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Cylinder boroscope critique

BruceMe

Well Known Member
I boroscoped my engine today, The general order (the cylinders are in order 1,2,3,4) is...

- Straight down on Piston from spark plug
- Cylinder walls (looking for hone marks)
- Intake / Exhaust (I swapped order)
- Intake / Exhaust seats (I may have swapped order)
- Intake / Exhaust stems

They are located here...

https://photos.app.goo.gl/K5htzaQnhSBSxeb39

My analysis is this (and this is my first time, I'd like a critique if you can)
- The cylinder walls all showed good honing
- The exhaust valves showed even round patterns, no edge burn
- The seats don't look smooth and clean, but I can't tell if that bad
- The valve stems all looked good, they showed excellent clean stems
- Exhaust valve 4 didn't seem to open as wide, not sure what that means.

I really appreciate any help you can provide.
 
Boroscope

What kind of boroscope are you using? Those photos are the best I've seen!
 
I
- Exhaust valve 4 didn't seem to open as wide, not sure what that means.

I really appreciate any help you can provide.

The valves are only fully open for about 10-20 degrees of crank revolution, though they are close to fully open for a longer period. If you were in exactly the same piston position in the same phase (exh stroke) for each inspection, that is a possible sign of a worn cam lobe. It is more likely that the pistons were not in the same position and that accounts for the difference.

If you are concerned, make two marks on the flywheel (where piston is about 50% up from BDC - this is near the exh valve peak height) and only compare the two cylinders that share each mark. Don't compare cylinders across the marks, as you don't have a way to make them the same without a degree wheel. If you can visually see a difference in valve height, that points to a worn cam lobe.

Larrt
 
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It appears you have had some cylinder rust events. At least one.

One exhaust valve appears to have hot range about 150 deg of the perimeter - a look at that specific area is warranted.

I can not see the contact areas of the valves in focus very well.
 
Bill, this is great feedback, thank you!

It appears you have had some cylinder rust events. At least one.
It has, for sure.

One exhaust valve appears to have hot range about 150 deg of the perimeter - a look at that specific area is warranted.

Which cylinder?

I can not see the contact areas of the valves in focus very well.

I had a hard time getting that, I'll try again.
 
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