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To all.
I agree that Bill Trails explanation is excellent.
I did a P-type flywheel about 10 years ago & another just a couple of
years ago & I still have the paper work that came with both those ring
gears purchased in Australia for approx 20 pounds Sterling.
Those instructions are very close to what Bill says.
"Aint" the internet great for this type of thing.
Just as an after thought, I am working on developing a WEB site with an
interactive "chat" capability so that anyone will be able to ask such
questions live & obtain an immediate response if I am sitting at my
computer.
Regards
Pip Bucknell
"Bill Traill" <bill@clovermachine.com>
Sent by: owner-mg-mmm@autox.team.net
09.06.2000 09:09
Please respond to "Bill Traill"
To: mg-mmm@autox.team.net
cc:
Subject: Ring gear shrink
Hi Brian,
About 20 years ago I machined off my J2's very warn ring gear and
shrunk on a new one. The gear was purchased thru Barry Walker
or Mike Dowley and had an instruction tag attached. I never throw
anything away so knew that tag was around somewhere...found it.
Unfortunately, I don't remember the inner diameter of the ring, but
the tag says to turn to 9.359". If luck is with us your PA gear may
be the same as the J2. replacement.
The J2 ring gear is about 10.55" OD with 83 teeth. The tag say's...
" "Shrunk-on" ring gear. Size C83, Turn 9.359, Chamfer 9/16".
The back say's... "To expand the gear before fitting DO NOT
EXCEED 290deg C. you may destroy the gear if you do." (Note:
there is no 9/16 chamfer on the gear, but it is 9/16" wide).
290 degC. is about 550 deg F. or within kitchen oven limits. I
calculate the ring will grow .028" in diameter at this temperature. I
will guess the flywheel should be .010 to .012" larger than the ring
at room temperature, but that is a guess.
When machining the flywheel, leave a radius on the inside corner
to avoid a stress riser and possible future crack. The ring gear
should have a chamfer to allow a small radius.
An old time automotive machinist heated mine by "eye" with an
acetylene torch and it went on with no problem.
Before heating make sure you have the gear in proper orientation
so it does not go on down side up! A pair of gloves and two pliars
to grab it would be helpfull too.
Have an accomplice ready with a hammer in case it jams, you
have about one second to tap it down.
It should slip on easily, and when it does, tap gently on the
flywheel a little to set up a vibration to help it seat evenly.
If it jams you will have to hack saw it partially thru and split it with a
cold chisel to remove.
For what it is worth:
I machined mine flush to the flywheel. My old time automotive
machinist friend who had apprenticed in the 1920's, said I should
have machined in another .03" and left a small wall a few
thousands high to keep the gear from being knocked off by the
bendix. Said he had seen a few do that in the old days. Naturally
the gear would have to slip over the wall when hot. I have not put
mine to the test, but I am not too worried.
Good luck
Bill Traill
Santa Clara, Calif.
Re:PA
> Finally, on a new flywheel ring gear installation what would be the
> correct measurement for shrink fit? Any comments appreciated. Thanks,
>
> Brian.
>
Bill
--=_alternative 0004691F4A2568F9_=
<br><font size=2 face="sans-serif">To all.</font>
<br><font size=2 face="sans-serif">I agree that Bill Trails explanation is
excellent.</font>
<br>
<br><font size=2 face="sans-serif">I did a P-type flywheel about 10 years ago
& another just a couple of years ago & I still have the paper work that
came with both those ring gears purchased in Australia for approx 20 pounds
Sterling.</font>
<br>
<br><font size=2 face="sans-serif">Those instructions are very close to what
Bill says.</font>
<br>
<br><font size=2 face="sans-serif">"Aint" the internet great for this
type of thing.</font>
<br>
<br><font size=2 face="sans-serif">Just as an after thought, I am working on
developing a WEB site with an interactive "chat" capability so that
anyone will be able to ask such questions live & obtain an immediate
response if I am sitting at my computer.</font>
<br>
<br><font size=2 face="sans-serif">Regards</font>
<br>
<br><font size=2 face="sans-serif">Pip Bucknell</font>
<br>
<br>
<br>
<br>
<br>
<table width=100%>
<tr valign=top>
<td>
<td><font size=1 face="sans-serif"><b>"Bill Traill"
<bill@clovermachine.com></b></font>
<br><font size=1 face="sans-serif">Sent by: owner-mg-mmm@autox.team.net</font>
<p><font size=1 face="sans-serif">09.06.2000 09:09</font>
<br><font size=1 face="sans-serif">Please respond to "Bill
Traill"</font>
<br>
<td><font size=1 face="Arial"> </font>
<br><font size=1 face="sans-serif"> To:
mg-mmm@autox.team.net</font>
<br><font size=1 face="sans-serif"> cc:
</font>
<br><font size=1 face="sans-serif"> Subject:
Ring gear shrink</font></table>
<br><font size=2><tt>Hi Brian,<br>
<br>
About 20 years ago I machined off my J2's very warn ring gear and <br>
shrunk on a new one. The gear was purchased thru Barry Walker <br>
or Mike Dowley and had an instruction tag attached. I never throw <br>
anything away so knew that tag was around somewhere...found it. <br>
Unfortunately, I don't remember the inner diameter of the ring, but <br>
the tag says to turn to 9.359". If luck is with us your PA gear may
<br>
be the same as the J2. replacement.<br>
<br>
The J2 ring gear is about 10.55" OD with 83 teeth. The tag say's... <br>
" "Shrunk-on" ring gear. Size C83, Turn 9.359, Chamfer
9/16".<br>
The back say's... "To expand the gear before fitting DO NOT <br>
EXCEED 290deg C. you may destroy the gear if you do." (Note: <br>
there is no 9/16 chamfer on the gear, but it is 9/16" wide).<br>
<br>
290 degC. is about 550 deg F. or within kitchen oven limits. I <br>
calculate the ring will grow .028" in diameter at this temperature.
I <br>
will guess the flywheel should be .010 to .012" larger than the ring <br>
at room temperature, but that is a guess.<br>
<br>
<br>
When machining the flywheel, leave a radius on the inside corner <br>
to avoid a stress riser and possible future crack. The ring gear <br>
should have a chamfer to allow a small radius. <br>
<br>
An old time automotive machinist heated mine by "eye" with an <br>
acetylene torch and it went on with no problem. <br>
<br>
Before heating make sure you have the gear in proper orientation <br>
so it does not go on down side up! A pair of gloves and two pliars <br>
to grab it would be helpfull too. <br>
<br>
Have an accomplice ready with a hammer in case it jams, you <br>
have about one second to tap it down.<br>
<br>
It should slip on easily, and when it does, tap gently on the <br>
flywheel a little to set up a vibration to help it seat evenly.<br>
<br>
If it jams you will have to hack saw it partially thru and split it with a <br>
cold chisel to remove.<br>
<br>
For what it is worth:<br>
I machined mine flush to the flywheel. My old time automotive <br>
machinist friend who had apprenticed in the 1920's, said I should <br>
have machined in another .03" and left a small wall a few <br>
thousands high to keep the gear from being knocked off by the <br>
bendix. Said he had seen a few do that in the old days. Naturally
<br>
the gear would have to slip over the wall when hot. I have not put <br>
mine to the test, but I am not too worried.<br>
<br>
Good luck<br>
<br>
Bill Traill<br>
Santa Clara, Calif. <br>
<br>
<br>
Re:PA <br>
> Finally, on a new flywheel ring gear installation what would be the<br>
> correct measurement for shrink fit? Any comments appreciated.
Thanks,<br>
> <br>
> Brian.<br>
> <br>
<br>
<br>
<br>
Bill<br>
<br>
</tt></font>
<br>
<br>
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