First thing tonight I reinstalled the rocker arms for the #2 cylinder. It was much harder to compress the hydraulic lifters this time than the last time I did it last summer. The only thing I can think of is the engine was cold (40 degrees), causing the thick oil to be a little stubborn to leave the lifters.
Always a sad day of the year - when I need to take the hangar heater out of hibernation.
I have been meaning to buy a borescope for some time, and with all of the lower plugs removed, it was just as good of a time now than any to do a quick inspection. I settled on the Oasis Scientific Inc Vividia VA-400 USB Borescope based on many people recommending it on VAF. Amazon had it listed for $150, but I found a vendor on Ebay to accept my offer of $120 for it. I have heard you can get them as low as $100 if you are willing to wait for it to ship from China, which I was not.
The unit is very well made for a $120 borescope. I particularly liked that on the light intensity control module that is inline on the USB cord, there is a button that allows the software running on your computer to create a screenshot of whatever is on the camera. More on the results of the borescope below.
With everything back together, it was time to do a runup. Two good things were first noticed - fuel pressure was where it was supposed to be, and the #2 CHT was in line with the other cylinders.
After a full runup, followed by a static RPM test, all my numbers looked perfect. EGT's were all in line and the mag check was flawless.
Here are the results of the borescope. #1 Exhaust Valve.
#1 Intake Valve
#2 Exhaust Valve.
Looks like there is some lead built up near where the exhaust valve seats.
#2 Intake Valve
The seat for the #2 intake valve looked great.
This is the only pic I grabbed of the cylinder wall, off of #3. Nothing looked out of the ordinary on any cylinder wall.
#3 cylinder exhaust valve.
#3 intake valve.
#4 exhaust valve.
#4 intake valve.
Last Modified: August 13, 2023