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Conference vmszoo::rc

Title:	Welcome To The Radio Control Conference
Notice:	dir's in 11, who's who in 4, sales in 6, auctions 19
Moderator:	VMSSG::FRIEDRICHS

Created:	Tue Jan 13 1987
Last Modified:	Thu Jun 05 1997
Last Successful Update:	Fri Jun 06 1997
Number of topics:	1706
Total number of notes:	27193

780.0. "How do you fix a cracked Engine case" by TARKIN::HARTWELL (Dave Hartwell) Mon Nov 28 1988 14:18

    I have this OS .40 SF engine. Only problem is that the engine
    case is cracked where the carb slides into the engine. Since
    I'm sure that a new carb and engine case will cost more than
    a new engine, I would like to know if any of you have had any
    luck in repairing this sort of problem. The engine case is only
    cracked on the upper 2/3 'rds of the carb mount, and all pieces
    are still intack.... I donot want to trash this engine if their
    is a way to bubblegum it together to get more life out of it..
    
    
    Any suggestions????
    
    
    
    					Dave
    
    Sole owner of a Sport-Air 40 with an uncanny affinity to re-aquaint
    itself with mother earth at the wrong possible moments.

T.R	Title	User	Personal Name	Date	Lines
780.2	SPORT-AIR??	MPGS::PERCUOCO		`Mon Nov 28 1988 14:37`	6
	Dan, Is you SPORT-AIR still in the box?? How much??????? Tom
780.4	Try a hose clamp	STRINE::CHADD	Go Fast; Turn Left	`Mon Nov 28 1988 15:01`	28
	Forget it Dave. The job cannot be done properly. I have a box full of cracked OS 40 cases all cracked from the front right to rear left screw hole on the bottom of the case. I have tried getting them welded many ways, the best found was Mig(sp) welding which is quite expensive. It does distort the case and it needs to be re-machined to get things to fit and align properly. What also happens is the heat changes the grain structure and weakens the case so it break's again soon after. After saying that from the crack you describe you may be able to do a "fence wire" repair that will last a short time at least. This is when it gets difficult translating to American describing a component. People who call a spanner a wrench!!!???. Get yourself a small hose clamp. The type of clamp used to hold the radiator hoses on your car but only very small, about the same � as the carb mount. File part of the clamp away so it fits on to the mount. Mark and drill the positions of the carb mounting screws in the clamp. It could be worth getting some Locktite aluminum cement but it will not add that much. Position the clamp, tighten it up, fit the carburetor, cross your fingers and give it a go. Best of luck. John.
780.5	Cheap Fix	WR2FOR::BEATTY_WI		`Mon Nov 28 1988 19:52`	7
	If you can still secure the carb with the screws try some high temp (red) silicone sealant. Run a bead around the base of the carb and over and around the crack and carb boss. Be careful not to let it touch the crank below the carb as it does emit a mild acid while it cures that can etch the crank. Good Luck! Where theres a Will theres a way...
780.6	Cheap FIx should work!	LEDS::WATT		`Mon Nov 28 1988 20:58`	12
	I agree with the last suggestion if your carb will stay in place ok. Silicone will hold up well if it is only sealing the crack. As long as you don't have an air leak, the damaged case shouldn't cause any problems. I wouldn't try anything drastic to patch the case. Too bad it isn't the older FSR model where the front of the case is a separate piece. THe cost would be reasonable to replace it. Good luck, Charlie
780.7	don't shoot messenger :-)	ITHIL::CHAD	Hi	`Thu Oct 01 1992 09:04`	16
	My brother is a university physics student and is now taking a class where they get acquainted with a machine shop (you know, to put together all those nifty toys for those experiments they do). Anyway, a friend of ours has an ASP with cracked case somewhere where the carb attaches (I haven't seen it so I can't tell you exactly where). Anyway, they are going to try and repair this in the machine shop. I'll report on the success (also a bent crankshaft, they want to try and machine a new one). They also have a plan I am trying to convince him/them is not a good plan, if nothing else, a waste of time. They want to take apart his Royal .40 and measure all the parts, CAD them up on a PC, and then machine their own engine, buying bearings and using a ringed piston, not ABC like the Royal is. I said that it was a waste of time, if it worked it wouldn't run as well as a bought engine ($65), etc. Comments? Chad