93 1.8L head cc

Archives of Posts to the NZ MX5 List back in 2003
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PeterD

93 1.8L head cc

Post by PeterD » Wed Aug 06, 2003 8:36 pm

Here is a technical one for you. Im building a motor and need to check
the compression ratio. My Burette is broken but it is only a double
check.

Lou are you out there.

PeterD

lou Girardin

93 1.8L head cc

Post by lou Girardin » Thu Aug 07, 2003 8:08 am

In the old days it was the ratio of cylinder swept area divided by combustion
chamber capacity and squish area on the top of the piston. You will need a
burette or similar. Sorry, I can't remember the area formulas. What have you
changed to alter the c/r?

PeterD

93 1.8L head cc

Post by PeterD » Thu Aug 07, 2003 9:33 am

Thanks Lou, I have the calculation but just need to know the volume of
the head chamber.

Recon includes last os pistons and head skim, I just want to check the
figures obtained from the net.

PeterD

lou Girardin

93 1.8L head cc

Post by lou Girardin » Thu Aug 07, 2003 9:47 am

If I was to guess I'd say an increase of .5 to .75 c/r.

Mikkels
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93 1.8L head cc

Post by Mikkels » Thu Aug 07, 2003 12:01 pm

You can fill the combustion chamber with water up to level
with the head. Suck the water back out and weigh it. 1gm of
water = 1cc Will work as well as a burette but requires
accurate scales to 0.1 gm or better.

Don

[...]
1990 NA with a 1.8 conversion SOLD
2005 NC Limited edition 2470/3500 6MT

DBM58
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93 1.8L head cc

Post by DBM58 » Thu Aug 07, 2003 12:16 pm

If you sucked it out using a graduated pipette you would not need the expensive accurate scales.

David Moughtin
David

peter.dixon

93 1.8L head cc

Post by peter.dixon » Thu Aug 07, 2003 1:09 pm

Great idea David, one problem though. The head is away being ceramic coated and
I would like to do a dummy build on the bottom end this weekend to check
heights etc.

PeterD

Quoting David Moughtin <Davidm@Snackmate.com>:

[...]

lou Girardin

93 1.8L head cc

Post by lou Girardin » Thu Aug 07, 2003 2:14 pm

Why are you concerned about c/r, unless the heads been shaved considerably or
the piston crowns are different to stock, an overbore of that size shouldn't
cause you any problems with excessive c/r.

SLYDIT
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93 1.8L head cc

Post by SLYDIT » Thu Aug 07, 2003 7:02 pm

I thought you couldnt use water to CC a head as it
has a funny skin effect at the very top of the chamber
making it innacurate. Engine builders use an alcohol
type solution instead dont they??? Good excuse to
break out the Vodka bottle from the cupboard!
RED '90 TURBO.
SCARING PRIUS DRIVERS SINCE 2002

lou Girardin

93 1.8L head cc

Post by lou Girardin » Fri Aug 08, 2003 8:01 am

You're talking about capillary effect and you're right if you need to
calculate the precise chamber capacity. But if you just want to equalise the
chambers, water would do.

DBM58
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93 1.8L head cc

Post by DBM58 » Fri Aug 08, 2003 8:46 am

A good night's sleep is letting me think a little clearer - why even use a graduated pipette when you already have a graduated buerette to measure the volume that you put in in the first place. Isn't that what chemists use when they are carrying out titrations?

David Moughtin
David

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