Spent some quality time with my io-540 today. Changed oil and cleaned, gapped, and rotated my plugs. Every time I'm near my engine with the plugs out, I take the opportunity to stick a borescope in and look at the exhaust valves. They're definitely still there. Anyway, I had heard that you can get a look at a couple of the cam lobes in a lyco through the oil fill port. It's kind of a pain to wiggle it down in there, but I thought the view was cool enough to take a video to show you all, at the risk of being stuck into the aviation media forum (fwiw this video is "unlisted")...
Nice, but not as interesting as your last video demonstrating lots of lubrication. Of course, that one was not on POA.
It’s always wild to me that there’s so little clearance in all engines between cam and crank and they spin at thousands of rpm. No need for extra room that would take extra metal weight in the block/case. Thanks for sharing. Nice camera!
yeah, I'd be worried about crunching that camera head whilst turning the prop. Hay, there's a loose conrod nut!! kidding; made you look
It's so tight in there. I'm also impressed by one lobe doing double duty. The little spin imparted on the lifter is cool to see too. I'm aware of all this stuff on an academic level, but seeing it IRL is fun. Glad to see the three visible lobes all nice and shiny as well. I keep meaning to stick the camera up the sump strainer hole, but forgot....again.
I had never considered that until I built a stroker for my Camaro. I was researching all kinds of options, displacements, etc and came across the issue of crank to cam interference…never occurred to me until I went out to the garage and looked at the block how close those get.
I have had to notch the bottom of the clys on a V8 to clear the stroker crankshaft and rods. I also had to use steel rods instead of aluminum to clear. I filled the block so I could notch it.
Much more difficult. The sump is below the crankcase, and the crankcase is bolted together top and bottom, leaving narrow slots along the bottom for oil drainage. If you do manage to snake a small camera through there, the crankshaft is in the way.
Vividia Ablescope VA-400 USB Rigid Borescope Endoscope with 180 Degree Articulating 8.5mm Diameter Probe https://a.co/d/eUgZkrk As recommended by Mike Busch. Works great.
Am I the only one that thought of Tommy Boy when I read this... My maturity level is sub middle school so it may just be me
Not to mention that the typical Lycoming suction screen is a long cylindrical screen inside a housing that you'd never get the typical cheap borescope outside of. Now if you dropped the pan and had a good camera you could probably go through the drain slots and get a look. I know I could with the camera I have at work, but it's an $85,000 camera. Not something most guys have laying in their toolbox.
You could go up through one of the oil drain holes. Most have at least two of those. But the crank will still be in the way. And getting the camera in there without a drop of oil getting on its lens would be frustrating indeed.
The expensive ones do. Count on $5K anyway. The eyepiece has a couple of knobs that work tiny cables in the snake that bend the tip in any direction, and fairly tightly, too. Just like tendons in sheaths in your body. Think fingers, worked by muscles in your forearm.
True. I was mainly responding to the part where Jim was talking about trying to put a camera in the oil screen hole. I don’t see much useful information from that.
Yes. You’re going to spend some real money if you want a decent camera. I use the one at work for internal engine and after treatment inspections to get photos of areas that can’t be seen or to take photos prior to disassembly.
When done properly, camshaft selection can be incredibly challenging given the number of things you need to check, I think in many ways a pushrod engine is the hardest. Cam to crank/rod interference, just getting the stupid thing in through the cam bearings can be a challenge, lifter selection, correct pushrod lengths, appropriate rockers, rocker height, and rocker tip pivoting correctly on the valve head, valve spring selection, valve stem length selection, piston-to-valve clearance, valve cover height, valve lash... You see these magazine articles with enormous camshafts getting thrown in aftermarket builds like it's nothing, but if you truly do that, you'll probably end up with an expensive pile of broken parts.
Valvetrain ignorance is common. I'm pretty sure a large number of engines built using cams sourced from Summit Racing's website have geometry issues. The builders have no idea they exist, nor the knowledge to fix them.
100% correct. I spent a lot of time looking at this to source the cam for my Cobra build. I wasn't able to go with as high of lift as I had originally wanted given the restrictions on the cylinder head (mostly coming down to maximum lift the valve springs would support). But, I feel confident they're aren't issues with what I have. Now I just hope it doesn't wipe out a lobe during break-in, but so far so good.
I've never lost a solid lifter cam on startup. I could attribute it partly to luck, but I like to think it's because I'm such a knowledgeable engine builder.
Yeah, I figure it's the sort of thing that really isn't as common as they make it out to be. But, I did try very hard to make sure that I did the proper set up and break-in on the cam at initial start. And I also tried to make sure I had the right oil for break-in, and have been putting in the appropriate additive for an old flat-tappet cam, etc.
