Cracked c145-2 case

[tlallen31]

Found Aluminum in my oil filter during my annual. Pulled a cylinder and found an huge crack in the case between the 2 and 4 cylinder attached at the crank bearing. Bummer
Any one have a case or core they need to get rid of. Thanks Tom

[rydfly]

Sorry to hear. Any chance it could be weld-repaired by an overhaul shop?

Can you post a picture?

[FredMa]

The case Is cast aluminum I believe. Not sure anyone would even try to weld it. I personally would not want mine welded since it is a precision machined part that would become distorted to some degree If welded. The engine would have to be completely torn down anyway. If you are paying for that, why not just replace the case? It's enough to make one cry, I know. I just wonder what made it crack. Improper assembly and torqueing perhaps.

[blueldr]

I've seen cases welded and line bored as a repair. Seems to me that an outfit in Tulsa specializes in case repairs. Might be wortha call.

[FredMa]

On an engine sump with a weld repair not close enough to affect the machined mating surface between the sump and engine, I would not be as concerned. The case at the cylinder base is different. without knowing what caused the crack in the first place, I would be worried about it simply cracking again, regardless of the quality of the weld. The machined surfaces of the cylinder base and crank bearing journals can become distorted, if not from a bad weld, from the engine being operated with loose through bolts or whatever caused the initial crack. This would have to make a big impact on the resale value as well. How do you explain that one to a potential buyer? "Yeah the engine did break in half once but it's all good we welded the halves back together" Maybe I just don't feel lucky when it comes to something like this. I can see myself having it crack a second time and having to practiclly overhaul it twice. Like welding a prop blade back on, I just don't have a warm fuzzy felling about it.

[bagarre]

With the cost of replacing the case and overhauling the motor, why not look into the cost difference of the Lycoming STC with a decent mid-time O360 and fixed pitch prop?

Just a thought.

[GAHorn]

DivCo (and some others) have been in business a long time welding crankcases successfully. I have owned two of their repairs and had no problems whatsoever, and the question Fred asks at resale never posed a problem because the repair was by a Certified Repair Station and well-documented as an approved repair. This should have no more effect of resale than any major airframe repair as long as the work was performed and documented properly.

Having said that, it is also true that weld repairs introduce heat and stress to repaired parts. Good shops anneal after their work to stress-relieve, then machine or line-bore to correct dimensions and fitment.

The failure of a crankcase at the main bearing boss is serious however, and is usually traced to improper procedures being followed during cylinder repair/replacement involving movement of the crankshaft while the cylinder is removed and/or improper re-torque during re-installation. (Try not to unnecessarily move the crankshaft while the thru-bolts are not torqued to avoid main bearing shell movement. If you must rotate the crank with the cyl removed, consider placing sufficient washers beneath the thru bolt nuts and torquing them before moving the crank.)

[HA]

I've had many cases repaired at Nickson's Machine in Santa Maria CA, and Divco in Tulsa OK. There are several others but I don't have personal experience with those. You'd be amazed at what they can legally and correctly fix. As George pointed out, once the case is welded then everything is machined back to specs and the case is line bored for the crank and cam, also they'll true up the parting surfaces. The only cases that were rejected for repairs either had too many cracks or major damage like big chunks missing.

Call them for tips on packaging up your case for shipment, for instance put cardboard between the case halves then tie it all together with tyraps to keep from fretting during shipping. If you're in a hurry they might have exchange cases too.

[spduffee]

I was just about to purchase a 1950 170-a that has been asleep for 7 years. The mechanic stated before he would sign the annual, not only would he want to do the standard compression check (all low to mid 70's) but because the plane has been sitting for so long, he wanted to pull a jug and see what's inside. He was excited to see the great condition of the inner workings until he saw a cracked piston (nr. 4) and then the same crack as mentioned by rlallenin the original post, between nr's 2 and 4 on the main journal. I'm glad I found this posting - maybe the two companies can help....Thanks!

[russfarris]

Tom and Spduffee - check out the thread linked below. I took apart a C-145 a year ago and found the same crack in the main bearing saddle, left side of the case between #2 and #4 cylinders. Pictures in the link; do the cracks look like this? I'm just trying to determine if there is a pattern here.

Russ Farris

http://www.cessna170.org/forums/viewtop ... f=2&t=8307

[spduffee]

Russ,

I hope you can see the link below.
I have heard so many opinions on this in such a short time. An old friend who has been working on planes long since before I was born ('67) said not to even worry about it. Others say it's death on a tight schedule.
It's frustrating. But the owner has lowered the price by some $3800 based on this.
Sigh....

(Inoperative hypertext-link deleted by moderator. When such links are posted by new or unknown participants of our Forums they are deleted due to suspicion. Please confirm you links prior to posting. )

[blueldr]

The more I read about cases like this, the more I think about parting out that engine I have in my hangar.
If anyone has any idea about the asking prices on major parts of one of these engines, I'd appreciate an email or a PM with ideas. I sure wouldn't want to break it down for parts if it wasn't economically viable.

[blueldr]

Good luck to anyone going looking for a serviceable Lycoming O-360 to convert a C-170. With the "Vans" crowd building faster than Cirrus, O-360s are premium items today.

[tlallen31]

The photos are the same as my case. Almost like it was my photos