Oil Sump Corrosion

How to keep the Cessna 170 flying and airworthy.

Moderators: GAHorn, Karl Towle, Bruce Fenstermacher

User avatar
T. C. Downey
Posts: 548
Joined: Sat Jan 26, 2013 5:58 am

Re: Oil Sump Corrosion

Post by T. C. Downey »

blueldr wrote:It looks like a gas or TIG weld. The gaseous welding shield must keep the magnesium from igniting unless it is done inside some sort of a compartment filled with an inert gas. Magnesium burns like hell, but I suppose it must have to have an oxygen source for combustion.
Mag fires are very easy to put out, we have a squirt bottle of plane old water, If you do get a fire you simply squirt it with water the steam will blow away the burning material, and cool the rest. and the sparklers burn out on the floor.

But in reality the mag never should get hot enough to catch fire. but when it does, it will provide its own O2 and fuel to continue to burn in any atmosphere, Plus the more material burning the harder it is to extinguish.

Another tid-bit, Tungsten Inert Gas welding (TIG) was invented during WWII to weld Mag parts for the war effort. and it does a fine job in the right hands.

FAR 43-A states that welding on an engine structural component is a major repair, now the question is, is the sump a structural component?
User avatar
T. C. Downey
Posts: 548
Joined: Sat Jan 26, 2013 5:58 am

Re: Oil Sump Corrosion

Post by T. C. Downey »

Bruce Fenstermacher wrote: It is a shame there isn't a coating that could easily be put in over the weld to seal what seems to be the inevitable crack you might get around the outside of the weld..
Cracking around the parameter of a weld area is caused by the use of the wrong filler material (rod), it will swell and shrink at different rates and cause the crack.

And yes, the OAE repair coating can be done over a weld repair.
User avatar
T. C. Downey
Posts: 548
Joined: Sat Jan 26, 2013 5:58 am

Re: Oil Sump Corrosion

Post by T. C. Downey »

spduffee wrote:Well, I'm glad my posting brought about so much good information and comments. It is done, and I am sure the solution I chose may not thrill others, may enforce the view of its proponents, but it is done. I had the pan welded at a specialty shop - not DivCo - (I'm already putting of one their kids through college with the block repair) and below are the results. Fire away...
Once they got into it, it was worse than I suspected. The first pick at the corrosion brought daylight through the body. From then on it was a struggle. I guess I'm happy with it, I mean, it's like the first welded Magnesium oil sump I have ever seen, so....
That looks like a fine job of welding the sump to me.
User avatar
Bruce Fenstermacher
Posts: 10313
Joined: Tue Apr 23, 2002 11:24 am

Re: Oil Sump Corrosion

Post by Bruce Fenstermacher »

George I have to share with you that you had me for about 5 minutes. I was thinking "if he knows it's not Glyptal, I wonder if he knows what it is and if we can get our hands on it". Then I thought "wonder why the green stuff would slow the corrosion better". :oops:
CAUTION - My forum posts may be worth what you paid for them!

Bruce Fenstermacher, Past President, TIC170A
Email: brucefenster at gmail.com
User avatar
Bruce Fenstermacher
Posts: 10313
Joined: Tue Apr 23, 2002 11:24 am

Re: Oil Sump Corrosion

Post by Bruce Fenstermacher »

T. C. Downey wrote:
Bruce Fenstermacher wrote: It is a shame there isn't a coating that could easily be put in over the weld to seal what seems to be the inevitable crack you might get around the outside of the weld..
Cracking around the parameter of a weld area is caused by the use of the wrong filler material (rod), it will swell and shrink at different rates and cause the crack.

And yes, the OAE repair coating can be done over a weld repair.
We were told by OAE when we visited about 2007 they couldn't or wouldn't coat a welded repair. They didn't say why. Maybe they just hadn't tried or or had the approval to do it when we were there. Are you sure of this Tom?
CAUTION - My forum posts may be worth what you paid for them!

Bruce Fenstermacher, Past President, TIC170A
Email: brucefenster at gmail.com
User avatar
T. C. Downey
Posts: 548
Joined: Sat Jan 26, 2013 5:58 am

Re: Oil Sump Corrosion

Post by T. C. Downey »

Bruce Fenstermacher wrote: We were told by OAE when we visited about 2007 they couldn't or wouldn't coat a welded repair. The didn't say why. Maybe the just hadn't tried or or had the approval to do it when we were there. Are you sure of this Tom?
No I'm not positive but I see no reason it can't be, They told me they dye check the sump prior to adding the coating. If it is a good weld I see no problem.

maybe they know some thing I don't.
User avatar
GAHorn
Posts: 20968
Joined: Fri Apr 12, 2002 8:45 pm

Re: Oil Sump Corrosion

Post by GAHorn »

Bruce Fenstermacher wrote:George I have to share with you that you had me for about 5 minutes. I was thinking "if he knows it's not Glyptal, I wonder if he knows what it is and if we can get our hands on it". Then I thought "wonder why the green stuff would slow the corrosion better". :oops:
Thats an appropriate payback.....for the oneupsmanship you got on me in the Directory. :lol:
'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. ;)
User avatar
Bruce Fenstermacher
Posts: 10313
Joined: Tue Apr 23, 2002 11:24 am

Re: Oil Sump Corrosion

Post by Bruce Fenstermacher »

gahorn wrote:Thats an appropriate payback.....for the oneupsmanship you got on me in the Directory. :lol:
I'm getting off easy.
CAUTION - My forum posts may be worth what you paid for them!

Bruce Fenstermacher, Past President, TIC170A
Email: brucefenster at gmail.com
User avatar
gfeher
Posts: 571
Joined: Fri Sep 26, 2014 9:19 pm

Re: Oil Sump Corrosion

Post by gfeher »

I'm reviving an old thread with updated information.

I recently acquired a spare oil sump for my C-145, so I decided to call Okanagan Aero Engine to get the latest information on their epoxy treatment/repair. I spoke to Dan, who was really helpful. Here's the latest:

They are still doing the epoxy treatment/repair, and report continued success with it. It is approved by Transport Canada, and you will receive an 8130 with the treated/repaired unit. I asked him what kind of damage can be repaired, and here are his responses:
Corrosion pits? Yes.
Hole? Pinhole only, but nothing larger and assuming their preparation of the sump does not open the hole further.
Crack? No. They can't touch it.
Previously welded sump? No. Dan said that in their experience, all welds on the sumps crack. So they will not treat a previously welded sump. (Note: I've edited this answer from my original post because Dan subsequently emailed me that after further thought, they decided they won't treat previously welded sumps.)

He said that they have not had any issues with overhaul shops accepting sumps with their treatment. In fact he said many send sumps to them for treatment. As far as how long the treatment lasts, he said that they have been doing it since 1987, and during overhaul run across sumps that still look inside like the day they were treated. Current cost is $500 Canadian (about $375 US at today's exchange rate). Turn around time is 5-10 work days.

Here's their current contact info:
Okanagan Aero Engine
#1 550 Aerospace Drive
Kelowna, BC Canada V1V1S1
250-765-9718

Dan recommends that if you are interested but not sure your sump can be treated, take a picture of the inside and email it to him at danokaero at shaw.ca (of course, substitute @ for " at " in that address).
Last edited by gfeher on Thu Mar 14, 2019 5:11 pm, edited 1 time in total.
Gene Feher
Argyle (1C3), NY
'52 170B N2315D s/n 20467 C-145-2
Experimental J3 Cub Copy N7GW O-200
User avatar
lowNslow
Posts: 1530
Joined: Mon Apr 22, 2002 4:20 pm

Re: Oil Sump Corrosion

Post by lowNslow »

Gene, thanks for the update. I recently bought a backup sump, I had my current sump welded some years ago and it seems to be holding up but decided having a spare would be a good idea. I am thinking of sending the spare in for the coating as an extra precaution.
Karl
'53 170B N3158B SN:25400
ASW-20BL
User avatar
gfeher
Posts: 571
Joined: Fri Sep 26, 2014 9:19 pm

Re: Oil Sump Corrosion

Post by gfeher »

I just received an email from Dan at Okanagan Aero saying that after further thought, the've decided that they won't treat previously welded sumps because in their experience, the welds crack. Sorry for any confusion. I've edited my last post above to reflect this decision.
Gene Feher
Argyle (1C3), NY
'52 170B N2315D s/n 20467 C-145-2
Experimental J3 Cub Copy N7GW O-200
User avatar
GAHorn
Posts: 20968
Joined: Fri Apr 12, 2002 8:45 pm

Re: Oil Sump Corrosion

Post by GAHorn »

Since epoxy is a protective (as well as a sealing) material... if I were to overhaul/rebuild/repair my engine these days... even if the sump were in fine condition...I think I'd spend the $375 to have it treated anyway for preventive purposes.
'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. ;)
User avatar
gfeher
Posts: 571
Joined: Fri Sep 26, 2014 9:19 pm

Re: Oil Sump Corrosion

Post by gfeher »

I received my sump back from Okanagan, so I thought I would share the results. Total turn around time was about 2 weeks. Cost was $375.87 US ($500.00 Canadian) for the work, plus about $51.00 US to ship the sump to Okanagan via USPS, plus $37.50 US for them to ship it back to me via Canadian post, plus about $5.00 credit card currency conversion fees = $469.37 total cost/outlay. Not too bad.

Here's a "before" photo of the inside of the sump at the critical area where most corrosion occurs:
Before - Inside
Before - Inside
And here are "after" photos showing the sump now, including the same area shown in the photo above:
After - Outside
After - Outside
After - Outside 2
After - Outside 2
After - Top
After - Top
After - Inside
After - Inside
They did a nice job.
Gene Feher
Argyle (1C3), NY
'52 170B N2315D s/n 20467 C-145-2
Experimental J3 Cub Copy N7GW O-200
epeter786
Posts: 19
Joined: Tue Nov 14, 2017 5:58 pm

Re: Oil Sump Corrosion

Post by epeter786 »

That does look nice.
User avatar
c170b53
Posts: 2527
Joined: Mon Apr 22, 2002 8:01 pm

Re: Oil Sump Corrosion

Post by c170b53 »

Somewhere, someone suggested using a boro to look at the sump. I doubt it would work. The following is a sump as it was removed
0544BEFB-96EC-496B-935E-A6E0A4DEA33D.jpeg
Problem is the sludge, it’s thick, which traps fluids against the case and causes the corrosion. How could it be removed to do a boro?
26317E43-7EA2-46C5-871D-D1C789445F1E.jpeg
A closer look, probably 1/8 to 1/4 thick at the base of the carb boss
Jim McIntosh..
1953 C170B S/N 25656
02 K1200RS
Post Reply