F&M Oil adapter slippage and leakage

How to keep the Cessna 170 flying and airworthy.

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2723D
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F&M Oil adapter slippage and leakage

Post by 2723D »

I think I'm having a growing oil leak from my F&M filter housing, and as you can see in the picture it has moved, rotated. My mechanic took it all apart at the last annual and replaced the gaskets etc per current recommendations, but I feel this setup is prone to issues, or at least my mechanic can't seem to solve it and it is costing me a lot to continue to trouble shoot this thing. After my last flight I had a decent amount of oil on the belly, more than usual and it was dripping off which is worse than ever.

So, where to go from here? Two owners ago they tried one of these adapters and removed it due to these issues. Then the last owner tried again and that is what is on there now.

Do I go back to a screen?

Install the air wolf filter? I had one of these on my 170 years ago in Alaska and I had no issues, but not sure I want the expense of this.

Recommendations before I talk to my mechanic again?
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Richgj3
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Re: F&M Oil adapter slippage and leakage

Post by Richgj3 »

Is it safety wired per the AD? Or perhaps the wrong size copper gasket used. Did that move on its own or is it the result of removing the oil filter?

Mine has been on for many years with no leaks. I already had the copper gaskets installed by a previous owner. We complied with the AD by marking and safety wiring per the AD.

There are older threads on here I’ve seen that talk about the proper initial install. Might be worth a search.
Rich Giannotti CFI-A. CFI-I SE.
1952 C170B
N2444D s/n 20596
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GAHorn
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Re: F&M Oil adapter slippage and leakage

Post by GAHorn »

Was it ACTUALLY TORQUED TO SPECIFICATION? Did someone tell you that?…or did you ACTUALLY CONFIRM IT IS PROPERLY TORQUED?
'53 B-model N146YS SN:25713
50th Anniversary of Flight Model. Winner-Best Original 170B, 100th Anniversary of Flight Convention.
An originality nut (mostly) for the right reasons. ;)
2723D
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Re: F&M Oil adapter slippage and leakage

Post by 2723D »

Maybe if you used all caps I might understand GAHORN? I gotta say I was on this forum years ago and left because of the moderator, and I see nothing has changed a decade later.

As I said, at the last annual the mechanic took it off and put the "correct" parts on per the AD. Did he actually do everything correctly, and torque it correctly I don't know. That is why I'm asking here, if he didn't do it right the last time and he said he did, I don't have faith it gets done right the next time, hence asking for advice.

Yes, I read all the install posts, but I'm not the installer folks, I don't really have a great way to verify myself unless next time I stand next to them while they do it, but I'm tired of pouring money into this adapter.

I guess I have him take it apart and install it again, but I feel it will leak, and that is what happened with the previous owner as well.

Previous question: yes it moved on its own somehow, which baffles me a bit.

So do I invest in the mechanic doing a reinstall? Remove and go back to a screen? Or go to the air wolf filter setup?
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n2582d
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Re: F&M Oil adapter slippage and leakage

Post by n2582d »

Moderators,
It would be helpful if the various threads on this subject be combined to make it easier for owners to find information on this on one thread. I would suggest this thread. Maybe add El Reno / Tempest / Stratus to the title.

Shane,

-As I look at the photo you provided it looks like the torque putty marks show that adapter has actually tightened rather than loosened from when the torque seal was added. Am I possibly looking at a picture that has been reversed?

-In looking at the safety wire securing the adapter, it is nearly 90 degrees to the sealing face of the adapter. Is it possible to secure that wire more in a clockwise spiral?

-Would it be possible to see a picture of the adapter which shows the filter as well? My engine is mounted to the engine mount which is on an engine stand. I can rotate the filter on the adapter from about the 4 o'clock position to the 9 o'clock position when viewed from the rear looking forward. As the engine is not on the aircraft, I'm not sure if that range is available when the engine is mounted on the airframe. If it is, I would mount the filter as close to the 4 o'clock position as possible so that, if the adapter was to rotate, the weight of the filter would be trying to tighten the adapter rather than loosen it.

-It appears that you adapter is sealed with a copper crush gasket which is in compliance with AD2022-04-04. In that AD the FAA writes, "One commenter requested that the FAA make the manufacturer design a better gasket, installed with a torque commensurate with the torqued material, such as fiber gasket material similar to the gaskets used in propeller governors. The commenter stated that the gaskets used in propeller governors are manufactured with an oil-resistant outer layer, a stainless steel mesh center layer, and an oil-resistant inner layer. The commenter reasoned that these gaskets would cover the entire sealing faces of the oil filter adapter and the oil pump, unlike the copper gasket, which uses only a portion of the sealing area." While the FAA disagreed with the commenter, I do think that if the gasket had more sealing area it would be less likely to allow the adapter to rotate. It appears that Tempest also feels this might be the case as they came up with an Alternate Method of Compliance (AMOC) for this Airworthiness Directive as seen here. They've gone back to a special fiber gasket between the accessory case and the adapter. $29 for a gasket is highway robbery, especially as it's to correct their design flaw. If you have an O-300A this AMOC is technically not approved -- but then again the AD doesn't technically apply to the O-300A either. Someone needs to rattle the chain of the FAA's ASO office in Atlanta to get the O-300A listed on both the AD and the AMOC.

-My final thought regards the threads in the accessory case. There are only about 4-5 threads that hold this adapter on. In the thread I linked at the top of this entry John Barrett writes,
johneeb wrote:It is time to review the other discussions that we have had here that deal with the problem with the threads that the adapter screws into. If they are not clean no amount of diligent torqueing technique is going to get the proper amount of pressure against the adapter and the accessory case. When installing a oil filter adapter the first time borrow the thread tap from F&M and clean the threads before installing the adapter.
I have a 1 3/4"-16 tap if anyone needs to clean the threads of the accessory case. I see that Air Wolf, in their installation instructions, writes, "On some Continental engines, you may find the 1-3/4"-16 UNF-3B threads in the oil pump/accessory case where the oil screen was located, to be damaged or not complete causing our CON-10 adapter to bind during installation. DO NOT FORCE our engine adapter into these damaged threads as galling WILL occur. A specially ground 1-3/4"-16 UNF-3B tap is available from Airwolf that usually will cleanup these threads." Might be a bit nervy to ask Air Wolf to borrow their tap to clean threads to install a Tempest adapter! What do other A&Ps think about using Loctite on these threads? If you'd use it, what version would you use?
Gary
2723D
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Re: F&M Oil adapter slippage and leakage

Post by 2723D »

Good catch on the tightening vs loosening of the adapter, it does look like it did move tighter - how in the world did that happen? Since the last oil change they did do some work in there, so maybe someone pushed down on the filter causing it to move. If so I get an F grade for not noticing that, but I really don't think so because I check the oil every flight and it is right there and bright, I really feel I would have noticed that before.

The filter was installed in the 4 o'clock position as noted above. I have a slightly better photo attached. Take from the pilot side cowl opening.

I really appreciate the info on the alternate gasket option, I'll look into that, I have a C-145 btw. I need to spend some more time researching the above information as well and will as I talk with my mechanic this week. All the right words are in the logbook as far as compliance described above, so who knows what may have happened.

I think I'll take one more run at getting this installed correctly, but if I keep getting these issues I think I either go back to the screen or to the air wolf.
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darhymes
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Re: F&M Oil adapter slippage and leakage

Post by darhymes »

I just wanted to point out that the outer portion of the filter adapter is a sleeve that is held in place by friction between the crush gaskets and sleeve. It is important to note that the adapter sleeve can be moved either direction without tightening or loosening the nut…any movement simply breaks the seal and allows oil to seep out.

I believe there are three key points to make sure this assembly does not move (including following the manufacturers instructions, of course):
1. All contact surfaces must be clean and dry before assembly and should not be leaking fluid during the assembly process.
2. Use a block of wood or something similar to brace against the adapter sleeve during final torque and make absolutely sure there is no movement of the indicator marks.
3. Safety wire both directions.

Also-at every oil filter change I use a custom-sized piece of wood to keep the adapter sleeve from moving while removing the filter. I have had the adapter slip before using the wood block. If it slips, remove it, clean it, dry it and start over with new crush gaskets.
Dustin Rhymes
'55 170B N4410B S/N 26754
'06 G550 “The Silver Bullet”
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GAHorn
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Re: F&M Oil adapter slippage and leakage

Post by GAHorn »

2723D wrote:Maybe if you used all caps I might understand GAHORN? I gotta say I was on this forum years ago and left because of the moderator, and I see nothing has changed a decade later…..?
I don’t quite know how to respond to that… Some people see ALL CAPS as shouting…. I use it for emphasis in lieu of bold (because I’m lazy and it uses less key-strokes)…. but it puzzles me when someone asks for help and when help is offered they get their feelings hurt and then become insulting. Kinda takes any helpful wind out of the sails….especially in a Free Forum where someone donates their time to help who he THOUGHT was a friendly airplane enthusiast… so don’t get your shorts in a wad when you get a response intended to assist you.
n2582d wrote:Moderators,
It would be helpful if the various threads on this subject be combined to make it easier for owners to find information on this on one thread. I would suggest this thread. Maybe add El Reno / Tempest / Stratus to the title.
….
When I created these Forums 23 years ago I was new to computers and the internet and I made plenty of mistakes…and still do…and I used “Yahoo” to do it because it was “free”…. sort-of…. but it became very troublesome when all participants became deluged with “spam” as yahoo worked it to their monetary-benefit. Soo…. when I approached the Board of Directors of TIC170A to see if the Assoc’n might like to Host them (in return for me sharing my participant-list of almost 500 which could (and did) improve the Membership-Rolls of a declining “type club”… the BOD was keen on the idea but short on budget and agreed providing it could be done on the cheap…. so we (Dale Medendorp who was treasurer at the time) and I decided to use “phpBB” (the software driving this Forum) because it was “freeware”. The problem with freeware is that it is cheap. In other words, it is not a simple matter to collate all the various Discussion-Threads on any particular Topic without risking corrupting many of those discussions and any effort to do so is so time-consuming (especially for volunteer moderators with other things to do in their lives)…. HOWEVER (emphasis intended…not shouting) we, meaning the IT-Committee and the BOD have recently employed a new Host for our Forums/Website and the BOD at the last annual meeting in Vermont authorized an expenditure to improve our Forum and Website capabilities…. so we’ll hopefully soon see what changes can be made…. However, I doubt the problem of many different threads on similar subjects/topics will be “combined” because it would require too much human involvement and would likely result in threads so repetitive as to become near-worthless.

Sometimes it’s good to revisit a Topic from an entirely new viewpoint anyway.

Back to Oil Filter Adaptor issues: As Dustin points out the El Reno/FM-Enterprises/Tempest/Stratus spin-on oil filter adaptor has a history of gasket/attachement issues. It has the advantage of fewer parts and no hoses but the disadvantage of a large, weighty filter on a long-arm-of-moment which can allow it to “twist” unless a gasket system offering considerable friction is used. The device ORIGINALLY used only copper crush gaskets of the AN900 variety but they have a low coefficient of friction and allowed the adaptor to twist which could allow the filter to contact nearby objects (generator/alternator/gasolator/engine-mount/etc.)…. so an early modification to the STC provided a FIBER gasket at the base where the adaptor contacts the accessory-case and this helped. <edit> (As Dustin pointed out, this “twisting” of the adaptor neither “tightens” nor “loosens” the attachment of the device…. it only shifts it upon the central tube which is held to the engine by the torque’d square-nut.)

Unfortunately the mating surfaces are so small that it could damage the fiber gasket, cut it, and dump the oil overboard …so the AD addresses that by returning to the AN900 crush-washer-gaskets…and the shifting of the adaptor was addressed by additional safety-wiring and witness-marks to detect any shift.

2723D … My intent in my earlier post was to help you and I wanted to emphasize that reliance upon some mechanic who may not be completely familiar with this adaptor and its’ history might be a contributor to your issue. I don’t mean to imply that you personally must participate in the actual work… but I hoped to get you personally-involved to the point that you might educate your mechanic to the importance of that Torque-Value so that sufficient friction is obtained before the safety-wire is installed so the adaptor is well-secured.
I don’t know if you do your own oil changes…or if you employ others to do them….but ANYONE who messes with that filter needs to be educated about not acting like a gorilla when manipulating the filter …so that the adaptor is not dislodged from it’s intended permanent postiion.

Hope this helps. (please notice I made the word “before” bold rather than ALL CAPS.) :wink:
'53 B-model N146YS SN:25713
50th Anniversary of Flight Model. Winner-Best Original 170B, 100th Anniversary of Flight Convention.
An originality nut (mostly) for the right reasons. ;)
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n2582d
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Re: F&M Oil adapter slippage and leakage

Post by n2582d »

Reviewing the history of oil leak problems with the Stratus oil filter adapter and similar Cessna adapter make me uneasy about installing mine. I've added several links to this history here. On my wood splitter the Honda engine has an oil level sensor. If the oil level gets to low, the engine ignition is shut off. Someone needs to come up with an STC for a similar switch on the O-300 ... only hook it up to a warning light rather than the ignition! A low oil pressure light might also give a pilot a bit of warning before the engine seizes from an oil dump but not as much time as a low oil quantity switch. The problem is where would one mount it. This might be one solution. PMA approval would no doubt be cost prohibitive.

I see that in Service Bulletin SEB 93-1R1 Cessna calls for using Loctite 271 to secure the male stud to the adapter. It would be tempting to try this on the 1 3/4"-16 threads in the accessory case. Overhaul shop would curse you if you did -- Loctite says it's "only removable once cured by heating parts up to 500°F".
Gary
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n2582d
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Re: F&M Oil adapter slippage and leakage

Post by n2582d »

Shane,
I’ve added a link to Savvy Aviation’s article on this filter problem to the applicable AD in the Maintenance Library. You were asking about going to the Air Wolf remote filter. Here’s what Mike Busch concludes in that article:
The NTSB doesn’t say so, but we think the design of these oil filter adapters—both Cessna and F&M—is inherently problematic. The oil filter, when full of oil, constitutes a heavy weight mounted on a lever arm that is trying its best to twist the oil filter adapter when subject to engine vibration. The only thing that prevents the adapter from twisting is the preload created by the properly torqued retention nut (Cessna) or retention bolt (F&M). The problem is that the retention nut or bolt is securing a “soft joint” that has a gasket separating the parts being joined (adapter to oil pump housing). As the gasket deteriorates over time, preload is inevitably lost, allowing the adapter to twist when subject to engine vibration. This twisting causes further damage to the gasket, which causes further loss of preload, which causes increased twisting...and the assembly enters a death spiral that—unless noticed in time—inevitably results in loss of oil and possible loss of engine power.
Although frequent inspection—hopefully mandated by an AD—increases the chances of catching this problem before it becomes catastrophic, we think these adapters are fundamentally flawed. While we definitely recommend retrofitting an oil filter to any piston aircraft engine not so equipped, we would feel a lot more comfortable with a remote-mounted filter (e.g., the Airwolf) that has the filter firmly secured to the firewall and not subject to engine vibration.
Gary
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Joe Moilanen
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Re: F&M Oil adapter slippage and leakage

Post by Joe Moilanen »

I installed the F&M adapter on my O-300D 21 years ago. Unlike others I have never had a problem even when I was using the fiber gaskets. There were times when it would rotate slightly when I changed the filter but still no leaks, I was probably lucky. If I were to do it again or if I have future problems I'll problems I will install a remote filter. The design flaws are pretty obvious just by looking at it. I gave it a lot of scrutiny when I safety wired it and replaced the gaskets with copper crush gaskets when the last bulletin came out. There are a lot of different ways to safety wire it against rotation, and I believe if it is done correctly with the proper safety wire tension in the correct orientations rotation is EXTREMELY minimal, not enough to cause anything catastrophic leak-wise with the copper gaskets.

Joe
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n2582d
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Re: F&M Oil adapter slippage and leakage

Post by n2582d »

Joe,
As you face forward, what position does your filter hang relative to the inlet? 4 o'clock? 6 o-clock? etc. I found it interesting that Shane's filter, mounted at 4 o'clock, still rotated, but rotated tighter -- i.e. clockwise -- and was leaking. There is three times the torque on those threads as they originally had with the oil screen yet some are still not staying put. I'm wondering if the gasket is becoming brittle with heat and age and then cracking when engine vibration combined with the weight of the filter rotates the adapter. If that were the case, I would think mounting the filter as close to 6 o'clock -- but not beyond 6 o'clock -- would help. (I'm not certain if that's even possible while maintaining clearance from the engine mount). The other thing I was wondering about is whether the spool is actually rotating in the accessory case or is it staying stationary while the outer part of the adapter is rotating on the spool? The only way to determine this would be to add some torque seal across the top gasket in addition to where it is now called for between the accessory case and the outer housing.

I was looking at Service Difficulty Reports (SDR's) on these adapters and ran across one way NOT to fix the problem. This was on a C-172 with an IO-360.
OIL FITLER ADAPTER SEPARATED FROM ENGINE AT CRANKCASE COVER MOUNTING BOSS ALLOWING OIL SUPPLY TO BE EXHAUSTED. INVESTIGATION REVEALED 80 PERCENT OF THE MOUNTING THREADS CONTAINED IN THIS BOSS WERE STRIPPED. HIGH TEMP RTV WAS FOUND ON THESE THREADS AS WELL AS THE THREADS OF THE OIL FILTER ADAPTER. THE TCM OVERHAUL MANUAL DOES NOT CALL FOR SEALER IN THIS AREA.
Gary
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Joe Moilanen
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Re: F&M Oil adapter slippage and leakage

Post by Joe Moilanen »

n2582d wrote:Joe,
As you face forward, what position does your filter hang relative to the inlet? 4 o'clock? 6 o-clock? etc. I found it interesting that Shane's filter, mounted at 4 o'clock, still rotated, but rotated tighter -- i.e. clockwise -- and was leaking. There is three times the torque on those threads as they originally had with the oil screen yet some are still not staying put. I'm wondering if the gasket is becoming brittle with heat and age and then cracking when engine vibration combined with the weight of the filter rotates the adapter. If that were the case, I would think mounting the filter as close to 6 o'clock -- but not beyond 6 o'clock -- would help. (I'm not certain if that's even possible while maintaining clearance from the engine mount). The other thing I was wondering about is whether the spool is actually rotating in the accessory case or is it staying stationary while the outer part of the adapter is rotating on the spool? The only way to determine this would be to add some torque seal across the top gasket in addition to where it is now called for between the accessory case and the outer housing.

I was looking at Service Difficulty Reports (SDR's) on these adapters and ran across one way NOT to fix the problem. This was on a C-172 with an IO-360.
OIL FITLER ADAPTER SEPARATED FROM ENGINE AT CRANKCASE COVER MOUNTING BOSS ALLOWING OIL SUPPLY TO BE EXHAUSTED. INVESTIGATION REVEALED 80 PERCENT OF THE MOUNTING THREADS CONTAINED IN THIS BOSS WERE STRIPPED. HIGH TEMP RTV WAS FOUND ON THESE THREADS AS WELL AS THE THREADS OF THE OIL FILTER ADAPTER. THE TCM OVERHAUL MANUAL DOES NOT CALL FOR SEALER IN THIS AREA.
Mine is approximately at the 4 o'clock position when viewed from the cockpit looking forward. I believe they required the filter to be at least 1/2" from anything close. The 4 o'clock position puts it a little over 1/2" from the battery box ('53 model with battery box on passenger side) and I believe the gasculator on the bottom side. I'll look next time I'm at the hangar but I'm pretty sure it's the gasculator that kept me from mounting it straight down, which would have obviously been the best choice for non-rotation as well as changing the filter when changing oil. I can still change the filter without taking the cowling off but safety wiring the new filter usually brings about choice words...I'm also wondering if some people are not getting enough torque on it since you need a socket that fits a square head. I made my own, hopefully my attachment comes through okay of the one that I fabricated. It was as simple as welding the open end of an open end wrench to a socket.

Joe
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GAHorn
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Re: F&M Oil adapter slippage and leakage

Post by GAHorn »

I had exactly the same experience as Joe… when I first made the installation it called for a fiber gasket and that was never changed for almost ten years with no problem…except when the Service Bulletin came out about changing the fiber gasket I noticed the original had “squeeze-out” slightly…so I ordered a new fiber gasket and reinstalled it.

Occasionally the filter-change might make a small movement of the adaptor on the “spool”…but it made no leaks and I didn’t concern myself too much over it.

When the AD came out…next oil change…I performed the AD on both the 170 and the 172 (we have this adaptor on both airplanes)….using the AN900 copper crush washers. I have no issues with it and prefer it over the Wolf because Continental and myself like to avoid unnecessary hoses (with the exception I prefer a hose over the OEM copper oil pressure line…along with a pressure-reducer fitting.)

My filter is also at the 4-o’clock position…to avoid the battery box and between it and a strut off the engine-mount.

I posted a link to a 1”-square-socket (8-point, 1/2” drive)I found reasonably priced ($20) at Amazon: https://www.amazon.com/gp/product/B007Y ... UTF8&psc=1

(For you guys who work on Pratt & Whitney PT -6s and some radials…. that company Williams also makes square 8-point sockets in the other sizes to fit those unique P&W nuts….see the same link and select the size you need.)
'53 B-model N146YS SN:25713
50th Anniversary of Flight Model. Winner-Best Original 170B, 100th Anniversary of Flight Convention.
An originality nut (mostly) for the right reasons. ;)
hilltop170
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Re: F&M Oil adapter slippage and leakage

Post by hilltop170 »

This is not advice, just an explanation of something I have seen done in a similar situation.

A similar condition exists on some Jacobs engines that have had an auxiliary oil sump added to the existing engine oil sump. There are two large diameter hollow bolts that secure the aux oil sump with crush gaskets under the bolt heads and against the existing oil sump that are notorious for leaking after a few hours after installation.

What is done to completely eliminate the leaking is the aux oil sump bolt holes are chamfered and additional o-rings are added inside the crush washers. When torqued down, the o-rings are compressed into the chamfers and do the sealing. The o-rings also keep the crush washer centered better than before. This has been done for years and works perfectly.

I’m surprised none of the manufacturers of these oil filter adapters have figured this out as the o-rings will allow some rotation of the adapter without leaking.
Oil sump before chamfer, note o-ring inside of crush washer
Oil sump before chamfer, note o-ring inside of crush washer
Oil sump after chamfer, note o-ring inside of crush washer and Ultra Black sealant
Oil sump after chamfer, note o-ring inside of crush washer and Ultra Black sealant
Last edited by hilltop170 on Sun Nov 20, 2022 7:25 pm, edited 4 times in total.
Richard Pulley
2014-2016 TIC170A Past President
1951 170A, N1715D, s/n 20158, O-300D
Owned from 1973 to 1984.
Bought again in 2006 after 22 years.
It's not for sale!
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