Author Topic: oil leak  (Read 1179 times)

Offline spyke

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oil leak
« on: 29.04. 2011 17:16 »
Hi chaps
Newly rebuilt engine is running as sweet as a nut but after only 30 miles i think there is some oil leaking out of the head joint.Two fold question, is it poss for oil but not combustion products to be leaking and secondly ,why with a newly recon head ,annealed and  slightly greased solid copper gasket torqued evenly to 34ftlbs is it leaking so soon? I took the upmost care assembling all the motor and its a bit demoralising to have this so soon after a two year rebuild.
Spyke
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A10 spitfire style

Offline trickytree

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Re: oil leak
« Reply #1 on: 29.04. 2011 20:31 »
I presume that the head and barrel mating surfaces are perfectly flat. Does the A10 have the oil return holes like the unit twins? If so a thin smeer of silicone around them usually does the trick or some folk put a couple of small O-rings in but I havnt tried that one.
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Online muskrat

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Re: oil leak
« Reply #2 on: 29.04. 2011 21:21 »
G'day Spyke,
                  I know the feeling  *sad2*  *conf*.
Did you tension in the correct order? Center first then 4 outside then 4 inside.
After years of building various motors and always tensioning from the center out, I couldn't get the cafe head to seal (10.5:1). Then a friend said read the book. DOH, it's sealed.
Cheers
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Offline iansoady

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Re: oil leak
« Reply #3 on: 30.04. 2011 16:04 »
Mine's got a slight weep as well (iron head) - looks as though it's from the pushrod tunnels. I'll probably live with it for the time being although I seem to have cured the breather from dripping.
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Ian.
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Offline A10Boy

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Re: oil leak
« Reply #4 on: 03.05. 2011 11:32 »
You said "I think there maybe some oil leaking", which suggests that its just a tiny amount, is that the case or is it a proper leak? Could it just be the grease heating up and running down the fins?
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Regards

Andy

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Offline spyke

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Re: oil leak
« Reply #5 on: 03.05. 2011 16:13 »
Good point, it is a tiny amount ,will do a few more miles and see , youve cheered me up,hope not just temporarily.
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Offline mitch

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Re: oil leak
« Reply #6 on: 14.05. 2011 14:37 »
I had a similar problem on my A10 Super Rocket.
Spent a lot of time and effort on preparig the gasket surfaces, cleaning out threads, counter sinking the holes around the threads etc.
After my first ride (engine running sweet) i noted that there was oil bubbling out of the barrel base studs and the head gasket.
Also had a serious wet sumping problem. (see my entry under A10 wet sumping)
Stripped the motor to discover that i had misssed the anti-flow back ball when i rebuilt the motor.
The ball is directly behind the delivery side of the oil pump, accessed from inside the crank case, next to the timing side main bearing.
It was out completely and the oil pump was delivering direct into the crank case!  OOps!
(i had not stripped the motor, got it as a basket case). Note that the Haynes manual i was using makes no reference at all to this component in the strip down restoration or assembly procedures.
(except a small pic on the parts listing). Hence i missed this first time round! (yes guys, i felt like a fool when i eventually worked this out).
So the result was excessive oil in the crank case and over pressuringing of the crank case forcing oil up and out of my well preapres gasket surfaces.
I dont know exactly what has caused your problem, but it is worth checking that the crank case breather is not blocked and that the crank case is not pressurising on the down stroke.
If you run the motor with the oil tank cap off and then stop the motor, you may well hear a hissing sound int the oil tank, if the sump is holding pressure!
That may well be a possibel cause!
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Offline Andrew

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Re: oil leak
« Reply #7 on: 15.05. 2011 08:50 »
Q

just an idea, is your breather timming correct?
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Andy