Brodhead Pietenpol Association

Original Posted By: walter evans
For all of you guys who wanted this, This isn't fancy and you can make it at home. All that you need is acontinuity light. You can use one of those flashlights with thealligator clip plug in if you have it. Or make it with a flashlightbattery soldered to a flashlight bulb with some wires attached ( hook itup so that when the ends of the long test wires touch , the light comeson). First I would pull the plugs, so your not fighting the compression. Then hook the gadget with one wire end to the engine case (or ground)The other lead goes to the terminal out of the mag that would go to thekill switch on the dashboard( either disconnect the kill switch or putin on position, this is so not to have a parallel circuit).Now setting the timing, is to make the points open when the engine is inthe exact BTDC degree position that is required in the CORRECT rotation. Have the bulb laying like on top of the engine so you can see it realwell.Now rotate the prop so the timing mark starts at , say 9:00 and rotatetill the light goes from full bright , to dimmer. This is the exactpoint that the points open. This should be right at the timing mark. If not loosen the mag hold down nuts and rotate slightly. When You getit correct tighten the mag and recheck the timing, it might move whenit's tightened.Remember only check the mark to the bulb in the correct engine rotation(not each time when you turn it slightly backwards to try it again) When you check the impulse mag, you must pull it past the impulseclick, then back up to a point that the points are closed but not farenough to get into the impulse. I haven't looked that close at my Continental 65 to know about timingmarks, but the 1/2 VW , that Dick Lawson ( my AP) built for me, had aBendix mag on it . Dick explained the right way to find TDC ( top deadcenter) of an engine that has no marks. If you just stick a screwdriverin a cyl. the piston will seem to be on top through quite a sweep ofdegrees of the crank. Heres what you do. He has a tool that fits inthe sparkplug hole, but you can just make one. find a bolt or post( wooddowell would probably be good) and secure it somehow so that it willbump the top of the piston. Be careful not to damage the threads inspark plug hole. Make it hit as close to the top without letting it goover the top..When you are set, rotate the crank in one direction till it solidlybumps the stop. put a mark on the shaft to the split in the case( usingthis for refference, now rotate the other way till bump. Mark the crankto the same split in case.The space between these marks is the exact TDC. Do it this way becauseany looseness in rod bearing or wrist pin will be cancelled out . Markit as TDC. then using a protractor measure in degrees to the right ( ifclockwise rotation) and mark this as timing mark. This timing mark isthe one to use with the light gadget.So the most you'll have to pay for the whole process , includingbattery, bulb, and protractor, is about $4:00.BE CAREFULL..... IF YOU TRY TO TIME WITH PLUGS IN AND WIRES ON, BYOPENING THE KILL SWITCH TO DO THE TEST, THE MAG WILL BE HOT AND THEENGINE WILL FIRE. A mag that has the small wire disconnected is readyto run.Whew,walt PS Dick Lawson has taught me a wealth of building tips( but I'm sureI've only scratched his surface) Stuff like making a beautiful "backrivit joint" ( think I named it right) to make a flush flathead rivitjoint like on the surface of a Cessna. With a simple homemade tool.OR. Annealling 6061 aluminum to make it work like taffy withoutcracking, and how it rehardens.waltFor all of you guys who wantedthis, This isn't fancyand you canmake it at home. All that you need is a continuity light. You canuse oneof those flashlights with the alligator clip plug in if you have it. Ormake itwith a flashlight battery soldered to a flashlight bulb with some wiresattached( hook it up so that when the ends of the long test wires touch , thelightcomes on).First I would pull the plugs,so your notfighting the compression. Then hook the gadget with one wire endto theengine case (or ground) The other lead goes to the terminal out of themag thatwould go to the kill switch on the dashboard( either disconnect the killswitchor put in on position, this is so not to have a parallelcircuit).Now setting the timing, is to makethe pointsopen when the engine is in the exact BTDC degree position that isrequired inthe CORRECT rotation. Have the bulb laying like on top of theengine soyou can see it real well.Now rotate the prop so the timingmark starts at, say 9:00 and rotate till the light goes from full bright , todimmer.This is the exact point that the points open. This should be rightat thetiming mark. If not loosen the mag hold down nuts and rotateslightly.When You get it correct tighten the mag and recheck the timing, it mightmovewhen it's tightened.Remember only check the mark to thebulb in thecorrect engine rotation( not each time when you turn it slightlybackwards totry it again) When you checkthe impulsemag, you must pull it past the impulse click, then back up to apoint thatthe points are closed but not far enough to get into theimpulse. I haven't looked thatclose at myContinental 65 to know about timing marks, but the 1/2 VW , that DickLawson (my AP) built for me, had a Bendix mag on it . Dick explainedtheright way to find TDC ( top dead center) of an engine that has nomarks.If you just stick a screwdriver in a cyl. the piston will seem to be ontopthrough quite a sweep of degrees of the crank. Heres what youdo. Hehas a tool that fits in the sparkplug hole, but you can just make one.find abolt or post( wood dowell would probably be good) and secure it somehowso thatit will bump the top of the piston. Be careful not to damage thethreadsin spark plug hole. Make it hit as close to the top withoutletting it goover the top..When you are set, rotate the crankin onedirection till it solidly bumps the stop. put a mark on the shaftto thesplit in the case( using this for refference, now rotate the other waytillbump. Mark the crank to the same split in case.The space between these marks is theexactTDC. Do it this way because any looseness in rod bearing or wristpin willbe cancelled out . Mark it as TDC. then using a protractor measure indegrees tothe right ( if clockwise rotation) and mark this as timing mark.Thistiming mark is the one to use with the light gadget.So the most you'll have to pay for the whole process,including battery, bulb, and protractor, is about $4:00.BE CAREFULL..... IF YOU TRY TO TIME WITH PLUGS INAND WIRESON, BY OPENING THE KILL SWITCH TO DO THE TEST, THE MAG WILL BE HOT ANDTHEENGINE WILL FIRE. A mag that has the small wire disconnected isready torun.Whew,waltPS Dick Lawson has taught me a wealth ofbuilding tips(but I'm sure I've only scratched his surface) Stuff like making abeautiful back rivit joint ( think I named it right) to makea flushflathead rivit joint like on the surface of a Cessna. With a simplehomemadetool.OR. Annealling 6061 aluminum sp tomake it worklike taffy without cracking, and how it rehardens.walt ________________________________________________________________________________

Original Posted By: Mike Chanter
Just a few notes, a good timing light has another function other thanjust a continuity checker. It also grounds the mag so it won't fire. Ifyou do have the plugs in, to check timing you either need to turn themags on or disconnect the "P" lead. This will leave the mag hot and itcould fire as you turn the prop. If you have a combustible fuel airmixture in the cylinder and the plug fires, the engine will start. Ifyou are in the way of the prop you will get hurt! You can use acontinuity checker but it won't provide the safety of a true timinglight.walter evans wrote:> For all of you guys who wanted this, This isn't fancy and you can> make it at home. All that you need is a continuity light. You can use> one of those flashlights with the alligator clip plug in if you have> it. Or make it with a flashlight battery soldered to a flashlight bulb> with some wires attached ( hook it up so that when the ends of the> long test wires touch , the light comes on). First I would pull the> plugs, so your not fighting the compression. Then hook the gadget> with one wire end to the engine case (or ground) The other lead goes> to the terminal out of the mag that would go to the kill switch on the> dashboard( either disconnect the kill switch or put in on position,> this is so not to have a parallel circuit).Now setting the timing, is> to make the points open when the engine is in the exact BTDC degree> position that is required in the CORRECT rotation. Have the bulb> laying like on top of the engine so you can see it real well.Now> rotate the prop so the timing mark starts at , say 9:00 and rotate> till the light goes from full bright , to dimmer. This is the exact> point that the points open. This should be right at the timing mark.> If not loosen the mag hold down nuts and rotate slightly. When You get> it correct tighten the mag and recheck the timing, it might move when> it's tightened.Remember only check the mark to the bulb in the correct> engine rotation( not each time when you turn it slightly backwards to> try it again) When you check the impulse mag, you must pull it> past the impulse click, then back up to a point that the points are> closed but not far enough to get into the impulse. I haven't looked> that close at my Continental 65 to know about timing marks, but the> 1/2 VW , that Dick Lawson ( my AP) built for me, had a Bendix mag on> it . Dick explained the right way to find TDC ( top dead center) of> an engine that has no marks. If you just stick a screwdriver in a> cyl. the piston will seem to be on top through quite a sweep of> degrees of the crank. Heres what you do. He has a tool that fits in> the sparkplug hole, but you can just make one. find a bolt or post(> wood dowell would probably be good) and secure it somehow so that it> will bump the top of the piston. Be careful not to damage the threads> in spark plug hole. Make it hit as close to the top without letting> it go over the top..When you are set, rotate the crank in one> direction till it solidly bumps the stop. put a mark on the shaft to> the split in the case( using this for refference, now rotate the other> way till bump. Mark the crank to the same split in case.The space> between these marks is the exact TDC. Do it this way because any> looseness in rod bearing or wrist pin will be cancelled out . Mark it> as TDC. then using a protractor measure in degrees to the right ( if> clockwise rotation) and mark this as timing mark. This timing mark is> the one to use with the light gadget.So the most you'll have to pay> for the whole process , including battery, bulb, and protractor, is> about $4:00.BE CAREFULL..... IF YOU TRY TO TIME WITH PLUGS IN AND> WIRES ON, BY OPENING THE KILL SWITCH TO DO THE TEST, THE MAG WILL BE> HOT AND THE ENGINE WILL FIRE. A mag that has the small wire> disconnected is ready to run.Whew,walt PS Dick Lawson has taught me a> wealth of building tips( but I'm sure I've only scratched his> surface) Stuff like making a beautiful "back rivit joint" ( think I> named it right) to make a flush flathead rivit joint like on the> surface of a Cessna. With a simple homemade tool.OR. Annealling 6061> aluminum to make it work like taffy without cracking, and how it> rehardens.walt--David B.Schober, CPEInstructor, Aviation MaintenanceFairmont State CollegeNational Aerospace Education Center1050 East Benedum Industrial DriveBridgeport, WV 26330-9503(304) 842-8300Just a few notes, a good timing light has another function other than justa continuity checker. It also grounds the mag so it won't fire. If youdo have the plugs in, to check timing you either need to turn the magson or disconnect the "P" lead. This will leave the mag hot and it couldfire as you turn the prop. If you have a combustible fuel air mixture inthe cylinder and the plug fires, the engine will start. If you are in theway of the prop you will get hurt! You can use a continuity checker butit won't provide the safety of a true timing light.walter evans wrote:For allof you guys who wanted this,This isn't fancy and you can make it at home. All that you need is a continuitylight. You can use one of those flashlights with the alligator clipplug in if you have it. Or make it with a flashlight battery soldered toa flashlight bulb with some wires attached ( hook it up so that when theends of the long test wires touch , the light comes on).FirstI would pull the plugs, so your not fighting the compression. Thenhook the gadget with one wire end to the engine case (or ground) The otherlead goes to the terminal out of the mag that would go to the kill switchon the dashboard( either disconnect the kill switch or put in on position,this is so not to have a parallel circuit).Nowsetting the timing, is to make the points open when the engine is in theexact BTDC degree position that is required in the CORRECT rotation.Have the bulb laying like on top of the engine so you can see it real well.Nowrotate the prop so the timing mark starts at , say 9:00 and rotate tillthe light goes from full bright , to dimmer. This is the exact pointthat the points open. This should be right at the timing mark.If not loosen the mag hold down nuts and rotate slightly. When You getit correct tighten the mag and recheck the timing, it might move when it'stightened.Remember onlycheck the mark to the bulb in the correct engine rotation( not each timewhen you turn it slightly backwards to try it again)When you check the impulse mag, you must pull it past the impulseclick, then back up to a point that the points are closed but not far enoughto get into the impulse.I haven't looked that close at my Continental 65 to know about timing marks,but the 1/2 VW , that Dick Lawson ( my AP) built for me, had a Bendixmag on it . Dick explained the right way to find TDC ( top dead center)of an engine that has no marks. If you just stick a screwdriver ina cyl. the piston will seem to be on top through quite a sweep of degreesof the crank. Heres what you do. He has a tool that fits inthe sparkplug hole, but you can just make one. find a bolt or post( wooddowell would probably be good) and secure it somehow so that it will bumpthe top of the piston. Be careful not to damage the threads in sparkplug hole. Make it hit as close to the top without letting it goover the top..When youare set, rotate the crank in one direction till it solidly bumps the stop.put a mark on the shaft to the split in the case( using this for refference,now rotate the other way till bump. Mark the crank to the same split incase.The space betweenthese marks is the exact TDC. Do it this way because any loosenessin rod bearing or wrist pin will be cancelled out . Mark it as TDC. thenusing a protractor measure in degrees to the right ( if clockwise rotation)and mark this as timing mark. This timing mark is the one to usewith the light gadget.So the most you'll haveto pay for the whole process , including battery, bulb, and protractor,is about $4:00.BE CAREFULL..... IF YOU TRY TO TIMEWITH PLUGS IN AND WIRES ON, BY OPENING THE KILL SWITCH TO DO THE TEST,THE MAG WILL BE HOT AND THE ENGINE WILL FIRE. A mag that has thesmall wire disconnected is ready to run.Whew,waltPSDick Lawson has taught me a wealth of building tips( but I'm sure I'veonly scratched his surface) Stuff like making a beautiful "back rivitjoint" ( think I named it right) to make a flush flathead rivit joint likeon the surface of a Cessna. With a simple homemade tool.OR.Annealling 6061 aluminum sp> to make it work like taffy without cracking,and how it rehardens.walt--David B.Schober, CPEInstructor, Aviation MaintenanceFairmont State CollegeNational Aerospace Education Center1050 East Benedum Industrial DriveBridgeport, WV 26330-9503(304) 842-8300________________________________________________________________________________