Auto-conversion adapter plate

[Ernest Christley]

Well, I sold my big, custom-made bellhousing to another builder that
wanted to get that radial look out of a rotary engine. That 21 pound
chunk of aluminum just wasn't going to go nicely into the front of my
Delta, so it's all for the best.

But now I'm in somewhat of a lurch. I need to build an adapter plate to
match my PSRU up to my engine. The Mazda 13B rotary is nice in that the
engine comes apart like loaf bread (after you remove the 17 large
tension bolts), so I have a nice template to make the housing from so
that I could just match drill the bolt holes. What I can't figure out
is how get the alignment correct. I can drill a hole in a plate of
aluminum for the PSRU, but how can I then hold that hole concentric to
the engine's output shaft while I do the match drilling? Alignment is
critical, as any offset will vibrate my teeth out and will eventually
destroy the coupling.

Any ideas would be greatly appreciated, as I think I'm going to be down
to spending money at the machine shop for this one.

--
This is by far the hardest lesson about freedom. It goes against
instinct, and morality, to just sit back and watch people make
mistakes. We want to help them, which means control them and their
decisions, but in doing so we actually hurt them (and ourselves)."

[LCT Paintball]

> is how get the alignment correct. I can drill a hole in a plate of
> aluminum for the PSRU, but how can I then hold that hole concentric to the
> engine's output shaft while I do the match drilling? Alignment is
> critical, as any offset will vibrate my teeth out and will eventually
> destroy the coupling.
>
> Any ideas would be greatly appreciated, as I think I'm going to be down to
> spending money at the machine shop for this one.

Excuse my ignorance, but are you drilling clearance holes for the bolts?
If so, I would drill the hole for the output shaft first. Then, I would put
transfer screws into the motor to mark the bolt holes.

[Dave S]

Just FYI...

Tracy Crook's PSRU adapter plate does not use the tension bolts to
attach to his rotary.. He uses the seven perimeter bolt holes on the
outside margin of the rear end plate. I dont recall which PSRU you are
using, but I am assuming its not designed for the mazda.

Is there any reason that the PSRU you are using cant be adapted in this
manner? By using the Tension bolt holes, you are placing the
flywheel/gear ring and counterweight device on the PSRU side of the
plate.. thats what you are wanting to do?

I apologize if I missed this question and thread on FlyRotary for some
reason...

Dave

Ernest Christley wrote:
> Well, I sold my big, custom-made bellhousing to another builder that
> wanted to get that radial look out of a rotary engine. That 21 pound
> chunk of aluminum just wasn't going to go nicely into the front of my
> Delta, so it's all for the best.
>
> But now I'm in somewhat of a lurch. I need to build an adapter plate to
> match my PSRU up to my engine. The Mazda 13B rotary is nice in that the
> engine comes apart like loaf bread (after you remove the 17 large
> tension bolts), so I have a nice template to make the housing from so
> that I could just match drill the bolt holes. What I can't figure out
> is how get the alignment correct. I can drill a hole in a plate of
> aluminum for the PSRU, but how can I then hold that hole concentric to
> the engine's output shaft while I do the match drilling? Alignment is
> critical, as any offset will vibrate my teeth out and will eventually
> destroy the coupling.
>
> Any ideas would be greatly appreciated, as I think I'm going to be down
> to spending money at the machine shop for this one.
>

[Dave S]

Ok.. looked through the archives on FlyRotary and saw the thread..

And looked at your page pics..

http://ernest.isa-geek.org/Delta/Dyke_Engine.html

One of a kind PSRU... Interesting..

First unrelated suggestion, get rid of the manual tranny flywheel and
get an auto flywheel/ring gear and counterweight.. can be had for less
than 30 bucks on ebay and cuts the weight in half... unless you PLAN on
using a clutch/flywheel interface with its built in damper plate for
your powertrain..

Second, related suggestion... I would say go with the machine shop
suggestion. We are talking thousanths of an inch here and parts rotating
up to 7000 rpm. Let them look at the back end of this engine and have
them measure it and cut it on a CNC machine.

Or get a PSRU that is purpose made for the mazda...

Dave


Dave S wrote:

> Just FYI...
>
> Tracy Crook's PSRU adapter plate does not use the tension bolts to
> attach to his rotary.. He uses the seven perimeter bolt holes on the
> outside margin of the rear end plate. I dont recall which PSRU you are
> using, but I am assuming its not designed for the mazda.
>
> Is there any reason that the PSRU you are using cant be adapted in this
> manner? By using the Tension bolt holes, you are placing the
> flywheel/gear ring and counterweight device on the PSRU side of the
> plate.. thats what you are wanting to do?
>
> I apologize if I missed this question and thread on FlyRotary for some
> reason...
>
> Dave
>
> Ernest Christley wrote:
>
>> Well, I sold my big, custom-made bellhousing to another builder that
>> wanted to get that radial look out of a rotary engine. That 21 pound
>> chunk of aluminum just wasn't going to go nicely into the front of my
>> Delta, so it's all for the best.
>>
>> But now I'm in somewhat of a lurch. I need to build an adapter plate
>> to match my PSRU up to my engine. The Mazda 13B rotary is nice in
>> that the engine comes apart like loaf bread (after you remove the 17
>> large tension bolts), so I have a nice template to make the housing
>> from so that I could just match drill the bolt holes. What I can't
>> figure out is how get the alignment correct. I can drill a hole in a
>> plate of aluminum for the PSRU, but how can I then hold that hole
>> concentric to the engine's output shaft while I do the match
>> drilling? Alignment is critical, as any offset will vibrate my teeth
>> out and will eventually destroy the coupling.
>>
>> Any ideas would be greatly appreciated, as I think I'm going to be
>> down to spending money at the machine shop for this one.
>>
>