Original Posted By: Les Lampman
Hi Greg: This may be my own terminology, although it is used by our on field shop.It is where you screw in the compression gauge on a warm engine, and ratherthan just check the cylinder and go on to the next one, you leave the status asis for at least 2 min. to see if the compression leaks down. It seems thatreally well built and properly broken in engines maintain their compression.WarrenGreg Yotz wrote:> I'm not sure what you mean about 'leak down test'? Is this an ongoing test> of the compression so that you know about wear?>> Greg Yotz>> Warren Shoun wrote:>> > Bill,> > With good machine shop work, I think that you will have a great> > power plant. Bored, balanced, polished and flow matched, with today's> > fuel and ignition, you should see 70 hp without any stress or strain. I> > have seen one that dynoed out at 106 hp at 2250 rpm! The actual> > compression of the old "A" was often only 4 or 5 to one so that it could> > run on the fuels of the day. If you build in even a 7 or 8 to one and> > maintain it on a leak down test, you will do very well. You may want to> > consider some type of bolt on harmonic balancer, and these old beauties> > will run forever, and their sound is just good for the soul! Good> > luck.> > Warren> >> > Bill Talbert wrote:> >> > > Warren> > >> > > The 8N motor is way to heavy for flight, what I was thinking> > > is using the "A" block bored for sleeves and bushings and> > > getting away from the babbit. As far as the purists, I bet> > > they are not using vintage gas or plugs, so where do you> > > draw the line?. My hope is to do as you suggest, get more> > > power from the ford.> > >> > > thanks for the quick response> > > Bill________________________________________________________________________________
Pietenpol-List: Re: Leak Down Test
Pietenpol-List: Re: Leak Down Test
Original Posted By: Warren Shoun
Hi,In addition to the test mentioned by Warren there is actually a leak-downtest gauge available. I use one in my shop (I repair outboards). Itconsists of 2 identical pressure gauges mounted together. One end of thegauge unit is connected to an air source, the other screws into the sparkplug hole just like the compression gauge. On my unit there is a knob onthe inlet side that allows me to regulate the air pressure. You set thepiston on your test cylinder to top-dead-center. Then open the inlet valveto 10 PSI (or whatever the gauge instructions say) below your compressor'srating (I use 100 psi). The left gauge shows the inlet pressure, the rightgauge shows the pressure in the cylinder. If the right gauge startsdropping you've got a problem. Because you're supplying air under pressureyou can usually hear where the air is bleeding. Out of the exhaust pipe oroutlet would be the valves (at least the exhaust) or out of the crankcase(by listening at the oil fill) would indicate the rings. I think most autoparts stores have the gauges and they aren't super expensive (I think minewas around $60).Best Regards,Les-----Original Message-----ShounSent: Monday, March 15, 1999 10:21 AMSubject: Pietenpol-List: Re: Leak Down TestHi Greg: This may be my own terminology, although it is used by our on fieldshop.It is where you screw in the compression gauge on a warm engine, and ratherthan just check the cylinder and go on to the next one, you leave the statusasis for at least 2 min. to see if the compression leaks down. It seems thatreally well built and properly broken in engines maintain their compression.WarrenGreg Yotz wrote:> I'm not sure what you mean about 'leak down test'? Is this an ongoingtest> of the compression so that you know about wear?>> Greg Yotz>> Warren Shoun wrote:>> > Bill,> > With good machine shop work, I think that you will have a great> > power plant. Bored, balanced, polished and flow matched, with today's> > fuel and ignition, you should see 70 hp without any stress or strain. I> > have seen one that dynoed out at 106 hp at 2250 rpm! The actual> > compression of the old "A" was often only 4 or 5 to one so that it could> > run on the fuels of the day. If you build in even a 7 or 8 to one and> > maintain it on a leak down test, you will do very well. You may want to> > consider some type of bolt on harmonic balancer, and these old beauties> > will run forever, and their sound is just good for the soul! Good> > luck.> > Warren> >> > Bill Talbert wrote:> >> > > Warren> > >> > > The 8N motor is way to heavy for flight, what I was thinking> > > is using the "A" block bored for sleeves and bushings and> > > getting away from the babbit. As far as the purists, I bet> > > they are not using vintage gas or plugs, so where do you> > > draw the line?. My hope is to do as you suggest, get more> > > power from the ford.> > >> > > thanks for the quick response> > > Bill________________________________________________________________________________
Hi,In addition to the test mentioned by Warren there is actually a leak-downtest gauge available. I use one in my shop (I repair outboards). Itconsists of 2 identical pressure gauges mounted together. One end of thegauge unit is connected to an air source, the other screws into the sparkplug hole just like the compression gauge. On my unit there is a knob onthe inlet side that allows me to regulate the air pressure. You set thepiston on your test cylinder to top-dead-center. Then open the inlet valveto 10 PSI (or whatever the gauge instructions say) below your compressor'srating (I use 100 psi). The left gauge shows the inlet pressure, the rightgauge shows the pressure in the cylinder. If the right gauge startsdropping you've got a problem. Because you're supplying air under pressureyou can usually hear where the air is bleeding. Out of the exhaust pipe oroutlet would be the valves (at least the exhaust) or out of the crankcase(by listening at the oil fill) would indicate the rings. I think most autoparts stores have the gauges and they aren't super expensive (I think minewas around $60).Best Regards,Les-----Original Message-----ShounSent: Monday, March 15, 1999 10:21 AMSubject: Pietenpol-List: Re: Leak Down TestHi Greg: This may be my own terminology, although it is used by our on fieldshop.It is where you screw in the compression gauge on a warm engine, and ratherthan just check the cylinder and go on to the next one, you leave the statusasis for at least 2 min. to see if the compression leaks down. It seems thatreally well built and properly broken in engines maintain their compression.WarrenGreg Yotz wrote:> I'm not sure what you mean about 'leak down test'? Is this an ongoingtest> of the compression so that you know about wear?>> Greg Yotz>> Warren Shoun wrote:>> > Bill,> > With good machine shop work, I think that you will have a great> > power plant. Bored, balanced, polished and flow matched, with today's> > fuel and ignition, you should see 70 hp without any stress or strain. I> > have seen one that dynoed out at 106 hp at 2250 rpm! The actual> > compression of the old "A" was often only 4 or 5 to one so that it could> > run on the fuels of the day. If you build in even a 7 or 8 to one and> > maintain it on a leak down test, you will do very well. You may want to> > consider some type of bolt on harmonic balancer, and these old beauties> > will run forever, and their sound is just good for the soul! Good> > luck.> > Warren> >> > Bill Talbert wrote:> >> > > Warren> > >> > > The 8N motor is way to heavy for flight, what I was thinking> > > is using the "A" block bored for sleeves and bushings and> > > getting away from the babbit. As far as the purists, I bet> > > they are not using vintage gas or plugs, so where do you> > > draw the line?. My hope is to do as you suggest, get more> > > power from the ford.> > >> > > thanks for the quick response> > > Bill________________________________________________________________________________
Pietenpol-List: Re: Leak Down Test
Original Posted By: Greg Yotz
Hi Les, Thanks for the added info. This is what I really like about this diversifiedgroup---some new and useful info on a regular basis.WarrenLes Lampman wrote:> Hi,>> In addition to the test mentioned by Warren there is actually a leak-down> test gauge available. I use one in my shop (I repair outboards). It> consists of 2 identical pressure gauges mounted together. One end of the> gauge unit is connected to an air source, the other screws into the spark> plug hole just like the compression gauge. On my unit there is a knob on> the inlet side that allows me to regulate the air pressure. You set the> piston on your test cylinder to top-dead-center. Then open the inlet valve> to 10 PSI (or whatever the gauge instructions say) below your compressor's> rating (I use 100 psi). The left gauge shows the inlet pressure, the right> gauge shows the pressure in the cylinder. If the right gauge starts> dropping you've got a problem. Because you're supplying air under pressure> you can usually hear where the air is bleeding. Out of the exhaust pipe or> outlet would be the valves (at least the exhaust) or out of the crankcase> (by listening at the oil fill) would indicate the rings. I think most auto> parts stores have the gauges and they aren't super expensive (I think mine> was around $60).>> Best Regards,> Les>> -----.________________________________________________________________________________
Hi Les, Thanks for the added info. This is what I really like about this diversifiedgroup---some new and useful info on a regular basis.WarrenLes Lampman wrote:> Hi,>> In addition to the test mentioned by Warren there is actually a leak-down> test gauge available. I use one in my shop (I repair outboards). It> consists of 2 identical pressure gauges mounted together. One end of the> gauge unit is connected to an air source, the other screws into the spark> plug hole just like the compression gauge. On my unit there is a knob on> the inlet side that allows me to regulate the air pressure. You set the> piston on your test cylinder to top-dead-center. Then open the inlet valve> to 10 PSI (or whatever the gauge instructions say) below your compressor's> rating (I use 100 psi). The left gauge shows the inlet pressure, the right> gauge shows the pressure in the cylinder. If the right gauge starts> dropping you've got a problem. Because you're supplying air under pressure> you can usually hear where the air is bleeding. Out of the exhaust pipe or> outlet would be the valves (at least the exhaust) or out of the crankcase> (by listening at the oil fill) would indicate the rings. I think most auto> parts stores have the gauges and they aren't super expensive (I think mine> was around $60).>> Best Regards,> Les>> -----.________________________________________________________________________________
Pietenpol-List: Re: Leak Down Test
Original Posted By: "Sayre, William G"
That makes perfect sense. Very much like my gauges for auto A/C. When I get tothe engine rebuilding phase...(a little farther down the line..) I'll understandhow to check compression better.I'm trying to add to my 'A' knowledge more and more. I know a few have discussedthe use of a 'A' off of a combine but I never did hear if anyone has used one foraPiet. I bring this up because I think I've found two but I haven't gone and lookedat them yet. I wanted to know if I was wasting my time.Greg YotzWarren Shoun wrote:> Hi Greg:> This may be my own terminology, although it is used by our on field shop.> It is where you screw in the compression gauge on a warm engine, and rather> than just check the cylinder and go on to the next one, you leave the statusas> is for at least 2 min. to see if the compression leaks down. It seems that> really well built and properly broken in engines maintain their compression.> Warren>> Greg Yotz wrote:>> > I'm not sure what you mean about 'leak down test'? Is this an ongoing test> > of the compression so that you know about wear?> >> > Greg Yotz> >> > Warren Shoun wrote:> >> > > Bill,> > > With good machine shop work, I think that you will have a great> > > power plant. Bored, balanced, polished and flow matched, with today's> > > fuel and ignition, you should see 70 hp without any stress or strain. I> > > have seen one that dynoed out at 106 hp at 2250 rpm! The actual> > > compression of the old "A" was often only 4 or 5 to one so that it could> > > run on the fuels of the day. If you build in even a 7 or 8 to one and> > > maintain it on a leak down test, you will do very well. You may want to> > > consider some type of bolt on harmonic balancer, and these old beauties> > > will run forever, and their sound is just good for the soul! Good> > > luck.> > > Warren> > >> > > Bill Talbert wrote:> > >> > > > Warren> > > >> > > > The 8N motor is way to heavy for flight, what I was thinking> > > > is using the "A" block bored for sleeves and bushings and> > > > getting away from the babbit. As far as the purists, I bet> > > > they are not using vintage gas or plugs, so where do you> > > > draw the line?. My hope is to do as you suggest, get more> > > > power from the ford.> > > >> > > > thanks for the quick response> > > > Bill________________________________________________________________________________
That makes perfect sense. Very much like my gauges for auto A/C. When I get tothe engine rebuilding phase...(a little farther down the line..) I'll understandhow to check compression better.I'm trying to add to my 'A' knowledge more and more. I know a few have discussedthe use of a 'A' off of a combine but I never did hear if anyone has used one foraPiet. I bring this up because I think I've found two but I haven't gone and lookedat them yet. I wanted to know if I was wasting my time.Greg YotzWarren Shoun wrote:> Hi Greg:> This may be my own terminology, although it is used by our on field shop.> It is where you screw in the compression gauge on a warm engine, and rather> than just check the cylinder and go on to the next one, you leave the statusas> is for at least 2 min. to see if the compression leaks down. It seems that> really well built and properly broken in engines maintain their compression.> Warren>> Greg Yotz wrote:>> > I'm not sure what you mean about 'leak down test'? Is this an ongoing test> > of the compression so that you know about wear?> >> > Greg Yotz> >> > Warren Shoun wrote:> >> > > Bill,> > > With good machine shop work, I think that you will have a great> > > power plant. Bored, balanced, polished and flow matched, with today's> > > fuel and ignition, you should see 70 hp without any stress or strain. I> > > have seen one that dynoed out at 106 hp at 2250 rpm! The actual> > > compression of the old "A" was often only 4 or 5 to one so that it could> > > run on the fuels of the day. If you build in even a 7 or 8 to one and> > > maintain it on a leak down test, you will do very well. You may want to> > > consider some type of bolt on harmonic balancer, and these old beauties> > > will run forever, and their sound is just good for the soul! Good> > > luck.> > > Warren> > >> > > Bill Talbert wrote:> > >> > > > Warren> > > >> > > > The 8N motor is way to heavy for flight, what I was thinking> > > > is using the "A" block bored for sleeves and bushings and> > > > getting away from the babbit. As far as the purists, I bet> > > > they are not using vintage gas or plugs, so where do you> > > > draw the line?. My hope is to do as you suggest, get more> > > > power from the ford.> > > >> > > > thanks for the quick response> > > > Bill________________________________________________________________________________
Pietenpol-List: Re: Leak Down Test
Original Posted By: Michael Conkling
I had always heard this refered to as a differential pressure test. The"leak-down" test that I'm familiar is described in the Cont. O/H manualand is performed with Continentals, as well as other engines withhydraulic lifters, to measure the amount of leakage in the lifter itself. KenOn Mon, 15 Mar 1999, Warren Shoun wrote:> Hi Greg:> This may be my own terminology, although it is used by our on field> shop. It is where you screw in the compression gauge on a warm engine,> and rather than just check the cylinder and go on to the next one, you> leave the status as is for at least 2 min. to see if the compression> leaks down. It seems that really well built and properly broken in> engines maintain their compression. Warren> > Greg Yotz wrote:> > > I'm not sure what you mean about 'leak down test'? Is this an ongoing test> > of the compression so that you know about wear?> ________________________________________________________________________________
I had always heard this refered to as a differential pressure test. The"leak-down" test that I'm familiar is described in the Cont. O/H manualand is performed with Continentals, as well as other engines withhydraulic lifters, to measure the amount of leakage in the lifter itself. KenOn Mon, 15 Mar 1999, Warren Shoun wrote:> Hi Greg:> This may be my own terminology, although it is used by our on field> shop. It is where you screw in the compression gauge on a warm engine,> and rather than just check the cylinder and go on to the next one, you> leave the status as is for at least 2 min. to see if the compression> leaks down. It seems that really well built and properly broken in> engines maintain their compression. Warren> > Greg Yotz wrote:> > > I'm not sure what you mean about 'leak down test'? Is this an ongoing test> > of the compression so that you know about wear?> ________________________________________________________________________________
> Re: Leak Down Test
Original Posted By: jmcnarry(at)techplus.com (John McNarry)
Subject: Pietenpol-List: RE: Leak Down Test>Hi Ken,>>Probably lots of names for the same beast running around. I walked intothe>auto supply place and asked for a leak-down tester and they handed me the>contraption I described. Which was actually what I wanted for once! I>think the main thing is to know what you're testing for ... that is, if>you're wanting to test the valves and rings beyond the simple compression>test get the unit I described; whether it's a differential pressure tester>or a leak-down tester. Tell the folks at your tool supply place what you>want to accomplish and see what they call the thing
.>>Cheers,>Les>>-----Original Message----->Beanlands>Sent: Monday, March 15, 1999 4:07 PM>To: Pietenpol Discussion>Subject: Re: Leak Down Test>>I had always heard this refered to as a differential pressure test. The>"leak-down" test that I'm familiar is described in the Cont. O/H manual>and is performed with Continentals, as well as other engines with>hydraulic lifters, to measure the amount of leakage in the lifter itself.>>Ken>>On Mon, 15 Mar 1999, Warren Shoun wrote:>>> Hi Greg:>> This may be my own terminology, although it is used by our on field>> shop. It is where you screw in the compression gauge on a warm engine,>> and rather than just check the cylinder and go on to the next one, you>> leave the status as is for at least 2 min. to see if the compression>> leaks down. It seems that really well built and properly broken in>> engines maintain their compression. Warren>>>> Greg Yotz wrote:>>>> > I'm not sure what you mean about 'leak down test'? Is this an ongoing>test>> > of the compression so that you know about wear?>>>>________________________________________________________________________________
Subject: Pietenpol-List: RE: Leak Down Test>Hi Ken,>>Probably lots of names for the same beast running around. I walked intothe>auto supply place and asked for a leak-down tester and they handed me the>contraption I described. Which was actually what I wanted for once! I>think the main thing is to know what you're testing for ... that is, if>you're wanting to test the valves and rings beyond the simple compression>test get the unit I described; whether it's a differential pressure tester>or a leak-down tester. Tell the folks at your tool supply place what you>want to accomplish and see what they call the thing
.>>Cheers,>Les>>-----Original Message----->Beanlands>Sent: Monday, March 15, 1999 4:07 PM>To: Pietenpol Discussion>Subject: Re: Leak Down Test>>I had always heard this refered to as a differential pressure test. The>"leak-down" test that I'm familiar is described in the Cont. O/H manual>and is performed with Continentals, as well as other engines with>hydraulic lifters, to measure the amount of leakage in the lifter itself.>>Ken>>On Mon, 15 Mar 1999, Warren Shoun wrote:>>> Hi Greg:>> This may be my own terminology, although it is used by our on field>> shop. It is where you screw in the compression gauge on a warm engine,>> and rather than just check the cylinder and go on to the next one, you>> leave the status as is for at least 2 min. to see if the compression>> leaks down. It seems that really well built and properly broken in>> engines maintain their compression. Warren>>>> Greg Yotz wrote:>>>> > I'm not sure what you mean about 'leak down test'? Is this an ongoing>test>> > of the compression so that you know about wear?>>>>________________________________________________________________________________Pietenpol-List: Re: Leak Down Test
Original Posted By: Greg Yotz
Hi Ken,Probably lots of names for the same beast running around. I walked into theauto supply place and asked for a leak-down tester and they handed me thecontraption I described. Which was actually what I wanted for once! Ithink the main thing is to know what you're testing for ... that is, ifyou're wanting to test the valves and rings beyond the simple compressiontest get the unit I described; whether it's a differential pressure testeror a leak-down tester. Tell the folks at your tool supply place what youwant to accomplish and see what they call the thing .Cheers,Les-----Original Message-----BeanlandsSent: Monday, March 15, 1999 4:07 PMSubject: Pietenpol-List: Re: Leak Down TestI had always heard this refered to as a differential pressure test. The"leak-down" test that I'm familiar is described in the Cont. O/H manualand is performed with Continentals, as well as other engines withhydraulic lifters, to measure the amount of leakage in the lifter itself.KenOn Mon, 15 Mar 1999, Warren Shoun wrote:> Hi Greg:> This may be my own terminology, although it is used by our on field> shop. It is where you screw in the compression gauge on a warm engine,> and rather than just check the cylinder and go on to the next one, you> leave the status as is for at least 2 min. to see if the compression> leaks down. It seems that really well built and properly broken in> engines maintain their compression. Warren>> Greg Yotz wrote:>> > I'm not sure what you mean about 'leak down test'? Is this an ongoingtest> > of the compression so that you know about wear?>________________________________________________________________________________
Hi Ken,Probably lots of names for the same beast running around. I walked into theauto supply place and asked for a leak-down tester and they handed me thecontraption I described. Which was actually what I wanted for once! Ithink the main thing is to know what you're testing for ... that is, ifyou're wanting to test the valves and rings beyond the simple compressiontest get the unit I described; whether it's a differential pressure testeror a leak-down tester. Tell the folks at your tool supply place what youwant to accomplish and see what they call the thing
.Cheers,Les-----Original Message-----BeanlandsSent: Monday, March 15, 1999 4:07 PMSubject: Pietenpol-List: Re: Leak Down TestI had always heard this refered to as a differential pressure test. The"leak-down" test that I'm familiar is described in the Cont. O/H manualand is performed with Continentals, as well as other engines withhydraulic lifters, to measure the amount of leakage in the lifter itself.KenOn Mon, 15 Mar 1999, Warren Shoun wrote:> Hi Greg:> This may be my own terminology, although it is used by our on field> shop. It is where you screw in the compression gauge on a warm engine,> and rather than just check the cylinder and go on to the next one, you> leave the status as is for at least 2 min. to see if the compression> leaks down. It seems that really well built and properly broken in> engines maintain their compression. Warren>> Greg Yotz wrote:>> > I'm not sure what you mean about 'leak down test'? Is this an ongoingtest> > of the compression so that you know about wear?>________________________________________________________________________________Pietenpol-List: Re: Leak Down Test
Original Posted By: Les Lampman
It all a matter of semantics guys. The differential pressure test or as wecall it in the heavy Diesel trade cylinder leakage test will help you todecide where the leakage is. We usually use regulated air supply set at 100psi and then it is an easy mental calculation to come up with a percentagefor leakage. No cylinders are going to seal at 100%. You may also find thatthe results will change depending on when the engine was run last and if itwas working or just idling. The point is that you can only use these testfor comparitve purposes. The real test comes in how much power the enginewill produce. If you perform the tests regularly and establish a base foryour engine then you will be able to monitor change. I'll bet that you willnotice any changes by the way the engine performs before you discover themby testing.The shop that does the annual on the PA12 I sometimes fly told us it neededa major 5 yrs ago. His assement was based on his differential pressure testresults. The aircrafts owner and I couldn't see that as we both knew theengine was performing well when we last flew it. Sure enough when we pulledit through by hand the cylinders felt soft.(the engine had not been run forseveral weeks) We flew a couple of circuits and retested the engine itpassed on all cylinders. The point is that many things can vary testresults.John Mc-----Original Message-----
It all a matter of semantics guys. The differential pressure test or as wecall it in the heavy Diesel trade cylinder leakage test will help you todecide where the leakage is. We usually use regulated air supply set at 100psi and then it is an easy mental calculation to come up with a percentagefor leakage. No cylinders are going to seal at 100%. You may also find thatthe results will change depending on when the engine was run last and if itwas working or just idling. The point is that you can only use these testfor comparitve purposes. The real test comes in how much power the enginewill produce. If you perform the tests regularly and establish a base foryour engine then you will be able to monitor change. I'll bet that you willnotice any changes by the way the engine performs before you discover themby testing.The shop that does the annual on the PA12 I sometimes fly told us it neededa major 5 yrs ago. His assement was based on his differential pressure testresults. The aircrafts owner and I couldn't see that as we both knew theengine was performing well when we last flew it. Sure enough when we pulledit through by hand the cylinders felt soft.(the engine had not been run forseveral weeks) We flew a couple of circuits and retested the engine itpassed on all cylinders. The point is that many things can vary testresults.John Mc-----Original Message-----