2.3 NF block with MC-1 head?

[Brady Moffatt]

Hi Alan/All,

You have omitted one important item. How much of the effective combustion
chamber is in the head vs. the piston dish? If both the KV and NG have
flat-top pistons, this is a moot point. But if even one doesn't, then your
calculations could be way off.

Also, static compression ratio is calculated as (total volume at BDC)/(total
volume at TDC), which means:
KV: to find combustion chamber volume (let's call it x) (in head, piston
dish, gasket thickness volume, etc.) 10/1= (445.2 + x)/x, so 9x=445.2, so
x=49.47cc, NOT 44.52cc.

For NG, 9x=461.8, so x=51.31cc, NOT 46.18cc

Cheers,
Brady Moffatt
Montreal, Quebec, Canada
86 4kq with 306,000km
86 4kq parts car
72 Datsun 240Z with 180,000 miles
92 VW Golf with 194,000km FOR SALE
in early stages of quattrosis accumulatus

----- Original Message -----
From: "Alan Pritchard" <apritchard at seaeye.com>
> --
> [ Picked text/plain from multipart/alternative ]
> Just want to confirm my thoughts on this for my turbo project. My engine
> consists of a kv bottom end (2226) and an ng head (2309), both engines are
> spec'd at 10:1 compression ratio.
> KV engine: 81 Bore, 86.4 Stroke
> NG Engine : 82.5 Bore, 86.4 Stroke
> So capacity of each cylinder =
> KV 2226/5 = 445.2
> NG  2309/5 = 461.8
> Therefore for both engines to have 10:1 compression ratio, at tdc the
volume
> above the piston must be:
> KV 445.2/10 = 44.52
> NG 461.8/10 = 46.18
> So logic dictates that if the ng head is fitted to the kv bottom, the
> compression will be lowered: so working on the fact that my 2226 engine
now
> has 46.18 cc above the piston at tdc gives me....
> 2226/5 (capacity of cylinder) = 445.2/46.18 (new volume above piston) =
> 9.64:1
> Does this follow, or have I missed something, my goal has always been
8psi.
> my head says yes, but when I posted before no one could back me up.
>
>
> Best Regards,
> Alan Pritchard
> Network Administrator
>
> Seaeye Marine Ltd.
>
> Tel.  01329 289000
> Fax. 01329 289001
> www.seaeye.com


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