Northstar 6 Speed (Page 5/20)
Zac88GT OCT 18, 09:50 PM
As far as axles go i have decided to try the press fit sleeve method first. After some calculations in another thread i found out that interference fits can actually transmit a substatial amount of torque. Press fits are designated on a scale of FN1-FN5 where 1 is a light press fit and 5 is heavy. I had machined the axle ends to give a .005" interference with the sleeve. After looking at the specifications for an FN5 fit, a maximum interference of .0035" for that shaft diameter, i decided to reduce the interference to match that. The calculations said that it would take ~40 tons to press the axles together but it only took about 12 . Since it only took 12 tons to press together i'm a little worried about the amount of torque that it will be able to transmit. With 40 tons of force to put together it would be able to transmit about 3700 ft lbs of torque. If the press fit doesn't hold the worst that will happen is the axles will spin inside the sleeve, this might spin weld them internally or it might not. If they dont weld themselves after spinning then i will . The original getrag passenger side axle is long enough that both new shafts can be made out of this one piece and the diameter is sufficient enough to re-machine splines on for the cobalt inner cv tripot. I found a place locally that can machine the splines for a reasonable price. I will be cutting the passenger. side getrag axle into two pieces and haveing them machine the new splines on to the ends so i will have a spare set of axles that are solid. The solid one piece axles will only be used if the pressed sleeve and welded pressed sleeve method fails. I want to try the sleeve methods so that other people can put axles together cheaply and because i really just want to see if it works. On to some specs now.



The passenger side axle will be the longer of the two with a total length of 16 5/16"
The distance from the outer edge of the c clip groove (fiero side) to the start of the splines or face of the tripot bearing (cobalt side) is 13 7/8"


The driver side axle is 12 7/16 total length
The distance from the outer edge of the c clip groove (fiero side) to the start of the splines or face of the tripot bearing (cobalt side) is 10"

I have also ordered the clutch line and bleader piece for the hydraulic TOB. The clutch line and bleader are not available seperately and must be purchased as an entire master cylinder assembly which makes it rather pricey. The assembly comes with the master cylinder, clutch line, bleader, resevoir and cap and costs ~$180 cdn. Hopefully i'll be able to make some more progress soon. I have to re-do the 3d model for my flywheel adapter in solid works because master cam isn't reading the inventor file for some reason

edit: I own page 2

[This message has been edited by Zac88GT (edited 10-18-2007).]

Zac88GT OCT 24, 10:04 AM
Bump just to keep near the top. I'll have more updates soon. My solid one piece shafts are at the machine shop now getting resplined. On a side note a couple of my friends and I are starting to take on an interesting northstar project. Paul has an 89 Lotus Esprit turbo that we're going to put a northstar into and a corvette power steering rack. We're not sure what tranny we're going to use, we have the UN1 tranny from the lotus that we just rebuilt and we also have a G64 porche tranny that we modded for 2wd. The G64 trans has a pretty sexy controllable limited slip diff.

[This message has been edited by Zac88GT (edited 10-24-2007).]

gascarracer OCT 24, 06:30 PM
Great information, great thread. This is very interesting.

Please take the next comment in the light I am giving it. Just information to be considered.

I do not think welding a clutch up is a good idea. Welding bulds up stresses that need to be relieved. Balancing.

I think you are asking for trouble. I have seen pictures of the aftermath of clutch explosions. Think about where the clutch is located.

This is the last you whill hear on this from me. I feel I would be amiss if I didn't at least mention it.

------------------
Ernie

1988 Silver GT
One owner 47000 miles.
Soon to be a 3.4 DOHC powered.

Zac88GT OCT 24, 08:35 PM

quote
Originally posted by gascarracer:
Great information, great thread. This is very interesting.
Please take the next comment in the light I am giving it. Just information to be considered.
I do not think welding a clutch up is a good idea. Welding bulds up stresses that need to be relieved. Balancing.
I think you are asking for trouble. I have seen pictures of the aftermath of clutch explosions. Think about where the clutch is located.
This is the last you whill hear on this from me. I feel I would be amiss if I didn't at least mention it.



Point duelly noted, opinion remains the same.
SPRING GUY OCT 26, 12:37 AM
Zac, Your car just keeps gettin better and better, nice work!
Zac88GT OCT 31, 12:38 AM
Today i got my axles back from the machine shop and picked up the clutch master cylinder assembly that i ordered in. The axles turned out beautifully and it only cost $190 to get them both resplined. I wanted to buy just the bleader and hydraulic clutch hose for the G6 transmission but they only sell the entire assembly so i had to pay $200 for that. It's a very interesting assembly though, lots of snap together connections and the surprising thing is they ship the assembly already full of fluid!




Next step will be to assemble the axles with the sleeved shafts and hurry up and get this flywheel adapter underway. We're trying to use some cool new features with mastercamX so it's taking a little longer to set it up.
Joseph Upson OCT 31, 05:41 AM
Nice work, Moser does resplining at $110 a pair for future reference. When having axles modified or made similar to the original axles by a machine shop, be sure to give instructions and measurements as if the individuals doing the work are complete and total idiots short of needing connect the dots instructions; Case in point, rather than match the snap ring groove dimensions to the original for the outboard joint, they made the groove wider and deeper, on the surface it didn't seem like a big deal. Unfortunately I didn't give it enough thought, it turns out aside from the snap ring groove being moved inward further than what I intended shortening the axle an additional 1/4", the increased depth of the groove allowed the snap ring to move from its centric position to eccentric after the joint was installed, in other words, the joint is now permanently snapped onto the axle. So be aware of this and make sure the copied groove is as close to exactly like the original as you can get it.

I still managed to get it to work but it's not perfect.
Joseph Upson OCT 31, 05:51 AM
Also what precautions are you planning to take with the hydraulics? I'm not sure how much volume is necessary to disengage the 6spd clutch so I loosened the mastercylinder retaining nuts to allow it to sit nearly a 1/4" away from the firewall to reduce the amount of pushrod travel into the cylinder at full pedal travel, amazingly the amount of travel left was still enough to disengage the clutch so now I'm concerned that applying the full volume of the stock clutch mastercylinder might cause a problem. I'm using the OE 6 spd assembly, the disc hub is not as thick as the aftermarket/earlier sprung hubs being used so my fear is of the possibility of over extending the roller end of the throwout bearing in the event there is no locking mechanism preventing that from happening instead of hub interference.
Alex4mula OCT 31, 08:06 AM

quote
Originally posted by Joseph Upson:

Also what precautions are you planning to take with the hydraulics? I'm not sure how much volume is necessary to disengage the 6spd clutch so I loosened the mastercylinder retaining nuts to allow it to sit nearly a 1/4" away from the firewall to reduce the amount of pushrod travel into the cylinder at full pedal travel, amazingly the amount of travel left was still enough to disengage the clutch so now I'm concerned that applying the full volume of the stock clutch mastercylinder might cause a problem. I'm using the OE 6 spd assembly, the disc hub is not as thick as the aftermarket/earlier sprung hubs being used so my fear is of the possibility of over extending the roller end of the throwout bearing in the event there is no locking mechanism preventing that from happening instead of hub interference.



My setup has no provision for this but the clutch releases very high. I have an adjustable banjo so I need to cut some slack there as I prefer a lower release. I guess maybe I'm used to the almost close to the floor of a worn normal getrag/clutch setup
Zac88GT OCT 31, 09:31 AM
After shipping both ways plus duty and any other crap it would have been more expensive to have them machined by moser. The place i took them to was really nice cause it was local and they have a great rep. They do all the narrowed ford 9" rear ends around here and know what they're doing. They didn't need any drawings or details, only an example spline and the bearing that it fits into. I haven't thought to much about the volume of clutch fluid being moved because i haven't had a chance to get the tranny plugged into the car and see what happens. Once i get the hydraulic hose adapted then i'll do that, but i'm thinking to limit the pedal travel i'll either take out the master and make the banjo adjustable or just weld a block under the clutch pedal. Although really crude i like the block idea best because it allows the pedal to have positive stops on both sides and it keeps the pedal at the upper end of it's travel region. I think if you used the banjo bolt, depending on how much adjustment is required, there would be the possibility of bottoming out the master cylinder.