A friend of mine owns a Savage with 15K miles, and it suddenly developed a MASSIVE oil leak from the head area. Instead of trying to verify where the leak originated I figured it HAD to be the head gasket and proceeded to pull it apart. I got it all together, fired it up, and in less than a mile there was oil everywhere again. But this time I could see where it was coming from ....... a tiny pinhole in the casting just above the spark plug. The hole that was machined to facilitate clearance for the spark plug had cut through to the internal well that the camshaft lobes swing through. Why it had lasted until now is anyone's guess. The hole was TIG welded closed. So now it's together again, and this time a mysterious leak is originating from the right side of the head via the hole on the head casting (you can see the right rear cylinder head bolt through this hole). Without sawing the head in half I don't know what internal passages this thing leads to. The oil does not appear to be traveling down any bolts, so I can't blame the copper washers under the head nuts.  
Has anyone else had problems with oil leaks that seem to originate from defective head castings?

Pin holes in the casting are not a defect?

The pinhole was right next to the spark plug. When I pulled everything apart again I could pass a small wire through the hole and into the bucket the cam lobes swing through! Upon closer inspection, the bottom of the pinhole had a nice clean radius to it that corresponded exactly with the curve of the cam lobe bucket.

The machining tolerance between the cam lobe bucket and the spark plug clearance hole was insufficient on this particular casting. Clearly there must have been a thin metal skin covering it for the last 15K miles, and somehow the thermal stresses & vibration worked it loose over time.

I now have a leak on the other side. The pinhole patch is not leaking, the rubber plug is not leaking, the head cover "gasket" is not leaking, and none of the head bolts are leaking. I have examined each of these carefully by sight and by touch and there is no sign of oil around any of them. And yet ...... there is oil dripping out of that side with less than 1 mile on it since reassembly, apparently coming from somewhere near the center of  that cooling tunnel, which is suspiciously close to where the bottom of the cam lobe bucket is on that side. If it's the same problem I doubt I can fix it from the outside, I'll probably need to pull the cam.

Yep, oil is messy.  

Tonight I'm going to clean it again and blast the right side air tunnel dry with the compressor, all the while keeping the bike on the sidestand. When it's all dry I'll tilt it to the left for a minute and see if I can get that leak to start. If it is indeed another pinhole, then (like before) I won't even need to fire up the engine.

Savage_Greg wrote on 12/31/69 at 16:00:05:


Just a an aside, are you including some of the more notorious pics of failures on the CD you're creating?

x-ray?

Sorry guys, I'm an idiot.



My "second leak" turned out to be nothing more than a loose clamp ..... the one that holds the intake manifold to the front of the carb ..... DOH!!  At least this time I had sense enough not to tear anything apart until I identified exactly where the leak was coming from. It was a bit insidious, the angle of everything caused the spill to leak into the right side air tunnel.  This time I looked at it immediately after riding it around the block and shutting off the engine, and the "oil" was sizzling on the fins.

?????

Oil shouldn't do that. Wiped it with a rag and it smelled like gasoline. That's what prompted the inspection of the carb clamp. Now, why it was mixed with oil is another story. My guess is the intake guides are a bit leaky, but it's running oil tight and not fouling plugs, so I'm going to leave it alone.

By the way, how much mechanical noise should these engines make? It sure seems like a lot of clattering and clunking going on. Is 15K miles considered high mileage for these things?