Gearbox gaskets pretty much - grease sealing - cork is too porous to be good for much else.lefty wrote: Just for future reference, is there anything the cork material is good for?
Sorta, but bass-ackwards. Overheating thermal expansion and contraction causes those head bolts to come loose, usually caused by poor maintenance especially to the cooling (The flywheel screen is also part of cooling system, it needs to be kept clear, not just a regular cleanout of cooling fins every so often). Loose head bolt causes blown head gasket. *edit to add* Note that head bolt, I will bet anything it is the lower corner, close to the exhaust area, which is the hottest corner, and even hotter when it isn't getting enough cooling..lefty wrote:I'm guessing that the head gasket broke causing repetitive expansion and contraction and vibration caused it to back out. Figured the rest followed suit as the clamping pressure was now uneven.
Am I close?
Yes blown gasket can cause excess oil use, but oil in air box is lack of maintenance , oil pumping through breather, if air cleaner gets too dirty , air starts sucking in from crankcase, and brings oil with it. Bad breather can be a cause too (more likely plugged drain holes in breather) as well as tipping mower on side (oil flowing past breather and into air cleaner box) - Overall I'd say most all of your problems would have been prevented by better maintenance.
My second question is, what's a possible cause for all the oil in the airbox? Could it be related to the blown gasket and loose head? Bad breather or some other potential issue? I'm planning on removing the flywheel to get a look at the breather shortly. It's the round type on top.
Thanks
In my own experience (which is a LOT of those, and similar Briggs.. used to go through 30-40 head gaskets a year) , it was fairly rare to find them warped beyond reason, there were some that ran that way so long (more often on Kohler K-181 engines) that the head gasket blew through completely and then started melting a notch into the head gasket surface.. but that was pretty rare as they usually didnt get hot enough due to the poor performance once head gasket started leaking.. maybe a few here and there that warp was so bad (usually warpage between multiple bolt holes I had to run heads over some 600 grit wet-dry paper on a flat pane of thick glass (using water to lubricate things) but most of the others there was sometimes a bit of warp that was self-correcting once you torque the head down in proper sequence... never had problems with those that didn't have warp between bolt holeslefty wrote:
Should I be concerned about warpage given the fact that the head was so loose?
It's kind of a judgment call.. takes experience and understanding how the gasket you will be using will handle the sealing of the surfaces.. if you got a straightedge over gasket surface and bolt holes over at least 3 holes, and see gaps between holes then it may require some sanding.. one trick if you have any doubt is make sure you have a hard, perfectly flat surface, and some extra fine (As I said I used 600 grit wet/dry paper) sandpaper and give it a few scrubs , you can then see from the sanded and non-sanded areas where your warp is at.. .009 is quite a bit though but it depends on where that .009 is measured at.. if you do end up sanding head, you might wanna practice on an old scrap head first to refine the technique.. if it needs a lot of work, you can rough it in with some coarse paper(maybe 120 grit) until you start getting some scratches on the low spots , then finish it off with finer paper (220 grit would be as coarse as I'd go for a finish sanding) - works best with wet/dry paper, and keep dropping water on the paper as you work the head over it, and rather than circular motions you can twist (at the wrist) while sanding back and forth, and then rotate head 45 degrees , sand some more, and so on - basically less effort in sanding back and forth and by rotating head around a bit at a time, you'll get a more even pattern with less elbow grease.. depending on the gasket being used (metal clad does not handle filling warpage gaps as well as the graphite ones, but metal clads are more durable and even in a pinch, re-usable) you don't need to get the head perfectly flat. also be sure when you are doing your flatness check the head is perfectly clean and all trace of old gasket is removed (Obviously..)lefty wrote:Reason I ask is that I held this up to the light and could visibly see it out of wack. Kind of wavey. I'm able to get a .009 feeler gauge in there when I hold a straight edge the long way. Is that too much? Or can I get away with sanding and torque?
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