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Discussion Starter #1
I have a freshly rebuilt 72 CL350 and after my first 50 miles a leak has developed along the cam case cover. Not a drop from the head gasket or base gasket. All new gaskets were used and all the old material was removed from the engine prior to reassembly. Isn't this area kinda "low pressure" as far as oil goes? I've never had a leak happen from this area. It's mostly from the front left side. The right side is dry. I'm going to try and retorque the engine to 13.5 lbs. If that doesn't help, what should I be looking for when I pull the engine and to see what might cause this?

This is been a bit disappointing since the bike was almost 100% complete. But it's all a part of the learning experience and I'm okay with that.

20190910_092704.jpg
 

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First, make sure the oil isn't coming from the inside of the points cover, from the seal on the camshaft behind the points plate. If it isn't, then it's likely you put the gasket on the cam bearing cap backwards... though they look like they will fit the same no matter which side is facing outward, they have to be put on correctly or the gasket will pinch one of the rocker shaft o-rings IIRC
 

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Discussion Starter #3
Thanks for the reply. First thing i did check was inside the points housing. I thought that too, but it's dry in there.

I know the orientation is critical for the gasket alignment because it looks like it symetrical, but im pretty sure i put it on correctly.
 

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Discussion Starter #4
I went out and purchased a digital torque wrench to get a precise reading on the head bolts. I wasn't too far off. I know I went to the lighter side rather than over-tightening and most of the nuts were torqued around the 12 lbs range. So I retorqued all of them to 13.5 lbs. And unfortunately, the problem persisted. Looks like I'll be pulling the engine. A bit bummed, but what can you do.

I do have a question since the engine runs perfect. Can I pull the cam case cover off without disturbing the head gasket? I think this could be accomplished by leaving in the two bolts under the spark plugs? The engine was assembled probably about a month ago. If I have to redo all the gaskets, I'll do that rather than pulling the engine twice.

Thanks!
 

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My experience with rebuilding these engines has me going to a higher torque spec than the FSM uses. Originally the spec I use came from reading about building race engines.

The spec I use is first to oil the threads and washer then torque in stages to 16.5 foot pounds. Obviously a higher torque value plus adding the oil increases the actual torque reading.

If you pull the cam box and replace the gasket then torque to a higher spec you should be OK but as you state it would be a pain to pull it again if your gamble doesn't pay off.
 

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Find the EXACT source of the leak FIRST...... Clean and baby powder will show it....
.Then fix that, whatever it takes....You will NOT be happy if you shear a screw......
 

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Over Torqueing the bolts will NOT be the solution to your problem.
It WILL in fact create problems.
It will begin a cascade of failures from metal fatigue. Resulting in broken fasteners etc.
DON'T DO TI ! !

Not only is the idea of overtorquing fasteners bad but the concept of oiling the threads and then over torquieing them is worse.
Torque Values are ALWAY given for DRY fasteners.

ANY Type of lubrication INCLUDING - Anti-Seize throws off the actual effective Torque.
A bolt that has been oiled then torqued to 10 Ft Lbs. has an effective Torque of approx 12-14 Ft Lbs.
The bolts will stretch then add heat and cooling the end result will be a metal fatigue failure.

**Right Click on the Pic below and OPEN in a NEW TAB to see full size.**

Torque Effect-Oil.JPG

Sourec: https://www.engineeringtoolbox.com/torque-lubrication-effects-d_1693.html
 

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Over Torqueing the bolts will NOT be the solution to your problem.
It WILL in fact create problems.
It will begin a cascade of failures from metal fatigue. Resulting in broken fasteners etc.
DON'T DO TI ! !

Not only is the idea of overtorquing fasteners bad but the concept of oiling the threads and then over torquieing them is worse.
Torque Values are ALWAY given for DRY fasteners.

ANY Type of lubrication INCLUDING - Anti-Seize throws off the actual effective Torque.
A bolt that has been oiled then torqued to 10 Ft Lbs. has an effective Torque of approx 12-14 Ft Lbs.
The bolts will stretch then add heat and cooling the end result will be a metal fatigue failure.

**Right Click on the Pic below and OPEN in a NEW TAB to see full size.**

View attachment 290316

Sourec: https://www.engineeringtoolbox.com/torque-lubrication-effects-d_1693.html
I don't disagree with your comments except that in my experience the method and torque settings I use on the head bolts has not resulted in any issues on the 8 engines I have rebuilt using it. No broken studs, no striped nuts and no leaks at any of the joints over a period of 10 years for the first one and nothing on the more more recent ones either.

Of course your experience may vary.
 

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Discussion Starter #10
I spent some time researching oil leaks and came across some posts about blocked breather hoses. My breather hose is definitely not blocked nor pinched but i do have a small filter attached to the end. This wouldn't cause enough pressure to force oil out of the cam case gasket? The leak happens more at higher rpms, for what it's worth. Just thought I'd ask before the motor is pulled tomorrow.
 

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Nope, wouldn't be a breather issue.
Maybe you forgot to install a dowel or it's getting stuck on the dowel and not seated?
Is the oil coming from the rear?
There's not really any oil at the front
 

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Is your breather filter oil saturated?... IF SO, it can cause enough restriction, or be the source of the drips......
 

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Discussion Starter #13
The breather filter is bone dry. And yes. Oil is only showing up on the front left side around the area of the tappet housing. I was meticulous with the parts and not missing anything. but i think i remember one was sorta tough to drop in place. Maybe it slightly twisted enough to cause an issue. Nothing felt odd when torquing down the engine.

Going to pull the engine today. Was going to yesterday but it was 100 degrees with 85 percent humidity. Today is much cooler.
 

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Did you replace the o-rings in the round tappet covers?....... O-rings on adjuster eccentrics?......
 

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Discussion Starter #17
As i just removed the gas tank, i noticed that the crossover line was resting against the breather tube and it definitely looks like it was being pinched.

New question, if this was enough to block off the vent, i know the pressure has to go somewhere and maybe it was through the cam case gasket? If this is all true, do you think my gaskets are still good? Should i try loosening the head bolts and retorque again? Just trying to figure out how to proceed from here. Thanks again for your guys help with this.
 

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Discussion Starter #19
After a couple hours, the engine was out and on a bench. I think I found the cause of the leak around left exhaust side cam case tower. On the back side, I found a pretty good gouge on the mating surface. I attached a picture of where you can see the oil pooling. I'm going to get a sheet of glass and lightly level the surfaces. I cant believe I missed this.

20190913_020545.jpg
20190913_023412.jpg
 

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The pic's show a small gouge in the area of the exhaust valve on the HEAD.
I'd be surprised if that small gouge was the leak it has flat areas all around it - ASSUMING the matching surface of the Cam Rocker Box is Flat.

To flatten that with Wet/Dry paper on Glass you would have to remove ALL of the Valves, Springs and maybe the guides as I seem to remember they sit proud of that surface.
That is a lot of work.
You don't show the matching surface of the Cam Rocker Box.
 
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