Alex's Porsche 968 - 07K Transplant

[alxdgr8]

For my own reference later, Nina's 20vt swap: http://ninas20vt.blogspot.com/search?up ... results=17

931 bellhousing with a hydraulic TOB:

[the german]

The 931 bellhousing definitely looks like the nicer option; looks like that one was modified to add the hydraulic T/O bearing. I'm guessing that would still require an adapter plate (?). Does the tunnel need to be widened to accommodate the starter with this bellhousing? might be a chance to try out a starternator if so

[alxdgr8]

The 931 bellhousing definitely looks like the nicer option; looks like that one was modified to add the hydraulic T/O bearing. I'm guessing that would still require an adapter plate (?). Does the tunnel need to be widened to accommodate the starter with this bellhousing? might be a chance to try out a starternator if so

The 931 bellhousing matches 4 of the Audi bolts (middle and top ones), but with the 07K you'd lose the top two. I think I'd have to weld ears on the bottom for a couple more mounting points. Starter would be in the 944 position basicaly near the bottom of the motor so it would clear just fine. The 931 clutch fork is a pull instead of the 944's push so I could modify for that or do the hydraulic TOB as shown above.

[Mcstiff]

How feasible would it be to chop a bellhousing off of an Audi transaxle and adapt it to the torque tube?

[the german]

Ears would be easy to weld on- sounds like the 931 bell housing is a winner

[alxdgr8]

How feasible would it be to chop a bellhousing off of an Audi transaxle and adapt it to the torque tube?

Any AWD/RWD bellhousing is most likely going to be too long and you'd have to do a LOT of chopping (nearly right through the front diff). The nice part about the FWD bellhousing is that it has a nice flat spot arlready to mount the torque tube adapter to.

The regular 924 (early 2.0 Audi motors, not the 924S with 2.5 944 motor) are the same as the 931, but they use a cable clutch. If I'm going to convert to hydro TOB anyways, they are easier to find so I might do that. I think I have a line on a 931 bellhousing though.

[alxdgr8]

Pulled the pan tonight after I got it on an engine stand. As suspected it's a cast crank (p/n 07K101L)



Looking at the layout of the oil sump, the pickup should be easy to relocate forward of the crossmember/steering rack. The issue that's more concerning is the bulge in the pan is where the oil pump is. That can't be relocated. Let's hope the engine doesn't sit any further forward, otherwise the crossmember will have to be modded to allow space for the oil pump.

[alxdgr8]

Not much to report, but...
Scored a forged early crank for $150 shipped off of ebay. I'll need to back-date the timing chain setup (which will cost about $500 for OEM parts), but this will save me from having to buy a $1200 TT-RS crank and allow me to still run my low-mileage newer block.

10688229_10104748643098098_8869868516797190794_o by alxdgr8, on Flickr

[alxdgr8]

Back-dating the chain tensioner setup
This allows you to back-date a new engine to the early style chain setup. Why would you want to do this? This allows you to find an early forged crank, and run it in a later block that's much easier to find with lower miles. This is the route I'm now taking as I found an early forged crank on ebay for $150 shipped. I will back-date the newer 35k mile engine and not have to buy a $1200 TT-RS crank to get a forged one.

Early chain parts diagram: http://www.partscats.info/volkswagen/en ... id=2249070

Late chain parts diagram: http://www.partscats.info/volkswagen/en ... id=3473991

Parts that are the same:

• camshaft adjuster unit 07K109083F
• gear wheel shaft 07K109224
• seal 07K109235A
• mounting 07K109237A
• socket head bolt with inner multipoint head 06E109281A
• slide rail 07K109469G
• chain tensioner 07K109510B
• slide rail 07K109513D
• chain sprocket 07K109571D
• multi-point socket head bolt with collar N 91124601
• socket head bolt with inner multipoint head (kombi) N 91050202
• socket head bolt with inner multipoint head N 91099101
• cylinder pin WHT000041
• threaded pin WHT000195

Parts that are different ([Name] [Old P/N] [New P/N] [Cost for Old]:

• chain sprocket 07K109077D 07K109077E $102
• camshaft timing chain 07K109120A 07K109231A $113
• chain tensioner 07K109217E 07K109510B $64
• camshaft timing chain 07K109231A 07K109158B $116
• chain tensioner 07K109467B 07K109467F $46
• chain sprocket 07K115121E 07K115121F $36
• slide rail 07K109514D 07K109513D $33

This brings you to about $510 in new OEM parts to back-date the engine. Another alternative is to find an early motor for cheap (good or bad condition, you can find them for $200) and grab the timing stuff off of that. You'll most likely want to refresh the chain and guides, but that'll save you a few dollars on buying new gears. Or if you buy an early motor with a known forged crank but with a lot of miles, you could look for a later motor with low miles and combine two to make one.

[alxdgr8]

Forged Crank Identification
Here's how to identify a forged crank from a cast crank. This is handy when browsing cranks on ebay, BUT BE CAREFUL. Make sure that the pictures displayed are the actual item and not stock photos. Also, contact the seller if they list multiple items being available, but only provide one picture. Make sure you get the exact crank pictured that you've identified as being forged.

Forged Crank:
Look for the large, wide flash lines on the lobes of the crank. These should be very noticeable as shown in the photo below.



Cast crank:
Cast cranks do not have the large flash lines like a forged crank does. They have very small, thin lines that are sometimes very hard to see.

[loxxrider]

Great info Alex, thanks for posting this. It's nice that you're getting a whole new chain setup because now that's one less thing you'll have to worry about failing for a long time.

[PRY4SNO]

Epic posts!

Thanks for your explicit detail, I'm following with rapt attention.

[varia]

GJ ALex, thats what I wanted to ask when you were here!

[lucidmatt]

awesome update- seeing those costs *almost* makes me want an 07k in the ur-s! But really, This Porsche chassis is a great platform for the 07k, and I cant wait to see this thing come together. keep it up! excellent info in here.

[the german]

Sooo much good information. Thanks Alex!

[alxdgr8]

Finally picked up a 931 bellhousing.

IMG_20150717_210930296 by Vex Art, on Flickr

Sadly, it looks like the 931 bellhousing, despite being used on an Audi I4 has the I5 bellhousing pattern (along with sharing the lower 2 944 bellhousing botls). This doesn't really help since the 07K uses the VW I4 pattern. They only have 1 bolt in common.

931 pattern bolts up perfectly to the 'vintage' I5.

IMG_20150718_200259661 by Vex Art, on Flickr

01E bellhousing (modified to fit 07K; two bolt holes at the top need trimmed off) on top of the 944 bellhousing. Red are the VW I4/07K bolts, black are the vintage I5 bolts. The lower 944 bellhousing bolts share the vintage I5 bolts. A large portion of the upper 944 bellhousing would need to be removed. Two of the 07K bolts could possibly be added to the 944 bellhousing by drilling holes and/or adding welding on a small amount of material to the bellhousing.

IMG_20150718_231906658 by Vex Art, on Flickr

The 01E bellhousing template mounted on the 07K engine. The red shows the 07K bolts, and yellow shows the 931/I5 bolts. Only one bolt is shared.

IMG_20150718_205425310 by Vex Art, on Flickr

I think it would be possible to add at least two more shared bolts to the 931 bellhousing pretty easily. The 07K red hole could easily be drilled, there is a nice flat spot on the bellhousing for it.

IMG_20150718_231546048 by Vex Art, on Flickr

The other one would require a small tab to be welded to the 931 bellhousing. This would give 3 matching bolts. I'd want to find at least one more.

IMG_20150718_231558430 by Vex Art, on Flickr

One ear on the 931 bellhousing would need to be removed (much like the 01E) to clear the 07K timing chain cover. But not nearly as much material as the 944 bellhousing would need.

I'm going to order an OEM 01E spacer to help do some more planning. I think both the 944 and 931 bellhousing would take the same amount of work to make work with the 07K. The 944 would require a lot more trimming and then welding to 're-enclose' the bellhousing. The 931 would require slight modifications and no welding to 're-enclose'. An adapter plate might be the best route and would probably work better with the 931 bellhousing. I need to get an 07K clutch/flywheel so I can figure out stack heights and see if I can even run a spacer/adapter plate.

Progress will continue to be slow, the 968 is at the bottom of the list of many projects...

[alxdgr8]

Broke out my 3D scanner for the first time in a long time and scanned the rear of my 07K. Then built a crude model of an 012 bellhousing (since that's what I had a drawing for and it's basically an 01E).
You can see here why the 01E has to be modified to fit the timing cover and you can see bolt holes that line up (marked in red). I missed some holes on my wood mockup since some of them you can't practically fit a drill bit through the backside.

07K_Interference by Vex Art, on Flickr

Next step is to order an 01E spacer. I'm going to mock it up and see if it could be welded to a modified 944 bellhousing to be used as an adapter.

[pete82]

Did you ever get any further with this?

[alxdgr8]

Not yet... :(