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03 engine case

Posted: Wed Jan 21, 2015 4:23 pm
by rtboone
Greetings all

A few months ago, I purchased a 03 Wombat bottom end on E-BAY. The seller stated that the crank was frozen and I could see a bit of rust on the flywheel in his photos.Not a problem. I can re-build the crank. I usually do that anyway.
When I split the cases, I found that the crank was a total mess and could not be salvaged and that there was considerable pitting in the aluminum.
I media blasted the pitted areas and filled with industrial J-B weld and sanded them smooth. The cases fit together nicely and there are no gaps from the left to right sides.
My question is, can these be used or should they be retired to the recycle bin ?

Thanks

Tom

Re: 03 engine case

Posted: Wed Jan 21, 2015 4:43 pm
by BrianZ
I had the same problem with some Road Toad cases, and I ended up replacing them. Personally I didn't feel comfortable building up a motor with damaged cases, and I just wouldn't feel confident in the longevity of JB Weld. Having said that, I have heard a lot of good things about JB Weld, and I know several people who have used it to repair rotted magnesium cases. So far it has worked for them (one season of racing). It comes down to where your comfort level is, and of course the availability of replacement cases.

Brian

Re: 03 engine case

Posted: Wed Jan 21, 2015 5:42 pm
by junker2k
If I was building an all out racer I would replace them but for just a rider use them. As long as the cases seal and bearing surfaces are good with new bearings, I sure don't see any reason not to use them.
Jack K

Re: 03 engine case

Posted: Wed Jan 21, 2015 6:15 pm
by dcooke007
Jack's opinion would match my thoughts also. I am not sure I would have used the JB Weld though. I like JB Weld but not sure it helps much under these circumstances.
Danny Cooke

Re: 03 engine case

Posted: Wed Jan 21, 2015 6:32 pm
by taber hodaka
Just old thoughts from the dark past. The machined part of the cases look good to me. some pitting inside would not make any difference to me I don't see anything that would affect the motor structurally. ------------Clarence

Re: 03 engine case

Posted: Thu Jan 22, 2015 4:20 am
by Bullfrog
;) Actually, I think the cases should be recycled. Send them to Captain Eddie's Recycling. Upon receipt of the cases, Captain Eddie will even send you a reimbursement check for the cost of mailing! ;)

Ed
PS: As long as the preparation for the application of the JB Weld was thorough, you shouldn't have any issues with it. I've got two seasons on a cylinder which was converted from reed valve back to piston port induction by way of JB Weld. I was apprehensive at first, but I can't argue with the success of the modification.

Re: 03 engine case

Posted: Thu Jan 22, 2015 4:34 am
by bchappy
My experience with JB Weld is that if it was media blasted to where all the oil deposits were off it will stay. I also have used it on cylinders and it stayed. I have noticed there are several new JB Weld formulas and I think we are all talking about the original.

Re: 03 engine case

Posted: Thu Jan 22, 2015 5:01 am
by hodakamax
I'm with Clarence, It looks sound to me--I'd go for it.

Maxie

Re: 03 engine case

Posted: Thu Jan 22, 2015 6:59 am
by racerclam
I really wouldnt be concerned with pitting in the cases , all it would do is increase crankcase volume an imeasureable amount. And I have found permatex cold weld to be a better product than JB weld . I have tested JB and cold weld applied to a stick and soaked in a cup of gasoline and the JB softened but cold weld didnt . And if you have a higher alcohol content in your fuel permatex metal mend is not affected with alcohol. It was important for me to find out with all the carbs I do with venturi dividers since they must be glued into the slots cut into the carb. One customer I did a carb for runs straight methonal in a mini sprint car . So I clled permatev to find the product that alcohol wont affect. The thickness that is used will also determin how resiliant JB will be , since mainly the surface will be affected. thats why Eds port filling is successful . But in the crankcase it will eventually start peeling off.

Rich