t56 mechanical speedo
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Author:  DarkBlood [ Fri Aug 15, 2014 10:14 pm ]
Post subject:  t56 mechanical speedo

Soooo... does anyone know anyone locally who does this conversion ? or anyone who has the tailhousing already modified for sale ?

Yes I know they have a Cable x unit which will convert the vss to mechanical output. But I would rather spend the money on something more reliable and accurate. Worst case I will machine it myself and buy all the parts. I was just wondering if anyone's done this conversion, or knows anyone who does them at a reasonable price.

Author:  6speedIROC [ Fri Aug 15, 2014 11:48 pm ]
Post subject:  Re: t56 mechanical speedo

I've done this conversion and did the machine work myself..maybe 15yrs ago now. I have some sketches with measurements if you want them. Did all the work on a bridgeport vertical mill and used T5 parts.
Its worked flawlessly.

You should check out as well.

Author:  6speedIROC [ Tue Aug 19, 2014 12:49 am ]
Post subject:  Re: t56 mechanical speedo

Here is the info I have. Parts are from a T5.
I originally machined the tailshaft housing and had a solid block welded in , then machined to suit the gears (per the attached drawing). Worked flawlessly for 1000's of km's in 1998. I didn't keep the electronic vss as I didn't need it on my tpi.
When I swapped the tpi out for the LT1, I had a bung for the vss welded back on at the shaft centerline, but further forward on the mainshaft. This worked well, but after a few years I would get a vss error code. Turns out the vss was right on the edge of the reluctor wheel, so I machined a recess in the reluctor wheel and re-positioned it so the vss tip was fully on the reluctor wheel.
You can also see the passenger side of the trans mount had to be welded up as well. After the machining there was a small opening deep in the slot.
I recall I had the parts welded at GG Alloy weld in Toronto back in the day.
For machining I think I used a 3/4" drill bit, then reamed to 0.800. Face the new welded in block to provide proper driven gear depth. The driven offset was referenced from the original vss hole centerline.

Good luck.

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Author:  6speedIROC [ Tue Aug 19, 2014 12:52 am ]
Post subject:  Re: t56 mechanical speedo


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Author:  DarkBlood [ Sat Aug 23, 2014 6:46 pm ]
Post subject:  Re: t56 mechanical speedo

ahh awesome. Yea that looks about right for the machining. I noticed it looked as though it would have needed a block of somesort welded up there to have enough material to machine out. Good job! and thank you. ill look further into this.

Author:  Daz [ Tue Aug 26, 2014 9:06 am ]
Post subject:  Re: t56 mechanical speedo

Just curious.

Wouldnt an aftermarket electronic speedometer work?

Author:  DarkBlood [ Wed Aug 27, 2014 5:44 pm ]
Post subject:  Re: t56 mechanical speedo

Aftermarket speedo will work daz. But my brand of guages doesnt offer an electric speedo. So if i go with a different brand speedo, that means I have to buy a whole new set of guages to match the 1 guage. : / and I like my guages. they is seksi.

Author:  Daz [ Wed Aug 27, 2014 10:33 pm ]
Post subject:  Re: t56 mechanical speedo

OK thanks

Author:  colin911 [ Tue Sep 09, 2014 10:39 pm ]
Post subject:  Re: t56 mechanical speedo

This guy isn't local by any stretch, but just passing it on:

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