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Discussion Starter #1
In my ongoing challenge to design an adapter plate for my '66 Datsun,
without stripping the ICE down to a bare block, I hit upon an idea
and would like some feedback.

Background:
The stock Datsun engine (J13) is installed with a factory adapter
plate (no common bolts between the engine and transmission.) I think
I can use this thick plate (3/16th inch) as the basis for my motor
adapter. The machine shops I've contacted about mapping the crank
center to the transmission locating holes want to have the crank out
of the block (they want the block with main caps and the factory
plate.) I want to sell a J13 with 92k miles original miles on it when
I'm done with it.

This factory plate has a hole in the center for the crank flange to
fit through, however, this is not a precision hole. Its off center by
around 0.01 inch. I need an accurate centering hole for a motor
spacer ring. I'm not comfortable getting this information off the
face of the transaxle because the input shaft has a certain amount of
"wiggle room."

My idea:
I take a piece of metal stock and drill a couple of holes in it to
pick up 2 of the crank flange bolt holes. This piece extends past the
crank flange so I can attach some type of hard point to it that can
score the stock (steel) adapter plate. I pull the spark plugs and
give the front of the crank 2 full turns and observe the line I've
scribed. If its a single line the tool stayed true and I have a
perfectly centered circle. If its a double line my tool didn't stay
true and I need to pick a new location, modify the scribing tool as
needed, and try again.

With a perfectly centered scribed circle a machine shop should be
able to bore a hole, of the diameter needed for a motor centering
ring, that is true to the scribed circle. (Right?) I'm less clear on
what to use for the point and exactly how I would build the part that
would hold it against the motor plate (spring loaded would be nice.)

Input on any (or every) part of my idea is welcome :)

Thanx
Paul "neon" Gooch


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Discussion Starter #2
Paul wrote:


> My idea:
> I take a piece of metal stock and drill a couple of holes in it to
> pick up 2 of the crank flange bolt holes.

> Input on any (or every) part of my idea is welcome :)

It sounds elegant in its simplicity to me!

I think that having two scribing points is simply going to test the
accuracy with which you've made the two 'arms' of your scribing plate
equal in length. It seems that if you have a single scribing point you
are guaranteed to get a single, centered circle unless the crank flange
itself wanders around.

For scribing, you could use a compass point or similar securely fastened
to the scribing plate. You could 'paint' the plate with machinist's
(Prussian?) blue or something similar to make the scribe mark more
visible and to eliminate the need to "deeply" score the plate.

This seems like a technique that would be usable for any vehicle: just
take a piece of plate and cut a hole large enough for the crank flange
to poke through, then mark and drill the bolt/alignement dowel holes so
it can bolt to the engine block, then scribe a circle to establish the
center.

Cheers,

Roger.

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Discussion Starter #3
just get a little pieces of sheet metal. Have some
holes drilled out to match all the bolt holes on the
tranny. (You may need to get a dowel for the tranny
shaft). Then glue them all together.

Supposedly there are shops all over country where you
just take your tranny and they'll draw a picture where
all the holes are within .001"...

but I wouldn't know


--- Roger Stockton <[email protected]xx> wrote:

> Paul wrote:
>
>
> > My idea:
> > I take a piece of metal stock and drill a couple
> of holes in it to
> > pick up 2 of the crank flange bolt holes.
>
> > Input on any (or every) part of my idea is welcome
> :)
>
> It sounds elegant in its simplicity to me!
>
> I think that having two scribing points is simply
> going to test the
> accuracy with which you've made the two 'arms' of
> your scribing plate
> equal in length. It seems that if you have a single
> scribing point you
> are guaranteed to get a single, centered circle
> unless the crank flange
> itself wanders around.
>
> For scribing, you could use a compass point or
> similar securely fastened
> to the scribing plate. You could 'paint' the plate
> with machinist's
> (Prussian?) blue or something similar to make the
> scribe mark more
> visible and to eliminate the need to "deeply" score
> the plate.
>
> This seems like a technique that would be usable for
> any vehicle: just
> take a piece of plate and cut a hole large enough
> for the crank flange
> to poke through, then mark and drill the
> bolt/alignement dowel holes so
> it can bolt to the engine block, then scribe a
> circle to establish the
> center.
>
> Cheers,
>
> Roger.
>
> _______________________________________________
> For subscription options, see
> http://lists.sjsu.edu/mailman/listinfo/ev
>

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Discussion Starter #4
Apparently I wasn't clear (its good to know when that happens :)

I was only talking about a single scribing point. 2 turns of the
crank should make a single circle, if the point is nice and stable.
If not, then pick another circle, stabilize the scribe tip (whatever
changes required) and do it again.

I'm not sure how to attach a scribe securely and still be able to
adjust it in or out as required to make a nice clean line.

Paul Gooch

Roger Stockton wrote:

> I think that having two scribing points is simply going to test the
> accuracy with which you've made the two 'arms' of your scribing plate
> equal in length. It seems that if you have a single scribing point
> you
> are guaranteed to get a single, centered circle unless the crank
> flange
> itself wanders around.

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Discussion Starter #5
Paul wrote:

> Apparently I wasn't clear (its good to know when that happens :)

Or, I didn't read closely enough...

> I was only talking about a single scribing point. 2 turns of the
> crank should make a single circle, if the point is nice and stable.
> If not, then pick another circle, stabilize the scribe tip (whatever
> changes required) and do it again.

Just as one scribing point is better than 2, I think a single turn may
be better than 2 (or more). If the scribing point has wandered, then
the two ends of the line won't meet to form a closed circle and/or the
"circle" will be visibly non-circular.

I think the possible drawback to multiple turns is that the first circle
may be perfect, but the scribe shifts during a subsequent turn which
either result in having to repeat the process or in a line that is wider
than it needed to be and may wary a little from perfectly circular.

How well centered do you want this circle to be? I suspect that you
want to scribe the finest (thinnest) line possible; if the line is
0.020" wide due to a blunt scribing point or multiple turns of the
crank, then the machinist likely can't cut a hole centered closer than
0.020" line width.

> I'm not sure how to attach a scribe securely and still be able to
> adjust it in or out as required to make a nice clean line.

The simplest scribe arrangment might be to simply bend over a sharp
corner of the scribe plate so that the spring pressure of the scribe
plate itself holds the corner against the surface to scribe. A possible
problem is that the corner might wear if too many turns are made and so
result in a wider line or even a radius that increases or decreases
slightly from start to end.

Another might be to drive a sharp screw through the scribing plate so
that its point scribes the line (drywall screws are nice and sharp).
"Tighten" the screw until the scribing plate (which might even be a
length of wood) flexes enough to hold the point tightly enough against
the surface to scribe.

Cheers,

Roger.


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Discussion Starter #6
Sounds like it would work. A magnetic post might hold on strong enough to work. I bought a Harbor Freight one I like.

----- Original Message ----
From: Paul <[email protected]>
To: Electric Vehicle Discussion List <[email protected]>
Sent: Thursday, August 23, 2007 3:25:21 PM
Subject: Re: [EVDL] Designing adapter plate questions


Apparently I wasn't clear (its good to know when that happens :)

I was only talking about a single scribing point. 2 turns of the crank should make a single circle, if the point is nice and stable. If not, then pick another circle, stabilize the scribe tip (whatever changes required) and do it again.

I'm not sure how to attach a scribe securely and still be able to adjust it in or out as required to make a nice clean line.



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Discussion Starter #7
Probably just put a scriber in a mag-base, the kind with a fine
adjustment knob.

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Discussion Starter #8
How does one determine the thickness and material (? aluminum, ?? of what
type) one should use for the adapter plate?



Thank you,

Dave Delman
1981 Electric DeLorean Project



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Discussion Starter #9
Using the time honored WAG method(wild ass guess)?

Seriously I needed more setback to handle the shaft adapter than the
thickness of the plate could reasonably provide. So I made it thick
enough to hold the threads i wanted and thin enough to waterjet and
afford. I fine tuned this to make my bell dpth standard and the plate
thickness standard. I felt that keeping it thicker than the tranny
casting meant it was strong enough.

*Adapter plate http://www.jfs-tech.com/cvevs/dsc00037.jpg
motor bell http://www.jfs-tech.com/cvevs/dsc00056.jpg

misc other pictures http://www.jfs-tech.com/cvevs/




*Please Don't laugh at the strange profile. I thought I was gonna need
additional mounts to frame and the flat top was gonna hold a shelf for
the battery box or controller. I decided I didn't want to subject them
to the road shocks.

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