Vegas993

That super leaky line that's part hardline and part steel braided that runs from the oil filter housing, behind the engine and into the driver's side of the block looks to be one that was made, not OEM. It shouldn't have a gap between the hardline and steel braid, someone likely tried to save a few bucks by having one made but it looks like it's leaking pretty heavily.

I set out to replace that and install a Ruf cup pipe at the same time... 100 hours and several thousand dollars later, it was back on the road, lol!

Lorenzoh

stripped head bolt??

Vegas993

Lol, no, thankfully. I just went down the rabbit hole - decided to have my tins powder coated and then ultimately replaced pretty much everything from ignition components to gaskets and fuel lines to o-rings and intake stacks.

Spyerx

Doesn't look that bad.
Just clean it up and tackle the ones you can get at one at a time with the engine in the car.
The rest save for a necessary engine out service.

BTW, the one with the oil on the cylinder fins (#3 I think), that is likely coming from up above. Make sure your oil level is, when hot, pointed to about 4 o'clock, no higher than 3 o'clock on the gauge. This should mirror what you read on the dip stick assuming your gauge is reading right.

Running higher than that can cause excess blow-by to get into the intake and then drip on top of cylinders 2-3 and the fan then blows it to the bottom of the motor.

I can get this on my car and it doesn't leak (knock on wood).

Lorenzoh

Sounds about right 😉

Catorce

Surprise surprise, another leaker Porsche motor. Looks totally normal, but at the same time unacceptable after such a short rebuild.

We have measured lots of 3.6 cases for my repro case, and the vast majority of them are not flat on the case parting surfaces which introduces a bunch of leaks and incorrect geometry. It's a mass produced part with not a lot of attention to detail and many, many potential leak areas of which you have the most common ones.

cobalt

Totally agree. I just reworked a 993 engine that the owner had overfilled and drove for quite some time. I was shocked at how dirty the intakes were coated with a layer of oil not to mention the underside and just about everything else was covered in oil yet many of the seals were still in good condition. After I stripped the motor down, cleaned everything and removed the dead mouse and nest we decided to change all the seals anyhow.

I am curious how many cases and a % of the total measured you found not to be collinear? Of the last 6 I had inspected all were well within spec even after 145k miles. The 996 cup case with a hard 400 track hours on it was also within spec. I found a lot of issues with the earlier cases and the mag cases but not as many 964 prefixed cases. No doubt it is a concern and should be checked prior to proceeding with any work.

Catorce

Anthony,

We've only measured 3.6 cases of the 964 / 993 variety. I'm going to say overall about 10 of them over the years. I don't have my notebook right in front of me, but every single one of them had some defect or another. As an example, just about ALL of them had their cylinder spigots not correctly lined up horizontally or vertically. Sure, they look like they are all in a nice row to the human eye, but once you measure them you find they are really not.

We just did a 993 case last week believe it or not, because I did the GT3 oil pump clearance mod for a friend.

Case was a 1997 case with 65,000 documented miles, it was by far the newest looking case and the newest case in general I have ever tested. It was so clean it looked ready to use, a real low mileage gem.

I was shocked to measure the main bore and find it to be oval on every main. Each main was out by as much as 2 thou over spec (i.e. larger than spec).

The centerline between the main bore and layshaft bore was also out of spec (too big).

Case flatness was measured and the mains where quite flat, but the case perimeter had a nasty diagonal raised portion on opposite ends of the case by about 3 thou.

I was very, very surprised that a 65K mile pristine looking case basically needed to have both its case halves flattened and it's main bore align bored.

Because there was no obvious signs of damage or wear I can only chalk this up to extremely shoddy workmanship, not sure what else might be the cause.

cobalt

Interesting. I expected my 993 case to have issues after being turbo charged and driven hard but relatively low miles. The cylinders were slightly out of round needing to be stripped and re-plated but the case was fine and well within spec. I don't do the measurements myself I have an old school veteran machinist that is as good as they get (certified to do warranty work on most all exotics and does every variant of air-cooled and water cooled 911 engines) Some of the top shops use him as well. I have been laying out castings like this for decades so I know he knows what he is doing. I really expected the 996 cup case to be a mess. It is one of the longest running factory sealed cup engines I know or heard of. After a leak down test and checking it on the dyno we saw 20% loss and around 200 WHP which is quite low for a cup car. Surprisingly the workmanship was top notch the case was fine. It was an early '99-00 case quite similar to the 993 with tooling adjusted for water jacketed cylinders and no cooling fan. The pistons and aluminum sleeves were shot so we are updating it to 3.8 l with hydraulic lifters and steel Nikasil sleeves.

Guess CA cars are great for no rust but it appears you guys abuse your engines more. I am not going to argue but I find it hard to believe that he factory would release engines that are out of spec. I know about 20 veteran well known Porsche mechanics who have been around for a long time some date back to the 356 others worked for teams like TRG and have full race background. I have heard comments that sometimes tolerances are closer to the limits than they would care them to be but nothing they would consider shoddy workmanship. When heat treating a casting like this keeping it from warping durning the quench process is next to impossible many heat treat facilities don't properly rack the parts or will allow them to slap the quench broad side which will distort the casting. This sometimes complicates the machining process but the parts are either within tolerance or they are not and if not should be rejected.

Catorce

My guess would be that very few of these experts have the same measuring equipment as I do, so not a lot of it is being caught. At the end of the day your average engine machine shop has a 1) sunnen dial bore gauge and 2) a height gauge on a granite table and maybe 3) a set of digital calipers.

What I have found in my (long) journey is that most engine machine shops do not have CNC capability and much of the rehab work on these cases is done manually on knee mills and other manual methods.

We have all of the measuring devices that I mentioned but the trick with these are HOW GOOD ARE YOUR TOOLS - A typical bore gauge that reads to half a thou does not have the resolution to measure a bore that has a 4 tenths tolerance. Our granite table is flat to laboratory specs, not just to QC specs, and we have a $1500 Starrett height gauge with expensive test blocks to calibrate it.

Lastly, we have the Renishaw probe on the 5 axis mill that is accurate to 1 micron. It would be highly unusual for your average engine shop to have anything like this and it detects flaws not normally possible with hand tools. Oh, and it only comes on a $100K CMM machine or a $275K mill.

As to why most cases measure in spec I'll leave you with this: One prominent Porsche engine machine shop here in CA that is ultra famous and in Wayne's book likes to flatten case halves by using an abrasive board that they drag over the case parting surfaces, and all of their boring operations are done on a bridgeport style knee mill that looks like it hasn't had it's ways scraped since WW2.

SO yeah, lots of these builders measure things as being "in spec" while using ancient tools of questionable calibration and call it good.

my $.02

cobalt

Catorce, No disrespect. However.

You spent a lot of money on fancy equipment. Big woops.

I can assure you my tools are not state of the art like yours but more than adequate to do the job at hand providing consistently reliable results. The experience of these people is IMO priceless and far more valuable than a fancy CMM. I don't want to get into a debate over how good your foundry is or accurate your equipment but this isn't your engine cases for sale thread.

I hope everything you spent a small fortune on is calibrated prior to use then regularly at prescribed intervals adequate to assure accuracy along with after each servicing by a qualified technician other than the operator. Is traceable to NIST standards. I am glad to see you have standardized gauge blocks which i Hope are calibrated annually, your surface plate is at least AA grade, calibrated prior to use and at a minimum of every 3 years and maintained in a climate controlled environment including humidity. I have the same Starrett 24" high dual beam height gauge and all the attachments but mine cost $1200 in 1985. Fantastic tool along with all my Starrett and Mitutoyo gauges. There are a lot of people in the field and as a foundry-man any part incorrectly machined was automatically kicked back to me because it had to be the foundries fault. I can't tell you how many latest version of the best CMM's operated by qualified technicians in the aerospace industry lost a fight to my 40 year old equipment. As I entered their facility they exuded pride about the accuracy of their measuring stick. I left with them wondering how they screwed up.

I applaud what you are doing but calling the work Porsche's QC department passed as shoddy workmanship is IMO stretching it. Especially since you are inspecting old used parts vs what left the factory in as new condition. I know my stuff and I don't want to start picking Porsche or your processes apart, which I hate to say I can easily do. I have been bitting my tongue for quite some time. I wish you well but I'm not buying it. I offered to help you with all due respect I still feel your understanding of this field and what it takes to call a part aircraft quality isn't up to my standards and there are a lot of things an aircraft quality casting needs to meet to wear that title. So unless it complies meeting and exceeding every aspect of QQ-A-601 superseded by ASTM-B-26 latest revision requirements or equivalent and what inspection grade is being used, it is just another cast part to me despite all the money spent. I don't think bashing what Porsche did 25-30 years ago during hard times in mass quantities is helping you. I have inspected enough parts in my time as a certified inspector to know a good part and what it takes to make it.

If life didn't throw me the curve ***** it did we wouldn't be having this conversation I would have had these to market a long time ago along with 935,962 and 917 NLA parts in both aluminum and magnesium. I assure you I cast a superior part despite all your efforts.

So let's not turn an oil leak thread into a sell my product one. I hope you sell a lot of cases without issue but let's cut out the Porsche made crap, crap.

I have said all I wish to I hope I don't need to say more.

Catorce

You're missing the point - the point of this thread to keep it on topic is that many, many of these motors are leakers, and many of them are unknowingly out of spec. The case I just got had 65K easy miles and is out of spec, way out. So the better your tools are the better you can detect stuff like this.

If I could not comment from a position of having accurate tools, my comments would be worthless. You can call it a fancy CMM all you want but if you don't have one, you aren't getting medical, defense, or aerospace work, period. At least not in SoCal.


I am not sure what prompted that war story, but OK.

I am not sure we have claimed to strictly adhere to aircraft standards, because we aren't making aircraft parts or claiming to make aircraft parts. I recall only saying that we use aircraft aluminum which as you know is kind of a misnomer, but heck, just about anyone that makes billet parts is claiming to use "aircraft aluminum" which is probably a lot like Corinthian Leather.

And yes, I absolutely am calling out Porsche on the build quality of their late production street car cases. Except Porsche didn't make these, a variety of foundries and machining outfits did. They don't last, they leak, and they are made to very loose tolerances. You can't compare the cup car and race stuff - they actually paid attention to those. It is what it is, don't take it personal, I have 12 Porsches, I love the brand as much as you do, but I will not defend their workmanship on some of this stuff.

So I guess life only threw YOU curve *****. OK, great. The rest is woulda, coulda, shoulda, and talk. The simple fact is, you did not make them, period, end, full stop, and I really don't care to hear more about your illustrious foundry career as if you are the only person on the planet qualified to cast parts. Saying your parts would have been better than mine is really a slap in the face of all the people who toiled to bring something to market for years that no one else had the ***** to.

Again, you missed the point. If this motor was rebuilt 50K ago I am not suggesting, I am TELLING the OP to have the flatness checked on the case halves I guarantee they are out and contributing to the many leaks on this motor. Whoever did the case machining in the rebuild probably was a hack.

I am not trying to sell more cases in this thread - the guy already has a case why would he want mine?

Lorenzoh

I’m a bit confused...this is about leaking lines. It happens on almost all 964s. We all know the leaking issues on early cars with the cylinder issue. And we all know the other various leaks that happen with chain boxes, gaskets and so on and so on...

I’ve never heard of cases leaking so badly they require being split?? Or, cases being so out of spec that they fail and cause catastrophic damage, thrown rods etc?? I could be wrong, but a lot of this strikes me as people getting waaaaay too caught up in millimeters that really don’t make that much of a difference. These aren’t F1 cars. They’re 25+ year old street cars that, from what I can tell, when maintained properly, are some of the most reliable motors ever built and can take a tremendous amount of abuse before failing.

Not sure what all the fuss is about.

abarthguy

Dollars.....
It's all about dollars.

cobalt

I have never disputed the need to inspect parts and I agree accuracy is key but having a CMM is not a guarantee to accuracy. I have proven it on many occasions in my years of supplying the DoD and aerospace industries. I don't care how accurate your CMM is and how many decimals if the first three are correct the rest is fluff for these applications..

I can't tell you how many threats I received from my customers for not spending up for the latest CMM or paying for NADCAP accreditation but they continued to make allowance as they had no other foundry that was able to constantly produce the quality, complexity of my parts in both mag and aluminum with less than a 2% scrap rate of the raw castings and only a handful of rejects over 30 years. It is possible by today some 7 years later they would have pulled the plug but I would have been out of the racket and making parts like this instead. Having accurate tools is great leave it at that, the bashing of parts from the past when times were different isn't doing anything but stroking yourself IMO.

The stories and there were many was an attempt to show that having the latest state of the art CMM doesn't make a better product or guarantee accuracy. I have gone up against a lot of engineers using the latest CMM and I proved with just hand tools that they were incorrect on so many occasions. I can't tell you in 30 years how many times I was confronted by "your parts are wrong, my CMM says so" and then the rejection was overturned and they had their CMM between their legs.

This is from your website.

LOL what is that supposed to mean? It either is or it isn't. What specs are you using to verify the incoming material meets the requirements of A356.0T6. Do you test the raw material and does your foundry segregate it from other alloys? Remove the reference to aircraft aluminum it is just aluminum or it is made to the appropriate specs which in your case is not so. Otherwise it is sales pitch and gibberish in my book. Can't tell you how many crappy foundries out there who pour 356 and the parts crumble when machined.

BS is all I can say. I know these cars and especially the castings as well as anyone and yes the race parts are hand picked from a lot of factory parts using the most select and accurate parts. They aren't made differently. That doesn't make the rest junk and the best parts are susceptible to the same issues as any street case. I wouldn't consider the tolerances loose by any means. If you want to build a motor to race inspect it and make adjustments if needed. Clearly Singer is taking old worn cases and reworking them to their standards to build their $700k 964 backdates. My stock 96 993 engine didn't measure much differently than the 996 cup case so how is it inferior? Don't tell me you need to put it on your CMM to tell me how? I have no doubt their are considerable variations in these cases but from what I have witnessed for the most part these newer cases are fairly constant and tolerances are tighter for the race engines but not by all that much. I don't care how many zeros you can print on your inspection report. Bring me a NOS case and measure it, then we can continue this conversation.

I didn't want to bother everyone with my wows but it was a lot more than a curve ball.

Deleted since it doesn’t help the op

I just finished a reseal on a 993 engine that other mechanics said need to be rebuilt. it was a mess just like the picture above but it was all simple seals and fixing shoddy work by shade tree mechanics. I have seen leaks like this countless times and I highly doubt the case is leaking. This appears to be your typical leaks from oil lines and old seals. I have no doubt that the metal gaskets used to seal the timing chain covers to the case are leaking but that can be lived with. Don't try to scare everyone by saying that if you rebuild your case it will be done by a hack and it will look like this. I read between the lines and I hear BUY MY CASES they are SUPERIOR.

I apologize fo such an off topic rant and to you as well as I was hoping you would leave it be but this is long past due and as much as I would like to see these cases come to market I would wait a long time for them to prove their integrity before buying one or more transparency on what is being sold is made.

To the OP clean the underside drive it and if the leaks persist address them. If the case needs splitting vet the shop doing the work and have everything inspected.

this is the 993 engine everyone thought leaked and had case issues. It has near perfect leak down and compression numbers with a documented 120k miles but I suspect the actual miles are higher.

Before (after a light cleaning) and after (after a full cleaning and reseal)





So far 0 leaks. Will run it some more to verify.