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ceweaver
08-20-2008, 08:07 PM
Evening Group,

For those who read my intro post a few weeks ago, my thumb is healing nicely (will require surgery to remove the remaining nailbed and reshape a little...but that's the price of making a less than intelligent maneuver) and I have about 4 hours in my Tri-Pacer now. The plane has an O-320-A2B in it and we're (IA and most everybody at airport and carb shops my IA has called) fairly certain that I have a problem with my accelerator pump (at a minimum). My IA couldn't get the full number off the carb but could see 10-3678-?2 (the "?"appears to have been restamped). I have access to a carb off a O-320-E3D for a test flight, but the TCDS for that engine lists a 10-5009 as the carb. I have seen that the 10-5009 is also listed on the O-320-A2B (on the Kelly Aerospace website) but it is not listed on the PA-22 TCDS. What are the differences between these carbs? Can the 10-5009 be used on the plane since it isn't listed on the PA-22 TCDS? Also what's the difference between the -32 and -12? I'd like to get this resolved before Labor Day so my family and I can fly down to the beach for the weekend so I'll probably just order a carb from either Chief or Aircraft Spruce...their prices are fixed and the same as the shops my IA has called.

Also, am I making too much out of the differences since they all are listed for the O-320-A2B in various places?

Thanks in advance,
Chad "Peanub" Weaver

Steve Pierce
08-20-2008, 10:13 PM
The -12 runs leaner than the -32. Not sure on the other number you posted but when I talked to the Kelly tech guy a few weeks ago he gave me a similar number that had a better atomizing nozzle. I will look up my notes and part numbers at the shop. The just is you are really not legal with a carb not called out in the TCDS however I have used data like the engine TCDS which calls out the other carburetor part number as data to get a field approval. Did it on a PA11 which calls for a Stromberg carb but the airplane had a Marvel Schebler and the TCDS on the C90 allowed it. Field approval was no problem but that was a year or so ago.

longpacer
08-21-2008, 12:58 PM
The 10-5009 should work for a test flight. The big difference is that these carbs have a smaller main jet opening than the 10-3678-32 -- about 10% smaller. (My guess is that you have the -32 carb which seem to be more common than the -12.) The 5009s also lack an economizer feature present in the -32, but losing this is no big deal.

If you try the 5009, one thing to watch is the cylinder head temps during long climbs due to less fuel flow and therefore leaner operation. I believe the 5009 was created for the Cessna 172s which have much better cooing systems than our old Pipers.

There are two versions of the 5009. If the part number is 10-5009N, then it has been modified in the field with an improved main discharge nozzle which provides better fuel atomization for more equal fuel distribution among the cylinders. (Lycoming Service Instruction 1305C deals with this. It is a worthwhile mod.)

I fly my experimental Pacer with an O-320 A2B running a 10-5217 carb, which is a later version of the basic 5009N design and uses the same improved nozzle. I like the carb, but I found I had to open up the main jet to get more fuel flow to keep the cylinder head temps under 400 in climbs.

Steve Pierce has a good point about the legal issues, but from an operational perspective, I would have no problems in doing a test flight with the 5009. I just wouldn't engage in long climbs. I would keep the full power climb to maybe 1500 feet then go to a more relaxed on route climb to the test altitude.

Bob

ceweaver
08-26-2008, 07:32 PM
Steve and Bob,

Thanks for the information. Is there a desired carb for the 150hp PA-22? Was the -12 intended for planes based and flown in higher areas of the country? Sorry for all the questions. I ordered a -32 before pulling my carb because I had to fly the plane to Lynchburg (LYH) for radio work yesterday. We're planning a trip to Myrtle Beach the weekend after Labor Day to spend with my parents and I'm trying to make sure we have everything in time for me to put a couple of hours on the plane before starting out.

Y'all are a big help to a new Shortwinger.

Thanks,
Chad

Curly
08-27-2008, 12:12 AM
G'Day Chad,

I have a copy of a PA22 Overhaul manual on CD that I ordered on Ebay(somewhere in the 'States but can't remember where). It has a parts manual for PA22 plus overhaul and parts manuals for 0215, 0290 and 0320. Also has overhaul manuals for every starter, generator and carby ever fitted to a '22. Good value for, I think, $US35.

It lists seven different carby assemblies depending on which model engine was fitted:
OEM Carb. No. -- Carb. No. -- Model No.
61547 -- A10-3103-1 -- MA3A
69250 -- A103678-12 -- MA.4SPA
72394 -- A103678-32 -- MA.4SPA
71098 -- A103878 -- MA-4-5
71710 -- A10-4164-1 -- MA-4-5
72920 -- A10-4401-1 -- MA-6AAA
72740 -- A10-4404 -- MA-4-5

I am sure Steve P or JW will also have the same information and can steer you in the right direction.

Curly

jay heil
08-28-2008, 12:50 AM
i dont think your supposed to put a -32 on the same sump as a -12 one has a tapered throat sump one is straight dats what the carb guru at bulducs in mpls told me although you can get a conversion kit for it which is 180.00

taildraggerpilot
01-05-2011, 04:09 PM
What is the better alternative or your recommendation?

I have the wrong carb (10-3678-32) installed on my engine (O-320-B2A). To retain the -32 carb, I need to install Lycoming kit 71186 per Lycomign SB258. This kit installs a sleeve and retainer pin to improve the flow of the -32 carb.

I could also exchange my newly rebuilt carb for a 10-3678-12 carb and not modify the oil sump. Which is the better alternative?

What is the typical fuel burn of a -32 carb with the sleeve installed? Would installing the sleeve improve fuel consumption? Or should I bite the bullet and exchange the carb.

The kit costs about $80
An exchanged carb is about $700

On the surface installing the kit is cheaper, but would the additional fuel savings make buying a -12 carb advantageous?

Thanks,

Gilbert Pierce
01-05-2011, 08:34 PM
It is hard to say what the typical fuel burn it as the fuel burn vs rpm transfer curve is really vertical in the cruise range. Small change in RPM makes a big change in fuel burn. I lean aggressively. At 2450 rpm and leaned I burn about 8.8 gph. Pull it back to 2350 and I see 7.5 plus or minus. At 2550 it's about 9.5 to 9.8 gph. I occasionally fly with a T-P owner who told me he had a -32 carb. He would be burning 10 gph while I was burning slightly less then nine. When we got to the fuel pumps it was evident.
Ask folks their fuel burn and it is all over the map. I have an EI FP5L fuel computer and can now see why. Just small changes in the mixture or throttle or altitude all effect fuel burn. Based on flying with others and fueling up at the same time I am comfortable that my fuel burn is less then most. Part of it is the -12 carb, part of is aggressive leaning with my EI UBG16 engine analyzer.

Steve Pierce
01-06-2011, 07:45 AM
Ben, I have a sleeve you could borrow to rest. It is tapered and would be captured between the carburetor and the small diameter of the sump. The STC to install the 160 hp engine on a Super Cub requires a -32 carburetor but the TCDS on the 160 hp Tri-Pacer allows a -11, -12 or -32. Have consistently seen less fuel burn with the -12 and was confirmed by a carburetor OH facility. That being said I know 160 HP SC drivers w/-32 carbs with a similar fuel burn to the my Dad is posting. If you want to do some testing I could loan you the sleeve.

andya
01-06-2011, 09:17 PM
I have an A2B, 150hp with the -32 carb. I typically cruise between 8000-9000, lean to about 80-100 rich of peak with the throttle backed off just enough to not have the enrichment valve working. Seems to consistently do about 8.8-9.0 gph and TAS of 108 knots with a 60" pitch prop and turning about 2500+ at those altitudes and pwr settings. I have the one piece venturi that was installed by an old timer and it seems to work well.

Throttle Pusher
01-06-2011, 09:35 PM
Can the -12 be put on the 160 hp B engines?

taildraggerpilot
01-06-2011, 10:25 PM
Hey Steve:

Thanks a bunch for the offer of loaning me your part, but I already ordered the sleeve. I really do appreciate it though.

On another note, I just realized my membership has expired and need to renew.

Steve Pierce
01-07-2011, 08:05 AM
Keep us posted on your results Ben.

You can go here and put your username in step 2 so Cathy knows who the membership applies to and hit "Submit Step 2". Thanks.

Gilbert Pierce
01-07-2011, 02:40 PM
Can the -12 be put on the 160 hp B engines?
My Clipper has B2B and -12. FAA Approved.

taildraggerpilot
01-07-2011, 02:49 PM
My Clipper has B2B and -12. FAA Approved.

How does that work? Isn't the butterfly on the -12 larger than the -32? By installing the sleeve in the sump per SB 258, the throat dia is reduced. Wouldn't this reduction create a step between the carb and sump disrupting airflow on the -12 carb? Per the SB, installing the sleeve effectively changes the engine, in my case, from an B2A to a B2B. This would lead me to belive you have a sleeve installed in your sump also since it is a B2B as well? Perhaps the true B2B has a different sump p/n than the B2A Just curious.

taildraggerpilot
04-09-2012, 07:54 PM
What is the better alternative or your recommendation?

I have the wrong carb (10-3678-32) installed on my engine (O-320-B2A). To retain the -32 carb, I need to install Lycoming kit 71186 per Lycomign SB258. This kit installs a sleeve and retainer pin to improve the flow of the -32 carb.

I could also exchange my newly rebuilt carb for a 10-3678-12 carb and not modify the oil sump. Which is the better alternative?

What is the typical fuel burn of a -32 carb with the sleeve installed? Would installing the sleeve improve fuel consumption? Or should I bite the bullet and exchange the carb.

The kit costs about $80
An exchanged carb is about $700

On the surface installing the kit is cheaper, but would the additional fuel savings make buying a -12 carb advantageous?

Thanks,

Just a quick follow-up. I installed the kit with my original -32 carb. The engine smoothed out slightly and fuel burn improved from about 11 gph to 10.5-10.2 gph. However, the engine ran rough at RPMs below 1000. I decided to buy a -12 carb and retain the lycoming sleeve. The engine now runs like a sewing machine, very smooth and I'm able to lean. The fuel distribution is greatly improved. The #1 and #3 cylinders are very close on the EGT with the -12 carb. With the -32 carb, the #1 and #3 were about 150 degrees apart. I did a number of touch and go's and some cruising, but with all of the climbing and little cruise, my fuel burn droped to 9.5 gph. I'll take a small cross country to update the fuel burn and report back. So far switching to a -12 was a good decision.

Gilbert Pierce
04-09-2012, 09:26 PM
Ben,
I am glad to hear your change to the -12 worked out. Others I know who have switched from the -32 to the -12 have had similiar experiences. Flying for 3 hours along side a -32 equiped T-P I used much less fuel when we stopped to fill up.
On my recent trip to Sun n' Fun the CHT variation was less then 15 degrees as indicated on my 4 channel EI UBG16 engine analyzer while flying at 7500', full throttle and leaned. For the trip my fuel burn was 9.1 gph at 75% power when below 7500' msl. That included climbs to 9500' on several occasions.

To recap, the -32 was used to overcome engine surging in cold weather, 20F and below. To accomplish this it was necesssary to provide a richer mixture. Cold air is more dense hense the mixuture is leaner when the intake air is extremely cold. Lean mixtures can cause engine surging in this condition. The Lycoming SB that implemented the -32 said to do it when experiencing engine surge in cold climates.

Brian
01-26-2014, 01:03 AM
Sorry to revisit this old thread but....doing my annual and I've decided the carb needs attention. The choices are send out for overhaul or exchange for overhauled carb. Since I rarely fly in cold WX I believe I would be better suited to have the -12 carb and enjoy some fuel savings. Oddly enough my carb appears to have originally been a -12 and got modified to a -32. See attached photo, the numeral 1 has been over struck with a 3. This carb does behave like a -32 as the mixture gets a lot richer when the throttle is advanced that last 1/2 inch of travel which is what the power enrichment feature (economizer) was designed to do. When I look up into my sump I see a round cylinder with no tapper and no sign of a sleeve, so I should be able to use a -12 or -32 either right ? Throttle pusher seems to have switched from a -32 to a -12 successfully in his post in this thread.

Brian
01-30-2014, 11:12 PM
I went ahead and purchased a rebuilt 10-3678-12 from ACS earlier this week. I choose the factory rebuilt vs. overhaul for about 10% more cost. Spoke with Marvel customer support who said they put a lot of new parts in the rebuilt carbs where as a lot of serviceable parts go in the overhauled carbs. Made the mistake of taking the free ground shipping option on the ACS web site knowing ACS is only 30 miles from home, but carb is instead being drop shipped from NC so will be late next week before I get my hands on it.

Brian
04-28-2014, 10:37 AM
I have about 3 hours TIS on my new -12 carb. It does run much leaner compared to the -32 as has been reported by others. I keep the mixture full rich now for cruse power settings below about 4K MSL, and see EGT of 1450 F or so. With the old -32 and full rich mixture would have resulted in around 1200 F and I typically kept the mixture about ¾ to 1 inch back from full rich to get proper lean. At full throttle the EGT cools down by about 150 F as did the -32, so this -12 carb still incorporates an economizer function. Idle can be adjusted down to about 550 RPM or so prior to roughness. I’m still playing with the idle mixture adjustment looking for that slight RPM increase at idle shutoff. That’s a tricky adjustment to get right.

Steve Pierce
04-29-2014, 12:41 PM
Just overhauled and installed a 160 hp O-320 with a -12 carb. Haven't seen a need to lean it as of yet as the fuel burns are low.

sophistical
04-29-2014, 09:42 PM
The -12 sounds ideal in most conditions, but what about cold climates? Is this an option for those operating in cold climates?

taildraggerpilot
04-29-2014, 09:48 PM
Steve:
What is your fuel burn on the -12 carb? My engine runs much smoother with the -12, but I still burn right at 10gph vs 11 with the -32 carb. However, I operate 75 degrees ROP. If I lean to 50 ROP, I typically see 9.5. I also typically cruise between 2500 and 2550 rpm. If I slow it down, it doesn't seem to impact the fuel burn by much.

Steve Pierce
04-30-2014, 06:48 AM
Was seeing 8.5 gallons an hour at 2550 rim full rich on this 160 he Pacer. The prop is a 52" pitch which is getting re pitched to 58" today.

taildraggerpilot
04-30-2014, 07:08 AM
This puzzles me. I would love to get 8.5 with my carb. I wish I understood why mine is running so rich compared to yours. I have a 60 pitch prop, so maybe with a 52 running at 2550 it isn't using as much power. I'd be interested to see what it gets at 2550 with the 58 pitch.

Steve Pierce
04-30-2014, 07:20 AM
Ben, I am curious as well. I think you are correct in that it is not working the engine with such a low pitch. Will post some numbers with the 58" prop.

Gilbert Pierce
05-01-2014, 09:50 AM
I started using the attached Lycoming Power Chart.

When leaning to about 1490 degrees EGT on #4 cylinder I was at about peak power with CHT never above 360. My fuel flows were always about 0.2 to 0.3 gph below what the chart said I should have for the given altitude and rpm setting.

Since installing the Sutton Exhaust my I have not sorted out the EGT issue as you cannot put each probe the the same distance from the flange. I now just lean to the chart fuel flow and my CHT's are running the same as before, Example; at 5500' and 2550 rpm the chart shows 9 GPH and I would see 8.8 with #4 leaned just below 1500- degrees so I now lean to 9GPH.

I used 1500 degrees as the limit because that is the limit EI said you should not exceed. I now question that logic as EGT is just a relative number depending on where your probes are.

I also lean at all altitudes. If cruising at 1000' msl I lean and I lean during climb but keep the EGT's to what they are at sea level full rich; about 1350 degrees. If you do that when you get to altitude and level off and set cruise power you need to push the mixture in a little because as Brian Neal said, full throttle you have an enrichment valve. Come off full throttle while leaned your EGT's will shoot up as that enrichment valve closes.

59pacer
05-01-2014, 07:14 PM
A little bit 'off thread' but---
Pitch can have a big effect on fuel flow. Running a 69x54 and a 69x48 prop on my O-200 Continental, using 2550 rpm at 4000' will give 7.1 and 5.8 USG/hr respectively. The props were both 'approved' props, different ages and manufacturers, but that's about 20% difference! What would most probably tell the full story would be to see what the MAP was in each case, as that should tell the actual power output. The change in speed was about 10%.
After 500hrs on my current Pacer with a 160hp O-320, 61" pitch prop, Leading Edge exhaust, slightly different nose bowl to original, mainly long distance, heavy weight, high temperature operations, diligently watching CHTs and EGTs, I have never had a CHT anywhere within a bull's roar of the limit. I used the POH guide for 75% (2400rpm at sea level, plus 25rpm per 1000'), ran it slightly under that, and leaned for smooth running. I consistently get 8.7 to 9USG/hr average (includes climb and descent).
My concern was that I could be accidentally running over 75% and leaning too much, so a while back I ripped out the CHT/EGT system, and put a MAP gauge in the hole.
With a bit of fiddling I was able to blow up the appropriate power charts from the POH so I can read them, and had them plastic laminated so I could draw lines all over them. Now I can enter with RPM, MAP, altitude and temperature, get the %power, fuel flow etc.
The POH rule of thumb method is always at or below 75% (mostly just below), and the leaning method is fine. I'd have no trouble with pulling the MAP gauge out and forgetting all the complication, but I'd have to fill the hole with something!
The only change to my operating technique when the aux is full, and I'm a 'little bit' overweight, is to stay about 1500' and empty the aux as quickly as possible, then climb higher. Avoiding the early long heavy climb tends the average burn towards the lower end. If I have to climb early, the average burn is towards the higher end.
Got another trip 'outback' in September--started out as a week trip, but its gradually getting longer as destinations get added. Great machines these short wings!

cozzmo81
08-21-2016, 11:27 AM
I am in the process of overhauling a O320-A2A for use on my Pacer. While I'm waiting to purchase new cylinders I thought I would go over my engine accessories. My O320 had a
10-3678-32 carburetor installed and the oil sump has the tapered intake port. Before I spend money on overhauling the carb. I want to make sure I am going with the correct one. It is my understanding that If I am going to use the -32 carb I would need to install the sleeve in the sump inlet per SB 258? If I were to switch to the -12 carb I would need to use my sump as is with the taper? I see that people generally get better fuel burn with the -12 carb. What carb would you recommend? Also does anyone know of any overhaul shops that will take a -32 core for a -12 carb? Thanks in advance for your suggestions.

Steve Pierce
08-22-2016, 06:31 AM
Just merged your thread with another on the subject. Should be lots of information.

cozzmo81
08-22-2016, 11:26 AM
Steve,
Thanks for merging my questions with this post. I have previously read this thread and just re-read it. It looks like some people are saying they are using the -12 carb with the straight sump and others are using the -12 with the tapered sump. Which is the correct configuration? The was I'm reading it is that the -12 is supposed to use the tapered sump. Is this correct? I found an overhaul shop that will exchange my -32 for a -12 for no additional cost.

Thanks
Chris

Steve Pierce
08-22-2016, 11:37 AM
Straight riser for the -32 and tapered riser for the -12.

cozzmo81
08-22-2016, 12:47 PM
Thanks Steve, Thats what I thought

Gilbert Pierce
08-22-2016, 12:49 PM
The -12 works fine with the straight riser.

Jon Hankins
04-23-2019, 04:23 PM
Hello all, I'm in the process of upgrading engine in my colt to O-320
I have picked up a O-320-A3B that was removed from a PA23 Apache.
I am converting to O-320-A2B.
I replaced the 7/16 prop flange bushings with 3/8 bushings and installed the front plug in crankshaft, removed the governor drive and installed cover plate over drive.

My question is the proper carb.

According to the TC you can have 3 different carbs
10-3678-11, 10-3678-12, or 10-3678-32

The oil sump induction has be modified for the for the straight riser.

And it looks like only -12 or -32 carbs are available now.

So which ones are you guys using?


Thanks

Stephen
04-23-2019, 10:30 PM
My 0-320 A uses the -32 carburetor

Steve Pierce
04-24-2019, 06:44 AM
Jon, You want the straight riser for the -32 and tapered riser for the -12. Some very good information in this thread.
http://www.shortwingpipers.org/forum/showthread.php?4760-12-or-32-was-Carb-Differences

Jon Hankins
04-29-2019, 08:57 PM
Steven and Steve, That's for the responses so it looks like I will need to go with the -32 carb, but after reading the thread about the -12 and -32 differences, I could use either one.

I'll probably go with the -32 though. any one know of a preferred overhaul shop. the core carb I have is a -11.

Thanks

Steve Pierce
04-29-2019, 09:18 PM
Bobby at Aircraft Carburetor and Fuel Injection of Texas.
http://www.aircraftcarbs.com/

If it needs lots of parts might be cheaper to buy one off the shelf from Spruce but I prefer to use Bobby.

Stephen
04-29-2019, 10:24 PM
I just bought an overhauled -32 from AC Spruce. There carburetors are overhauled by Marvel Schebler and are flow tested. My last carburetor was done 11 years ago by a cheaper source who did not flow test. It was never right, it required aggressive leaning from the get go, which means fuel was coming in somewhere. When it recently stopped shutting off at lean mixture cutoff and it was not the primer, it was time for a replacement. LyConn also flow tests their carburetors but I could not get a replacement in the 5 days it takes Spruce or anspecific price. AC Spruce's $830 seems like a lot for a glorified tractor carburetor, I was going to do my own rebuild but, parts alone we're $700. I used to rebuild 4 barrel Holley carbs for a whole lot less. Oh well. BTW, I'm impressed by the tech support at Marvel Schebler.

I don't know anything about Steve's recommendation but, I would trust Steve's judgement.

Stephen
05-06-2019, 04:49 AM
It's nice to have a property working carburetor. The fuel consumption is down significantly, and the lean idle cut off works again.

Jon Hankins
09-06-2019, 04:24 PM
Does anyone know if the 10-5009 carb is the same as the 10-3678-32 carb, looking at TCDS and then the list on approved carbs is list the 10-5009
has anyone used this carb is a 150 hp shortwing? this is for O-320-A3B converted to -A2B with straight riser sump.

SMO22
09-06-2019, 09:40 PM
Does anyone know if the 10-5009 carb is the same as the 10-3678-32 carb, looking at TCDS and then the list on approved carbs is list the 10-5009
has anyone used this carb is a 150 hp shortwing? this is for O-320-A3B converted to -A2B with straight riser sump.


https://www.shortwingpipers.org/forum/showthread.php?4760-12-or-32-was-Carb-Differences&p=23044&viewfull=1#post23044 (https://www.shortwingpipers.org/forum/showthread.php?4760-12-or-32-was-Carb-Differences&p=23044&viewfull=1#post23044)


The 10-5009 should work for a test flight. The big difference is that these carbs have a smaller main jet opening than the 10-3678-32 -- about 10% smaller. (My guess is that you have the -32 carb which seem to be more common than the -12.) The 5009s also lack an economizer feature present in the -32, but losing this is no big deal.

If you try the 5009, one thing to watch is the cylinder head temps during long climbs due to less fuel flow and therefore leaner operation. I believe the 5009 was created for the Cessna 172s which have much better cooing systems than our old Pipers.

There are two versions of the 5009. If the part number is 10-5009N, then it has been modified in the field with an improved main discharge nozzle which provides better fuel atomization for more equal fuel distribution among the cylinders. (Lycoming Service Instruction 1305C deals with this. It is a worthwhile mod.)

I fly my experimental Pacer with an O-320 A2B running a 10-5217 carb, which is a later version of the basic 5009N design and uses the same improved nozzle. I like the carb, but I found I had to open up the main jet to get more fuel flow to keep the cylinder head temps under 400 in climbs.

Steve Pierce has a good point about the legal issues, but from an operational perspective, I would have no problems in doing a test flight with the 5009. I just wouldn't engage in long climbs. I would keep the full power climb to maybe 1500 feet then go to a more relaxed on route climb to the test altitude.

Bob


Both are still available listed on Marvel site

https://msacarbs.com/product-category/carburetors/ma-4spa/?orderby=price

https://i.imgur.com/HKNPCXDr.png

Steve Pierce
09-07-2019, 06:33 AM
Good information I had forgotten about. I merged the two threads so it is easier to get all the info later down the road.

Jon Hankins
09-07-2019, 08:29 PM
thanks for the info, I will get my carb overhauled to a -32 or find an exchange -32, just waiting on prices before I send out this old -11 that I have

SMO22
09-07-2019, 08:50 PM
I would like the -12 not -32 , lots of good info about it running jus fine and burning 20% less gas. If you dont plan on flying in extreme cold wx the 12 should work according to the passdown here in this thread.

CamTom12
09-07-2019, 09:02 PM
I’ve not heard anyone else mention it: with a -32, can you not just pull the red knob out and gain back that 20% difference folks have mentioned?

I would think that any differences in fuel burn would be noted at full rich. If that’s the case, give me the carb that flows more fuel. If I need less fuel, I can control that with the red knob. It’s hard to get more fuel out of a carb once that knob is full rich.

dbudd
09-11-2019, 07:29 PM
https://msacarbs.com/technical-data/engine-eligibility/

Gilbert Pierce
09-11-2019, 08:42 PM
I had this service bulletin applied to my -12 carb. My CHT’s run within 10 to 15 degrees of each other depending on Power settings. My EGT’s are within 25 to 75 degrees again depending on power setting.

https://msacarbs.com/pdf/SB-22_O%20New%20Fuel%20Nozzle.pdf

Todd
11-14-2019, 05:49 PM
Does that perforated fuel nozzle apply to the -12 as well? I see it's specifically intended for the CC 340 engines that run a -32. I'm just breaking in a rebuilt O-320 A2B with Sutton exhaust and -12 carb. After several hours, the front CHTs are in the low 300s, w/ EGTs about 1200, but both rear cyls. running 360-370 w/ EGTs in the 1450 range full rich @ 75% power (11.8 gph). Probably still breaking in, but certainly running leaner than the front. Thought it's experimental only, the new nozzle seems like a good idea if it helps even out split temps.

Gilbert Pierce
11-14-2019, 05:57 PM
I had a 12 converted. The SB applies to the -34. Evidently the 12 and 34 can exchange a few parts to become the other.
Lycon did the mod.

Todd
11-14-2019, 07:00 PM
Very interesting. What kind of temp spread did you see before the mod?

andya
11-14-2019, 09:31 PM
Have a neighbor that built a carbon cub with the O-340. The have a problem with the carb they selected that has just the opposite split in CHT/EGT. His front cylinders went thru the roof while the aft cylinders were much lower. I flew it and experimented a little, flew it stabilized with about 22 inches MP and and full rich mixture. began to lean to find peak and
it hit peak egt after a 10 deg rise. Continental believes the problem with the carb they selected is that at approaching full throttle, the mixture ratio starts to go lean for the front cylinders. I think it also must have something to do with the intake
configuration in that particular engine.

Wouldn't likely be a factor with an old established Lycoming.

Steve Pierce
11-15-2019, 07:31 AM
The engine was spec'd with an MA4-5 carburetor like on your O-360 but it didn't fit under their carbon fiber cowl. Change out the 25 dgree flywheel for the 22 degree part and the problem will be solved. Has your friend done the nozzle, intake insert and ground adjustable cowl flaps? There is also a mod to drill the main jet that we got from one of the ECI engineers and did. No problems except in very high altitudes he needs full throttle.

andya
11-15-2019, 11:08 AM
Not sure about the adj cowl but he does not have the intake insert or could get any guidance on drilling the main jet.
I talked with a ECI rep but wouldn't recommend what steps to take with the jet. Would be interested in what you have on both those items.
He did change the timing with the 22 degree part but didn't do as much has he had hoped.

Gilbert Pierce
11-15-2019, 12:21 PM
Very interesting. What kind of temp spread did you see before the mod?

Attached is a picture of my UBG16 after the nozzle change. The CHT's, the bottom bars are only 19 Degrees apart. The bars change at each 30 degree increment even though 2 cylinders had 2 bars and 2 had 3 bars they are only 19 degrees apart.
I lost all my download data after the nozzel change. Typically I see cylinders 1,2, and 3 about 1 to 2 degrees apart and #4 10 to 20 degrees lower depending on power setting. Go Figure. I've checked everything on #4 and can only attribute it to the new cylinders I put installed in January 2018. Prior to that #4 had the highest EGT.

Prior to the nozzel change the bars never lined up. Typically the CHT's's had a 50 degree spread low to high and the EGT's had a 130 plus or minus spread. All of this is 75% power setting leaned.
Power settings and leaning make a big difference in the temperature and spreads.



15991

Stephen
11-15-2019, 01:10 PM
The EGT's look impressive. But, how about 2560 and 8.2 gph flow. Where's your left fuel tank gauge?

Sent from my BTV-W09 using ShortWingPipers.Org mobile app (http://r.tapatalk.com/byo?rid=95463)

Gilbert Pierce
11-15-2019, 05:32 PM
The left tank retained the original float gage under the wing. Much more reliable and accurate than the electric gage.
The 160 burns less fuel as you know. Higher compression more efficient use of fuel.

Todd
11-15-2019, 10:41 PM
Thank you Gilbert, that’s very convincing. Sets a new goal! Is this fuel nozzle mod approvable as a minor mod, logbook entry or only experimental?

Gilbert Pierce
11-16-2019, 10:06 AM
https://msacarbs.com/pdf/SB-22_O%20New%20Fuel%20Nozzle.pdf

I let the professional cab shops do the aircraft carbs since they flow the carb on a test bench after working on them. Automotive carbs I have no qualms about tearing into. I assume from reading the service bulletin you can do it if you have CC11-160 Aircraft Maintenance Manual. The SB says after completion of the installation to make a logbook entry. A repair station did mine and sent me the 8310-3 maintenance release and made a look book entry siting the 8310-3 work order.

Todd
11-16-2019, 11:15 AM
A logical approach, thank you.

Stephen
11-16-2019, 12:29 PM
I also agree, years ago during the big carburetor phase of automobiles I had a job rebuilding. Now as an AP I send out my much simpler aircraft carburetor.
https://msacarbs.com/pdf/SB-22_O%20New%20Fuel%20Nozzle.pdf

I let the professional cab shops do the aircraft carbs since they flow the carb on a test bench after working on them. Automotive carbs I have no qualms about tearing into. I assume from reading the service bulletin you can do it if you have CC11-160 Aircraft Maintenance Manual. The SB says after completion of the installation to make a logbook entry. A repair station did mine and sent me the 8310-3 maintenance release and made a look book entry siting the 8310-3 work order.

Sent from my BTV-W09 using ShortWingPipers.Org mobile app (http://r.tapatalk.com/byo?rid=95463)

Gilbert Pierce
11-20-2019, 09:44 PM
Attached is a picture of my UBG16 after the nozzle change. The CHT's, the bottom bars are only 19 Degrees apart. The bars change at each 30 degree increment even though 2 cylinders had 2 bars and 2 had 3 bars they are only 19 degrees apart.
I lost all my download data after the nozzel change. Typically I see cylinders 1,2, and 3 about 1 to 2 degrees apart and #4 10 to 20 degrees lower depending on power setting. Go Figure. I've checked everything on #4 and can only attribute it to the new cylinders I put installed in January 2018. Prior to that #4 had the highest EGT.

Prior to the nozzel change the bars never lined up. Typically the CHT's's had a 50 degree spread low to high and the EGT's had a 130 plus or minus spread. All of this is 75% power setting leaned.
Power settings and leaning make a big difference in the temperature and spreads.



15991

Flew today to get some Ten-a-see BBQ. Leaned at 3000’, 2525 rpm (75% power) my EGT spread was 47 degrees and my CHT spread was 6 degrees. At lower power setting the spreads are little larger. Prior to the nozzle change I saw spreads likes these only above 7500’ and full throttle: the throttle was not partially blocking the throat disrupting the fuel/air distribution. Bottom line the new nozzle with all the holes in it provides better mixture distribution.