X-Junk-Score: 0 [] X-Cloudmark-Score: 0 [] X-Cloudmark-Analysis: v=2.2 cv=ApKs561P c=1 sm=1 tr=0 a=0P2ihwf57s0iRXT0khFp0w==:117 a=RR4aY7V_EVEA:10 a=lBVr4_lnuv0A:10 a=x7bEGLp0ZPQA:10 a=Fee85h93u3AA:10 a=2JCJgTwv5E4A:10 a=Ia-xEzejAAAA:8 a=IRhtOSDp8KQ76KZ7Yo0A:9 a=QEXdDO2ut3YA:10 a=Bfx1YNfT_JiboWGg7-UA:9 a=H_MGan_eN-jH_YaP:21 a=gKO2Hq4RSVkA:10 a=_W_S_7VecoQA:10 a=Urk15JJjZg1Xo0ryW_k8:22 From: " Lehanover@aol.com" Received: from omr-a018e.mx.aol.com ([204.29.186.64] verified) by logan.com (CommuniGate Pro SMTP 6.2c4) with ESMTPS id 10164273 for flyrotary@lancaironline.net; Sat, 30 Sep 2017 13:06:05 -0400 Received-SPF: pass receiver=logan.com; client-ip=204.29.186.64; envelope-from=Lehanover@aol.com Received: from mtaomg-aam01.mx.aol.com (mtaomg-aam01.mx.aol.com [172.27.19.147]) by omr-a018e.mx.aol.com (Outbound Mail Relay) with ESMTP id 9167F38000DE for ; Sat, 30 Sep 2017 13:05:48 -0400 (EDT) Received: from core-mdd01d.mail.aol.com (core-mdd01.mail.aol.com [172.27.62.11]) by mtaomg-aam01.mx.aol.com (OMAG/Core Interface) with ESMTP id 42EC538000082 for ; Sat, 30 Sep 2017 13:05:48 -0400 (EDT) Full-name: Lehanover Message-ID: <37fae4.493ed212.470128eb@aol.com> Date: Sat, 30 Sep 2017 13:05:48 -0400 Subject: Re: [FlyRotary] Re: RX-8 Oil Pump Replacement To: flyrotary@lancaironline.net MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="part1_37fae4.493ed212.470128eb_boundary" X-Mailer: AOL 9.8 sub 2024 X-Originating-IP: [75.188.6.198] x-aol-global-disposition: G DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=mx.aol.com; s=20150623; t=1506791148; bh=50skC0DAjbQ9i+AvF5+rGmsEXWowhqUBQL+c5qxEMw4=; h=From:To:Subject:Message-ID:Date:MIME-Version:Content-Type; b=ozAkKaFL40maI27YDoZE7ukK/C5Nwd9uVjbMQIFlTFZQ0UWeAz1su71gQGs4LCk3/ UpagyeAiIzg9BNkrJXewD9Y+/2P4T7zV/LukSMGubGZRwx7MEaBlSk/pNGKEUW78gS 4fcz+duLTDTG1L9JlPKspkqcUnzdWxsb6XeoT5Ys= x-aol-sid: 3039ac1b139359cfceec7b8a --part1_37fae4.493ed212.470128eb_boundary Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Content-Language: en Part of the answer is oil pump wear. I suspect that Mazda does not make = =20 some of the equipment found in Mazda engines. Years ago I found that oil= pump =20 end play could be way out of spec. So I started with new pumps (when we=20 still used stock pumps) and shortened the pump body to the minimum allowe= d =20 dimension. =20 The other part of the problem is that the rotors in the engine tend to foa= m=20 the oil to excess. So from a long period where entrained air has escaped= =20 the oil over a night or a week of no use. Then you see good oil pressure= on =20 start up, then as you see oil temperature come up and oil foaming comes on= =20 during climb out, the oil pressure drops away. Foam in oil is air bubbles= .=20 Air is compressible. So the peak oil pressure is no longer available. Als= o=20 air in the foamed oil in the pick up expands to satisfy the lower pressur= e=20 in the suction side of the pump. This reduces the volume of oil the pump= =20 can acquire to pressurize.=20 =20 There are a number of items in play here. One is the oil brand, pour =20 weight, recipe, and application of the oil. Racing oils have additional additives that reduce foaming. Racing oils hav= e=20 additional anti scuff compounds. Better for cold starts and engines that sit for long periods between uses.= =20 Racing oils have much higher film strengths than conventional oils. Racing= =20 oils absorb heat and give it up more quickly than conventional oils. Do= you=20 see a pattern here? Remember that duty cycle thing? Start the car engine.= =20 Drive away on ice cold oil. Don't turn over 1,800 RPM ever. Listen on=20 shutdown as the condensate from the warm engine runs down into the sump.= The=20 first to be pumped to the bearings just before the cold oil on the next= start.=20 =20 Or, start the rotary powered plane. Warm the oil a bit. Take off and climb= =20 out with the front rotor never quite full of cooling oil, and the rear=20 rotor over filled and foaming like crazy. Now turning up 3 times the stre= et RPM all of this was designed for. Synthetic racing oils can be used in =20 rotaries. You must premix the fuel as synthetic sump oil will not burn = without=20 gumming. Use a synthetic 2 cycle oil as a premix or inject it with a modi= fied=20 pump. I use RedLine 50 weight in the sump (Dry sump) and 2 cycle RedLine= =20 in the premix. =20 While inspecting at annual, you can remove and inspect the stationary =20 gears. Just do not move the prop while the gears are out (one at a time).= Then =20 at least you can inspect and measure the main bearings, and reinstall the= =20 stationary gears. Metal in the filter makes the hair on my neck stand up. Not one oil relate failure since 1980. Lynn E. Hanover =20 =20 =20 =20 In a message dated 9/30/2017 11:35:07 A.M. Eastern Daylight Time, =20 flyrotary@lancaironline.net writes: =20 =20 Has anyone experienced low oil pressure due to wear of the Renesis oil=20 pump?=20 My Renesis engine on my RV-7 has had decreased oil pressure for a while.= =20 I changed the oil pump and now my oil pressure is back to normal.=20 I have 780 hours on the engine and about 2500 engine heat cycles =E2=80= =93 most of=20 my flights are very short. On takeoff with relatively cool oil the=20 pressure went to 80 PSI but as the oil heated up the pressure decreased to= as=20 low as 65 psi on a hot day during climb out.=20 I change the oil at 50 hours I always inspect the oil filter material an= d=20 had some very small shiny flakes in the pleats. The particles appear to= =20 be non-magnetic=20 A month ago I decided to remove the engine and replace the oil pump.=20 I found the aluminum oil pump housing had a slight amount of wear where= =20 the steel pump gear seals against the housing. Replacing the oil pump= has=20 resulted in much better oil pressure. =3D --part1_37fae4.493ed212.470128eb_boundary Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Content-Language: en
Part of the answer is oil pump wear. I suspect that Mazda does not ma= ke=20 some of the equipment found in Mazda engines. Years ago I found that oil= pump=20 end play could be way out of spec. So I started with new pumps (when we st= ill=20 used stock pumps) and shortened the pump body to the minimum allowed=20 dimension.
 
The other part of the problem is that the rotors in the engine tend= to foam=20 the oil to excess. So from a long period where entrained air has esca= ped=20 the oil over a night or a week of no use. Then you see good oil pressure= on=20 start up, then as you see oil temperature come up and oil foaming comes on= =20 during climb out, the oil pressure drops away.  Foam in oil is air bu= bbles.=20 Air is compressible. So the peak oil pressure is no longer available. Also= air=20 in the foamed oil in the pick up expands to satisfy the lower pressure in= the=20 suction side of the pump. This reduces the volume of oil the pump can acqu= ire=20 to pressurize.
 
There are a number of items in play here. One is the oil brand, pour= =20 weight, recipe, and application of the oil.
Racing oils have additional additives that reduce foaming. Racing oil= s have=20 additional anti scuff compounds.
Better for cold starts and engines that sit for long periods between= uses.=20 Racing oils have much higher film strengths than conventional oils. Racing= oils=20 absorb heat and give it up more quickly than conventional oils. Do you see= a=20 pattern here? Remember that duty cycle thing? Start the car engine. Drive= away=20 on ice cold oil. Don't turn over 1,800 RPM ever. Listen on shutdown as the= =20 condensate from the warm engine runs down into the sump. The first to be= pumped=20 to the bearings just before the cold oil on the next start.
 
Or, start the rotary powered plane. Warm the oil a bit. Take off and= climb=20 out with the front rotor never quite full of cooling oil, and the rear rot= or=20 over filled and foaming like crazy. Now turning up 3 times the street RPM<= /DIV>
all of this was designed for. Synthetic racing oils can be used in=20 rotaries. You must premix the fuel as  synthetic sump oil will not bu= rn=20 without gumming. Use a synthetic 2 cycle oil as a premix or inject it with= a=20 modified pump.  I use RedLine 50 weight in the sump (Dry sump) and 2= cycle=20 RedLine in the premix.
 
While inspecting at annual, you can remove and inspect the stationary= =20 gears. Just do not move the prop while the gears are out (one at a time).= Then=20 at least you can inspect and measure the main bearings, and reinstall= the=20 stationary gears. Metal in the filter makes the hair on my neck stand up.<= /DIV>
Not one oil relate failure since 1980.
Lynn E. Hanover
 
     
 
In a message dated 9/30/2017 11:35:07 A.M. Eastern Daylight Time,=20 flyrotary@lancaironline.net writes:

Has=20 anyone experienced low oil pressure due to wear of the Renesis oil pump?=

 

My=20 Renesis engine on my RV-7 has had decreased oil pressure for a while.

 

I=20 changed the oil pump and now my oil pressure is back to normal.

 

I=20 have 780 hours on the engine and about 2500 engine heat cycles =E2=80=93= most of my=20 flights are very short.    On takeoff with relatively coo= l oil=20 the pressure went to 80 PSI but as the oil heated up the pressure decrea= sed to=20 as low as 65 psi on a hot day during climb out.

 

I=20 change the oil at 50 hours  I always inspect the oil filter materia= l and=20 had some very small shiny flakes in the pleats.  The particles appe= ar to=20 be non-magnetic

 

A=20 month ago I decided to remove the engine and replace the oil pump.

 

I=20 found the aluminum oil pump housing had a slight amount of wear where th= e=20 steel  pump gear seals against the housing.   Replacing= the oil=20 pump has resulted in much better oil pressure.

 

=3D
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