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Re: [Shop-talk] Electric String Trimmers

To: <shop-talk@autox.team.net>
Subject: Re: [Shop-talk] Electric String Trimmers
From: Karl Vacek via Shop-talk <shop-talk@autox.team.net>
Date: Mon, 26 Aug 2019 12:22:05 -0500
Delivered-to: mharc@autox.team.net
Delivered-to: shop-talk@autox.team.net
References: <041656EE-650B-48B8-83F2-2A9B4805B775@me.com> <a1e09f60-d2ce-bbdc-c658-789685a6d38a@sackheads.org> <CAAoSWGOksJ1gOmvKeSWkp=mH9aEaEoUR_cDsZLGbGs+uoYfzqQ@mail.gmail.com> <2964d014-10fb-d2b2-34e2-476dafb5a837@milleredp.com> <004801d557a6$45fb9180$d1f2b480$@GMail.com> <29fb6ac3-3cf1-da2d-d0b2-1090a16c3080@earthlink.net> <007b01d55c19$679e8f00$36dbad00$@GMail.com> <085a5a12-bf21-c3c6-76b8-5b155aea28e8@milleredp.com> <CANuE7YCNLT=y_CtxXcMV-GgXgzSCzOi1zpYCFvwiqwEvcgkT=w@mail.gmail.com>
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The gas I buy at the airport for my lawn equipment is indeed aviation =
unleaded.  In the early 1980=E2=80=99s the EAA ran a project to prove =
that low-compression aircraft engines could safely run on unleaded car =
gas.  Peterson Aviation in Nebraska did a similar project.  Both sell =
STC=E2=80=99s to allow use of that specific fuel in applicable aircraft. =
 Basically a permit to allow the use of unleaded auto fuel a specific in =
aircraft under specified conditions.

=20

The wide marketing of gasohol soon after the STC=E2=80=99s became =
available caused issues =E2=80=93 the FAA permission is ONLY for =
straight unleaded =E2=80=93 no alcohol.  Here in the Peoples Republic of =
Illinois the corn lobby has us inundated with gasohol, and there are =
only a handful of places in the state where you can fill up a car or =
truck with ethanol-free car gas.

=20

For use in those planes so certificated, many airports now carry =
=E2=80=9Caviation mogas=E2=80=9D =E2=80=93 regular unleaded without =
alcohol.  It=E2=80=99s not to be sold for on-road vehicles, just planes. =
 And airports can legally pump it into cans for small-engine use.

=20

I have plenty of the blue stuff (100 LL) in the Stearman, but =
haven=E2=80=99t ever put it in any lawn equipment.  Almost the same =
price, so that=E2=80=99s not the issue, but my lawn equipment just =
doesn=E2=80=99t need lead.  Even my 3-wheel Harley (well, it=E2=80=99s a =
2-cycle Harley Davidson golf cart) uses unleaded just fine.

=20

Used to be better to use 80 octane (red) but that=E2=80=99s pretty much =
gone today.  That was good for mowers, etc. too.  As noted, 100 LL has =
4x the lead of old 80 octane, so lead fouling can be an issue in =
aircraft engines.  Some guys who have the auto fuel STC even run 75% =
auto gas and 25% 100 LL to simulate old 80 octane.  When 80 octane went =
away and 80 octane engines that to switch to 100 LL, many pilots =
experienced lead-fouling issues, and many top overhauls were done.  =
Sometimes guys lapped the guides with the cylinder in place too.  But =
that=E2=80=99s largely over now, as most engines have appropriate valves =
and guides to allow regular use of 100 LL.  Personally I=E2=80=99ve not =
had an issue with 100 LL in my engine, which has stock WWII era valves =
and guides, and I have indeed had occasion to pull three cylinders over =
the years and disassemble the valves, with no lead fouling issues =
present.

=20

As far as purple gas being available at Warbird events, I=E2=80=99ve not =
ever seen it, but my Stearman is at the lower end of the Warbird =
spectrum.  We do have a Grumman TBM Avenger on the field, and Tom uses =
100 LL in that =E2=80=93 it=E2=80=99s got a Wright 2600-20 (1900 HP).  =
And P-51=E2=80=99s regularly fill up with 100 LL.  Maybe the purple =
stuff is available sometimes, but not commonly, and as far as I know =
most Warbird engines run fine on 100 LL.

=20

One of the things that allowed higher boost pressures during WWII was =
water injection.  That=E2=80=99s still an option.

=20

Thanks !!

Karl

=20

=20

=20

Subject: Re: [Shop-talk] Electric String Trimmers

=20

Keep in mind that Low Lead Avgas, like 100LL, still has 4x the amount of =
lead that standard automotive gas contained.  The guys who run this =
stuff in race cars and the like often report issues with lead deposits =
on valve stems and seats.  I have personally see a valve stem so leaded =
up that it stuck open.  Use at your own risk.

=20


It was probably blue, and it was probably 100LL.  Half the lead of most=20
of the earlier grades, most everyone's pretty much still standardized on =

this.

Some places and applications (warbird events?) you may find more heavily =

leaded super-sauce for your high-boost blown motors.  The reason the=20
Merlin went from 800HP to 1700+HP in production was all that sweet,=20
sweet American leaded 130-octane gasoline.

John

=20


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vlink=3Dpurple><div class=3DWordSection1><p class=3DMsoNormal><span =
style=3D'font-size:11.0pt;font-family:"Calibri","sans-serif";color:#44546=
A'>The gas I buy at the airport for my lawn equipment is indeed aviation =
unleaded.=C2=A0 In the early 1980=E2=80=99s the EAA ran a project to =
prove that low-compression aircraft engines could safely run on unleaded =
car gas.=C2=A0 Peterson Aviation in Nebraska did a similar =
project.=C2=A0 Both sell STC=E2=80=99s to allow use of that specific =
fuel in applicable aircraft.=C2=A0 Basically a permit to allow the use =
of unleaded auto fuel a specific in aircraft under specified =
conditions.<o:p></o:p></span></p><p class=3DMsoNormal><span =
style=3D'font-size:11.0pt;font-family:"Calibri","sans-serif";color:#44546=
A'><o:p>&nbsp;</o:p></span></p><p class=3DMsoNormal><span =
style=3D'font-size:11.0pt;font-family:"Calibri","sans-serif";color:#44546=
A'>The wide marketing of gasohol soon after the STC=E2=80=99s became =
available caused issues =E2=80=93 the FAA permission is ONLY for =
straight unleaded =E2=80=93 no alcohol.=C2=A0 Here in the Peoples =
Republic of Illinois the corn lobby has us inundated with gasohol, and =
there are only a handful of places in the state where you can fill up a =
car or truck with ethanol-free car gas.<o:p></o:p></span></p><p =
class=3DMsoNormal><span =
style=3D'font-size:11.0pt;font-family:"Calibri","sans-serif";color:#44546=
A'><o:p>&nbsp;</o:p></span></p><p class=3DMsoNormal><span =
style=3D'font-size:11.0pt;font-family:"Calibri","sans-serif";color:#44546=
A'>For use in those planes so certificated, many airports now carry =
=E2=80=9Caviation mogas=E2=80=9D =E2=80=93 regular unleaded without =
alcohol.=C2=A0 It=E2=80=99s not to be sold for on-road vehicles, just =
planes.=C2=A0 And airports can legally pump it into cans for =
small-engine use.<o:p></o:p></span></p><p class=3DMsoNormal><span =
style=3D'font-size:11.0pt;font-family:"Calibri","sans-serif";color:#44546=
A'><o:p>&nbsp;</o:p></span></p><p class=3DMsoNormal><span =
style=3D'font-size:11.0pt;font-family:"Calibri","sans-serif";color:#44546=
A'>I have plenty of the blue stuff (100 LL) in the Stearman, but =
haven=E2=80=99t ever put it in any lawn equipment.=C2=A0 Almost the same =
price, so that=E2=80=99s not the issue, but my lawn equipment just =
doesn=E2=80=99t need lead.=C2=A0 Even my 3-wheel Harley (well, =
it=E2=80=99s a 2-cycle Harley Davidson golf cart) uses unleaded just =
fine.<o:p></o:p></span></p><p class=3DMsoNormal><span =
style=3D'font-size:11.0pt;font-family:"Calibri","sans-serif";color:#44546=
A'><o:p>&nbsp;</o:p></span></p><p class=3DMsoNormal><span =
style=3D'font-size:11.0pt;font-family:"Calibri","sans-serif";color:#44546=
A'>Used to be better to use 80 octane (red) but that=E2=80=99s pretty =
much gone today.=C2=A0 That was good for mowers, etc. too.=C2=A0 As =
noted, 100 LL has 4x the lead of old 80 octane, so lead fouling can be =
an issue in aircraft engines.=C2=A0 Some guys who have the auto fuel STC =
even run 75% auto gas and 25% 100 LL to simulate old 80 octane.=C2=A0 =
When 80 octane went away and 80 octane engines that to switch to 100 LL, =
many pilots experienced lead-fouling issues, and many top overhauls were =
done.=C2=A0 Sometimes guys lapped the guides with the cylinder in place =
too.=C2=A0 But that=E2=80=99s largely over now, as most engines have =
appropriate valves and guides to allow regular use of 100 LL.=C2=A0 =
Personally I=E2=80=99ve not had an issue with 100 LL in my engine, which =
has stock WWII era valves and guides, and I have indeed had occasion to =
pull three cylinders over the years and disassemble the valves, with no =
lead fouling issues present.<o:p></o:p></span></p><p =
class=3DMsoNormal><span =
style=3D'font-size:11.0pt;font-family:"Calibri","sans-serif";color:#44546=
A'><o:p>&nbsp;</o:p></span></p><p class=3DMsoNormal><span =
style=3D'font-size:11.0pt;font-family:"Calibri","sans-serif";color:#44546=
A'>As far as purple gas being available at Warbird events, I=E2=80=99ve =
not ever seen it, but my Stearman is at the lower end of the Warbird =
spectrum.=C2=A0 We do have a Grumman TBM Avenger on the field, and Tom =
uses 100 LL in that =E2=80=93 it=E2=80=99s got a Wright 2600-20 (1900 =
HP).=C2=A0 And P-51=E2=80=99s regularly fill up with 100 LL.=C2=A0 Maybe =
the purple stuff is available sometimes, but not commonly, and as far as =
I know most Warbird engines run fine on 100 LL.<o:p></o:p></span></p><p =
class=3DMsoNormal><span =
style=3D'font-size:11.0pt;font-family:"Calibri","sans-serif";color:#44546=
A'><o:p>&nbsp;</o:p></span></p><p class=3DMsoNormal><span =
style=3D'font-size:11.0pt;font-family:"Calibri","sans-serif";color:#44546=
A'>One of the things that allowed higher boost pressures during WWII was =
water injection.=C2=A0 That=E2=80=99s still an =
option.<o:p></o:p></span></p><p class=3DMsoNormal><span =
style=3D'font-size:11.0pt;font-family:"Calibri","sans-serif";color:#44546=
A'><o:p>&nbsp;</o:p></span></p><p class=3DMsoNormal><span =
style=3D'font-size:11.0pt;font-family:"Calibri","sans-serif";color:#44546=
A'>Thanks !!<o:p></o:p></span></p><p class=3DMsoNormal><span =
style=3D'font-size:11.0pt;font-family:"Calibri","sans-serif";color:#44546=
A'>Karl<o:p></o:p></span></p><p class=3DMsoNormal><span =
style=3D'font-size:11.0pt;font-family:"Calibri","sans-serif";color:#44546=
A'><o:p>&nbsp;</o:p></span></p><p class=3DMsoNormal><span =
style=3D'font-size:11.0pt;font-family:"Calibri","sans-serif";color:#44546=
A'><o:p>&nbsp;</o:p></span></p><p class=3DMsoNormal><span =
style=3D'font-size:11.0pt;font-family:"Calibri","sans-serif";color:#44546=
A'><o:p>&nbsp;</o:p></span></p><p class=3DMsoNormal><b><span =
style=3D'font-size:10.0pt;font-family:"Tahoma","sans-serif"'>Subject:</sp=
an></b><span =
style=3D'font-size:10.0pt;font-family:"Tahoma","sans-serif"'> Re: =
[Shop-talk] Electric String Trimmers<o:p></o:p></span></p><p =
class=3DMsoNormal><o:p>&nbsp;</o:p></p><div><p class=3DMsoNormal>Keep in =
mind that Low Lead Avgas, like 100LL, still has 4x the amount of lead =
that standard automotive gas contained.&nbsp; The guys who run this =
stuff in race cars and the like often report issues with lead deposits =
on valve stems and seats.&nbsp; I have personally see a valve stem so =
leaded up that it stuck open.&nbsp; Use at your own =
risk.<o:p></o:p></p></div><p =
class=3DMsoNormal><o:p>&nbsp;</o:p></p><div><blockquote =
style=3D'border:none;border-left:solid #CCCCCC 1.0pt;padding:0in 0in 0in =
6.0pt;margin-left:4.8pt;margin-right:0in'><p class=3DMsoNormal =
style=3D'mso-margin-top-alt:0in;margin-right:0in;margin-bottom:12.0pt;mar=
gin-left:11.4pt'><br>It was probably blue, and it was probably =
100LL.&nbsp; Half the lead of most <br>of the earlier grades, most =
everyone's pretty much still standardized on <br>this.<br><br>Some =
places and applications (warbird events?) you may find more heavily =
<br>leaded super-sauce for your high-boost blown motors.&nbsp; The =
reason the <br>Merlin went from 800HP to 1700+HP in production was all =
that sweet, <br>sweet American leaded 130-octane =
gasoline.<br><br>John<o:p></o:p></p></blockquote></div><div><p =
class=3DMsoNormal><o:p>&nbsp;</o:p></p></div></div></body></html>
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