Abby’s Guide > Outdoor Power Equipment (Lawn Mowers, Snow Blowers, Chain Saws and more) > Discussions > Cracked aluminum crankcase repair options?

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GtWtNorth

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Joined: Nov 16, 2008
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Cracked aluminum crankcase repair options?
Original Message Nov 21, 2012 9:50 pm

I picked up a nice clean 3000 watt generator from CL with a small crack in the bottom of the crankcase that allows the oil to drain out slowly (fell off the back of a pickup). Any one have any suggestions/experience for repairs other than welding? I'm hoping maybe Devcon, JB weld or some metal epoxy?
The motor is a clone, Lifan 168F2 196 cc and parts seem to be quite rare. The manufacturer will ship a replacement crankcase for $62.00 + transport, which is probably close to what I would pay to have it welded.
Thanks

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carlb

Joined: Nov 16, 2010
Points: 279

Re: Cracked aluminum crankcase repair options?
Reply #11 Nov 24, 2012 4:57 pm

I just got an add from Harbor freight and they have there 6.5hp predator engines on sale for 99 dollars and if you have a 20% off coupon its only about 80 dollars but that is a 3/4" straight shaft and yours may be a tapered shaft. If yours is using a 3/4" straight shaft I would just replace the engine.

This message was modified Nov 24, 2012 by carlb

trouts2

Location: Marlboro MA
Joined: Dec 8, 2007
Points: 1328

Re: Cracked aluminum crankcase repair options?
Reply #12 Nov 25, 2012 8:01 am

The way the cracks are open and metal distorted I don’t think glue would do much. If you tried to get things to line up they’ll just crack more.

I’d probably use it as is but pot the 4 areas on the crack4 picture filling them with a strong but non-brittle hard epoxy type glue, something with a little give or flexibility. Fill the inside areas and also run glue on the outside. No strength would be required from the glue on the outside sections. It would just be a leak stopper if that’s where the leaks are coming from i.e. the cracks around the oil outlet area. There is no picture which shows if the cracks run to the threads of the oil plug.

If the corner section stays in place and it probably would then the potting would stop bottom leaks and outside leaks would only need a patch.

hirschallan

If it aint broke don't fix it !!

Location: Northern Hills of NY
Joined: Aug 25, 2005
Points: 327

Re: Cracked aluminum crankcase repair options?
Reply #13 Nov 25, 2012 1:52 pm

I for one would degrease it very well and have a welding shop pre heat with a torch and Heliark weld that sucker. I see no problem at all since I have welded the impossible and still are going strong.

Shryp

Location: Cleveland, OH
Joined: Jul 26, 2010
Points: 532

Re: Cracked aluminum crankcase repair options?
Reply #14 Nov 25, 2012 2:49 pm

Looks to me that the main problem is the mounting configuration. If you do attempt to fix it maybe you can get a sheet of metal or plywood to put under the engine block so you can support the whole thing.

jrtrebor

Location: Michigan - 3 hours north of Chicago on the lake
Joined: Feb 10, 2010
Points: 539

Re: Cracked aluminum crankcase repair options?
Reply #15 Nov 25, 2012 5:55 pm

From the photos there is nothing left strength wise.
There is only one rib left and even that one has a crack by the bolt hole.
Boy, I wouldn't even consider trying any kind of fix other than having it welded.
Any welder that really knows what he's doing and how to mig or tig weld could fix that.
Then I would also as someone suggested redo the mounting.
If it were me I would mount the engine to a piece of 3/16" plate steel.
Bolt the engine to the plate using the other two currently unused mounting holes
Then remount the engine with the plate attached onto the shock mounts studs.

I've worked on a couple of generators that were mounted like that.
Found it easier to loosen up the shock mounts from the frame as well (all four).
Makes it easier to get them all lined up correctly with the engine mount holes.
If you get them turned even a little off line the shock mounts won't sit correctly
under the engine. In other words the stud coming off the shock mount won't
be vertical. It will be leaning one way or the other.

jtclays

Joined: Aug 7, 2011
Points: 16

Re: Cracked aluminum crankcase repair options?
Reply #16 Nov 27, 2012 7:54 pm

$62 in a heartbeat for me if I was going to use /count on it for service. Flipping it?,........... JB Weld and see ya later.

niper99

Location: London Ont
Joined: Dec 2, 2007
Points: 354

Re: Cracked aluminum crankcase repair options?
Reply #17 Nov 28, 2012 12:43 am

ONLY option i would do is to braze it with aluminum... u can not mig or tig it because the block becomes inpreganted with oil... ive brazed many many blocks (espically tecumseh with thrown rods) that are still holding up to this day...

jtclays

Joined: Aug 7, 2011
Points: 16

Re: Cracked aluminum crankcase repair options?
Reply #18 Nov 28, 2012 1:58 pm

Niper, Not to be rude, but would you be able to braze this for a customer for less than the $62 crankcase replacement?

GtWtNorth

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Re: Cracked aluminum crankcase repair options?
Reply #19 Nov 28, 2012 4:34 pm

Thanks for all the help. I got the crankcase open & on first inspection there does not seem to be any cracking on the inside, so it may be going out the drain hole then through the cracks there. I'll try to find a way to test that theory.
My intention was to flip this unit, so I'll probably try lots of JB then bolt a plate to the bottom of the crankcase to prevent the cracks from traveling further & weakening that bad corner. By the way, the supports at the other end broke off completely (by that's a fairly easy repair) so these things are not very robust for use around a construction site.

Cheers

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hirschallan

If it aint broke don't fix it !!

Location: Northern Hills of NY
Joined: Aug 25, 2005
Points: 327

Re: Cracked aluminum crankcase repair options?
Reply #20 Nov 28, 2012 5:13 pm

GtWtNorth wrote:

By the way, the supports at the other end broke off completely (by that's a fairly easy repair) so these things are not very robust for use around a construction site.

Cheers

These ope aren't meant to be dropped off the back of a truck either.

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