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Message started by borne2fly on 05/21/07 at 20:44:07

Title: Cylinder Head defect?
Post by borne2fly on 05/21/07 at 20:44:07

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?

Title: Re: Cylinder Head defect?
Post by Greg_650 on 05/21/07 at 20:58:43

Nope. Not a defect.

Just misdiagnosed from the beginning.

Title: Re: Cylinder Head defect?
Post by borne2fly on 05/21/07 at 21:04:01

Pin holes in the casting are not a defect?

Title: Re: Cylinder Head defect?
Post by Greg_650 on 05/22/07 at 04:09:54

I could be wrong, but I'd bet money that you didn't have a pin hole. Just as you said that you don't know why it lasted this long, sounds like even you have doubts.

The leak that you didn't fix, can be very deceptive because the oil goes everywhere anyway. The oil tends to run over to that side when the bike is on the side stand too.

Of course, this could be a first among the thousands of oil leak posts that we've discussed. Yet, I bet that you didn't need a new head gasket, either.

Did you say the pin hole was in this area?

http://i21.photobucket.com/albums/b277/gmdinusa/SparkPlug_1285.jpg

Title: Re: Cylinder Head defect?
Post by borne2fly on 05/22/07 at 09:58:33

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.

Title: Re: Cylinder Head defect?
Post by Greg_650 on 05/22/07 at 10:09:44

Maybe you could clean the motor, ride it and make it leak again...then post a photo of it.

Title: Re: Cylinder Head defect?
Post by LANCER on 05/22/07 at 14:31:15

Yep, oil is messy. ;D

Title: Re: Cylinder Head defect?
Post by Greg_650 on 05/22/07 at 14:45:51

Only when it's mine :P

Title: Re: Cylinder Head defect?
Post by borne2fly on 05/22/07 at 17:52:09

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.

Title: Re: Cylinder Head defect?
Post by Greg_650 on 05/22/07 at 22:29:37

borne2fly wrote:

A photo might be good for jump starting this discussion.

If it is a new leak, I'd like to see it.

Title: Re: Cylinder Head defect?
Post by Savage_Rob on 05/23/07 at 06:30:41

Greg_650 wrote:

A photo might be good for jump starting this discussion.

If it is a new leak, I'd like to see it.

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

Title: Re: Cylinder Head defect?
Post by borne2fly on 05/23/07 at 15:28:08

I've already patched the first hole so all I can photograph is the patched area, but there IS another hole in the casting (fortunately in a harmless area) that I might be able to get a pic of.

The leak I'm currently trying to fix seems to originate from somewhere under the cam lobe bucket, so I can't even see it. I would need one of those optical probes surgeons use. Before I go yanking out the cam I need to lean the bike to the right for a while and see if it leaks without any oil pressure and without getting warm. My biggest fear is that the head has developed a crack in the bottom of the cam bucket that only comes to life when the engine warms up.

Title: Re: Cylinder Head defect?
Post by vroom1776 on 05/23/07 at 15:47:25

x-ray?

Title: Re: Cylinder Head defect?
Post by justin_o_guy on 05/23/07 at 17:35:33

Tyhe cam lobes sit in the "bucket" & it is walled off all the way around to the journal nearest the chain. There isa half washer type retainer there that keeps the cam from moving back & forth across the head. I can't picture any instrument that would allow a guy to look in there. If thers a head issue, pop the oil fill plug. The compression will be able to escape from under the head cover & have a free shot, well, with some restriction as it comes around the end O the cam at the sprocket, & then the compressed & possibly combusted stuff will be headed for the crankcase. The blowby should be a sight to behold since the oil that is supposed to be there to keep things wet for the cam at startup will be being blasted into vapor. This is IF the head is messed up under that area, if it's messed up outside there, seems the pressure would be trying to blow the valve covers off. Surely those little Orings couldnt handle that. Good l;uck, sounds like youve got quite a puzzle.

Title: Re: Cylinder Head defect?
Post by borne2fly on 05/23/07 at 20:33:15

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?

Title: Re: Cylinder Head defect?
Post by justin_o_guy on 05/23/07 at 20:59:04

It's a noisy little engine.4 Valves clacking & a cam chain whizzing along its giudes. 15,000 miles isnt sucha big deal. It's getting about time to have a peek at the tensioner & see where it's sitting. Some guys get good long service outta the cam chain, others, not so good. The tensioner has no "stop" on it & can come apart & send the spring sproingin into gears & create havoc. I don't want to be an alarmist, but the dang thing can sure bite ya.If it was mine I would just have to look in there. You might get a pleasant surprise & your adjuster only be out 12 or 14 mm, or, it might not be so cool.