Briggs & Straton valve seats

Hi, I have a 99 sears garden tractor with a 19.5 hp B&S motor. My problem is the valve seats came loose on the right side of the motor. (I have heard this could happen from overheating due to grass clippings caught in the heat shield)
Sears will only send someone out to fix it for $100 and I have heard that the fix is NEW MOTOR, which I will not do.
I replaced the valve seats with new ones and used loctite valve seat glue/compound. The intake is holding but the exhaust still comes loose.
Does anyone know a fix for this, I saw no 'oversized valve seat' in the sears database. How about peening? (I am not sure what that entails or even if it pertains to this problem). I thought about drilling 2 small holes in the valve seat and trying to find some roll pins to hammer in to kinda hold it in the block (valve seats on the B&S are in the block, not the removable head.)
Anyone have any ideas?
Thanks in Advance!!!!
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Stan Poliskey wrote:

Excuse me - did you say that Sears will replace the motor for $100? If so, that is the bargain of the year.
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You'll find a forum here:
http://www.whatsthebest-lawnmower.com /
Some of the members run small engine shops.
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Do you get a new motor for 100 $ ,,, take the deal if so. I dought you will ever fix the seal problem as i suspect it was a design abandoned from failures .
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Stan Poliskey wrote:

... and I take it the $100 is just the service call fee? If they're going to R/R the motor for $100 all told, well, there's no decision to be made. Obviously...
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Stan Poliskey wrote:

the books i have that show installing valve seats show that you heat up the head in an oven and put the valve seats in a freezer and then they fit in pretty tight.... dont thing you would need any glue or loctite to do this.... matter of fact if you do need loctite then you ahve a problem as the seats are too small.. before you give sears $100.00 take the mower to a lawnmower shop and see what they can do.. probably alot cheaper and surer than sears....
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If you can put in a new valve seat by hand, then I assure you the seat is too small. Normally this can only be done by packing the new seat in dry ice and leaving it there for perhaps an hour. Meantime, clean the seat area (the hole you will put the seat in) very very clean - not one speck of anything. Then heat the block with a torch (not a little propane torch). When the block is hot, using forceps, remove the new seat from the ice and insert it into the block. It should drop in reasonably since it has shrunk from being cold. Make sure it is in correctly, and then leave it alone. As the temperatures stabilize, the seat will expand and the only way to get it out is to use a chisel and break it.
No need to use any adhesive of any kind. Hope this helps. Bob
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I think you are missing the point. He said he valve seats are loose. The only fix is an oversize seat. Any good machine shop can install an oversized seat for you, it's a very easy job. Even though Sears doen't offer one they are available aftermarkrt.
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Sorry for the confusion, but its $100 for the service call, and I am pretty sure the fix is a new engine. I wont spend $100 for someone to tell me I need a new engine I won't buy, since my next one wont be a B&S
The original valve seats, once loosened reamed out the holes and now won't seat since the holes are waaaaay to big. I put new ones in with adhesive, but they did not stay. I will try that forum mentioned earlier.
Thanks for all the replys!

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The problem you had with Loctite is that the exhaust valves do some incredible major temperatures.
Beyond that, I'm not all that sure what the answer is -- peening sounds possible. Or shim with something (aluminum foil?) and bang them in. Just thinking out loud. Two part epoxy not likely to work.
--

Christopher A. Young
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