Intake valve insert keeps poping out on B&S 11 hp

[GBertolet]

I have a B&S 11 hp 272707 engine, that keeps popping out the intake valve insert. I have staked it profusely several different times, and applied hi temp sealant also, but it eventually comes out again. Could hold for a month, 6 months, or a year, but eventually, it will come out again.

I contacted B&S over this issue, and they stated, it was due to the different expansion ratios of steel and aluminum, and that I should be sure, all the cooling fins are clean, and try running a richer air/fuel mixture, to reduce the engine temperature. Guess what, it hasn't worked!

What do the professionals do to resolve this repetitive condition? There isn't much undisturbed material around the insert left to stake. No trouble at all with the exhaust valve, as you would think that valve insert would get hotter, and be more likely to fail.

 

[USMC615]

@Onan18 ...

@WillG ...

...two of the best and most knowledgeable guys in this realm and business!

 

[farminkarman]

I have had this issue with the exhaust valve seat on several B&S engines, but never the intake. Does the seat "pop" while the engine is running, or when you shut it down? The method I used to repair some exhaust seats required overboring the block and pressing in a steel sleeve for the seat to be pressed into. If you don't have a buddy with machining capability, this method is not worth the expense.

 

[GBertolet]

It did it once while running, but usually, between when it is shut down, and restarted the next time.

 

[Atimm693]

I would probably bet the bore for the seat is just too worn to hold for long.

Some Loctite sleeve retainer may hold it, but I don't think that stuff tolerates high temps.

Is this an OHV or flathead? Is the valve worn?

 

[GBertolet]

It just popped out again. It's just a flathead engine. I was at the far end of the yard when it went. I was pulling my Trac-Vac leaf machine at the time. I believe the bore for the seat is worn. The seat pushes back in with only modest resistance. I cut a groove around the outer circumference of the seat with a Demel tool, and a matching groove in the bore seat. I had some 3000 degree crack sealer, which I flooded around the seat. I am hoping the grooves give the sealant something to grab to. I also staked the seat again, using a heavy hammer, and a big punch.

I wonder if it unseats again, I can use a pair of setscrews along the outer edge of the seat, to lock it in. I think I may have the clearance to do this. I am running out of material to stake with. I would hate to scrap the engine, but I am getting close to the point of no return here.