My '86 GTI build

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walterclark
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Re: My '86 GTI build

Post by walterclark »

I had a further thought yesterday...just before the new bearing arrived. Maybe the hub is also damaged. I cant find anything wrong with it other than it presses out of bearings without breaking them apart. I even assembled in into the old carrier and bearing, mounted a new wheel and checked for wobble at the wheels rim...under .010". But, I decided to go ahead and get another one and wait another day.

In the meantime I had a thought...probably just being paranoid and having too much time on my hands before I need to use the car. I have been pressing the new bearings into the carrier from the inside out, rather than from the outside in as described in the shop manual. The reason is simple. The carrier has a stable flat round face around the bearing carrier bore on the outside whereas the inside has all manner of arms and tabs projecting out from around the back side of the bore in the carrier forging. It requires a special cylindrical adapter that mates to the back side face of the bearing bore to have a stable surface against which to press a bearing in from the outside direction and I dont have one. So, I have been just pressing in the bearings from the back side. The bearings themselves appear to be symmetrical, except for a small taper on one edge of the bearing outer surface - which would normally go into the bore first and help keep the bearing from cocking, hanging up and then galling the carrier bore. But I dont see where it would matter if this taper ends up on the inside or outside of the assembly. The assembly calls for one circlip to be installed in a bore groove opposite the side into which the bearing is being inserted (by the manual this would be the inside groove, but by my approach it is the outside groove), then the bearing is pressed in until it contacts the circlip. Once in place the second circlip is inserted into the opposite groove. There is near-as-it-matters zero space from the second circlip to the bearing if properly pressed home. The only risk to my doing it without the special tool is that the tool is machined so that it not only supports the carrier but the pre-installed circlip as well so without it I could possibly push a bearing too far and damage the circlip, its groove or the bearing. I can easily feel the moment the bearing contacts the circlip in the pump handle of the shop press and have never damaged anything. I know a number of our hillclimbers and forum contributors replace these bearings as part of what they do for a living, so I ask... Is there a reason why my approach is simply wrong?


While waiting on the hub to arrive (today) I decided to try to solve the little issue of why the digital output of my 14point7 wideband controller would not talk to the module I added to the Megasquirt for this purpose. While the analog WB output works OK, the digital data stream offers faster response, higher accuracy and wider Lambda range reporting.

For those who speak Megasquirt, I added a TinyIOx module to the MS box. The 14point7 controller has a digital comm bus called a I2C bus. This is a 2 wire bus invented mainly to allow 2 or more controllers that share a module to communicate with one another. The TinyIOx has this I2C bus so it can talk with the 14point7 and it has a CAN bus so it can talk with the MS3. The TinyIOx also has 9 analog to digital converters, 6 timer channels and 2 spare digital IO ports as well which opens up a number of additional monitor and control options, but mostly I bought it for the I2C-CAN function.

In my configuration the 14point7 controller is in its own box and until now needed to talk to the TinyIOx in the MS box over about 3' of cable. Even with the recommended wiring and shielding, I was not able to get more than sporadic data across the I2C bus this way. I went back to using the analog output of the 14point7 for wideband data into the MS3.

Yesterday I decided to move the TinyIOx into the same box and the 14point7, then use the CAN bus - which is designed for hostile environments in a car - as the inter-box communications. If done right, such as going with a connector on the 14point7 box with lots of extra pins, I can more easily use some of those extra ports on the TinyIOx...I have just about used up all the spare pins on the Megasquirt box that could be used for inputs.

I decided to go with a D-sub 25 pin connection. D-sub connectors are used on the Megasquirt, and while they are not water tight like most automotive connectors, my boxes are inside the car on the dashboard, so not really at much risk. The present implementation with the TinyIOx moved requires 6 pins for the wideband cable, 4 pins for incoming 12V power and ground (doubled up - each pin is rated at 5A and even with the WB heater full on it should be less than that, but I didnt want to push it), 3 pins for the CAN and 2 for the WB analog output. So I still have 10 unused pins for expansion. Going with a connector on the 14point7 box also solves another problem I had with trying to remove the 14point7 box. The original "kit" has the wideband cable hardwired to the module in the box with the only connector up under the hood where it plugs into the Bosch WB connector. I had added inline connectors for power, analog output and the I2C bus, but the box was still hardwired to the car and the multiple connectors were messy and potentially a source of problems since they were all friction fit plugs and not actually locking.

Yesterday I got the TinyIOx moved into the 14point7 box, the boxes new 25 pin panel connector installed and everything re-wired internally. Today I work on getting the WB, power, CAN and analog wires into the mating connector and the new CAN cable wired into the designated CAN pins of the MS.
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dsldubn
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Re: My '86 GTI build

Post by dsldubn »

I don't think your method for bearing install is an issue. It should be ok as long as the race is bottomed to the clip. I've beat them in with a hammer and they still worked, not recommended hehe

They are pretty much symmetrical, but one side may have a different seal or mating surface. That might be the only thing that matters, having the right side toward the hub, but I can't remember without looking at one
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sdwarf36
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Re: My '86 GTI build

Post by sdwarf36 »

If VW tells you to put it a certain way, it's because they just planned on you using special tool #324456-8A to prop it up on the press.
Translating road racing to hillclimbing:
Proper tire selection== nothing hooks up on moss or wet leaves.
Staying on the racing line==anything paved is considered good.
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Super1303
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Re: My '86 GTI build

Post by Super1303 »

What your doing seems fine. Most shops don't pay this much attention, or an eighth of that, to the details.
And it seems there's no reason why you can't put a small taper on the other side of the bearing if that bothers you because of the reversed installation.
This is one bearing carrier I have not had to deal with tho, the two cir-clip variety, I just know on my old golf, as Jason stated, the one seal had a hum ring molded into it.
That would be the only difference if that is how your car gets it's wheel speed information from other than that... It's all good.
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walterclark
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Re: My '86 GTI build

Post by walterclark »

Thanks everyone. Embiggined by everyones comments I did it my way. With all new parts on that corner I finally have a wheel that doesnt wobble like a Weeble. (Fun with made-up words Wednesday).

The new quickener has eliminated the glitches I felt in the steering.

The car finally feels like it did before I ran out of talent at Ascutney last fall! :D

Reloating and rewiring of the wide band controller comm stuff got finished this AM and that even seems to work as it should...at least for one trip down and up the driveway.

By the way, the big winter project - the changover to the 02A and replacement of the pedal cluster and stock brake master cylinder - seems to be working just fine too. The stock cable shifter, with the replacement of one worn part, feels pretty decent and I really like the "up high" location of the shift knob. I can almost forgive the really long stock throw (for now).
Last edited by walterclark on Sat Apr 25, 2015 6:40 am, edited 1 time in total.
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Super1303
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Re: My '86 GTI build

Post by Super1303 »

It's mint how just raising the shiftier doubles the bad-ass.
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walterclark
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Re: My '86 GTI build

Post by walterclark »

Last (I think) of the replacement parts to fix issues from my spin arrived in the mail from merry olde England. Ordered in January...

Image

19mm ball joint extenders. Machined from EN24T - similar to 4340. These lower the outer end of the control arms (on an A2 the only suspension control arms are on the front lower) by 100mm to compensate for lowering the chassis from stock to correct camber curves and roll centers.

With these installed I can do the corner weighting and final front end alignment and the car is ready for Ascutney!

BTW, just to be completely anal about stuff I went thru a wheel bearing I removed some time back and checked dimensions and parts. The inside and outside bearing parts (races, carriers, balls, double seals, etc.) are identical dimensionally and where part numbers were embossed, the same. One of the old bearings even had identical tapers on both outside edges of the outer ring.
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sdwarf36
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Re: My '86 GTI build

Post by sdwarf36 »

You only need two-but I suppose having 35 spares isn't a bad thing. :lol:
Translating road racing to hillclimbing:
Proper tire selection== nothing hooks up on moss or wet leaves.
Staying on the racing line==anything paved is considered good.
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walterclark
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Re: My '86 GTI build

Post by walterclark »

Of course that was a pic from the guys web site... For what I paid for two, it seems like I should have received all of those.
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walterclark
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Re: My '86 GTI build

Post by walterclark »

OK, so I found one more thing to worry about...

I started reading about various DIY short shift tricks for the 02A shifter and stumbled across a few posts of people suffering failed cable ends, in particular the Front-Rear cable and the end on the transmission.

Here is mine right now...
Image

Kind of rusted in addition to being mostly 25 year old exposed plastic (the plastic bit seemed to the cause of failures in general). Probably OK for a daily driver with no drama involved, maybe not so much so for a racing car with an adrenalin charged driver moving the stick.

It looks like you can buy replacement cables...but they are just stupid expensive. Anyway the better solution seems to be to cut off the failing end and clamp it into one of these:

Image

Not really cheap, but better than the alternatives, and it certainly appears to be more than up to the task. So I have one of those (and one for the side-side cable as well) on the way.
The older I get the better I was.
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