G50 Conversion Project Begins

[ischmitz]

Very nice. I wonder if 1mm really will matter in the end. The tolerances when putting a 911 on a jig are +-3mm for the torsion bar mounting points. You might want to consider whether it's worth it to break the tags at all.

Just make sure you do not get too much distorsion from heat builtup when welding. Go slow and allow cooling inbetween.

Cheers,
Ingo

[1972_911T]

ischmitz +- 3mm thats very interesting information thanks. With the adjustability and movement in the rear swing arm I'm inclind to agree 1mm is unlikely to cause any bad effects. Lets face it slightly different tires pressures would push the tread pattern out considerably more than 1mm not to mention if we throw in any difference/movement due to bush wear.

As it happens I went back today and rechecked all measurements and all came back within 0.5 mm of each other so at the worst the center is off by 0.25mm so I left it as it was, your input is a greater relief.

Steve

[dozer]

I dont think its an issue...
0.25mm is "nothing".

[1972_911T]

So Dozer whats the deal with the measurement you got a G50 conversion planned?

[dozer]

Yes, but I'm going for the coilover solution.
Instead of cutting the torsion bar all the way, I'll try to leave as much of the tube intact , losing as little rigidity as possible .
Im using a 1988 G-50, so your measurements gives me an idea of how much i have to cut away.

EDIT: Of course i do have to reinforce.....

[dozer]

How things going Steve?
Give us an update if you got time

Thanx
Dozer

[1972_911T]

Ive got the bar fully welded in now except for about a 1 inch run on the front of each side that I need to cut a hole in the front of the seat to get to. So before I started cutting out more metal I wanted to put some back so started to put the new rear seat section in.



As the floor section and torsion tube were cut from the same car I used the support brackets to line up the new floor section along the original cut.





And now im just in the middle of welding in the new rear seat section. I may also look at ways to strengthen around where the torsion tube supports join this panel as they join close to the seam of the old and new panels.

[eimkeith]

Hey - we're building the same car!

Question, though - how did you go about sliding the insert inside the torsion bar tube across the seam? There are no pictures of that, did you abandon the idea? I don't think it is necessary for strength, perhaps just alignment?

Curious before I do my own car.

[1972_911T]

I still used the insert mainly for alignment rather than strength but it will help for that. I cut the insert about 4" long and slid it inside the remainder of the old tube then when the new tube was inplace I pushed them from inside the old part into the new with about a 2" overlap. This helped me loads as im doing this single handed so the tube was held perfectly in place for me to weld.

[racergt3]

Wow! Great work, but wouldn't it be easier if you just get Patrick Motorsport's "Shortened bell housing coversion kit for the G50". Sorry about sounding like a smart ass.

George

[1972_911T]

Im known for many things but never for taking the easy option
That was my initial idea however Im using A 3.2 engine with A DME that runs from the flywheel. The shortened bell housing kits I belive use a turbo flywheel and clutch which obviously wont work with the 3.2 DME. I think patrick did try to make a 3.2 kit but from what I heard he couldnt get it to work and it caused a lot of running problems with the engine. I tried to cantact him to see if the issue had been resolved but never got a responce.

The other issue with the shortend bell housing is moving back the engine. I belive Dean did did this and said it didnt affect handling however im still not too keen on this idea.

[eimkeith]

interested in making another set of those inserts?

[1972_911T]

Wouldnt be worth it to you for me to make them as im in the UK postage would be more than there worth. If you can tackle fitting the tube then inserts are easy. What I did is take the off cut from the old tube, slit it down the centre with an angle grinder then keep taking a bit of material off and clamping it in a vice untill it fitted inside another pice of old tube nice and tightly. Then holding it in the section of old tube I welded it down the seam gradually pusshing more out as I welded, then just ground down the weld it was a perfect fit.

Steve

[eimkeith]

ha! lowbuck lathework! I love it. Thanks.

[1972_911T]

Yeah the laith was the initial idea but as I cut the tube I noticed in places its not perfectly round as it as indentations in it etc. So going to the expence of laithe work seemed a bit ott.

[dozer]

Hi Steve.
Sendt you a mail aswell, didn't know where you would look first, so......
Here's the mesurements.
A= 56mm (center on bolt)
B= 33mm (aprox. the darn "thingy" isn't straight :-)
C= 94mm

Hope this helps:-)

[adomakin]

nice work steve, the flexibility you have by cutting out the floor is great. Im thinking of cutting out my rear bulkhead when I install my engine, just for the mountains of access it gives. if i make it removable then it becomes nice and easy to sort out any annoying sender leaks etc

[sewell94]

i am curious, what suspension arms and torsion bars are you using. looks like your using the same arms as you used with the 915 tranny. I considered doing somehting similiar with my 930 but was told that if i did that that i would have to use the g50 arms with g50 bars?? Looks liek your using the earlier arms with g50 bars. Also how many hrs do u think u have in this project?? thanks for any info

[1972_911T]

with the G50 torsion tube you need to use G50 torsion bars because the splines are different you also will have to use G50 spring plates because the bars stick further out of the torsion tube and the G50 spring plates accomodate for this. As far as im aware I can use the earlier swing arms.

So far I reckon fitting the tube ive spent about 30 hours including stripping the old suspension down.

Steve

[1972_911T]

Andy how do you intend to attach the fire wall to make it removable? I think with all your power you should be considering this conversion as well, what trans are you intending to use when the engine rebuild is done?