil pump
Porsche 997 4.0 intermediate shaft
For the induction:
Porsche 997 4,0 intake plenum
Porsche 997 4.0 intake runners
Porsche 997 4.0 intake lower manifolds
Head work by TPC Racing
Originally, I planned to use an aftermarket steel connecting rods and took a bank loan respective to the original parts budget. But then came across an opportunity to acquire a set of the factory 4.0 Ti connecting rods at the pre-updated price(which is still 3x more than well known aftermarket steel rods!). I took the deal because who doesn't want to say they have Titanium rods in their engine, right?! On top of the cost of the factory Ti rods, they required a 4.0 oil pump to clear the big end of the rods(aftermarket steel rods are made differently to gain clearance to oil pump). I could have machined the 3.6 oil pump to work as well as machined the 3.6 intermediate shaft but I want this engine build to be special to me and memorable by using as many factory 4.0 parts as I can acquire. We have certainly done wilder and higher power engine builds here at TPC Racing but this will be the grandest build for myself so I am really stoked and the hell with the budget and bring on those credit cards!
More to come.
During the past 6 weeks, the special ordered 4.0 parts have been arriving in from Germany(some took longer than others).
During the past weeks as each part came in I was a kid on Christmas day! When I unboxed the 4.0 plenum I noticed a dent on the underside. It was odd since the cardboard box arrived in perfect condition and there's plenty of bubble wrap inside the box. I was going to call the Porsche dealer to report this and request a replacement but then I recall seeing a dent in other plenums. An internet search confirms that all 4.0 plenums have a dent(or bump) on the underside near the "110" number casting.
Not sure if the bump is for clearance or just happened to be a defect on the production mold, but they all have it.
Back in the Fall, before the 4.0 build was within my scope, I was wanting to convert my 3.6 engine to 3.8. This conversion is quite simple using factory 102.7mm bore pistons & cylinders to replace the original 100mm bore, its direct bolt-on using 3.8 connecting rods. With just under 60K miles on my engine with zero issue and zero oil leak, I was going to do a "streamlined" conversion on the top end and leaving the bottom end alone. With that in mind, I bought a set of pristine condition used 3.8 pistons & cyls from a friend. This set was from a Cup engine with 25 hours, piston-to-cylinder clearance measured like new as expected since any typical wear on race engines of lower hour range is in the valvetrain. Some Cup owners elect to replace good pistons & cyls to be thorough while the engine is already open. Nothing wrong with that! Taking advantage of the opportunity I bought this set without hesitation and then bought new pistons rings from the dealer to update the set to newest factory spec. I was good to go!
Then a couple months later I came into a little bit of cash from the VW dieselgate buyback putting the 4.0 plan within scope with a small bank loan. Go big or go home, right? So...Stupid me, not realizing at the time the factory 3.8 and 4.0 including the GT America 4.0 race car use the same pistons I ordered another set(the rods, oil pump, intermediate shaft are different in the rotating assembly, not pistons, except for R and RSR). Here I am now with two sets. C'est la vie.
More piston talk - it shows in PET that 3.8(engine code M97.77) have different part number piston than 4.0(engine code M97.74), having both sets side by side, the only difference I can discern are the top rings, which PET does show a different part number for the top ring. The M97.74 top ring is part # 997 103 371 97 , this ring is for 4.0 street car, 2011-up 997.2 3.8 Cup, 991.1 3.8 Cup, GT America 4.0, and 997RSR. Excellent cred for a ring! From my measurement this ring is 0.03mm narrower width, my guess is for expansion. Don't know if there's a material difference. For those who already have a low mileage and good running 3.8(M97.77) who is considering a 4.0 building using factory crankshaft, re-ring the pistons can be a sound option.
09-30-2017, 04:43 AM
Let me tell ya, some of the ingredients for this recipe just aren't easy to come by so not being in a time crunch is nice. If you haven't guessed by the photos in the previous post the recipe is for a factory 4.0 engine build! Well, not exactly a complete factory MY2011 997.2 RS 4.0-spec build since factory 4.0 has VarioCam on the intake and exhaust camshafts, my MY2007 997.1 has VarioCam only on the intake. It'll be impractical (at this time) to replace the ECU, which has extra drivers for exhaust VarioCam, and the wiring harness, and make the .2 ECU compatible with .1 ABS and other modules. So for this build it is proper to say its a factory RS 4.0 engine "rotating assembly"(same as PMNA 4.0 Grand Am spec).
