Pull type clutch question…. Options

[Larmo63]

Do I need a special clutch/pressure plate for a pull type clutch system I'm assembling for my 911 conversion?

Will this work? The trans is a '70-71' I've been told. But, I'm not familiar with this stuff. Thanks for the help.


http://www.ebay.com/itm/Porsche-911-65-69-...ecAAOSwhcJWFxS7

[euro911]

Lawrence, you'll need an early 911 flywheel ('65 ~ '69), compatible pressure plate and a 215mm clutch disc to mate up with a standard 914 901 transaxle. The 901's input shaft is (spline count: 24, pilot diameter: 14.7mm, spline diameter: 20.6mm).


If you have a 915 trans, the input shaft is different than a 901's ... (spline count: 20, diameter: 14.9mm, Spline diameter: 22.2mm).

The 915's disc is also larger diameter (225mm), so you'll need a different flywheel and pressure plate too.

[rgalla9146]

Wait a minute, the trans is a '75 what ? a 914 trans or '75 911 (915) trans ?
What 6 cyl. engine ? does it have a 6 bolt flywheel or ?
more info needed

[euro911]

The engine came out of my '67 912-6. The case # indicated that its a '69 911E, but I don't know what P&Cs and cams were in it. Zenith carbs topped it off.

I sold it without the flywheel (6-bolt).

Since all he mentioned was that he has a '75 transaxle, I listed the specs for 901 and 915 just in case it is a 915. I think it's just a '75 914 901, though (IMG:style_emoticons/default/confused24.gif)

[ClayPerrine]

A 1975 transmission would be a 915. That clutch and pressure plate combo won't work with a 915 transmission.


If you are going to put this in a 911, just buy the 915 clutch parts. Any reputable parts house will be able to sell you the correct stuff. Besides a clutch kit, you will need a flywheel and ring gear. The ring gear is a separate part from the flywheel on the pull clutch. You also need the correct clutch cable.

[Larmo63]

Update, yes, the engine is a six bolt '69 911E and the trans is a 70-71 911 box.

I've been told that it is a "pull clutch" type, and that is where I'm confused. The flywheel I'm buying is a six bolt. The transmission will work with this engine, I just don't know how the "pull" vs "push(?)" clutch system differs.

[euro911]

Lawrence, is this all for Speedy?

Has the diff ring gear been flipped? ... 914 nose-cone and side-shift?

Also, post the #s stamped on the top rib of the transaxle. If it's a '70/'71, it should be one of the following:

911/01 (standard)

or ...

911/80\
911/81 |
911/82. > (with 904 main shaft)
911/83 |
911/84/


Curious why you want to use a 911/xx trans (IMG:style_emoticons/default/confused24.gif) ... but a side-shift 901 is good for up to about 250 HP if you're not too hard on it.


If the '70/'71 911 transaxle has been set up for a 914, you'll need the following [expensive] parts (Pelican #s & prices - new):

911-102-201-12 flywheel (& 6 bolts) - approx. $400.

911-116-239-04 ring gear (& 9 bolts) approx $150.

911CP-7071N - Pressure plate, 225mm disc & T/O bearing (kit) approx $900.

+ the other misc. parts like Clay mentioned above.

Personally, I'd stick with the 914's 901 trans ... you'd be way ahead of the game.

[jcd914]

70/71 911 pull type clutch uses a different pressure plate, throw-out bearing, flat flywheel and a separate starter ring gear.

Jim


Pressure pkate

[Larmo63]

Yes, it is a 911/01 tranny rebuilt with /6 gear ratios. 914 side shift & tail cone. Pictures and numbers tomorrow.

Case #4504590 The R & P are flipped for 914. Gearing is A GA O V ZA (standard 914/6 gearing, also 911S, 911E)

[oldie914]

A little history: For the 1970 911 model year, Porsche wanted a bigger clutch disk. To do this, they changed to a flat flywheel with the ring gear mounted on the pressure plate. The transmission case was reinforced with more ribs in the bellhousing and a steel insert inside the differential housing. The throw out arm bolt was threaded into the insert to keep it from pulling out of the case. The throwout arm was changed to fit the pull type throwout bearing. The throw out bearing is attached to the pressure plate and has two flat spots on the outer ring. To install, you have to bolt the transmission to the engine and the reach inside the bellhousing with a screwdriver to engage the throw out bearing and arm.
In 1972, Porsche introduced the 915 transmission which had a clutch throwout arm inside the bellhousing which simplified things a lot. They continued to use the the 1970-71 flywheel system.
Here is some information on parts interchangeability based on how we used to mix and match 40 years ago. I'll admit my memory is not perfect.
1. The same flat flywheel was used from 1970 until Porsche changed the number crankshaft bolts. I think for the SC in 1983.
2. The pressure plate and ring gear for the 2.4 and 2.7 911s will fit a 2.2.
3. The 1970-71 clutch disc is model specific because the 915 transmission input shaft has a different spline.
4. The 1970-71 throwout bearing is model specific because of the flat spots needed for assembly.
There was an article in Porsche Panorama in the 1970s about converting a 914/6 to a pull clutch.
Hope this helps.

[rgalla9146]

And now you've got all the dirt.
Enough to keep you scratching your head for a while
The easiest way out is to use a 914 trans.
No flipping of ring gear. No expensive pull clutch, pressure plate and flywheel.
Standard 914 clutch cable. Plentiful parts.
No explaining to parts people the combination you need.
No rotating the TOB to remove the trans etc etc etc
Ask me how I know.

[ClayPerrine]

I have this setup in my six conversion, and have been running it for years.

It works great. The bigger clutch prevents slippage and the clutch cable is a straight pull so the clutch tube is not stressed. So it won't break free from the body.


From experience, you MUST use the 2.2 pressure plate, throwout bearing and clutch disk. If you use anything else for a pressure plate, the threads for the clutch arm pivot bolt will pull out of the trans case. You can have the case machined so that it has a top hat shaped insert installed from inside the case to help alleviate some of that, but even if you do that you can still crack the case from the stress of a 2.4 or later pressure plate. Plus the clutch feel will be much stiffer with a 2.4 or later pressure plate. BTDT! Ruined a 71 911 case because I had a 2.4 pressure plate in it.

Also the throwout bearing is becoming very expensive these days.

[Larmo63]

Thanks guys, at least I know what to look for now, and you're right, this stuff is expensive (of course.)

[Mark Henry]

I would have used a 914 trans case*, 6 bolt '69 911 flywheel, standard 914/4 215mm pressure plate (PP) and disc.
Easy-peasy, semi cheap and done.

My second choice is using the stock 225mm flat flywheel and a Kennedy 228mm kit. The KEP kit comes with adaptor ring w/starter gear, a 228mm HD late VW bus PP disc and a TO bearing.
The big plus is if you up grade to a 3.0 you can still use this conversion kit.
But again I think you would need to use a 914 trans case*.


The pull clutch will be a pain to set up and as said it's expensive.
If you go this route I have a bearing that I pressed apart, inspected, cleaned and put back together with swepco grease. I'd sell it a lot cheaper than new.
I also have a PP, starter gear ring and stock disc, but the PP is a 911S aluminum shoe and the plating is starting to delaminate at the edges. Likely still OK for a 2.0.
So I do have everything but the flywheel.
PM me if interested in any of this.

*If you are handy with modifying you can cut and weld a 914/4 TO bearing arm to work push style in your 911-901 case. This can be done as I did it on the 1971 911-901 trans in my T4 engined 1967 bug, that uses a 914/4 clutch assembly.

[stownsen914]

I have the 70-71 clutch setup in my 914/6 racecar. I've had it for years without much trouble, though I did snap a clutch fork bolt once a few years ago at the track. Probably because I have the heavier-springed later clutch in my car. I think the clutch cable is from a 72 911, if memory serves correctly, in case you decide to go that route. It fits perfectly for the 914 conversion.

Scott

[Larmo63]

Do 914 CVs fit the 911/01 output flanges, or am I going to have trouble THERE too? (IMG:style_emoticons/default/headbang.gif)

[Mark Henry]

Do 914 CVs fit the 911/01 output flanges, or am I going to have trouble THERE too? (IMG:style_emoticons/default/headbang.gif)

Getting all this stuff sorted is a PITA.

Early 901's have an oddball output flange.
But IIRC you have a 70-71 trans, so yes 914/4 flanges bolt on, but...are you not doing a 5-bolt conversion as well?

If you are you want to keep the flanges that came with that 911-901, as they are one of the best ways to do the 5-bolt conversion.
In fact those flanges are sought after, so don't part with them till you have a final plan.

[euro911]

911 axles and CVs are larger and have 6 bolts. You'll need 911 half-shafts w/CVs and 6-bolt stub axles with the correct spline arrangement (-6) ... or you can check with the guys who've shortened their axles and used 944 CVs.

I think this is the main reason so many have recommended sticking with the 914's 901 trans - a lot less hassle (IMG:style_emoticons/default/idea.gif)

[euro911]

Ah ... Mark beat me to the post - while I was still typing (IMG:style_emoticons/default/type.gif)

[rgalla9146]

If you go with the pull clutch it will be near impossible to separate the trans from the
engine without removing BOTH from the car.
If you choose this route be sure to 'test' disengagement some way before installing the assembly, especially if you do it with a non-standard group of parts