Easy 5-Lug Conversion - 911 Running Gear, For High Power Applications... Options

[PRS914-6]

Adding to an already great thread...

Dimensions of a stock 914 transmission output flange



Overall length is 100mm

Total of 18 coarse splines

Warning! There is an output flange that looks EXACTLY like stock with larger CV's. I believe but I am not sure that they came off the automatic version of the 901. It will slip right in, looks perfect but the center 35mm dimension is slightly smaller, perhaps 1mm. It would be easy to bolt in and go with pending failure to come....it's that close. So make sure you measure your parts!!! I almost installed a set but noticed they fit in a little loose.

[chad newton]

Ok, so what if you went with the newer style everything. Like for my 78 I have. Do I need to make an adapter to make the 6 bolt cv's fit the trans axles? Or is there a different way then that?

'75-'79 (or so) has smaller cost reduced CVs (100mm) versus the earlier 108mm.

Later 915 with the 100mm variety CV have fine spline which won't fit the 901 coarse spline output...

So it would be all good if I ran a 915. I may not use them now, may keep them if I decide to go with a 915. Damn, what a pain in the a$$ this has been for me.

[Eric_Shea]

With a 915, be prepared to spend $4k+ converting it to work in a 914.

[Mark Henry]

For this you will need to get the 911-901 hubs, stubs and input shafts. Used prices vary but many like me have found these for around $300, but YMMV.
Be careful as the '69 and earlier 911-901 input shaft fits but is NFG and I believe some 915 coarse spline 108mm input shafts work, but the later fine spline does not.
Keep in mind that the CV boot flange (metal part) is NLA, not included in kits (but is included in full axles) and as rare as hens teeth....so make sure you get those as well. Don't worry if they are all bent up, as they can be straightened to serviceable condition quite easily.

The correct 1974 to mid-year 1975, 108mm CV (4-bolt, 2 pin) is NLA as a single, you can buy whole axles (press CV's off and toss the 911 axle, $454. for two axles on the bird) or you can modify'86-89 108mm, 6-bolt, G-50 CV's ($300. for 4 kits, includes CV, grease, boot straps and boot, but no CV boot flange).

911 axles are useless on a 914. Any way you go you have to buy the new axles from swayaway ($320) for this method.

Also if you have no bolts, washers, backing plates, gaskets.... that's an easy $100 if new.
You will also need two new rear bearings.

Now anyone considering doing this knows the whole price, no big surprises.

Then you need wheels and lugnuts... oh and the front end, brakes, caps, tires...... (IMG:style_emoticons/default/biggrin.gif)

[chad newton]

You guys are awesome. Thanks again.

[tomeric914]

BTW, I looked everywhere but couldn't find so I confirmed with Sway-a-way. The 2420 axles come with SAW's special circlips. Their catalog shows that you can buy them separately but they are not needed.

Also, I just purchased axles from Bugs and Buggies for $288 shipped. Note in the following link that the part number is correct for 28 spline axles, but the page description is wrong. http://www.bugsandbuggies.com/Parts.asp?CN...p;SN=2&GN=4

[tomeric914]

(IMG:http://www.914world.com/bbs2/uploads/post-1110-1232676459.jpg)

What size Oetiker clamp is on the small end?

I looked on PET and there is no small clamp listed. Were they required?

[SLITS]

Clamps are used to keep hot grease from coming out and messing things up. They would also keep the boot from sliding off its' mounting point.

I have seen rebuilders us snap ties (aircraft ties) in lieu of the metal clamps.

[KTL]

I've seen many racers use the simple plastic zip ties for securing CV boots. For people like us who service things quite regularly, the zip strips are the ticket. I think the Oetiker clamps are fantastic. But they're intended to be a longer-term/lifetime installation. Since we take things apart all the time, I think the zip strips are suitable.

I notice on the later 911 stub axles (both inboard on trans and outboard in trailing arm) the stubs have relieved/clearanced areas for the CV. Even the wimpy 100mm stubs have the cleared areas. Why is that?

All the stubs i've seen for high performance usage like dune buggy VW high performance racing abuse, where CVs take way more abuse than street driving or road racing, don't have the stubs cleared around the CV ball area. So the guys running the 108mm early 911 or 930 CV joints have no issue with CV ball clearance on their stubs I assume?

Thanks,
Kevin

[Mark Henry]

I've seen many racers use the simple plastic zip ties for securing CV boots. For people like us who service things quite regularly, the zip strips are the ticket. I think the Oetiker clamps are fantastic. But they're intended to be a longer-term/lifetime installation. Since we take things apart all the time, I think the zip strips are suitable.

I notice on the later 911 stub axles (both inboard on trans and outboard in trailing arm) the stubs have relieved/clearanced areas for the CV. Even the wimpy 100mm stubs have the cleared areas. Why is that?

All the stubs i've seen for high performance usage like dune buggy VW high performance racing abuse, where CVs take way more abuse than street driving or road racing, don't have the stubs cleared around the CV ball area. So the guys running the 108mm early 911 or 930 CV joints have no issue with CV ball clearance on their stubs I assume?

Thanks,
Kevin

I hope I don't have to take them apart often, one dirty job I hate.

The CV stubs used in this application don't have the reliefs, those are later 911 made to fit the 928 cup they use instead of the paper grease seals.

[tomeric914]

I have seen rebuilders us snap ties (aircraft ties) in lieu of the metal clamps.

Yep, I've done that myself. Was just trying to be fancy this time.

[Harpo]

Adding to an already great thread...

Dimensions of a stock 914 transmission output flange



Overall length is 100mm

Total of 18 coarse splines

One of my new (to me) trans out put flanges is 1mm small here. I'm going to add a shim to get rid of the slop

[KTL]

I agree the CV grease/build job is a filthy one. But it's a part of regular maintenance with racing or regular track use in my opinion. An occasional regrease can make your CVs last nearly forever and avoid a failure. CV failure can be really ugly sometimes!

OEM CV cages are rather brittle and can break, plus the fit is rather tight in new CVs. Some polishing on the races and use of a chromoly cage makes them almost bulletproof. That said, use of a high end grease is key to them lasting. The "stock" grease like the tube from GKN with a new CV is junk. The grease goes thin right away due to the tight fit (creates heat) & the grease itself is a cheap economy EP grease.

I've seen the 928 derived CV grease caps. The late 930 CV (85.5-89) and 85.5-86 915, and all G50 use those caps. I've got 'em on my '87 911 and they're a nice feature vs. those pesky gaskets. But the 75-85 915 and thru-84 930 don't have the grease caps and both of those stubs have the relieved area for the CV cage/balls. See this tech bulletin for the switch from 100 to 108

(IMG:http://www.914world.com/bbs2/uploads_offsite/forums.pelicanparts.com-16453-1380492136.1.jpg)

(IMG:http://www.914world.com/bbs2/uploads_offsite/forums.pelicanparts.com-16453-1380492136.2.jpg)

I guess my point is, the dune buggies with severe angularity & loading like these

http://www.appletreeauto.com/TYPE-1-TO-930...-AXLE-AC525100/

don't use stubs with reliefs but the factory Porsche stubs do? That seems odd. I can see the VW stubs have a deep bell to allow for more plunge. But that would lead me to believe the additional plunge would warrant some reliefs on the periphery of the stub axle flange. Apparently not.....

[PRS914-6]

See my warning about this size issue above. Get the correct ones. A shim won't work (for long). It's a critical fit and the shim will get beat to death..... but that's just my opinion as a machinist

[Harpo]

I will post over @ pelican and see what comes up

David

[Mark Henry]

Behold my new 914 axles with 911 C/V joints and sway-away axles. However where can I find new boot clips? The originals have 74 oetiker stamped on them.

For those of you considering this route the C/V joints are pressed on the the axles and It took 500 psi with a press to separate them. Thanks for your help Eric.

I was going this route, but I'm thinking of using the later G50 CV, mainly because I'm a CSOB (would save me $150) and I should be able to figure out a solution for the gasket/end cap issue.

The G50 is 6 bolt X 10mm and has no relief for a gasket, but is suppose to be the same in all other regards.

http://forums.pelicanparts.com/porsche-911...patibility.html

Part number for the G50 CV is 911-332-923-01-M60
http://www.pelicanparts.com/cgi-bin/ksearc...-332-923-01-M60

(IMG:http://www.914world.com/bbs2/uploads_offsite/forums.pelicanparts.com-26-1372786441.1.jpg)

(IMG:http://www.914world.com/bbs2/uploads_offsite/forums.pelicanparts.com-26-1372786892.1.jpg)

(IMG:http://www.914world.com/bbs2/uploads_offsite/forums.pelicanparts.com-26-1372786892.2.jpg)


Only real issues is the 6 bolt 10mm vs 4 bolt 2 pin and no gasket. It looks like the 928 cap will not fit into the early flange/stub.

(IMG:http://www.914world.com/bbs2/uploads_offsite/forums.pelicanparts.com-26-1372786893.3.jpg)

This is my solution, the late model G50 CV's that I have modified to accept the stock grease seal
The CV material was very hard (flame hardened) and could only be cut with carbide tooling.
I'll stick a length of rod in the 2 extra bolt holes to capture the roll pins, I may have to spread the roll pin slightly to ensure a tight fit in the CV.
Other than that it should fit like stock '74 CV's now, it will no longer need the 928 grease cap.

[naro914]

I think this might be a winter project of mine...been a LOOONG time since the axles have been serviced.
Question: Where do I find the CV gaskets? I'm sure if I looked hard I could find them, but it's easier to just ask... (IMG:style_emoticons/default/smile.gif)

[Eric_Shea]

CV Gaskets? Pretty common for say... a 1970 911.

[Mark Henry]

CV Gaskets? Pretty common for say... a 1970 911.

Yes this is the stock 10mm 911 CV gasket.
If you look at the chart above the 1974 911 CV and the later G50 CV are almost the same, except the G50 doesn't have the gasket seal relief cut into it. The G50 uses the 928 grease cap, but that will not fit in the early 911 stubs.

The roll pin area of the stub you can keep it 4 bolt and 2 pins or it will have to be drilled and taped for the two extra bolts.

[KTL]

Instead of machining the CV and using the gasket, why not apply some sealant to the exterior of the joint after it's assembled? Reason I suggest that is because the gaskets tend to compress over time and allow the clamping force to be lessened, sometimes quite a lot. Just a thought.