Widetrack for Birkin

[slomove]

I mentioned recently that I am rebuilding the front suspension of my Birkin with a (factory supplied) widetrack kit and KiwiBirkin asked if I could post a few build pictures for reference. Well, here it is.

Other people have done that before and I found it not too difficult so far.

 

 

The whole thing was not really planned but came as "one-leads-to-the-other" sequence of events. It started out at the Monterey historic racing event where Alaskossie almost lost a rear wheel. Actually the same day my Seven became a bit sick: the starter motor failed and the idle needed foot work to keep running. Not a good combination: on the way home I needed push starts at the gas stations and did not drink much to avoid peeing. Anyway, I made it home, although the exhaust became really loud, too.

 

At home I had the starter rebuilt and took the exhaust can off to stuff in more glass fiber, only to find the noise was from a large crack around the inlet tube. I welded that up and, looking for the reason I found the left motor mount damper element to be separated. I had bought new ones a while ago and replaced both of them.

 

While I was at it I went to check the wheel bearings (with Tom's fiasco in mind), and found one of the front bearings a bit wobbly. Took the hub off and found it to be corroded. Somehow water had gotten in. I removed both front bearing (a real pain in the arse) and ordered new bearings. Now that got me thinking since I had already many parts off to take the whole front end apart and replace other wear pieces, clean and repaint.

 

http://lh6.ggpht.com/_242PlvPtVpE/TIxPIxSOJJI/AAAAAAAACBk/cllnMvgppuc/s800/P1020404.JPG

 

 

That is how it looked like stripped to the bone and with new primer. But I found it not so easy to get the ball joints from (I believe) a 1975 Fiat 125 (my Birkin is a bit older) and looking around it just became obvious that the Birkin widetrack kit would solve a bunch of problems: new wear parts and wishbones, new rubber bushings, shielded new type ball joints (old ones were open and needed regular greasing), easy turnbuckle camber adjustment, and of course a few inches wider. Once that thought took hold I just had to convince myself that this is the best $1600 I would ever invest:

 

http://lh5.ggpht.com/_242PlvPtVpE/TIxPJ5opNPI/AAAAAAAACBo/j4Qlr9Snf6Y/s800/P1020405.JPG

 

These are the pieces: upper/lower wishbones, shock bracket, steering rack bracket, new ARB and (not in the pic) new uprights. Nice elliptical wishbone tubing and all very pretty TIG welds (I wish I could do that).

I had to keep the steering arms and the axle stubs. It will also work with the old shocks and springs, provided they have a rate of 300-350 lbs/"

 

http://lh5.ggpht.com/_242PlvPtVpE/TIxPLfyrV-I/AAAAAAAACBw/TFwnSAKl9k4/s800/P1020412.JPG

 

Test fit, looking good so far.

 

To be continued.

Edited September 12, 2010 by slomove

[slomove]

http://lh6.ggpht.com/_242PlvPtVpE/TIxPLxB-EEI/AAAAAAAACB0/riuNh0etlZI/s800/P1020416.JPG

 

Minor snag......

 

http://lh5.ggpht.com/_242PlvPtVpE/TIxPMmhCNxI/AAAAAAAACB4/iv3FFmcYhJU/s800/P1020420.JPG

 

The drill is your friend.

 

http://lh3.ggpht.com/_242PlvPtVpE/TIxPNl8M_sI/AAAAAAAACB8/-yhH2jYG8S4/s800/P1020423.JPG

 

Shock and hub installed, so far so good. However, the new shock mounts are M10, while my shocks have end rings for M12. I did not want to use a bushing and just reamed the holes to 12mm.

I also tapped the blind holes for the steering arms and brake mounting plate much deeper than delivered. The 8-9 mm depth in the aluminum casting did not give me much confidence for an M8 bolt.

FWIW, these are shorter steel steering arms than the stock aluminum arms (had them already before), to get quicker steering response.

The nub on top of the shock bracket is the new mounting point for the headlights.

 

http://lh3.ggpht.com/_242PlvPtVpE/TIxPOlyAEOI/AAAAAAAACCA/Z7RdyXzRc3o/s800/P1020425.JPG

 

Almost ready to roll again. Height, camber and toe-in roughly adjusted, all bolts torqued.

 

That is it for now. Next step is ARB and radiator install, re-route the brake plumbing, find a new home for the remote oil filter and related hoses, reinstall the coolant overflow and refill fluids.

 

Oh yes, I still need to fix the idle problem and see if the rebuilt starter really works.

Edited September 12, 2010 by slomove

[KiwiBirkin]

Thanks for posting Slomove looks like a interesting upgrade and I would be keen on your comments when you drive on the how you find it compared to you old setup.

[Kitcat]

In no particular order, I am impressed that you are doing all that outside on your drive way, at how stout the Birkin frame is, and that you have gotten so far on a single case of Miller Lite!

 

Mike

[pi7ot]

Gert.

Did you by any chance weigh all the new kit?

 

I was wondering how much weight this adds to the front of the car.

m

[slomove]

In no particular order, I am impressed that you are doing all that outside on your drive way, at how stout the Birkin frame is, and that you have gotten so far on a single case of Miller Lite!

 

Mike

 

:cheers:

 

- as for the driveway: I don't have a choice, the "garage" fits the Birkin like a glove. But then it is SoCal: No rain for the last 2 months or so and I can leave it sitting halfway outside.

 

- the frame is pretty stout. But in weighing shootout with other Sevens we found only minimal difference to similarly equipped Caterhams. Maybe 10-20 pounds more.

 

- The Miller box only holds the loose bolts and nuts. I don't drink that stuff. However, I did go through two boxes of Sam Adams.

[slomove]

Gert.

Did you by any chance weigh all the new kit?

 

I was wondering how much weight this adds to the front of the car.

m

 

Dang. Should have done that but forgot. I don't think the longer wishbones make for much of a difference and the steering rack bracket (the plate with the large holes) is maybe a pound or so. The major added component is the shock bracket that goes across. It is a welded box tube from sheet metal and just guessing from lifting it up it may be 3-4 pounds? Insignificant for me but for a pure racer it may be objectionable.

[Automoda]

Thanks for the pictures. I've been curious about this. I remember someone did this a while back and wrote about it on the Birkin email list. It'd be cool to dig that thread up and re-post it here.

 

Of course I sometimes want to just wait and buy a 2nd Birkin with IRS and wide track and LSD and the works... perhaps figure out a little turbo or supercharger... Someday....

 

 

 

You know it occurs to me that the leftover suspension parts could be useful to guys that happen to bend a piece while racing etc. Its not like we have junkyards for these cars ;o)

[slomove]

.....You know it occurs to me that the leftover suspension parts could be useful to guys that happen to bend a piece while racing etc.....

 

Well I have had a request from an owner in Australia who was willing to give me $250 for the old parts (wishbones and uprights with ball joints). But I have not heard from him after I wrote that the shipping was another $130-$200.

 

So, if somebody is interested, please let me know. Domestic shipping will surely be more sensible.

[slomove]

Another snag (self-inflicted) and the workaround.....

I tried to hook up the anti-roll-bar and found that my shortened steering arms will make the steering rack extensions collide with the ARB push-rods when turning hard:

http://lh6.ggpht.com/_242PlvPtVpE/TJGNZZOXeWI/AAAAAAAACC4/B1F1SHGhKFc/s800/P1020428.JPG

 

But... I did not like the flimsy aluminum clamps around the bar anyway. I guess they do the job, since I did not hear complaints from other drivers but I was looking for a cleaner solution.

 

http://lh3.ggpht.com/_242PlvPtVpE/TJGNaurLTZI/AAAAAAAACC8/4-jGRiywnd8/s1152/P1020433.JPG

 

I welded a stainless coupling nut into a stainless tube and ground conical as receiver for the push-rod ball joint. Then I slid the tube on the roll-bar and crimped it into a notch. I lost the adjustability but the wide-track roll-bar has anyway only minimal leverage. Should be good that way....

 

http://lh5.ggpht.com/_242PlvPtVpE/TJGNcx3Yn1I/AAAAAAAACDA/c3jtpTqA4_I/s1152/P1020435.JPG

 

To do that I tapped an M8 thread into the hex cap of the lower M12 shock mounting bolt as receiver for the lower ARB push-rod ball-joint.

Edited September 16, 2010 by slomove

[Dave W]

Slomove

 

I would try to find a lower rose joint with a larger 12mm I.D. and smaller threaded male end and just use a longer bolt and spacer on the shock. If you can not find the matching size, then you could use a female joint and install a two diameter stud with the correct threads on each end to connect to the bar.

Dave W

Edited September 16, 2010 by Dave W

[slomove]

That is a possibility but a 12mm ball joint would be quite bulky. The 8mm ball joints I am using now are the ones that came with the kit and well up to the task. The bolts themselves are 12.9 grade and very strong. Since the joint ball butts up against the receiver side, the bolt carries mainly a shear load (vs. bending).

 

Tapping a larger bolt with a smaller internal thread may be a bit unusual but it works actually very well, looks good and removes unnecessary hardware.

Edited September 16, 2010 by slomove

[nleroux7]

I do have the widetrack kit on my Birkin and I've almost done the exact same thing you did to the swaybar. Even with all the original Birkin parts the sway bar link was rubbing against the steering rack extension.

 

The flimsy bracket that Birkin provides with the sway bar for the wide track is really bad. It was moving and made a lot of noise.

 

Bolting the link at the end of the sway bar like you've done is the way to go !

[slomove]

I do have the widetrack kit on my Birkin and I've almost done the exact same thing you did to the swaybar.

 

Hah, great minds think alike :hurray:

[slomove]

Next step of the overhaul: brake calipers sandblasted, painted (high temp baked-on caliper paint) and re-built with new seals.

 

It did occur to me that painting calipers bright yellow is a really dumb idea with all the brake dust but at that point it was already too late.

 

I had also considered the Outlaw brakes but these VW GTI brakes work really well and they are only a little heavier. Running out of rebuild funds, too.

 

http://lh5.ggpht.com/_242PlvPtVpE/TJVn4BcDUYI/AAAAAAAACEA/er0ZX4nEqAE/s800/P1020436.JPG

Edited September 19, 2010 by slomove