So remember like a month+ ago when I was asking about CC'ing my U-20 head
and figuring out the compression ratio?
Well I finally got to it this weekend. Seems like I had to replumb and redo
our master bath first????
I made the measurements and well. could someone please check if my numbers
are at least in the ballpark.
Here are the measurements needed for calculating CR.
Combustion Chamber volume = 35.5 cc
Bore = 3.460 "
Stroke = 3.235"
Deck Height = .025"
Compressed Head Gasket Thickness = .04"
If I plug these #'s into one of the many online CR calculators I get a CR of
11.95!!!
That's a little high I think. Working the math I need a gasket of .175"
compressed thickness to get a CR of 8.51.
I know my head is probably thinner than it should be ~4.450" (I think that
was not as easy of a measurement to make as I thought..)
Do these numbers seem way wacky to y'all. I only have one decent digital
caliper to try and get these measurements and I have to admit that my
technique is not as repeatable as it should be.
I got a big syringe and used it to fill the combustion chamber with veggie
oil. I had a super hard time with the plastic over the dang head technique.
I kept getting air trapped under it or the oil would leak out the sides so I
gave up on it. I managed to get the head pretty darn level and fill it with
the veggie oil all the way up till it was just about to spill out. That's
how I got the 35.5cc number up above. Is that any kind of a reasonable way
to do it?
What's the best way to measure stroke?
What's the best way to measure bore?
What's the best way to measure deck height?
Thanks in advance,
Daniel Neuman
Oakland CA
|