Cracked aluminum crankcase repair options?

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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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trouts2

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

Re: Cracked aluminum crankcase repair options?
Reply #1 Nov 22, 2012 9:09 am

I've done over four rod caused block cracks with J. B. Weld. I forget the temp rating but it was enough. The cracks were all in non-load bearing areas. Engines with cracks across a structural member or where the crack edges don't line up because one side if puffed out a bit get scrapped.

Depending on the crack you can do:
Drill stop the ends of the crack.
Widen the crack to allow working in the glue.
Make a slight V on either side for holding.
Rough the area.

Not to quibble but what is the Lifan a clone of? Sometimes it seems any Chinese made engine is dubbed a "clone". A GX200 is 196cc and Lifan makes a clone of that (66014, 66015 and others) which are part for part interchangeable with the GX200. Lifan also makes a zillion other engines.

mkd55

Location: wisconsin
Joined: Dec 16, 2005
Points: 155

Re: Cracked aluminum crankcase repair options?
Reply #2 Nov 22, 2012 12:40 pm

i used jb weld to repair the casting where the drain plug is threaded into the bottom of a portable generator motor.the machined hole was not perfectly centered in the casting and one side was thinner than the other.wrapped some teflon tape on the plug threads and must of threaded it in too far and cracked one side of the threaded bore.drained the motor of gas and oil so i could tip the engine upside down to repair the casting.i was lucky because the crack was centered in a cast well with four sides that i was able to clean,degrease,and fill completely to the top with jb weld.i would try the jb first.

CharlesW

Joined: Jan 9, 2011
Points: 76

Re: Cracked aluminum crankcase repair options?
Reply #3 Nov 22, 2012 2:19 pm

I'm more of a buster than I am a fixer, but doesn't the expansion and contraction of the aluminum create problems with the JB Weld repair?

I guess my question has already been answered since you have had success doing it.

GtWtNorth

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Re: Cracked aluminum crankcase repair options?
Reply #4 Nov 22, 2012 2:57 pm

I haven't taken it apart yet, but comparing what I can see to on-line photos of the GX200, the casting features look just like the GX200. As soon as I get some time I'll start tearing down & add some photos. The crack is on the bottom of the crankcase on the side opposite to the crankcase cover, right next to a mounting bolt. I'll only know how long it is when I get the motor out of the chassis.

I was thinking of drilling stopping holes, but what size would you suggest? Although the aluminum may flex a bit more than steel from thermal cycling, I'm also hoping it won't spread any farther. I just have to remember to keep a constant eye out for oil leaks in that area in the future.

Thanks

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borat

Joined: Nov 10, 2007
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Re: Cracked aluminum crankcase repair options?
Reply #5 Nov 22, 2012 6:59 pm

Drill stop hole need to be just a bit larger than the width of the crack. The smaller the better. The objective of the hole is to distribute the stress around the arc of the circumference of the hole rather than the crack continuing on.

MN_Runner

Location: St. Paul, Minnesota
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Points: 622

Re: Cracked aluminum crankcase repair options?
Reply #6 Nov 23, 2012 9:13 pm

Why not just buy the new (or used if you can find one) crankcase if the price is fairly reasonable? If you want to re-sell it at some point, having a non-cracked crankcase (and non welded) will at least not scare the potential buyer away. Hopefully you can find a replacement.

GtWtNorth

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Re: Cracked aluminum crankcase repair options?
Reply #7 Nov 24, 2012 3:10 pm

Ok, I pulled the engine from the chassis to get a better look at the crack (or should I say cracks). Looks like the whole corner is not far from coming off. I wish the cylinder was separate from the crankcase. Here are some photos:

This message was modified Nov 24, 2012 by GtWtNorth

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GtWtNorth

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Re: Cracked aluminum crankcase repair options?
Reply #8 Nov 24, 2012 3:17 pm

Also got some pics of the engine. I'm not expert but it looks a heck of a lot like a GX200 clone to me.

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MN_Runner

Location: St. Paul, Minnesota
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Re: Cracked aluminum crankcase repair options?
Reply #9 Nov 24, 2012 3:22 pm

Looks like a tough fix. Not sure if welding (weldings) will hold. The hairline crack will likely get bigger during heating and cooling cycles.

borat

Joined: Nov 10, 2007
Points: 2692

Re: Cracked aluminum crankcase repair options?
Reply #10 Nov 24, 2012 3:26 pm

Looks very similar to the engines CTC had on sale for less than $150.00

Not sure but I think they were LCT or Champion engines. The 196cc is very similar to the Honda GX200 and from what I've read, parts are interchangeable. You'd probably be better off getting a new engine and keeping the one with the cracked block for parts.

carlb

Joined: Nov 16, 2010
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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
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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
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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
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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
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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

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Location: Northern Hills of NY
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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.

GtWtNorth

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Re: Cracked aluminum crankcase repair options?
Reply #21 Nov 30, 2012 3:29 pm

It seems like I was lucky after all. I filled the cracked oil drain hole with JB weld and buttered up the drain plug before screwing it in. Nnow that it's hardened, the leaking seems to be stopped(knock on wood). The cracking is limited to the corner base area & didn't propagate through the case.

So I'll close her up & fill with oil to confirm. Let you know how it goes.

Cheers

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mkd55

Location: wisconsin
Joined: Dec 16, 2005
Points: 155

Re: Cracked aluminum crankcase repair options?
Reply #22 Nov 30, 2012 3:53 pm

gtwt! you also could jb weld all the wells(valleys) where the cracks are visible in the pics. i filled the whole cavity adjacent to the drain plug casting.

Bill_H

Location: Maine
Joined: Jan 12, 2008
Points: 354

Re: Cracked aluminum crankcase repair options?
Reply #23 Nov 30, 2012 9:28 pm

I would just Alumiweld it. Should be a lot stronger.

Who the hell let all the morning people run things?

GtWtNorth

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Re: Cracked aluminum crankcase repair options?
Reply #24 Nov 30, 2012 9:44 pm

mkd55, - I may still fill those cavities for the extra support.

Bill_H, I looked at the Alumiweld for a long time but the feedback I've seen doesn't give me a warm feeling. Plus I only have a propane torch so it would take a while to heat such a large mass, if it was possible. Plus I am too lazy to strip it right down to the casting so I'd be worried about how the heat would affect the other components, bearings & gaskets.

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niper99

Location: London Ont
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Re: Cracked aluminum crankcase repair options?
Reply #25 Dec 2, 2012 1:56 am

jtclays wrote:

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

l would agree money better spent on a new block espically at that price!!!... and i would probably charge $75-125 for a repair like this one.. but if u wanted to repair it...then brazing it in my opinion is the only permanent solution...

Denis

Location: CAN
Joined:
Points: 638

Re: Cracked aluminum crankcase repair options?
Reply #26 Feb 3, 2013 12:21 pm

I used JB Weld once, it was for filling crack on a ford 302 head it was leaking right front corner , It was not only the gasket, the engine has already 300,000KM so i did want to redone the heads, so I use JB weld and telling you I sold the van and the guy still running it with the repair and still not leaking.

This message was modified Feb 3, 2013 by Denis

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