The LyCon STC allows the Lycoming data plate to be stricken with new data. Basically, you install the LyCon data plate, then on top of that plate which has a place to put the Lycoming data plate with the old data lined out and the new data engraved upon it.
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Converting a 150hp to 160hp or is it 10:1?
- Thread starter Lawn Dart
- Start date
Pardon if this is redundant.
All of these topics I've found on this subject seem to be about certified aircraft. I've got a o-320a2b narrow deck engine on an experimental. I'd like to simply slap a set of 10:1 pistons in her. I dont care about stc's etc. Any issues I need to be concerned with on how the engine will run long term? Thanks
All of these topics I've found on this subject seem to be about certified aircraft. I've got a o-320a2b narrow deck engine on an experimental. I'd like to simply slap a set of 10:1 pistons in her. I dont care about stc's etc. Any issues I need to be concerned with on how the engine will run long term? Thanks
jgerard
Registered User
Seattle, WA
all 8.5:1 (160 hp) and higher compression ratio engines have chrome or nitrated cylinders. The standard steel cylinders do not hold up that long with high compression cylinders before you begin to wear the bore at the BTC and TDC of the stroke.
There are plenty of narrow deck 150's with the 8.5:1 160hp pistons in them and no stud kit or banana plates installed. Not sure I would put 10:1 in a 150hp narrow deck with out them.
Jason
Jason
There are plenty of narrow deck 150's with the 8.5:1 160hp pistons in them and no stud kit or banana plates installed. Not sure I would put 10:1 in a 150hp narrow deck with out them.
Jason
Jason
jgerard
Registered User
Seattle, WA
I think the stud kit is up to around $1200 now. When using the banana plates on the narrow deck engines you need longer cylinder hold down studs. All 160hp and up narrow deck engines have the banana plates. If you look in the parts book you'll see what I'm talking about when comparing the difference between 150-160 hp narrow deck 320's
Jason
Jason
Cub Builder
MEMBER
North Central AR
Notes from my web site when I built the 160 O-320-E2G (Wide Deck) for my SC clone. <http://jeffsplanes.com>
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For those interested in doing the 150 to 160 hp conversion, the cylinders, pistons, wrist pins and rings are all different. Make sure you get the right parts.
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If I remember correctly, the wrist pins have a thicker wall, although external dimensions are the same. The cylinders were a choked bore, although you can probably get away without that, and the 160 pistons had a wider ring groove, so the rings were also different, but you would change them with the pistons anyway. Since my engine is a WD, I didn't have to deal with stud kits and banana plates.
-CubBuilder
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For those interested in doing the 150 to 160 hp conversion, the cylinders, pistons, wrist pins and rings are all different. Make sure you get the right parts.
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If I remember correctly, the wrist pins have a thicker wall, although external dimensions are the same. The cylinders were a choked bore, although you can probably get away without that, and the 160 pistons had a wider ring groove, so the rings were also different, but you would change them with the pistons anyway. Since my engine is a WD, I didn't have to deal with stud kits and banana plates.
-CubBuilder
SchulerJL
BENEFACTOR
Peoria, Illinois
So the crankshaft, carb, carb heat box, alternator, starter - are all the same for the 150 to 160 conversion? How about going to 180hp?
jgerard
Registered User
Seattle, WA
An O-360 has the same bore diameter but has a different case, camshaft, crankshaft, sump, and carb. The 320-360 conversion is called an engine swap 
If you want an 180hp 0-340 like the carbon cubs have with the electronic ignition you need the ECI stroker 0-340 crankshaft kit which is for the 0-320 series engines.
Jason
If you want an 180hp 0-340 like the carbon cubs have with the electronic ignition you need the ECI stroker 0-340 crankshaft kit which is for the 0-320 series engines.
Jason
SchulerJL
BENEFACTOR
Peoria, Illinois
An O-360 has the same bore diameter but has a different case, camshaft, crankshaft, sump, and carb. The 320-360 conversion is called an engine swap
If you want an 180hp 0-340 like the carbon cubs have with the electronic ignition you need the ECI stroker 0-340 crankshaft kit which is for the 0-320 series engines.
Jason
For the 150 to 160 however, the carb, airbox, starter etc are all the same?
jgerard
Registered User
Seattle, WA
skywagon8a
MEMBER
SE Mass MA6
This is from the TC data sheet: [** See latest revision of Lycoming Service Instruction 1523 for alternate carburetors.] It seems that the carburetors are different.
Lycoming Service Instruction 1523
http://www.lycoming.com/support/publications/service-instructions/pdfs/SI1523A.pdf
Darrel Starr
Registered User
Plymouth, MN
To install a 160hp O-320 in a Super Cub using the Cubcrafters STC, the carb required is a -32, with a straight riser.
There is no advantage to a narrow deck and no particular disadvantage. Lycoming changed to get rid of the banana plates and the internal (strange) hold down nuts.
There is no advantage to a narrow deck and no particular disadvantage. Lycoming changed to get rid of the banana plates and the internal (strange) hold down nuts.
I did a few back when they could be done with a field approval. I have also done the STC versions. if it's on a type certified aircraft, no matter how it's done it has to be accomplished with approved data, and a form 337 completed as part of the records. Changing the horsepower rating is a major alteration by definition. and ya, if you are installing per an STC, you have to use all the stuff the stc says to use.... so if they specify a -32 carb, thats what you are supposed to put on. usually, however, you can do a minor alteration to the installation with no problem, but the IA needs to clear it with the PMI first.
the only real change is the piston... the carb is the same. Lycoming/Marvel Shebler/Precision/Tempest/MSA and who ever else made numbers on these carbs.... no matter, slightly different numbers, but those represent minor changes & the carb is the same.
as far as I know, all barrels are made with a choke bore. that helps them be "on size" when the engine is operating. the degree of choke can vary per manufacturer though.
the cylinder hold down plates were required on narrow deck engines with high compression. there was a 160 narrow deck built standard as far back as the late 50s. I don't know why the FAA won't approve the narrow deck alteration since it is only a configuration change on an existing line of approved products. no reason why it wouldn't work, but thats what my PMI told me... no approval
the only real change is the piston... the carb is the same. Lycoming/Marvel Shebler/Precision/Tempest/MSA and who ever else made numbers on these carbs.... no matter, slightly different numbers, but those represent minor changes & the carb is the same.
as far as I know, all barrels are made with a choke bore. that helps them be "on size" when the engine is operating. the degree of choke can vary per manufacturer though.
the cylinder hold down plates were required on narrow deck engines with high compression. there was a 160 narrow deck built standard as far back as the late 50s. I don't know why the FAA won't approve the narrow deck alteration since it is only a configuration change on an existing line of approved products. no reason why it wouldn't work, but thats what my PMI told me... no approval
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Darrel Starr
Registered User
Plymouth, MN
We changed to 160 hp with a log book entry. All inside the TCDS - minor change, wide or narrow deck.
wow... did you guys ask the FAA what they thought of that? I have switched TCM IO520s from E to D by log entry using their SB. and to me it makes sense, but that's not the line I got from my local FSDO with regards to Lycoming. They have a different take on it... they are reading that 4th paragraph as the rule
"Service Instruction No. 1304J
SUBJECT: Engine Nameplate Replacement
MODELS AFFECTED: All Textron Lycoming aircraft engines.
TIME OF COMPLIANCE: Whenever a nameplate is lost or an engine modification affects model
designation.
A replacement nameplate, to replace one that has been lost, will be issued only upon written request when
accompanied by a document from the FAA authorizing a replacement nameplate.
Upon receipt of the FAA letter, your written request, and a check for $125.00, a new nameplate will be
furnished.
Field facilities may not change data contained on an engine data plate; however, they may add a suffix
stamped at the end of the engine serial number to indicate alteration/conversion as follows:
• For all commercial engines in which the basic model has been altered or converted to another model
designation, the letter “C” added as a suffix on the engine serial number indicates a change from its
original manufacture.
• For all military designated engines rebuilt to commercial standards, the letters “MC” added as a suffix
on the engine serial number indicates a change from its original manufacture.
It will be the sole responsibility of the altering agent to attach the necessary service parts information
along with FAA Form 337, or its equivalent, to the permanent engine records and/or log book, and attest to
the Federal Aviation Agency as to the airworthiness of the alteration, conversion, or modifications
accomplished. In addition, all provisions of FAR 45.13 must be adhered to.
Replacement nameplates furnished by Textron Lycoming will reflect the configuration of the engine when
it left the factory. Replacement nameplates for altered or converted engines require the addition of a suffix,
as above. "
"Service Instruction No. 1304J
SUBJECT: Engine Nameplate Replacement
MODELS AFFECTED: All Textron Lycoming aircraft engines.
TIME OF COMPLIANCE: Whenever a nameplate is lost or an engine modification affects model
designation.
A replacement nameplate, to replace one that has been lost, will be issued only upon written request when
accompanied by a document from the FAA authorizing a replacement nameplate.
Upon receipt of the FAA letter, your written request, and a check for $125.00, a new nameplate will be
furnished.
Field facilities may not change data contained on an engine data plate; however, they may add a suffix
stamped at the end of the engine serial number to indicate alteration/conversion as follows:
• For all commercial engines in which the basic model has been altered or converted to another model
designation, the letter “C” added as a suffix on the engine serial number indicates a change from its
original manufacture.
• For all military designated engines rebuilt to commercial standards, the letters “MC” added as a suffix
on the engine serial number indicates a change from its original manufacture.
It will be the sole responsibility of the altering agent to attach the necessary service parts information
along with FAA Form 337, or its equivalent, to the permanent engine records and/or log book, and attest to
the Federal Aviation Agency as to the airworthiness of the alteration, conversion, or modifications
accomplished. In addition, all provisions of FAR 45.13 must be adhered to.
Replacement nameplates furnished by Textron Lycoming will reflect the configuration of the engine when
it left the factory. Replacement nameplates for altered or converted engines require the addition of a suffix,
as above. "
Darrel Starr
Registered User
Plymouth, MN
We rebuilt our narrow deck engine from 150 to 160 hp in 2003. So, perhaps the FAA has published or revised some rules in the last ten years. Back then, I called Bob Lutz who had (and possibly still has) a shop in Palmer, Alaska. He led me through the following logic published below. He told me he had modified over 100 narrow deck O-320s from 150 to 160 hp on the basis of this logic. At one point an FAA employee told him the FAA would have his shop shut down for this practice but Bob gave him documents with this logic. The guy went away and Bob wasn't hassled again. I also checked with a local well respected engine builder who had made similar modifications of 150 hp narrow deck engines without a 337. I wrote out the following document, shared it with my IA who agreed that we could make this change with a log book entry. We did not ask the local FSDO if they agreed with their own documents.
Why a 337 is not required to convert an O-320 from 150 to 160 hp
Only a log book entry is required to convert any O-320 (narrow or wide deck) from a
-27, 150 hp to a -39, 160 hp configuration. The reason this is true is because this change qualifies as a MINOR, not a MAJOR alteration.
A. Since most people would believe that a 337 is required, here is the logic string that proves the point.
FAR 1.1, General Definitions, states: Major Alternation means an alternation not listed in the aircraft, aircraft engine, or propeller specification (TCDS). The key point – if the alteration is listed in the engine specification (TCDS) then it is not considered to be a major alteration.
FAR 43, Appendix A - Major Alterations, Major Repairs, and Preventive Maintenance, states: (2) Powerplant Major Alterations. The following alterations of a powerplant when not listed in the engine specifications (TCDS) issued by the FAA are powerplant major alterations. The FAR goes on to list examples of major alterations including a compression change but the point once again is that the list of major alterations is applicable only if the change is not included in the engine specification (TCDS).
Type Certificate Data Sheet No. E-274 is the FAA certification document for the O-320 engine. All engine models listed in the document lie within O-320 engine specifications. In the TC block on each engine data plate “274” appears for all O-320 engines listed in the E-274 document. Revision 15 to E-274 dated February 19, 1998, lists 59 engine models that fall within this engine specification including O-320-A2A and O-320-B2B. Therefore converting an –A2A to a –B2B is a change within the engine specification and qualifies as a minor change.
Why a 337 is not required to convert an O-320 from 150 to 160 hp
Only a log book entry is required to convert any O-320 (narrow or wide deck) from a
-27, 150 hp to a -39, 160 hp configuration. The reason this is true is because this change qualifies as a MINOR, not a MAJOR alteration.
A. Since most people would believe that a 337 is required, here is the logic string that proves the point.
FAR 1.1, General Definitions, states: Major Alternation means an alternation not listed in the aircraft, aircraft engine, or propeller specification (TCDS). The key point – if the alteration is listed in the engine specification (TCDS) then it is not considered to be a major alteration.
FAR 43, Appendix A - Major Alterations, Major Repairs, and Preventive Maintenance, states: (2) Powerplant Major Alterations. The following alterations of a powerplant when not listed in the engine specifications (TCDS) issued by the FAA are powerplant major alterations. The FAR goes on to list examples of major alterations including a compression change but the point once again is that the list of major alterations is applicable only if the change is not included in the engine specification (TCDS).
Type Certificate Data Sheet No. E-274 is the FAA certification document for the O-320 engine. All engine models listed in the document lie within O-320 engine specifications. In the TC block on each engine data plate “274” appears for all O-320 engines listed in the E-274 document. Revision 15 to E-274 dated February 19, 1998, lists 59 engine models that fall within this engine specification including O-320-A2A and O-320-B2B. Therefore converting an –A2A to a –B2B is a change within the engine specification and qualifies as a minor change.
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I know the argument well, I have been down that road a few times.... won some, lost some..... I'll play devil's advocate.... FAR 43:13 says we have to use manufacturer's data when it exists. SI1304 is that data. I don't see specific instructions....
as you say....
The key point – if the alteration is listed in the engine specification (TCDS) then it is not considered to be a major alteration
things like making a Luscumbe 8A into an 8E, or a Ercoupe 415 C into a D was done as a minor because the entire procedure is either in the Spec or a bulletin that is listed in the Spec. also note that when you read the real FAR it does not say "Specification (TCDS)".... it only says Specification.... not TCDS... and they are not the same. the TCDS does not have as much information.
The TCM SB for model change within groups also has instructions that the Lyc SI above does not have. though they are not specific, they do to say it can be done if you change all the parts required. they are also not insisting on a 337 as Lyc is.(seems to be at least.... which indicates they think it is a major change)
ya, 10 years ago we did a lot of stuff with field approvals they won't approve any more. I used get a field approval to do 8:50s on a Cessna 180 over the phone.... not any more... now it has to be stc'd. 10 years ago... that was about the beginning of the end here in Alaska. they have gotten pretty constipated since.. I'll check around a bit & see how the wind blows.
as you say....
The key point – if the alteration is listed in the engine specification (TCDS) then it is not considered to be a major alteration
things like making a Luscumbe 8A into an 8E, or a Ercoupe 415 C into a D was done as a minor because the entire procedure is either in the Spec or a bulletin that is listed in the Spec. also note that when you read the real FAR it does not say "Specification (TCDS)".... it only says Specification.... not TCDS... and they are not the same. the TCDS does not have as much information.
The TCM SB for model change within groups also has instructions that the Lyc SI above does not have. though they are not specific, they do to say it can be done if you change all the parts required. they are also not insisting on a 337 as Lyc is.(seems to be at least.... which indicates they think it is a major change)
ya, 10 years ago we did a lot of stuff with field approvals they won't approve any more. I used get a field approval to do 8:50s on a Cessna 180 over the phone.... not any more... now it has to be stc'd. 10 years ago... that was about the beginning of the end here in Alaska. they have gotten pretty constipated since.. I'll check around a bit & see how the wind blows.
Darrel Starr
Registered User
Plymouth, MN
Does the Lycon STC cover narrow deck engines?
So..... the FAA in Alaska is saying if there is an stc.... you use it. no field approvals if there is an stc that covers the mod. anything/everything else must go through engineering. and, that it is standard procedure across the country. (actually this is the same line they have held up here for 6-7 years at least)
I also talked to well known engine builder about it some too & he is confirming that the stc is being required.... 2 stc in fact, because the Cub airframe needs one as well. he also told me that the older 320 narrow decks are supposed to change the crank bearing and through studs as well. I don't know about that... it would depend on the stc requirements, and they can be different from one stc to another (go figger).
One thing I know for sure is that if you have insurance.... the policy has an escape clause about keeping the aircraft "airworthy". by definition that can be boiled down to two words: condition and conformity. if the aircraft does not conform to type design, it is not airworthy.
I have been an expert witness on a couple of airworthiness cases... lawyers have a pretty good eye for details in the reading of law. I'll leave it at that.
I also talked to well known engine builder about it some too & he is confirming that the stc is being required.... 2 stc in fact, because the Cub airframe needs one as well. he also told me that the older 320 narrow decks are supposed to change the crank bearing and through studs as well. I don't know about that... it would depend on the stc requirements, and they can be different from one stc to another (go figger).
One thing I know for sure is that if you have insurance.... the policy has an escape clause about keeping the aircraft "airworthy". by definition that can be boiled down to two words: condition and conformity. if the aircraft does not conform to type design, it is not airworthy.
I have been an expert witness on a couple of airworthiness cases... lawyers have a pretty good eye for details in the reading of law. I'll leave it at that.
Darrel Starr
Registered User
Plymouth, MN
We have the Cubcrafters STC to install a 160 hp O-320 in a Super Cub.
Darrel Starr
Registered User
Plymouth, MN
Double check the carb compatibility. I believe the 150 hp has a -12 carb and the Cubcrafters 160 hp STC requires a -32. You can not make a -32 from a -12. Even if you don't need an STC, you should research why a -32 is required for this particular version.
0290 conversion weight and hp
Just 150hp Is all I would expect. Probably would just go with the low compression 7.5:1 pistons since it's a ND with no banana plates and steel cylinders to be safe. dont want to push my experimental luck with 8.5:1 pistons on a thinner 0-290 crank. Would keep manual tappets, punch it out, and swap out for a ma4spa carb, keep the whole swap cost under 1500 bucks with used parts.
btw that extra 30 lb out on the nose makes a HUGE difference in how a plane handles and the weight and balance. I would be way to far outside my envelope considering this thing had a c85 to begin with.
Just 150hp Is all I would expect. Probably would just go with the low compression 7.5:1 pistons since it's a ND with no banana plates and steel cylinders to be safe. dont want to push my experimental luck with 8.5:1 pistons on a thinner 0-290 crank. Would keep manual tappets, punch it out, and swap out for a ma4spa carb, keep the whole swap cost under 1500 bucks with used parts.
btw that extra 30 lb out on the nose makes a HUGE difference in how a plane handles and the weight and balance. I would be way to far outside my envelope considering this thing had a c85 to begin with.
the o-290 is 140 hp for 5 minutes.... METO is 135. on the 160 conversion for narrow deck 320s... get the case studs from an 0-290.as for the carb... I think you can make a case to use any carb approved for the 160 (which is almost all the ones approved for the 150)... that would be a minor alteration on the recording of the 337 (accessory manufacturer's application data is approved data) (but the installation instructions aren't... go figger)
farm_boy252
MEMBER
Norman wells, NT
Did lycoming make an a2b that was a wide deck?
But performance at altitude is much improved — when it's high and hot the higher compression engines simply work better.
If you try to get compression out of hot thin air you loose less power.
I never did 10 to 1 but I know of a guy running them and his cub with a narrow deck 150 Hp it performs identical to my 160Hp wide deck we both have performance exhaust systems and similar weight aircraft.
