After getting the engine pretty much back together I found this hole in the case and realize I must have forgotten one of the bolts when putting the case back together

Figured it was a standard 13mm head bolt I can't seem to get one to start in the threads. A little embarassed, but any ideas?

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That bolt is easy to miss. You got the right size bolt but if you can't get it started you'll need to pull the case apart. The bolt goes through the oil pickup so maybe it isn't lined up with the hole. Check it out. Good luck

In the picture it looks like the ring on the top of the oil pickup is blocking the hole. The bolt is supposed to go through the ring but it looks like your oil pickup is low. See if you can push the pickup up, if not maybe you can loosen a few case bolts then push the pickup up so you can get the bolt through. Make sure you don't strip anything and especially make sure you do not over tighten the bolt once you get it in- it can crack a piece of the case off (see pic).

Here is a picture of the ring that i was talking about.

That one only gets 7 ft.lbs.torque........

It is the nut for the oil sump plate that is torqued to 7 ft lbs.
The case bolt get the same torque as the other 8mm case bolts.

make sure you didn't install a bolt to hold the pick before you put the case together, it will yield the result in the above picture, you can see the hex imbedded into the case halve where its broke.

Took off oil strainer, everything lined up, put in bolt, torqued, all fixed! Thank God!!