Help!! I Can't Remove OS32 cooling head due to rounded hex bolt

[Paul Williams]

Hi chaps

After a rare unexpected engine cut this weekend I thought I would take a
closer look at the motor whilst I was rebuilding what is left of my
helicopter! I found there were built up burnt deposits on the piston head.

I tried to remove the cooling head from the OS 32 motor so that I can clean
this off.

One of the hex bolts on cooling head was stuck pretty tight and my attempts
to undo it has caused the hex bolt to become rounded. I can't get at the
bolt from the side because it is buried between the cooling fins. Anybody
got any ideas how to get the bolt out so I can remove the head??? Surely
this has happened to other people.

On another note, I've had this motor for 4 years or so and must have run it
for several hundred hours by now. I've never done any maintenance on it. How
long do these motors last? and should I be thinking of replacing any of the
internal components?? Are there any people out there that can overhaul these
motors???

Cheers for the help chaps

Paul Williams

[Marcin Romaszewicz]

There are a couple of things you can try. Sears sells screw extractor
bits for drills. They are designed so that they drill into the screw by
turning left then block completely, which will hopefully let you get the
screw out. I'm not sure if the make them small enough for those screws
though.

IIRC, my OS32-sx has no threads in the heatsink part of the head, only
in the engine body. If you carefully drill off the head of the bolt, you
should be able to get the heatsink off and then you'll be stuck with a
headless screw to take out. Since there is no longer pressure, it should
come out easily, if not, you can _GENTLY_ bend it over the side of
rounded needlenose pliers (make sure not to bend it where it goes into
the engine block). Once bent, you can use pliers to get it out. Before
doing this, however, make ABSOLUTELY sure there are no threads in the
heatsink.

-- Marcin

Paul Williams wrote:
> Hi chaps
>
> After a rare unexpected engine cut this weekend I thought I would take a
> closer look at the motor whilst I was rebuilding what is left of my
> helicopter! I found there were built up burnt deposits on the piston head.
>
> I tried to remove the cooling head from the OS 32 motor so that I can clean
> this off.
>
> One of the hex bolts on cooling head was stuck pretty tight and my attempts
> to undo it has caused the hex bolt to become rounded. I can't get at the
> bolt from the side because it is buried between the cooling fins. Anybody
> got any ideas how to get the bolt out so I can remove the head??? Surely
> this has happened to other people.
>
> On another note, I've had this motor for 4 years or so and must have run it
> for several hundred hours by now. I've never done any maintenance on it. How
> long do these motors last? and should I be thinking of replacing any of the
> internal components?? Are there any people out there that can overhaul these
> motors???
>
> Cheers for the help chaps
>
> Paul Williams
>
>

[Philip Martin]

If you have no socket left do as has been suggested and 'carefully' drill
off the bolt head to remove the engine head. But DON'T try bending the bolt
shank, you'll run the risk of buggering your engine. The tread is obviously
tight so warm the body up carefully and then remove the remaining stud. This
could be done by gripping the stud in a vice and rotating the engine block.
Be careful though, you don't want to damage the block, don't just unscrew it
but work it half a turn out and then a quarter turn in slowly. What your
trying to do is ease it out without damaging the existing thread!

Phil Martin.



---
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Checked by AVG anti-virus system (http://www.grisoft.com).
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[Paul Williams]

OK cheers

I'll try that.

I've also just noticed that the centre rotating shaft attached to the
cooling fan has a slight bit of play in it. It can be moved in and out
about half of 1 mm. Can't remember noticing that before. Could that be a
sign that the bearings are wearing down???

Paul


---
"Philip Martin" <philip.martin1@btinternet.com> wrote in message
news:b43f0j$1reaio$1@ID-129488.news.dfncis.de...
> If you have no socket left do as has been suggested and 'carefully' drill
> off the bolt head to remove the engine head. But DON'T try bending the
bolt
> shank, you'll run the risk of buggering your engine. The tread is
obviously
> tight so warm the body up carefully and then remove the remaining stud.
This
> could be done by gripping the stud in a vice and rotating the engine
block.
> Be careful though, you don't want to damage the block, don't just unscrew
it
> but work it half a turn out and then a quarter turn in slowly. What your
> trying to do is ease it out without damaging the existing thread!
>
> Phil Martin.
>
>
>
> ---
> Outgoing mail is certified Virus Free.
> Checked by AVG anti-virus system (http://www.grisoft.com).
> Version: 6.0.459 / Virus Database: 258 - Release Date: 26/02/2003
>
>

[Beav]

"Paul Williams" <paulswilliams@ntlworld.com> wrote in message
news:dtb9a.633$iE3.20@newsfep3-gui.server.ntli.net...
> OK cheers
>
> I'll try that.

Before you do, I think you should know that the carbon deposits on the
piston crown is perfectly normal and it's all but impossible NOT to get them
after a few tanks of juice have gone through the motor. It certainly doesn't
hurt and can in fact, help complression.

It's on the SIDES of the piston that deposits are problematic.
>
> I've also just noticed that the centre rotating shaft attached to the
> cooling fan has a slight bit of play in it. It can be moved in and out
> about half of 1 mm.

Did you fit the small thrust washer that comew with the motor before you
installed the fan/clutch? It's a black washer about 2mm this.

Can't remember noticing that before. Could that be a
> sign that the bearings are wearing down???

Nope. The bearing don't get "thinner" so play in that plane will be what
it's always been.

If it's not given you any problems before, it shouldn't now, so maybe you
don't need to strip the mtoro down after all.


--
Beav


Please note my E-mail address is "beavis dot original at ntlworld dot com"
(with the obvious changes)

Beavisland now lives at
www.beavisoriginal.co.uk

[Ed Smega]

Paul
If you have a dremel tool, use one of those very thin abrasive disks and
cut a slot in the bolt head then use a screw driver in the slot. I have
done this on any number of screws although never on an engine.
Ed



Paul Williams wrote:

>
>One of the hex bolts on cooling head was stuck pretty tight and my attempts
>to undo it has caused the hex bolt to become rounded. I can't get at the
>bolt from the side because it is buried between the cooling fins. Anybody
>got any ideas how to get the bolt out so I can remove the head??? Surely
>this has happened to other people.
>
>Paul Williams
>
>

[PETERWOJ]

>Nope. The bearing don't get "thinner" so play in that plane will be what
>it's always been.

Bearings do wear off and make the shaft feel "loose". I had that on at least 3
engines. Few lean runs will make those ball races notchy and hard to turn.
Usually next step is BB cage falls apart with all that metal going inside the
engine making it junk. If I remember he said the engine is 4 years old without
any maintenance. I would change ball bearings and piston/ ring at least. If the
sleeve is scorched I would get new engine as at some point parts are more
expensive. I do try to change BB on the engine even if not run much every 1 or
2 years after ball bearings fall apart on 3 of my engines. Funny thing is one
engine chew up the front bearing and kept running. It did change sound a little
but I didn't know it was major until landed and tried to start again. Changing
bearings is less expensive specially if they show any play or rust than buying
new engine, fuel tank, muffler and possibly whole new heli if you unlucky .

[Beav]

"PETERWOJ" <peterwoj@aol.com> wrote in message
news:20030304211125.09176.00000068@mb-ba.aol.com...
> >Nope. The bearing don't get "thinner" so play in that plane will be what
> >it's always been.
>
> Bearings do wear off and make the shaft feel "loose". I had that on at
least 3
> engines. Few lean runs will make those ball races notchy and hard to turn.

Yep, that's what happens when bearing wear, but long before there's any end
float the bearing usually dies completely and throws bits of itself around
the internals

> Usually next step is BB cage falls apart with all that metal going inside
the
> engine making it junk. If I remember he said the engine is 4 years old
without
> any maintenance.

I missed that bit.

I would change ball bearings and piston/ ring at least. If the
> sleeve is scorched I would get new engine as at some point parts are more
> expensive.

If the motor's been in use for 4 years, I'd change the whole thing:-)


I do try to change BB on the engine even if not run much every 1 or
> 2 years after ball bearings fall apart on 3 of my engines. Funny thing is
one
> engine chew up the front bearing and kept running. It did change sound a
little
> but I didn't know it was major until landed and tried to start again.
Changing
> bearings is less expensive specially if they show any play or rust than
buying
> new engine, fuel tank, muffler and possibly whole new heli if you unlucky
..

Indeed it is, and sometimes it's worth buying a new engine, particularly if
you've had your money's worth out of the original.


--
Beav


Please note my E-mail address is "beavis dot original at ntlworld dot com"
(with the obvious changes)

Beavisland now lives at
www.beavisoriginal.co.uk

[The Vail Family]

I'll add, after you have the head of the bolt off and the engine head off
and are looking at something to grab, use a propane torch to heat the case.

Bill Vail



"Paul Williams" <paulswilliams@ntlworld.com> wrote in message
news:oZ99a.603$iE3.31@newsfep3-gui.server.ntli.net...
> Hi chaps
>
> After a rare unexpected engine cut this weekend I thought I would take a
> closer look at the motor whilst I was rebuilding what is left of my
> helicopter! I found there were built up burnt deposits on the piston
head.
>
> I tried to remove the cooling head from the OS 32 motor so that I can
clean
> this off.
>
> One of the hex bolts on cooling head was stuck pretty tight and my
attempts
> to undo it has caused the hex bolt to become rounded. I can't get at the
> bolt from the side because it is buried between the cooling fins. Anybody
> got any ideas how to get the bolt out so I can remove the head??? Surely
> this has happened to other people.
>
> On another note, I've had this motor for 4 years or so and must have run
it
> for several hundred hours by now. I've never done any maintenance on it.
How
> long do these motors last? and should I be thinking of replacing any of
the
> internal components?? Are there any people out there that can overhaul
these
> motors???
>
> Cheers for the help chaps
>
> Paul Williams
>
>

[Paul Williams]

Err.. Black thrust washer you mention, Beav has been sitting in the motor
box for last 4 years or so!!

I think I got my moneys worth out of this thing. God knows how many hundred
hours I have run it but it must be a lot and in its time I can count the
number of deadsticks I've had on one hand, and come to think of it most of
them have been in the last six months!

It was annoying cause I was doing a session practising my autos, and as I
powered up to do another auto the sodding thing cut out on me unexpectedly.
In my panic I didn't flick the throttle hold switch to get the extra pitch
range I really needed to get the thing down. Not having much negative on my
hover curve I watched it slowly descend when I dropped the pitch and by the
time it reached the ground there was no head speed left......that wiped the
smug grin off my face!

Thank for the advice chaps but rather than start messing with it I think I
will invest in a new motor and say thank you to OS for the great service
that this one has given me.....

Paul Williams


"Beav" <beavis.original@ntloxoworld.com> wrote in message
news:L4c9a.12825$EN3.103818@newsfep4-glfd.server.ntli.net...
>
> "Paul Williams" <paulswilliams@ntlworld.com> wrote in message
> news:dtb9a.633$iE3.20@newsfep3-gui.server.ntli.net...
> > OK cheers
> >
> > I'll try that.
>
> Before you do, I think you should know that the carbon deposits on the
> piston crown is perfectly normal and it's all but impossible NOT to get
them
> after a few tanks of juice have gone through the motor. It certainly
doesn't
> hurt and can in fact, help complression.
>
> It's on the SIDES of the piston that deposits are problematic.
> >
> > I've also just noticed that the centre rotating shaft attached to the
> > cooling fan has a slight bit of play in it. It can be moved in and out
> > about half of 1 mm.
>
> Did you fit the small thrust washer that comew with the motor before you
> installed the fan/clutch? It's a black washer about 2mm this.
>
> Can't remember noticing that before. Could that be a
> > sign that the bearings are wearing down???
>
> Nope. The bearing don't get "thinner" so play in that plane will be what
> it's always been.
>
> If it's not given you any problems before, it shouldn't now, so maybe you
> don't need to strip the mtoro down after all.
>
>
> --
> Beav
>
>
> Please note my E-mail address is "beavis dot original at ntlworld dot com"
> (with the obvious changes)
>
> Beavisland now lives at
> www.beavisoriginal.co.uk
>
>

[Beav]

"Paul Williams" <paulswilliams@ntlworld.com> wrote in message
news:fFu9a.2005$lN.271744@newsfep1-win.server.ntli.net...
> Err.. Black thrust washer you mention, Beav has been sitting in the motor
> box for last 4 years or so!!

Ahaaa :-)
>
> I think I got my moneys worth out of this thing.


I missed the mention of you having it for 4 years or so, but knowing that
now, I'd say you had too.

God knows how many hundred
> hours I have run it but it must be a lot and in its time I can count the
> number of deadsticks I've had on one hand, and come to think of it most of
> them have been in the last six months!

Time to give it a rest in peace now then, rather than a rest in pieces
later:)
>
> It was annoying cause I was doing a session practising my autos, and as I
> powered up to do another auto the sodding thing cut out on me
unexpectedly.
> In my panic I didn't flick the throttle hold switch to get the extra pitch
> range I really needed to get the thing down. Not having much negative on
my
> hover curve I watched it slowly descend when I dropped the pitch and by
the
> time it reached the ground there was no head speed left......that wiped
the
> smug grin off my face!

Botched auto's do that:-)

>
> Thank for the advice chaps but rather than start messing with it I think I
> will invest in a new motor and say thank you to OS for the great service
> that this one has given me.....

That sounds like the actions of a reasonable mind.


--
Beav


Please note my E-mail address is "beavis dot original at ntlworld dot com"
(with the obvious changes)

Beavisland now lives at
www.beavisoriginal.co.uk

[The Vail Family]

If you're looking for a recommendation, and you didn't say you were, I've
run both the OS .32 and now the TT.39. The OS was everything you say it
is... reliable, friendly and easy to tune... but the TT is that and much
more powerful....

Bill Vail



"Beav" <beavis.original@ntloxoworld.com> wrote in message
news:xQy9a.14188$EN3.114600@newsfep4-glfd.server.ntli.net...
>
> "Paul Williams" <paulswilliams@ntlworld.com> wrote in message
> news:fFu9a.2005$lN.271744@newsfep1-win.server.ntli.net...
> > Err.. Black thrust washer you mention, Beav has been sitting in the
motor
> > box for last 4 years or so!!
>
> Ahaaa :-)
> >
> > I think I got my moneys worth out of this thing.
>
>
> I missed the mention of you having it for 4 years or so, but knowing that
> now, I'd say you had too.
>
> God knows how many hundred
> > hours I have run it but it must be a lot and in its time I can count the
> > number of deadsticks I've had on one hand, and come to think of it most
of
> > them have been in the last six months!
>
> Time to give it a rest in peace now then, rather than a rest in pieces
> later:)
> >
> > It was annoying cause I was doing a session practising my autos, and as
I
> > powered up to do another auto the sodding thing cut out on me
> unexpectedly.
> > In my panic I didn't flick the throttle hold switch to get the extra
pitch
> > range I really needed to get the thing down. Not having much negative
on
> my
> > hover curve I watched it slowly descend when I dropped the pitch and by
> the
> > time it reached the ground there was no head speed left......that wiped
> the
> > smug grin off my face!
>
> Botched auto's do that:-)
>
> >
> > Thank for the advice chaps but rather than start messing with it I think
I
> > will invest in a new motor and say thank you to OS for the great service
> > that this one has given me.....
>
> That sounds like the actions of a reasonable mind.
>
>
> --
> Beav
>
>
> Please note my E-mail address is "beavis dot original at ntlworld dot com"
> (with the obvious changes)
>
> Beavisland now lives at
> www.beavisoriginal.co.uk
>
>