Original Posted By: Dlwoolsey(at)aol.com
Subject: Pietenpol-List: Carbs>To all Corvair Piets,>>I have a big hole in my #6 piston... after advancing to 30 degrees. It>happened on the ground, then ran rough. I'm using 100 low lead. Thisshould>not have happened.>What kind of carbs are being used successfully?? Model #, Venturi size,jet>size???>What Size X Pitch props. are being used successfully??>I've flogged the timing issue to death already, but lets do it onceagain...>What timing is being set succssfully??>Should I weld the distributer centrifical weights NO! It wil be toohard to start! (in what position... fully>open or closed), or is the weaker springs O.K.?Yes, as the powersettings at full power and cruise will not be much different.>How much advance should the weights be producing?? The vacuum isalready>locked.>What RPM are being achieved? I have the 95 Cam with 110 heads.>I've ordered the new parts... replacing all pistons from Clark's, andam>having the cyl. honed(deglazed only). Staying standard, not overboringor>reducing the compression as I would like to stay with 100 L.L.>>At the End of my rope,>Domenic>Domenic If I may sum up of the past timing advice foryou:The advance curve and vacum advance are of no value on an engineused forsteady power output such as an aircraft.The only reason you need to vary the timing at all is to preventkickbackon starting. It should fire late, after tdc at cranking speeds and befullyadvanced at any useable power settings.If you are still using a point type distributor check that thebushings aregood. If the shaft wobbles the timing wanders. It might be okay on thecylinderyou timed it to but be out on some others. A good dwell meter shouldpick thisproblem up.You need to concern yourself only with the total advance. It seemsasthough 30 degrees is too much. See if you can get advice from someonelikeBig Jim on the max advance. I wouldn't go any more than thecarengine does with the vacuum disconnected.I still wonder about your induction system, it may be that you aretoolean. Too lean can cause detonation which leads to holes in pistons. Aleanmixture can burn so slowly that there is still flame in the cylinderwhen thenext intake event occurs. When you get it running again, try this as a mixtureindicator:Connect a hose to a propane torches shut off valve, and tiethe otherend so that it feeds well into the carb intake. With the engine runningandwarmed up open the propane valve, if the mixture was too lean theadditionalpropane will cause the engine to gain rpm. (power)If the engine dies down a bit and recovers when the propane is shutoff themixture is about right.Hope this helps John Mc________________________________________________________________________________
Pietenpol-List: Carbs
Pietenpol-List: Carbs
Original Posted By: Michael King
Subject: Pietenpol-List: Carbs>To all Corvair Piets,>>I have a big hole in my #6 piston... after advancing to 30 degrees. It>happened on the ground, then ran rough. I'm using 100 low lead. This should>not have happened.>What kind of carbs are being used successfully?? Model #, Venturi size, jet>size???>What Size X Pitch props. are being used successfully??>I've flogged the timing issue to death already, but lets do it onceagain...>What timing is being set succssfully??>Should I weld the distributer centrifical weights NO! It wil be too hard tostart! (in what position... fully>open or closed), or is the weaker springs O.K.?Yes, as the power settingsat full power and cruise will not be much different.>How much advance should the weights be producing?? The vacuum is already>locked.>What RPM are being achieved? I have the 95 Cam with 110 heads.>I've ordered the new parts... replacing all pistons from Clark's, and am>having the cyl. honed(deglazed only). Staying standard, not overboring or>reducing the compression as I would like to stay with 100 L.L.>>At the End of my rope,>Domenic>________________________________________________________________________________
Subject: Pietenpol-List: Carbs>To all Corvair Piets,>>I have a big hole in my #6 piston... after advancing to 30 degrees. It>happened on the ground, then ran rough. I'm using 100 low lead. This should>not have happened.>What kind of carbs are being used successfully?? Model #, Venturi size, jet>size???>What Size X Pitch props. are being used successfully??>I've flogged the timing issue to death already, but lets do it onceagain...>What timing is being set succssfully??>Should I weld the distributer centrifical weights NO! It wil be too hard tostart! (in what position... fully>open or closed), or is the weaker springs O.K.?Yes, as the power settingsat full power and cruise will not be much different.>How much advance should the weights be producing?? The vacuum is already>locked.>What RPM are being achieved? I have the 95 Cam with 110 heads.>I've ordered the new parts... replacing all pistons from Clark's, and am>having the cyl. honed(deglazed only). Staying standard, not overboring or>reducing the compression as I would like to stay with 100 L.L.>>At the End of my rope,>Domenic>________________________________________________________________________________
Pietenpol-List: Carbs
Original Posted By: greg(at)controlvision.com (Greg Yotz)
To all Corvair Piets,I have a big hole in my #6 piston... after advancing to 30 degrees. Ithappened on the ground, then ran rough. I'm using 100 low lead. This shouldnot have happened.What kind of carbs are being used successfully?? Model #, Venturi size, jetsize???What Size X Pitch props. are being used successfully??I've flogged the timing issue to death already, but lets do it once again...What timing is being set succssfully??Should I weld the distributer centrifical weights (in what position... fullyopen or closed), or is the weaker springs O.K.?How much advance should the weights be producing?? The vacuum is alreadylocked.What RPM are being achieved? I have the 95 Cam with 110 heads.I've ordered the new parts... replacing all pistons from Clark's, and amhaving the cyl. honed(deglazed only). Staying standard, not overboring orreducing the compression as I would like to stay with 100 L.L.At the End of my rope,Domenic________________________________________________________________________________
To all Corvair Piets,I have a big hole in my #6 piston... after advancing to 30 degrees. Ithappened on the ground, then ran rough. I'm using 100 low lead. This shouldnot have happened.What kind of carbs are being used successfully?? Model #, Venturi size, jetsize???What Size X Pitch props. are being used successfully??I've flogged the timing issue to death already, but lets do it once again...What timing is being set succssfully??Should I weld the distributer centrifical weights (in what position... fullyopen or closed), or is the weaker springs O.K.?How much advance should the weights be producing?? The vacuum is alreadylocked.What RPM are being achieved? I have the 95 Cam with 110 heads.I've ordered the new parts... replacing all pistons from Clark's, and amhaving the cyl. honed(deglazed only). Staying standard, not overboring orreducing the compression as I would like to stay with 100 L.L.At the End of my rope,Domenic________________________________________________________________________________
Pietenpol-List: Re: Carbs
Original Posted By: BELLISSIMO, DOMENIC
Domenic If I may sum up of the past timing advice for you:The advance curve and vacum advance are of no value on an engine usedfor steady power output such as an aircraft.The only reason you need to vary the timing at all is to preventkickback on starting. It should fire late, after tdc at cranking speedsand be fully advanced at any useable power settings.If you are still using a point type distributor check that the bushingsare good. If the shaft wobbles the timing wanders. It might be okay onthe cylinder you timed it to but be out on some others. A good dwellmeter should pick this problem up.You need to concern yourself only with the total advance. It seems asthough 30 degrees is too much. See if you can get advice from someonelike "Big Jim" on the max advance. I wouldn't go any more than the carengine does with the vacuum disconnected.I still wonder about your induction system, it may be that you are toolean. Too lean can cause detonation which leads to holes in pistons. Alean mixture can burn so slowly that there is still flame in thecylinder when the next intake event occurs.When you get it running again, try this as a mixture indicator:Connect a hose to a propane torches shut off valve, and tie the otherend so that it feeds well into the carb intake. With the engine runningand warmed up open the propane valve, if the mixture was too lean theadditional propane will cause the engine to gain rpm. (power)If the engine dies down a bit and recovers when the propane is shut offthe mixture is about right.Hope this helpsJohn Mc-----Original Message-----
Domenic If I may sum up of the past timing advice for you:The advance curve and vacum advance are of no value on an engine usedfor steady power output such as an aircraft.The only reason you need to vary the timing at all is to preventkickback on starting. It should fire late, after tdc at cranking speedsand be fully advanced at any useable power settings.If you are still using a point type distributor check that the bushingsare good. If the shaft wobbles the timing wanders. It might be okay onthe cylinder you timed it to but be out on some others. A good dwellmeter should pick this problem up.You need to concern yourself only with the total advance. It seems asthough 30 degrees is too much. See if you can get advice from someonelike "Big Jim" on the max advance. I wouldn't go any more than the carengine does with the vacuum disconnected.I still wonder about your induction system, it may be that you are toolean. Too lean can cause detonation which leads to holes in pistons. Alean mixture can burn so slowly that there is still flame in thecylinder when the next intake event occurs.When you get it running again, try this as a mixture indicator:Connect a hose to a propane torches shut off valve, and tie the otherend so that it feeds well into the carb intake. With the engine runningand warmed up open the propane valve, if the mixture was too lean theadditional propane will cause the engine to gain rpm. (power)If the engine dies down a bit and recovers when the propane is shut offthe mixture is about right.Hope this helpsJohn Mc-----Original Message-----
Pietenpol-List: FW: Carbs
Original Posted By: jmcnarry(at)techplus.com
Thanks John,I will try the propane test. Brian Kenney is also thinking along thoselines. Today he is going to look at my carb. to check the venturi and jetcombination. It was set up for an 85 H.P. and Mixture locked rich... itshoiuld be okay but it doesn't hurt to check.thanks a million,Dom. ----------________________________________________________________________________________
Thanks John,I will try the propane test. Brian Kenney is also thinking along thoselines. Today he is going to look at my carb. to check the venturi and jetcombination. It was set up for an 85 H.P. and Mixture locked rich... itshoiuld be okay but it doesn't hurt to check.thanks a million,Dom. ----------________________________________________________________________________________
Pietenpol-List: Carbs
Original Posted By: "AircamperN11MS"
Hello all Piet enthusiastsI want to encourage anyone who is "stuck" on/in their Piet project facing a"mountain" that has you stuck to either reach out to a fellow builder, orjust face it head on and push through it. I have just faced another"mountain" and I have overcome it. If I had not, my project would have begunto collect dust. This past weekend I began installing my wood straight axleLG fittings onto the fuselage and it is going quite well. A lot oftrepidation about drilling the bolt holes "true and straight" was my mainconcern followed by cutting out "slots" for the inner fittings. I trustedin my fabricated drill guide and I went for it. After seeing the first pairof fitting with bolts going through them I was very happy. I'm very excitednow about my progress on my Piet. Facing this challenge and completing theturtle deck has given me the even more confidence that I will complete itand continue to have a blast doing so.If your "mountain" is engine related, no matter what engine it is, CorvairCollege is a great place to go. Even as a spectator you will learn a lotabout building a flight engine, and it might be the catalyst that gets youover the mountain and allow you to look back and see it was just a mole hill- as I did on several occasions.Bob DewenterDayton OHNow an editorial:It looks like perhaps EAA is getting the message that many of us in the Pietcommunity feel like EAA is not looking out for the interests of the "grassroots" home builder. The new Experimenter monthly digital magazine is verynice, but is in danger of becoming its big brother "Sport Aviation". Forthose of you looking for a "grass roots" group focused on building airplanes"a hundred dollars at a time" consider also joining the newly re-startedSport Aviation Association. It's back and led by Ed and Val Fisher, alongwith several others in supporting roles. Ed and Val will be at the CorvairCollege in Barnwell in a couple of weeks. Ed Fisher along with Editor JeffLange have put out a first issue and it is the same flavor as is BPAN -printed, mailed, fun to read. Membership is donation based.They have a website:http://www.sportaviationassociation.org ... ___Subject: Pietenpol-List: Carbs
Hello all Piet enthusiastsI want to encourage anyone who is "stuck" on/in their Piet project facing a"mountain" that has you stuck to either reach out to a fellow builder, orjust face it head on and push through it. I have just faced another"mountain" and I have overcome it. If I had not, my project would have begunto collect dust. This past weekend I began installing my wood straight axleLG fittings onto the fuselage and it is going quite well. A lot oftrepidation about drilling the bolt holes "true and straight" was my mainconcern followed by cutting out "slots" for the inner fittings. I trustedin my fabricated drill guide and I went for it. After seeing the first pairof fitting with bolts going through them I was very happy. I'm very excitednow about my progress on my Piet. Facing this challenge and completing theturtle deck has given me the even more confidence that I will complete itand continue to have a blast doing so.If your "mountain" is engine related, no matter what engine it is, CorvairCollege is a great place to go. Even as a spectator you will learn a lotabout building a flight engine, and it might be the catalyst that gets youover the mountain and allow you to look back and see it was just a mole hill- as I did on several occasions.Bob DewenterDayton OHNow an editorial:It looks like perhaps EAA is getting the message that many of us in the Pietcommunity feel like EAA is not looking out for the interests of the "grassroots" home builder. The new Experimenter monthly digital magazine is verynice, but is in danger of becoming its big brother "Sport Aviation". Forthose of you looking for a "grass roots" group focused on building airplanes"a hundred dollars at a time" consider also joining the newly re-startedSport Aviation Association. It's back and led by Ed and Val Fisher, alongwith several others in supporting roles. Ed and Val will be at the CorvairCollege in Barnwell in a couple of weeks. Ed Fisher along with Editor JeffLange have put out a first issue and it is the same flavor as is BPAN -printed, mailed, fun to read. Membership is donation based.They have a website:http://www.sportaviationassociation.org ... ___Subject: Pietenpol-List: Carbs
Original Posted By: Michael Perez
Not sure if this link has been passed around before. If so, here it goes again.Great info on the Stromberg Carbs.(http://forums.matronics.com/posting.php ... wtopic&f=7)--------Scott LiefeldFlying N11MS since March 1972Steel TubeC-85-12Wire WheelsBrodhead in 1996Read this topic online here:http://forums.matronics.com/viewtopic.p ... ______Date: Wed, 24 Oct 2012 11:02:52 -0700 (PDT)
Not sure if this link has been passed around before. If so, here it goes again.Great info on the Stromberg Carbs.(http://forums.matronics.com/posting.php ... wtopic&f=7)--------Scott LiefeldFlying N11MS since March 1972Steel TubeC-85-12Wire WheelsBrodhead in 1996Read this topic online here:http://forums.matronics.com/viewtopic.p ... ______Date: Wed, 24 Oct 2012 11:02:52 -0700 (PDT)
Pietenpol-List: Re: Carbs
Original Posted By: BELLISSIMO, DOMENIC
Domenic If I may sum up of the past timing advice for you:The advance curve and vacum advance are of no value on an engine used forsteady power output such as an aircraft.The only reason you need to vary the timing at all is to prevent kickback onstarting. It should fire late, after tdc at cranking speeds and be fullyadvanced at any useable power settings.If you are still using a point type distributor check that the bushings aregood. If the shaft wobbles the timing wanders. It might be okay on thecylinder you timed it to but be out on some others. A good dwell metershould pick this problem up.You need to concern yourself only with the total advance. It seems as though30 degrees is too much. See if you can get advice from someone like "BigJim" on the max advance. I wouldn't go any more than the car engine doeswith the vacuum disconnected.I still wonder about your induction system, it may be that you are too lean.Too lean can cause detonation which leads to holes in pistons. A leanmixture can burn so slowly that there is still flame in the cylinder whenthe next intake event occurs.When you get it running again, try this as a mixture indicator:Connect a hose to a propane torches shut off valve, and tie the other endso that it feeds well into the carb intake. With the engine running andwarmed up open the propane valve, if the mixture was too lean the additionalpropane will cause the engine to gain rpm. (power)If the engine dies down a bit and recovers when the propane is shut off themixture is about right.Hope this helpsJohn Mc -----Original Message-----________________________________________________________________________________
Domenic If I may sum up of the past timing advice for you:The advance curve and vacum advance are of no value on an engine used forsteady power output such as an aircraft.The only reason you need to vary the timing at all is to prevent kickback onstarting. It should fire late, after tdc at cranking speeds and be fullyadvanced at any useable power settings.If you are still using a point type distributor check that the bushings aregood. If the shaft wobbles the timing wanders. It might be okay on thecylinder you timed it to but be out on some others. A good dwell metershould pick this problem up.You need to concern yourself only with the total advance. It seems as though30 degrees is too much. See if you can get advice from someone like "BigJim" on the max advance. I wouldn't go any more than the car engine doeswith the vacuum disconnected.I still wonder about your induction system, it may be that you are too lean.Too lean can cause detonation which leads to holes in pistons. A leanmixture can burn so slowly that there is still flame in the cylinder whenthe next intake event occurs.When you get it running again, try this as a mixture indicator:Connect a hose to a propane torches shut off valve, and tie the other endso that it feeds well into the carb intake. With the engine running andwarmed up open the propane valve, if the mixture was too lean the additionalpropane will cause the engine to gain rpm. (power)If the engine dies down a bit and recovers when the propane is shut off themixture is about right.Hope this helpsJohn Mc -----Original Message-----________________________________________________________________________________