>I have a series II as well. I have a 1725 with an electronic tach.
>Allthough I do not neccesarily agree that the mechanical is in any way
>superior "properly designed tach circuits are very accurate" , I would love
>to install the tach that looks correct for my car.
>
>Is the mod an extension to the oil pump shaft?
>If so please give us some details so we can make one too.
>
>
>Jarrid Gross
>SII EFI
Please do not judge me based on this modification.
What I did was make an extension of the drive key on the bottom of the
distributor shaft. (it would be too difficult to extend the oil pump shaft
as this would require dropping the sump & etc.)
I purchased a second hand housing with the cable drive in it, this is longer
than the standard housing. The drive gear which goes onto the shaft was
kindly provided by Tom W. This required an extension to meet with the top
of the oil pump shaft.
I took a standard distributor and removed the drive key and replaced this
with the drive key that has the tach gear drive. Then I modified the
original drive key to act as an extension. This involves machining the top
off it so that it is the correct length ( about 15mm, or 5/8", but you will
need to measure this yourself, because it needs to be just right) and then
cutting offset slots in it to accept the teeth from the drive key with the
tach gear. This extension then slides snugly onto the bottom of the
distributor shaft.
The final step is to machine the extension piece down to a smaller diameter
so that it doesn't interfere with the gear in the cable drive housing. This
involves placing it on a shaft and machining it into a cone shape. Narrow
on the end which mates with the drive key and thick at the end with the
mating to the oil pump shaft.
The last point to mention is that the pin which attaches the drive key to
the shaft needs to be shortened so that it doesn't foul the gear in the housing.
This work may seem complicated but after weeks of mulling it over in my
head, it was completed in one afternoon with a drill ( to do the turning ),
a hacksaw and a metal file.
| |
| |
| | distributor shaft
| |
_________
| |
| O | pin
|_________|
/ / / / / / / / /
/ / / / / / / / drive key gear
/ / / / / / / / /
| |
|_________|
/----||-----\ offset drive
/ || \
/ \ extension piece
|_________________| <---(distributor shaft ends about here)
||
|| offset drive which joins oil pump shaft
Another note is that putting the end of the series I or II oil pump on would
mean that everything would meet up but as mentioned by someone else a few
weeks back the number of teeth on this piece is wrong so that the
distributor won't rotate at the correct rate.
Also it is worth getting the tach reconditioned because if it seizes it
halts the cable and this can damage the drive keys. (nasty experience)
I hope all that helps
Anthony series II street sweeper ( it picks up little bits of fluff when you
drive it)
This archive was generated by hypermail 2b30 : Tue Sep 05 2000 - 09:25:36 CDT