Wednesday, August 15, 2018

Whoops... This is a new problem!

Ok, ok, it's not really a problem... at least, it's not a mistake or a roadblock or a money pit kind of problem. The last few weeks have been pretty good - I finished assembling my heads,



made a plate for bolting the cylinders on to check deck height for each piston/cylinder set,



(btw, this gave me wacky results - I had to remake the plate to cover *both* cylinders at once, the same way the head will when the engine is assembled)


(Again, not like this.) and then made a new two-cylinder capturing plate and measured deck height at final torque.

Deck heights were all pretty darn close - I had a spread of 0.1997", 0.122", 0.1225", 0.125". Because I have a lathe handy, I was planning on chucking up the pistons and dusting them all perfect - but after doing the math, I realized that by arranging the heads correctly, my compression ratio would range from 7.976:1 to 8.021:1. In other words, a maximum difference of 0.045:1......... I think that's close enough!

I went ahead and painted the cylinder numbers on the case according to convention, and then marked the cylinders and pistons accordingly.



Since I wanted the heads on certain sides, I went ahead and marked them as well.


The last thing I have to do on the engine for now is bag everything up - each head will get a bag, each piston/cylinder will get a bag, and the block will get a bag. I don't want to have to carry the assembled engine up out of the basement when we move in a few months, so I'll just leave it in pieces until it's in a shop that's on the ground floor. After that, I'll assemble it and bag it again, until I need to take more measurements off it or am ready to attach it to an airplane. So what's the problem, you ask? Well, this engine has been about the only thing I can do related to my plane right now. Every couple weeks we travel to see the rest of my family, and I can sneak away for a few hours to work on the plane when we're there, but otherwise it's just me and the engine. Now that I'm mostly done with that, I'm not sure how I'll keep making progress... and if I'm not making progress, I'll drive my wife over the edge. :)

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