I am making reproduction Porsche engine cases!
09-30-2017, 12:42 AM
#76
Drifting
Its not a failure I have personally experienced, but an annoying fact that Porsche Motorsports will only rebuild an engine twice on the original case. After two, you buy a new one.
Heck, if yours went thru 4 rebuilds it would pay for itself by comparison...and then some.
Heck, if yours went thru 4 rebuilds it would pay for itself by comparison...and then some.
09-30-2017, 01:01 AM
#77
Banned
Thread Starter
Wow, how many hours between rebuilds? I am guessing 40?
Mine will absolutely smoke a factory case for tensile strength and ease of rebuilding. The Spanish castings that Porsche has left over for GT3/TT are not that great and the tooling was at the end of its life when they produced the cases they have.
I should also point out that I am currently making the *air cooled* cases, but I am tooling for GT3 / TT because i have some water pumpers myself.
We shall see how mine does in battle....
Mine will absolutely smoke a factory case for tensile strength and ease of rebuilding. The Spanish castings that Porsche has left over for GT3/TT are not that great and the tooling was at the end of its life when they produced the cases they have.
I should also point out that I am currently making the *air cooled* cases, but I am tooling for GT3 / TT because i have some water pumpers myself.
We shall see how mine does in battle....
09-30-2017, 01:49 AM
#78
Drifting
The R/RSR 4.0L engines are 35 hour rebuilds, by the book - 45 if you are really pushing it... unlike the 3.8 Cup engines, and 3.6, that will go 100 hours without a fuss. The R/RSR engine is also a lot more high strung obviously.
Thank you for your response... I am just trying to think ahead. In recent years PAG has stopped producing major components of modern race cars in what seems to be an accelerated rate relative to their introduction. Obviously, the vintage owners feel this pain much more than I do, but the writing is on the wall for privateers, such as yourself, to "keep it all going."
For example:
997.1 and 997.2 Cup Tubs NLA (up to MY 2013)
991.1 Cup Tubs NLA (2014-2016) *um, that was last year!
Gearbox cases are also becoming a huge problem. The G97/71 and G97/72 cases are NLA... So if I crack my gearbox case on the R it means I have to go hunting...for a car that was produced just 3 years ago. No case = big paperweight.
I do realize, however, that the delta between race cars (along with specialized parts) and street cars in terms of production numbers is huge - and so is the demand.
Bravo to you for taking this on! I just hope somewhere down the line there is actually a source for those with a need. It's actually a bit alarming.
Thank you for your response... I am just trying to think ahead. In recent years PAG has stopped producing major components of modern race cars in what seems to be an accelerated rate relative to their introduction. Obviously, the vintage owners feel this pain much more than I do, but the writing is on the wall for privateers, such as yourself, to "keep it all going."
For example:
997.1 and 997.2 Cup Tubs NLA (up to MY 2013)
991.1 Cup Tubs NLA (2014-2016) *um, that was last year!
Gearbox cases are also becoming a huge problem. The G97/71 and G97/72 cases are NLA... So if I crack my gearbox case on the R it means I have to go hunting...for a car that was produced just 3 years ago. No case = big paperweight.
I do realize, however, that the delta between race cars (along with specialized parts) and street cars in terms of production numbers is huge - and so is the demand.
Bravo to you for taking this on! I just hope somewhere down the line there is actually a source for those with a need. It's actually a bit alarming.
09-30-2017, 02:11 AM
#79
Banned
Thread Starter
Well I am for sure making the water pumper 3.6 case which is the Mezger motor shared by the GT3 and Turbo (997 obviously). I am specifically tooling for this case for racers, because that's who needs it. it will be much faster to bring this case to market than the 3.6 964 style case I am doing now because we literally had to invent about a hundred different processes, but now we could tool for another case easily, and that is the plan.
Trans cases are a whole nother beast, obviously but I won't rule them out.....
Stay tuned in 2018!!!
Trans cases are a whole nother beast, obviously but I won't rule them out.....
Stay tuned in 2018!!!
09-30-2017, 09:35 AM
#80
Rennlist Member
As I said earlier being in this business for 30 years I hope you don't mind my questions.
I am curious if you did a spectral or chemical analysis of the factory cases? I was always confused by how Porsche noted alloy designation on many of their parts especially wheels but in most cases I found it was very close to A356.0T6. I also used to make a lot of cases years ago in both magnesium and aluminum for race applications. Although A356.0T6 is more than strong enough I found C355.0T6 held up better under extreme race conditions. I made cylinders and case for an alfa race engine for Joe Nastasi that ran the last 20 laps or so at LRP on speedvision without any coolant in C355.0T6. The car/engine won the race and went onto win. When they opened it up it looked like new and went on to win 6 more before a rod broke and went through the side of the case.
Not much can save a case from that.
I am also curious if they are using more than 1degree of draft? Why the need to remove it? Again just curiosity nothing but praise for your efforts.
Looking forward to the finished product . Nice work keep up.
I am curious if you did a spectral or chemical analysis of the factory cases? I was always confused by how Porsche noted alloy designation on many of their parts especially wheels but in most cases I found it was very close to A356.0T6. I also used to make a lot of cases years ago in both magnesium and aluminum for race applications. Although A356.0T6 is more than strong enough I found C355.0T6 held up better under extreme race conditions. I made cylinders and case for an alfa race engine for Joe Nastasi that ran the last 20 laps or so at LRP on speedvision without any coolant in C355.0T6. The car/engine won the race and went onto win. When they opened it up it looked like new and went on to win 6 more before a rod broke and went through the side of the case.
Not much can save a case from that.I am also curious if they are using more than 1degree of draft? Why the need to remove it? Again just curiosity nothing but praise for your efforts.
Looking forward to the finished product . Nice work keep up.
09-30-2017, 01:23 PM
#81
Banned
Thread Starter
Cobalt,
Besides extensive hardness testing on the Porsche aluminum and magnesium casings, we never really dug deep into what they were actually made of. Your average 964 case is nothing special and was a mass produced part that Porsche didn't put above average thought into.
Had we been trying to replicate one of their rarer or more exotic race cases, we would have definitely done a spectral analysis to see what the "secret sauce" was.
The reasons we used A356 T6 were several:
Very soon I will release the hardness testing numbers for a stock case vs our casting. Although the heat treat place does our hardness testing and provides a certificate, we also purchased our own hardness tester to be able to test our cases independently as well as test the Porsche cases.
Let's just say we have a Porsche case lying around that has loooooootsss of dimples in it....
As to draft, yes we have 2 degrees or more of draft in some spots. The notable ones I can think of are the cylinder bores and the chain box openings. Keep in mind this is a sand casting so there would be much more draft required than a die casting, and as you would expect the foundry always wants more draft and the toolmaker tries to cheat them by putting less draft in.
What I meant about removing draft refers to the machining process. In the chain boxes, for example, all that draft put on the inside faces is scrubbed off by the machining process. Kind of a waste but we have to do it this way.
GREAT questions!
Besides extensive hardness testing on the Porsche aluminum and magnesium casings, we never really dug deep into what they were actually made of. Your average 964 case is nothing special and was a mass produced part that Porsche didn't put above average thought into.
Had we been trying to replicate one of their rarer or more exotic race cases, we would have definitely done a spectral analysis to see what the "secret sauce" was.
The reasons we used A356 T6 were several:
- From a marketing standpoint it is one of the few cast aluminum alloys that can be called "aircraft grade aluminum" even though that doesn't mean much to people in the know.
- The foundry has an extensive work history with strontium modified A356; generally A356 has among the best recorded mechanical properties out there being so common.
- Strontium modified A356 heat treated to T6 specs and sand cast has a theoretical tensile strength of up to 40KSI which is more than strong enough for this application.
Very soon I will release the hardness testing numbers for a stock case vs our casting. Although the heat treat place does our hardness testing and provides a certificate, we also purchased our own hardness tester to be able to test our cases independently as well as test the Porsche cases.
Let's just say we have a Porsche case lying around that has loooooootsss of dimples in it....
As to draft, yes we have 2 degrees or more of draft in some spots. The notable ones I can think of are the cylinder bores and the chain box openings. Keep in mind this is a sand casting so there would be much more draft required than a die casting, and as you would expect the foundry always wants more draft and the toolmaker tries to cheat them by putting less draft in.
What I meant about removing draft refers to the machining process. In the chain boxes, for example, all that draft put on the inside faces is scrubbed off by the machining process. Kind of a waste but we have to do it this way.
GREAT questions!
09-30-2017, 02:48 PM
#82
Rennlist Member
Cobalt,
Besides extensive hardness testing on the Porsche aluminum and magnesium casings, we never really dug deep into what they were actually made of. Your average 964 case is nothing special and was a mass produced part that Porsche didn't put above average thought into.
Had we been trying to replicate one of their rarer or more exotic race cases, we would have definitely done a spectral analysis to see what the "secret sauce" was.
The reasons we used A356 T6 were several:
Very soon I will release the hardness testing numbers for a stock case vs our casting. Although the heat treat place does our hardness testing and provides a certificate, we also purchased our own hardness tester to be able to test our cases independently as well as test the Porsche cases.
Let's just say we have a Porsche case lying around that has loooooootsss of dimples in it....
As to draft, yes we have 2 degrees or more of draft in some spots. The notable ones I can think of are the cylinder bores and the chain box openings. Keep in mind this is a sand casting so there would be much more draft required than a die casting, and as you would expect the foundry always wants more draft and the toolmaker tries to cheat them by putting less draft in.
What I meant about removing draft refers to the machining process. In the chain boxes, for example, all that draft put on the inside faces is scrubbed off by the machining process. Kind of a waste but we have to do it this way.
GREAT questions!
Besides extensive hardness testing on the Porsche aluminum and magnesium casings, we never really dug deep into what they were actually made of. Your average 964 case is nothing special and was a mass produced part that Porsche didn't put above average thought into.
Had we been trying to replicate one of their rarer or more exotic race cases, we would have definitely done a spectral analysis to see what the "secret sauce" was.
The reasons we used A356 T6 were several:
- From a marketing standpoint it is one of the few cast aluminum alloys that can be called "aircraft grade aluminum" even though that doesn't mean much to people in the know.
- The foundry has an extensive work history with strontium modified A356; generally A356 has among the best recorded mechanical properties out there being so common.
- Strontium modified A356 heat treated to T6 specs and sand cast has a theoretical tensile strength of up to 40KSI which is more than strong enough for this application.
Very soon I will release the hardness testing numbers for a stock case vs our casting. Although the heat treat place does our hardness testing and provides a certificate, we also purchased our own hardness tester to be able to test our cases independently as well as test the Porsche cases.
Let's just say we have a Porsche case lying around that has loooooootsss of dimples in it....
As to draft, yes we have 2 degrees or more of draft in some spots. The notable ones I can think of are the cylinder bores and the chain box openings. Keep in mind this is a sand casting so there would be much more draft required than a die casting, and as you would expect the foundry always wants more draft and the toolmaker tries to cheat them by putting less draft in.
What I meant about removing draft refers to the machining process. In the chain boxes, for example, all that draft put on the inside faces is scrubbed off by the machining process. Kind of a waste but we have to do it this way.
GREAT questions!
I agree Although C355.0T6 is not well known as one of the "Aircraft Alloys" it has its purposes. I had only a few customers like Hamilton Sundstrand that specified it on their BP's, although strangely some of the BP's called out the min mechanical of A356.0T6 instead. Never was a problem we always exceeded them by a considerable margin. Just as in"Aircraft grade" Magnesium is most widely recognized as AZ91ET6 vs Dow metal (AZ92AT6) for the aluminum based alloys.
I haven't priced out the alloys lately but other than supply on hand the cost delta between the two was negligible and at times the 355 was less that was why I brought it up. No doubt A356.0T6 is the mostly widely used aluminum alloy.
No doubt a foundry always wants more draft and 2 degrees is a bit pushing it but non critical areas are better to the draft to allow the pattern to draw than have issues.
So I understand the potential up side of strontium infusion the obvious downside appears to be added porosity. I am assuming that is why you add the Hip-ing process?
I might suggest if you have the time to experiment with a simple nucleant additive that will grain refine and not add porosity. Also a hospital grade nitrogen purge to remove any unwanted gas. This should achieve the same mechanical properties exceeding 40kPSI tensile and remove an expensive step from the equation. No doubt proper solution treatment, quench and artificial age will be needed to achieve the ultimate tensile you are looking to achieve.
Looking forward to seeing final mechanical results. I am assuming you will be doing sub-sized bars cut from the casting as well or just separately cast?
Sorry for chiming in but it is hard to get the foundry out of my blood. I miss this stuff. 30 years of testing for Hardness(brinell), Tensile, zyglo, X-ray, heat treatment and manufacturing castings from drawings to finished product, is something most people don't understand how much thought has to be put into making sure everything is precise and accurate. If You were on the east coast I would be stopping by for a visit.
All the best.
09-30-2017, 03:09 PM
#83
Banned
Thread Starter
Man, if you were here I would be mad if you DIDN'T stop by for a visit. I like your insight and you clearly know what you are talking about. I'm sure there are others like you here, but I don't know them. I would have loved to have a "car guy" who also knows about casting help me out!
Ah, testing. Where do I begin.....what the foundry does as standard is a simple hardness test on one case per batch; a batch being 20 case halves (10 left and 10 right). That is for series production only. More like QC on a batch rather than individual basis.
The first cases I will use to build a motor will be X rayed before I build it, post machining. The foundry was a little puzzled as to why I wanted them x rayed AFTER machining rather than before - simple. No need to test metal that will wind up as chips on the floor, and there will be a lot of it. One case half weighs like 45 pounds prior to machining. It's gonna lose a ton of weight clearly.
HIP and Strontium modification: To be perfectly honest, with the hardness numbers we are getting from the case as it stands, it is stronger than the factory case. This much I can tell you. Definitely stronger.
We are all really wondering if HIP is even needed, quite frankly. It's a decision that I will make once we have more data and I have a chance to analyze some X rays. I know X rays don't really spot porosity on a small scale (spots large voids though), but honestly with the case as strong as it is, we are just thinking HIP is somewhat pointless at this stage.
Haven't made a decision, but that's the way I am leaning.
What is your opinion? Did you HIP any of your castings? If so, was there a measurable increase in hardness?
Ah, testing. Where do I begin.....what the foundry does as standard is a simple hardness test on one case per batch; a batch being 20 case halves (10 left and 10 right). That is for series production only. More like QC on a batch rather than individual basis.
The first cases I will use to build a motor will be X rayed before I build it, post machining. The foundry was a little puzzled as to why I wanted them x rayed AFTER machining rather than before - simple. No need to test metal that will wind up as chips on the floor, and there will be a lot of it. One case half weighs like 45 pounds prior to machining. It's gonna lose a ton of weight clearly.
HIP and Strontium modification: To be perfectly honest, with the hardness numbers we are getting from the case as it stands, it is stronger than the factory case. This much I can tell you. Definitely stronger.
We are all really wondering if HIP is even needed, quite frankly. It's a decision that I will make once we have more data and I have a chance to analyze some X rays. I know X rays don't really spot porosity on a small scale (spots large voids though), but honestly with the case as strong as it is, we are just thinking HIP is somewhat pointless at this stage.
Haven't made a decision, but that's the way I am leaning.
What is your opinion? Did you HIP any of your castings? If so, was there a measurable increase in hardness?
09-30-2017, 03:13 PM
#84
I am curious where the main stress is in a boxer case? Are they at either end where the main bearings are supported? Or around each stud for the piston barrels, even if in the center?
09-30-2017, 04:33 PM
#85
Banned
Thread Starter
My empirical experience rebuilding many of these motors however suggests the flat 6 Mezger case is a fairly low stress assembly overall. It is rare that I have seen cracks in the aluminum cases (when I do, they are either on the corner that joins the chain boxes to the cylinder spigots, or on the flywheel end). Mostly, I have seen plenty of catastrophic failures - rods going through the case wall and such.
Ultimately that is the price you pay for a high hardness level on the case. It is super strong, but not ductile, and when it breaks, it SHATTERS. the cases are not really good at surviving impact damage from inside, but that is clearly outside their design parameters.
This is probably a good time to mention that Porsche builds a GREAT engine case. By and large, they are pretty much problem free (with the exception of the mag cases), and we are really standing on the shoulders of giants here.
Sure, ours are stronger, but that takes absolutely nothing away from the Porsche cases that are built like tanks.....from people who have a history of building tanks
10-01-2017, 10:09 AM
#86
Rennlist Member
Man, if you were here I would be mad if you DIDN'T stop by for a visit. I like your insight and you clearly know what you are talking about. I'm sure there are others like you here, but I don't know them. I would have loved to have a "car guy" who also knows about casting help me out!
Ah, testing. Where do I begin.....what the foundry does as standard is a simple hardness test on one case per batch; a batch being 20 case halves (10 left and 10 right). That is for series production only. More like QC on a batch rather than individual basis.
The first cases I will use to build a motor will be X rayed before I build it, post machining. The foundry was a little puzzled as to why I wanted them x rayed AFTER machining rather than before - simple. No need to test metal that will wind up as chips on the floor, and there will be a lot of it. One case half weighs like 45 pounds prior to machining. It's gonna lose a ton of weight clearly.
HIP and Strontium modification: To be perfectly honest, with the hardness numbers we are getting from the case as it stands, it is stronger than the factory case. This much I can tell you. Definitely stronger.
We are all really wondering if HIP is even needed, quite frankly. It's a decision that I will make once we have more data and I have a chance to analyze some X rays. I know X rays don't really spot porosity on a small scale (spots large voids though), but honestly with the case as strong as it is, we are just thinking HIP is somewhat pointless at this stage.
Haven't made a decision, but that's the way I am leaning.
What is your opinion? Did you HIP any of your castings? If so, was there a measurable increase in hardness?
Ah, testing. Where do I begin.....what the foundry does as standard is a simple hardness test on one case per batch; a batch being 20 case halves (10 left and 10 right). That is for series production only. More like QC on a batch rather than individual basis.
The first cases I will use to build a motor will be X rayed before I build it, post machining. The foundry was a little puzzled as to why I wanted them x rayed AFTER machining rather than before - simple. No need to test metal that will wind up as chips on the floor, and there will be a lot of it. One case half weighs like 45 pounds prior to machining. It's gonna lose a ton of weight clearly.
HIP and Strontium modification: To be perfectly honest, with the hardness numbers we are getting from the case as it stands, it is stronger than the factory case. This much I can tell you. Definitely stronger.
We are all really wondering if HIP is even needed, quite frankly. It's a decision that I will make once we have more data and I have a chance to analyze some X rays. I know X rays don't really spot porosity on a small scale (spots large voids though), but honestly with the case as strong as it is, we are just thinking HIP is somewhat pointless at this stage.
Haven't made a decision, but that's the way I am leaning.
What is your opinion? Did you HIP any of your castings? If so, was there a measurable increase in hardness?
How are you testing your parts? Rockwell, Brinell Vickers ?? I was required to use Brinell using a 10mm ball with a 500kg load and although only 15 seconds indent was required I always used 30 seconds I found it gave me more accurate results. I would do my own testing if I were you. I found most heat treatment facilities and foundries rush through this test and the results are not always as accurate as they can be. The biggest issue is them not being careful enough not to twist the part while the indent is being made. This will elongate the indent and throw the numbers off.
I know it is expensive but as QA manager, visual and dimensional inspector amongst many other hats I wore I would sometimes process scarp castings and then have sub sized test bars excised from the casting in both thick and thin areas. It was always nice to show that I went beyond the minimum requirements of the specifications. Although standard .505 separately cast bars were all that were required for most parts we occasionally had to test actual castings depending on how critical the application.
Usually we found that although the casting only had to test at 75% of the required min yield and tensile of the separately cast bars our castings usually showed results exceeding 25% above what the separately cast bars showed.
I never once in 30 years had an issue with porosity in aluminum. Occasionally we would have a part that showed as porosity in X-ray but after sectioning the area determined it was loose sand from the mold that lodged itself in the casting but it usually was minor at best.
Mag on the other hand you needed to worry about microporosity or as we call it micro-shrinkage which is different than gas porosity as you know it.
If you find your self in a bind I am happy to help. I used to get calls from people I knew at Sikorsky and Hamilton when they ran into problems other foundries couldn't figure out. I think I enjoyed the challenge of troubleshooting problems more than anything.
BTW when you are ready to make something in Mag let me know I have a great new sand process that makes some of the smoothest cleanest sand castings I have ever seen. They look like investment castings when done and the skin coat has shown to hold up to no protective conversion coating process for 3 years now.
Also if you have any problems with X-ray or fluorescent penetrant inspection I was an ASNT III inspector for a number of years. I still have my reference radiographs on hand although seeing the 2-2T hole isn't as easy as it used to be. LOL
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10-01-2017, 02:02 PM
#88
Banned
Thread Starter
Yeah I never trust other people's test results, that's why I spent over a grand on a Rockwell hardness tester. It weighs 200 pounds and is a big unit, brand new, sits on a workbench.
Same exact testing scheme except driven to rockwell. It tests on the HRC (150kg load, diamond penetrator) or HRB (100KG load, 1/16" ball penetrator) scales and on those scales it is accurate to 1.5% HRC or HRB.
The most appropriate scale from all the research I have done and the users manual seems to be HRB - the 100KG secondary load and ball penetrator.
The unit came with a bunch of pre labelled hardness blocks and it tests out very accurately using those blocks.
I literally spent a couple weeks teaching myself how to use the thing, watching videos, and getting repeatable results with the thing because my intent is to hardness test EVERY case.
It has a big enough throat and a stable enough platform to fit the case half laying down on it's main journals, and the ball penetrator fits nicely in the flat spot between the two cylinders on the outside of the case half.
Here's one for you: I was fiddling with hardness testing the mag cases even though everyone already knows they are not as strong as the AL cases from a hardness standpoint. Using the exact same methods as all the aluminum stuff, except dialing down the load per the manual to account for magnesium, I could never get repeatable readings in the mag. They were literally all over the place.
Why is this? It bugs me not because I "NEED" to test magnesium, but I want to know what I am doing wrong that my machine is not giving me a repeatable result with magnesium.
On steel and aluminum, it works amazing.
Ideas?
Same exact testing scheme except driven to rockwell. It tests on the HRC (150kg load, diamond penetrator) or HRB (100KG load, 1/16" ball penetrator) scales and on those scales it is accurate to 1.5% HRC or HRB.
The most appropriate scale from all the research I have done and the users manual seems to be HRB - the 100KG secondary load and ball penetrator.
The unit came with a bunch of pre labelled hardness blocks and it tests out very accurately using those blocks.
I literally spent a couple weeks teaching myself how to use the thing, watching videos, and getting repeatable results with the thing because my intent is to hardness test EVERY case.
It has a big enough throat and a stable enough platform to fit the case half laying down on it's main journals, and the ball penetrator fits nicely in the flat spot between the two cylinders on the outside of the case half.
Here's one for you: I was fiddling with hardness testing the mag cases even though everyone already knows they are not as strong as the AL cases from a hardness standpoint. Using the exact same methods as all the aluminum stuff, except dialing down the load per the manual to account for magnesium, I could never get repeatable readings in the mag. They were literally all over the place.
Why is this? It bugs me not because I "NEED" to test magnesium, but I want to know what I am doing wrong that my machine is not giving me a repeatable result with magnesium.
On steel and aluminum, it works amazing.
Ideas?
10-01-2017, 02:04 PM
#89
Banned
Thread Starter
LOL a year and a half ago I would not know what the hell was being said here either. I was kind of forced to learn it, but I am glad i did.
The ****e you get into when you wake up one morning and go "let's make a Porsche case"
10-01-2017, 02:09 PM
#90
Rennlist Member
I think Anthony needs a trip out to SoCal. It’s gonna be getting cold soon in nj!