crankcase to transmission studs

[ttw18]

Hello all,

I can't find the part #'s for the studs and nuts that mount the transmission to the crankcase. I have use the parts diagrams but it is unclear which parts are the correct ones. It is for a 2.4 with a 901 transmission. Thanks in advance.

[KTL]

Original part number is 900 061 192 02 looks like the correct stud = M10 x 102mm. Pelican catalog says the aforementioned number has been superseded by 999 062 192 02 which is found here

http://www.pelicanparts.com/cgi-bin/PartsLookup/search.cgi?command=search&part_number=99906219202

http://www.pelicanparts.com/cgi-bin/PartsLookup/search.cgi?command=show_page&Catalog_Name=911_USA_70_73_KATALOG&Illustration=101-05&Line_Item=82

You should be able to get the nut at a local hardware store. Just a basic coarse thread M10 nut, which I think the pitch is 1.5

I am continually shocked at the Pelican catalog; freakin' awesome...........

[ttw18]

I ordered the 4 studs (M10 x 102) and 1 stud seems to be the right size the other 3 are too long. The stud that passes through the starter is the correct size. The other 3 have the unthreaded shaft exposed when the motor and trans are mated together.
1. Are these the wrong studs?
or
2. Are there spacers that compensate for the extra size on the 3 that seem to long.

[KTL]

It appears the 102 stud is one size that you need (#82 in the parts diagrams). If you look more closely, #7 is another stud that you need two of. No length is given. Sorry if I misled you to think #82 is the only size you need.

You could cut the long ones to the necessary length and thread them with a cutting die. I'd do that before using spacers. The extra stud length may make it difficult to join the engine & trans. and fasten them together.

[rlane]

I just replaced these on my 73, at least on the 73 the stud is M10 x 85 mm part #999-062-217-08-OEM

[ttw18]

rlane, you are probably using a different transmission than I am so the stud length may be different than what I need. Thanks for the info though. I need the right ones desperately! I am going on spring break from grad school and I would like to work on my project during my time off. It is the only roadblock to getting this project done. Does anyone have the hardware that I need? I would pay a premium to get these asap!

[ttw18]

Can anyone confirm the length of the smaller studs? The parts catalogs are not clear on this. I have been told anywhere between 72mm - 85mm.

Thanks

[Grady Clay]

OK, here is my contribution:

Stud at starter:
900.061.192.02 BM10x102 DIN 835-8.8 verz.
I measure this protruding from the crankcase 103 mm on a 73.5T case and an overall length 122.6 mm.

Lower 2 studs:
999.061.043.02 M10x67
I measure this stud protruding from the case 72 mm and an overall length of 91.75 mm

Bolt (upper right, opposite starter):
900.155.023.02 M10x72 DIN 70613-8.8 vrez.
I measure this bolt 72 mm under the head with about 43 mm unthreaded.
This bolt can be replaced with the same stud as the lower two (M10x67).

Nut at starter (same as cylinder head nut) 10 mm internal Allen.
901.104.382.01

Lockwasher, between the nut and flatwasher.
This is a spring steel ‘wavey’ washer with small OD. 10.5x18.5x0.75 mm.
999.523.103.01

Flatwasher 10.5 DIN 433- st verz. (this has the small OD – 10.5x20.9x2.5 mm)
900.031.005.02

Nut, 15 mm wrench size M10 DIN 7615-8.8 vrez.
This is one of the relatively unique pieces of hardware and I notice every time.
M10 x 8 mm tall x 15 mm wrench size.
900.157.002.02





For reference, the calipers are set to 102.0 mm.
The wrench is 15 mm.


The part numbers and descriptions are from the paper ’72-’73 parts manual.
Note the inconsistencies.
All the same hardware applies for 901, 911, 914 and 915.
The 901 had a 110 mm Allan bolt at the starter (about 85 mm unthreaded).
You must use the stud and a Allan nut with a 1.5 hp starter.

All the studs should (at least) have Helicoils in the crankcase.
TimeSerts or Case Savers are great 2nd tier repairs.
The studs should be held in with Locktite ‘Blue’ or ‘Green’ and tensioned before the Locktite sets.

The reason for using four studs is they help align the transmission before the
input shaft engages the clutch splines. This helps prevent damage to the hub
of the clutch disc.

Best,
Grady

[RWebb]

N-012-242-3-OEM is used under the Allen nut at the starter, right?

are 4 of the small O.D. flat & lock washers used? or just one?

what flat & lock washers are used on the other studs (the ones with "normal sized" nuts)?

[rlane]

Grady has just given you a textbook of info...what an incredibly nice and knowledgable Porsche man

[ttw18]

Thanks Grady, that's awesome!

[Neilk]

Resurrecting this thread.... I am in mid reassembly and this thread saved me. I thought my starter stud was too short but it measured out the same size as Grady's. Apparently the short section of threads goes into the case, if you put the long threads in the case, the stud will be too short to put the barrel nut on...

Hope this helps the next person...THANKS Grady!

[Lukesportsman]

The only place I could find these were Pat Motorsports

[KTL]

Originally Posted by Neilk

I thought my starter stud was too short but it measured out the same size as Grady's. Apparently the short section of threads goes into the case, if you put the long threads in the case, the stud will be too short to put the barrel nut on...

Hope this helps the next person...THANKS Grady!

Good observation on the short vs. long side of the stud. That barrel nut is a pain in the butt but I understand why they use it. Can't get a wrench or socket on a typical hex nut due to the tight clearance against the body of the starter.

I think we'll see a lot of thanks to Grady for his contributions here. Boy did he provide a lot of technical detail in his responses. The amount of knowledge he possessed is staggering. RIP my friend. You are certainly missed by many in many, many ways

[scootermcrad]

I'm resurrecting this older thread since it seems to have some incredible information in it from Grady and others, but maybe needs to be updated with a source for these studs. I can't seem to find them when looking for them in Pelican's catalog search, but I was never credited as the most technologically advanced person, either, so maybe I'm not searching correctly.

I'm working on a 1970-73 2.2L that will get a 915 transmission behind it. It seems from Grady's info below, the stud lengths should be basically the same, but maybe the starter stud will be different. Or maybe all of them.

I have no trans mounting studs and need to purchase all of them. The numbers given don't seem to come up anywhere for purchase, and the links no longer work. If someone can PLEASE point me in the right direction I would really appreciate it. And a verification of what is needed for a 2.2L case to 915 would be really appreciated!

Thanks to everyone who have already contributed to this thread!

Originally Posted by Grady Clay

OK, here is my contribution:

Stud at starter:
900.061.192.02 BM10x102 DIN 835-8.8 verz.
I measure this protruding from the crankcase 103 mm on a 73.5T case and an overall length 122.6 mm.

Lower 2 studs:
999.061.043.02 M10x67
I measure this stud protruding from the case 72 mm and an overall length of 91.75 mm

Bolt (upper right, opposite starter):
900.155.023.02 M10x72 DIN 70613-8.8 vrez.
I measure this bolt 72 mm under the head with about 43 mm unthreaded.
This bolt can be replaced with the same stud as the lower two (M10x67).

Nut at starter (same as cylinder head nut) 10 mm internal Allen.
901.104.382.01

Lockwasher, between the nut and flatwasher.
This is a spring steel ‘wavey’ washer with small OD. 10.5x18.5x0.75 mm.
999.523.103.01

Flatwasher 10.5 DIN 433- st verz. (this has the small OD – 10.5x20.9x2.5 mm)
900.031.005.02

Nut, 15 mm wrench size M10 DIN 7615-8.8 vrez.
This is one of the relatively unique pieces of hardware and I notice every time.
M10 x 8 mm tall x 15 mm wrench size.
900.157.002.02





For reference, the calipers are set to 102.0 mm.
The wrench is 15 mm.


The part numbers and descriptions are from the paper ’72-’73 parts manual.
Note the inconsistencies.
All the same hardware applies for 901, 911, 914 and 915.
The 901 had a 110 mm Allan bolt at the starter (about 85 mm unthreaded).
You must use the stud and a Allan nut with a 1.5 hp starter.

All the studs should (at least) have Helicoils in the crankcase.
TimeSerts or Case Savers are great 2nd tier repairs.
The studs should be held in with Locktite ‘Blue’ or ‘Green’ and tensioned before the Locktite sets.

The reason for using four studs is they help align the transmission before the
input shaft engages the clutch splines. This helps prevent damage to the hub
of the clutch disc.

Best,
Grady

[fanaudical]

The search feature for the website has changed - try using dashes in the part number instead of periods. Found these that way:

https://www.pelicanparts.com/More_Info/99906103402.htm?pn=999-061-034-02-OEM

[scootermcrad]

Originally Posted by fanaudical

The search feature for the website has changed - try using dashes in the part number instead of periods. Found these that way:

https://www.pelicanparts.com/More_Info/99906103402.htm?pn=999-061-034-02-OEM

That's a huge help! Thank you!

It appears I can use that 69 mm long stud for three of the locations.

I searched the part number Grady called out for the starter side (approx. 122mm long) and that number was superseded to this, but it is much longer at 145mm:
https://www.pelicanparts.com/More_Info2/99906219102.htm

PET calls out a 102 mm for a 70-73, (999-062-192-02)
https://www.pelicanparts.com/search/?q=999-062-192-02

...but it's suggested that 102mm could be too short. Can someone confirm what the correct lenth and/or part number would be if a 915 will be run behind a 70-73 case?

[fanaudical]

You might have to go measure the minimum distance yourself - it may be unlikely that somebody else has your specific combination of parts lying about.

Minimum stud length = thread depth in engine case + flange thickness of the 915 case in that area + thickness of flat washer + thickness of nut + (3 x thickness of lock washer)

I think you want at least one full thread past the end of the nut.

[scootermcrad]

Originally Posted by fanaudical

You might have to go measure the minimum distance yourself - it may be unlikely that somebody else has your specific combination of parts lying about.

Minimum stud length = thread depth in engine case + flange thickness of the 915 case in that area + thickness of flat washer + thickness of nut + (3 x thickness of lock washer)

I think you want at least one full thread past the end of the nut.

I haven’t bought the 915 yet, so unfortunately I have nothing to measure. That’s why I’m asking. All I have is an engine with no mounting hardware. Trying to get it on the yoke so I can get it cleaned up and inspected. Would like to buy the right studs out of the gate, if possible.

[Walt Fricke]

If Grady is right, and all four stud holes in the mag case have Helicoils (and Grady was seldom wrong, though you see he had a caveat about this - but you can easily check yours), then you needn't worry about getting the case on the engine stand. Just use some 10mm bolts from your junk box. You can deal with the rest later, like when you have your transmission and starter in hand. At that point, measuring will answer all questions if you still have doubts.

If it were a little easier for me, I'd go out into my garage and measure the flange thickness of the 915 transmission. But it isn't. I'd have to jack up the car, or move a bunch of stuff to get at a spare transmission. If I think of it, I will measure a starter flange thickness, though Grady suggests Porsche had two flange thicknesses. I've had no issues with using Tilton style starters, which I suspect have thinner flanges, but as long as you aren't using a barrel nut that's not a practical issue..

As to the starter stud - for sure use a hex nut, not the barrel nut Porsche used. Grady's post reminded me that some of the nuts for this application are 15mm wrench M10 nuts. That is because the space on the tranny bell housing is restricted in some places, so having these smaller nuts makes wrenching easier. Having all the same size makes wrenching a bit more convenient but isn't a big deal either way.