I just scanned all the post on this and one thing I would add that I
did not see mentioned (though maybe I missed it) is whether it has
the correct front timing cover. I have seen 1275s with the early
non-vented timing cover, which can exacerbate this problem. Also, If
the engine sat for a long period of time, sometimes the rings will
freeze in the ring lands making and this will make a big contribution
to the problem. As suggested a leak-down test would be the first
thing I would do to determine where you are losing "passing gas"...'-)
Gerard
At 3:03 PM -0700 5/19/04, Glen Byrns wrote:
>Craig wrote and I excerpted:
>
>"..... I just got a call from him and he said that the car has major leaks
>going out both the front and the back of the motor. Otherwise the car seems
>to run fine. Although the engine was rebuilt a few years ago it has very few
>miles on it.
>.......are there any thoughts as to what typically can cause this and what
>needs to be done to resolve it?"
>Craig
>
>Sounds like you suddenly have lots more blowby than before. This will force
>oil out both front and back. Remove the oil filler cap and place your hand
>above it then rev the motor. You should be able to tell if its blowing a
>ton more than usual. Things that change suddenly to create a large increase
>in blow-by include:
>
>1. Broken ring(s)
>2. Broken piston (top land of piston cracks down to first ring groove)or
>holed piston. These aren't that likely unles you're running a turbocharger
>or love flogging your motor with over-advanced timing
>3. Cracked block
>4. If you have one of them dang modern smoggy motors, could be a plugged
>PCV or non-functional gulp valve).
>5. Cracked head? Usually that puts water in the oil, oil in the water or
>combustion gasses into the water. I suppose it could possibly crack in a
>way that vented combustion gases into the oilways which would increase
>crankcase presure and cause the front/back leakage, but I've never
>experienced this.
>
>If the leakage has slowly and steadily increased over a period of time, it
>might just be badly worn rings, but your inquiry seemed to imply a very
>recent change on a very young motor.
>
>Time for a compression test and a quick check for bubbles being blown at the
>radiator filler hole, steam from the oil filler cap, tan scum on the
>underside of the filler cap, one different looking sparkplug. If it passes
>all those checks, then carefully open your checkbook and do a volume test of
>the balance.
>
>Glen
>
>PS If your're in N Cal, I'm going to do a teardown and rebuild of my
>bugeye motor next month if you want to see it done.
>
--
One meets his destiny often in the road he takes to avoid it.
~French Proverb
http://www.gerardsgarage.com/FS_Garage.htm
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