At this point I'm not confident that the problem description you have received is necessarily entirely accurate. I'm not accusing your repairer of protective colouration of the facts, but dealers in some products engage in this kind of thing routinely. Anyway, if the engine is being repaired on warranty, you are not out of pocket and you can hope the work will be done more successfully this time.

There are two "brands" of B&S OHV large engines: Vanguard and Intek. The Vanguard engines are designed and built in Japan, and have quite a good reputation. The Intek engines began as Vanguards but the design was revised by Briggs to make them cheaper to produce, and they are made in the US. As far as I am aware they have a bad reputation.

Post-edit: These pictures from spare parts listings may give you an idea why the Intek engines blow head gaskets and the Vanguard ones do not. Here is a 25 cubic inch Vanguard head gasket - I have added a red circle to show where it usually blows, from the combustion chamber to the pushrod chamber:
[Linked Image]

Here is an 18 cubic inch Vanguard head gasket - as far as I know these gaskets do not blow, though I have read about one slight oil weep:
[Linked Image]

Last edited by grumpy; 05/02/13 03:07 AM. Reason: Post edit to illustrate head gaskets