Gordon Misch
MEMBER
Toledo, Wa (KTDO)
Thanks Steve - I talked with Lycon this morning about the STC, and am waiting a call back from Ken re the details of the work. Would you happen to have the service bulletin number handy?
Cracked O-320 Case - Best way to proceed?
- Thread starter Gordon Misch
- Start date
Flying Bee
MEMBER
Washington 2S9
I think it's Service Instruction 1304J
Gordon Misch
MEMBER
Toledo, Wa (KTDO)
Thanks, yes. That one addresses the letter C being added to the data plate. I wasn't having any luck yet searching.
Steve Pierce
BENEFACTOR
Graham, TX
You need plated/nitrided cylinders. Ken told me the soft standard steel cylinders will wear the barrels out in a few hundred hours. Sent him an engine recently for prop strike inspection that had been recently converted to 160 hp by the owner. He argued with Ken that he did everything IAW the STC when he got a phone call about the soft steel cylinders and the gouged hone job. He called me complaining that he did it just like the STC as well. He didn't realize he was talking to the guy who owned the STC so he probably knew what he was talking about. 8)
moneyburner
FRIEND
Western Washington
Can you use mogas with a 160? I have an 0-320-B2B and it needs 100LL. Maybe I didn't look into it far enough?
moneyburner
FRIEND
Western Washington
That happened to mine. It was real hard to start when warm; mis-diagnosed as a failing starter until hand-propping was tried. The bearings were actually squeezing the crank when it was hot. Dodged a bullet with that one.
Gordon Misch
MEMBER
Toledo, Wa (KTDO)
Yes, the Peterson STC will cover it. http://www.autofuelstc.com/order_online.phtml
bob turner
Registered User
Tell us more about soft steel barrels? A local 160 Cub with 350 SMO just got an "unfavorable" oil analysis.
I know nothing about the PA-12 except that Gordon's is an honorary 18 - but having experience with 150, 160, and 180 Super Cubs, I can tell you the 160 version is best by a very wide margin. Opinion. If I ever re-engine my Decathlon, I will look into the 160.
I know nothing about the PA-12 except that Gordon's is an honorary 18 - but having experience with 150, 160, and 180 Super Cubs, I can tell you the 160 version is best by a very wide margin. Opinion. If I ever re-engine my Decathlon, I will look into the 160.
Gordon Misch
MEMBER
Toledo, Wa (KTDO)
Well, I've certainly learned that converting from 150 to 160 turns out to be somewhat more than just bolting on new cylinders, especially when starting with a narrow deck 150. Thanks to help from numerous members here I think I have it figured out, with a reasonable path to accomplishing it. I'll be talking details with my IA (who has very graciously agreed to supervise my work on the project) tomorrow to see if he concurs with my conclusions, and then take action. HOURS of research were involved for this amateur!
Many thanks to all of you who have helped me with this!
FWIW, here is my research summary for converting A2B narrow deck 150 HP to B2B wide deck 160 HP, given that an A2B wide deck case is available. No guarantees of this being perfectly accurate. I am not an A&P and this is not advice. It's the best I have to date, so thought I'd share as a preliminary report.
Many thanks to all of you who have helped me with this!
FWIW, here is my research summary for converting A2B narrow deck 150 HP to B2B wide deck 160 HP, given that an A2B wide deck case is available. No guarantees of this being perfectly accurate. I am not an A&P and this is not advice. It's the best I have to date, so thought I'd share as a preliminary report.
- Lycon STC to upgrade horsepower requires wide deck for the 160 engine.
- Crosswinds STC (160 HP in PA-12) specifies B2B with round airbox and rear-mount oil cooler. Airbox and rear-mount oil cooler can be deviated by IA discretion (I would want to deviate). Charly sez round airbox gives 10 - 20 additional RPM.
- Peterson STC for Mogas requires 91 octane (premium) auto fuel.
- AD 98-02-08 for 160 HP O-320 requires crankshaft internal inspection IAW Lycoming SB 505B. The overhaul yellow tag for my existing crankshaft specifies SB 505 complied with. However crank flange is not stamped PID to indicate the internal coating that terminates the AD. So appears to need visual internal inspection and termination of the AD by applying Urethabond 104. The SB specifies all O-320 engines, while the AD specifies only 160 HP versions. Seems like a good idea to re-inspect regardless?
- Lycoming Service Instruction 1304J specifies to mark data plate with a “C” as a suffix to the serial number, to indicate modification of the engine model designation.
- Lycon says there are some accessory case gear differences between narrow deck and wide deck. The differences weren’t specified on the phone. From the parts manual it looks like just the crankshaft idler gear and bushing.
- Per Lycoming parts manual (WCF = wide deck, and STD = narrow deck in parts book nomenclature):
- Case same for A2B WCF and B2B WCF
- Crankshaft same for A2B STD and B2B WCF (AD 98-02-08 applies)
- Crankshaft main bearings DIFFERENT for A2B STD and B2B WCF (fig 1-2)
- Crankshaft idler gear and bushing DIFFERENT for A2B STD and B2B WCF (fig 1-7)
- Camshaft same for A2B STD and B2B WCF
- Lifters same for A2B STD and B2B WCF
- Pushrods appear to be the same for all O-320. Different P/N’s available, different lengths? Might need some DIFFERENT length pushrods. Need to consult overhaul manual for determination. Shorter rods will result from milled case halves.
- Connecting rods and crankpin bearings same for A2B STD and B2B WCF
- Sump same for A2B STD, A2B WCF. and B2B WCF
- Piston pins appear to be “heavy” for low compression A models and “regular” for other models. Probably DIFFERENT fig 3-1
- Piston pin plug - no mention of what to use with nickel plated cylinders. Probably DIFFERENT Fig 3-1
- Accessory housing same for A2B STD and B2B WCF
- Carburetor same for A2B STD and B2B WCF Charly Center says carb may need re-jetting to be a little richer.
- Magnetos same for A2B STD and B2B WCF
- Dipstick same for A2B STD and B2B WCF
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Gordon......thanks for this synopsis! I am getting ready to do the same project, and this save me a lost of research and work! Have a newly reconditioned narrow deck case, and since I am taking additional parts to Aircraft Specialties on Monday, will take the case to them and see if we can make a trade for the wide deck case. Sounds like my reconditioned crank will work (still standard dimensions). Thanks again!
Fabricman
Sent from my iPad using Tapatalk
WhiskeyMike
MEMBER
West Boxford MA
Going back to the start of this thread, my 2 cents is that prop strikes can lead to serious issues further down the line, sometimes years apart. THere's generally no warning. It cracked for a reason. That's 1 cent. The other penny is that it's hard to beat new cylinders. Otherwise why have we continually had them last till TBO or beyond without a whisper of trouble vs. bad guides, cracks etc etc. Pay now, or pay later - maybe at a higher price.
cubpilot2
SPONSOR
Anchorage Alaska
Gordon......thanks for this synopsis! I am getting ready to do the same project, and this save me a lost of research and work! Have a newly reconditioned narrow deck case, and since I am taking additional parts to Aircraft Specialties on Monday, will take the case to them and see if we can make a trade for the wide deck case. Sounds like my reconditioned crank will work (still standard dimensions). Thanks again!
Fabricman
Although the crankshafts may interchange, there is a difference between the wide deck and narrow deck as the wide deck has a solid flange and the narrow has the "lightening holes"; which need to be monitored for cracks between the holes. (not very common but has happened).
I have seen narrow deck engines with solid flanges; where the crank was replaced but have not seen a wide deck with the older shaft.
Fabricman
Although the crankshafts may interchange, there is a difference between the wide deck and narrow deck as the wide deck has a solid flange and the narrow has the "lightening holes"; which need to be monitored for cracks between the holes. (not very common but has happened).
I have seen narrow deck engines with solid flanges; where the crank was replaced but have not seen a wide deck with the older shaft.
skywagon8a
MEMBER
SE Mass MA6
I have seen this with all of the webs cracked except just one. This on a TriPacer where I was taking the prop off for some reason and found the cracks by accident.
mike mcs repair
Registered User
chugiak AK
Atlee's has a nice stainless steel airbag now if you decided to http://www.fadodge.com/carb-heat-box/
Gordon Misch
MEMBER
Toledo, Wa (KTDO)
My IA is willing to approve my requested deviations, however that's good to know. Thanks Mike.
Gordon Misch
MEMBER
Toledo, Wa (KTDO)
Update, now that the engine is disassembled.
The first thing I saw after splitting the case was significant wear at the aft 1/2" of the front main bearing, and on the center main bearing. Copper was showing from under the babbit in each location. So I feared for crankshaft straightness. Turns out the crank is straight - runout at the center main is .0005 TIR. Also, the main journals measure well within "new" tolerance for .010 undersize. There are flecks in all of the bearing shells, so I expect I'll be replacing the rod bearing shells and bolts also, but will wait for inspection by my IA, first part of the week.
The wear patterns on the bearing shells suggest over-torquing or fretted case. A straightedge on the parting face shows about .002" gap at the center main bearing and the aft end of the front main bearing on one case half, but almost none on the other. So I suspect fretting damage. The case is scrap, and will be replaced anyway.
Crankshaft axial clearance is way out of tolerance at .034". New limit is .016 and service limit is .026. The thrust face on the case is lightly scored and obviously worn. The thrust face on the crank has some very small scuff-like roughnesses. I think they will polish out, but need to check with my IA. I need to check for possible partly-plugged oil passage that could possibly contribute to this condition. More likely, given that the aft portion of the front main was squeezed too tight, there would have been reduced oil flow from the main journal aft toward the thrust surface. Just now thought of that, and I bet that's the problem.
Camshaft is straight with some very light wear on lobes. Lifter faces show some light wear and either prior rust or spalling indications. Again, need IA's opinion on that.
Bottom line, it appears that the case might not have been "right" when this engine was assembled at overhaul. Once I found the bearing issues inside, I'm glad the engine is apart. This time I will do the assembly myself (supervised by IA) and will be thinking exclusively about the reliability of the engine, rather than how long till 5 o'clock!
The first thing I saw after splitting the case was significant wear at the aft 1/2" of the front main bearing, and on the center main bearing. Copper was showing from under the babbit in each location. So I feared for crankshaft straightness. Turns out the crank is straight - runout at the center main is .0005 TIR. Also, the main journals measure well within "new" tolerance for .010 undersize. There are flecks in all of the bearing shells, so I expect I'll be replacing the rod bearing shells and bolts also, but will wait for inspection by my IA, first part of the week.
The wear patterns on the bearing shells suggest over-torquing or fretted case. A straightedge on the parting face shows about .002" gap at the center main bearing and the aft end of the front main bearing on one case half, but almost none on the other. So I suspect fretting damage. The case is scrap, and will be replaced anyway.
Crankshaft axial clearance is way out of tolerance at .034". New limit is .016 and service limit is .026. The thrust face on the case is lightly scored and obviously worn. The thrust face on the crank has some very small scuff-like roughnesses. I think they will polish out, but need to check with my IA. I need to check for possible partly-plugged oil passage that could possibly contribute to this condition. More likely, given that the aft portion of the front main was squeezed too tight, there would have been reduced oil flow from the main journal aft toward the thrust surface. Just now thought of that, and I bet that's the problem.
Camshaft is straight with some very light wear on lobes. Lifter faces show some light wear and either prior rust or spalling indications. Again, need IA's opinion on that.
Bottom line, it appears that the case might not have been "right" when this engine was assembled at overhaul. Once I found the bearing issues inside, I'm glad the engine is apart. This time I will do the assembly myself (supervised by IA) and will be thinking exclusively about the reliability of the engine, rather than how long till 5 o'clock!
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C-FIJK
Registered User
Lewisporte N.L.
Bob i did this last year at overhaul went from 150 -160 wide deck in my 1955 super cub best money spent yet and 82-43 borer prop .
Gordon Misch
MEMBER
Toledo, Wa (KTDO)
Gerry, would you be able to share any performance numbers, before and after? For example takeoff distance, rate of climb, fuel consumption. Thanks - -
C-FIJK
Registered User
Lewisporte N.L.
Gordon i have no real numbers before and after sorry , rpm is up about 175 more on take off and the plane climbs like never before, this was a huge improvement over the 150 hp i fly on floats and have it at gross weight most often. Gets up on step and pulls hard off the water and in climb .
Gordon Misch
MEMBER
Toledo, Wa (KTDO)
Well, another update.
Wally, my IA came to look this afternoon and we agree that it would make sense to make the "repair" a major overhaul. The cam and lifters have some minor wear, the thrust face on the crank is lightly scuffed and needs polishing, all of the bearing shells have flecks of metal in them (probably aluminum).
So - it will be a replacement wide deck case from DivCo, new 8.5 Lycoming nitrided cylinders from AeroSport, reworked cam and lifters from Lycon or AeroSport, and of course all the ferrous parts magnafluxed.
Needless to say, I'm not thrilled with the prior overhaul, 480 hours ago. This time I will do the assembly, double and triple checking everything, under the watchful eyes of Wally, Bill another IA friend, and A&P Craig (FlyingBee) for phone consultation. This time it'll go TBO and beyond;-)
BTW, I'm sure glad I kept measuring instruments from when I sold my machine shop!
Wally, my IA came to look this afternoon and we agree that it would make sense to make the "repair" a major overhaul. The cam and lifters have some minor wear, the thrust face on the crank is lightly scuffed and needs polishing, all of the bearing shells have flecks of metal in them (probably aluminum).
So - it will be a replacement wide deck case from DivCo, new 8.5 Lycoming nitrided cylinders from AeroSport, reworked cam and lifters from Lycon or AeroSport, and of course all the ferrous parts magnafluxed.
Needless to say, I'm not thrilled with the prior overhaul, 480 hours ago. This time I will do the assembly, double and triple checking everything, under the watchful eyes of Wally, Bill another IA friend, and A&P Craig (FlyingBee) for phone consultation. This time it'll go TBO and beyond;-)
BTW, I'm sure glad I kept measuring instruments from when I sold my machine shop!
Gordon Misch
MEMBER
Toledo, Wa (KTDO)
Yes, I do. Thanks.
Other than the cracked case that made me open this engine up, I believe its assembly at the last overhaul was likely deficient. I'm convinced that the extra squeeze on the front main bearing caused, or at least contributed to, the thrust face failure which in turn spread aluminum throughout the engine.
FWIW, the narrow deck 7.0 cylinders are still good.
mike mcs repair
Registered User
chugiak AK
i thought you crashed/prop striked it...
metal in an engine is normal, metal caught in soft bearings is normal... maybe not what you wish for, but....
Gordon Misch
MEMBER
Toledo, Wa (KTDO)
Yes, but that was prior to prop strike inspection together with major overhaul. I'm quite sure the metal in the bearings is from the thrust face of the case. The front main was squeezed too tight, partly blocking oil from the thrust bearing. Copper showing on the aft portion of the front main bearing, and the case parting surface is concave. The axial clearance, crankshaft to case, is .020" greater than mfg max and .010 greater than service max.
Steve Pierce
BENEFACTOR
Graham, TX
Gordon, Talk to LyCon about the Lycoming DLC coated cam and lifters. They do not rust, pit or wear. Ken told me about one on it's third overhaul still measures new. He is working on approval to do Continental cams and lifters.
Gordon Misch
MEMBER
Toledo, Wa (KTDO)
Steve, I saw your other post about that, read the Wikipedia article you referenced, and made a note to call them and inquire. Thanks!
Edit: I just talked with John at Lycon and he confirmed what you said about longevity. He also said the coating is on new Lycoming tappet bodies, but not the cam. They're investigating also coating the cam, but at this stage are not certain of the interaction of coating against coating. So the cam lobes are still steel. The tappet bodies are $116 each, no cores taken.
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Gordon Misch
MEMBER
Toledo, Wa (KTDO)
Another update - Those coated tappets come with a price of about $110+ each. Resurfacing plain steel more like $40 each. That's close to a $600 difference up front. So whether the new technology is "worth it" depends a lot on personal perspective.
Gordon Misch
MEMBER
Toledo, Wa (KTDO)
Yes. I'm trying to remember how "tight" the engine felt fresh out of overhaul. But it's been a while - - And the overhauler ran it in on a test stand, so babbit might have redistributed before I even got the engine back.
