Triumph1974
Well Known Member
I am still in phase 1 testing and have been having an issue with the Crankshaft seal leaking a little oil...basically not long into phase 1 testing. The leak is always between the crankshaft and the seal (my crank is 10/1000 undersized). I have changed the seal several times, but am beginning to think it may be an issue of to much pressure in the crankcase, but I know I don't have a breather tube restriction issue.
Here is some background:
An A/P friend and I overhauled the engine, and had all the existing cylinders/values done by a local shop. New crankshaft thrush washers where installed etc.
I have the Ney Nozzle STC which sprays oil up on the camshaft when ever the engine is running...
#2 CHT is always about 30 degrees cooler in cruise that the other 3 which are 1-5 degrees apart , but on decent all the cylinders are within a couple of degrees of each other.
When hand cycling the engine cold I notice that one cylinder is "weaker" as the others is not as much effort required to pull the prop through on the one cylinder
Did an simple test of removing the top spark plugs on #1 and #2 and there is definitely less air blowing in your face out the #2 spark plug hole when rotating the prop on the upstroke to TDC position.
I did install the crankcase vacuum system from AntiSplat hoping it would solve the leaking seal and ran it for 3 hrs the other day and noticed that the bypass safety had a very small amount of oil film on top of the exhaust pipe which is a little below where the bypass hose terminates....so I am thinking the bypass was activated at some point due to over pressurization, and there was a small amount of oil coking one one side of the vacuum pipe that goes into the exhaust after 3 hrs of run time....so it looks like a lot of blow by oil is getting out of the engine, but not enough to say the engine "uses oil" beyond normal...and I am likely still breaking the engine in...it has 33 hrs.
Questions:
What is the best way to see if a bad or weak cylinder is the issue and causing
over pressurization of the engine case, and is there anything other than a broken ring that can cause over pressurization, and what are the best ways visually tell if is a ring is broken prior to removing the cylinder?
What is best what to measure crankcase pressure, and what is a normal pressure reading and can this be done by hand rotation, or does the engine need to be running?
Thanks for any advice.
Paul
RV7A Phase 1 testing O-360
Here is some background:
An A/P friend and I overhauled the engine, and had all the existing cylinders/values done by a local shop. New crankshaft thrush washers where installed etc.
I have the Ney Nozzle STC which sprays oil up on the camshaft when ever the engine is running...
#2 CHT is always about 30 degrees cooler in cruise that the other 3 which are 1-5 degrees apart , but on decent all the cylinders are within a couple of degrees of each other.
When hand cycling the engine cold I notice that one cylinder is "weaker" as the others is not as much effort required to pull the prop through on the one cylinder
Did an simple test of removing the top spark plugs on #1 and #2 and there is definitely less air blowing in your face out the #2 spark plug hole when rotating the prop on the upstroke to TDC position.
I did install the crankcase vacuum system from AntiSplat hoping it would solve the leaking seal and ran it for 3 hrs the other day and noticed that the bypass safety had a very small amount of oil film on top of the exhaust pipe which is a little below where the bypass hose terminates....so I am thinking the bypass was activated at some point due to over pressurization, and there was a small amount of oil coking one one side of the vacuum pipe that goes into the exhaust after 3 hrs of run time....so it looks like a lot of blow by oil is getting out of the engine, but not enough to say the engine "uses oil" beyond normal...and I am likely still breaking the engine in...it has 33 hrs.
Questions:
What is the best way to see if a bad or weak cylinder is the issue and causing
over pressurization of the engine case, and is there anything other than a broken ring that can cause over pressurization, and what are the best ways visually tell if is a ring is broken prior to removing the cylinder?
What is best what to measure crankcase pressure, and what is a normal pressure reading and can this be done by hand rotation, or does the engine need to be running?
Thanks for any advice.
Paul
RV7A Phase 1 testing O-360