If your looking for power at the top end , use popup pistons ... The head is
worked so the combustion chamber is opened up so the valves breath better
then a domed piston is used to get what ever compression you want..
using 1600 will get you around 12.5 to one , 220 lbs. at crank with solex
cam ... the more duration on the cam you have on the cam the higher
compression you can go without having detonation problems on pump gas..
with the 1600 pistons it is a good idea to eye brow the pistons for valve
clearance, and then unshroud the valve by opening up the combustion chamber,
this will get you about 11 to 1 compression, and with a high duration cam
330 deg, running on 93 octane pump gas , you should get no detonation ..
BTW 1600 pistons need the skirts cut for the crank throw clearance ...on a
2000
as far as custom pistons you cam order any compression you like
.
Mike Kerr
Restoration Products
3730 todrob Ln.
Placerville, CA 95667
Ph# 530-644-6777
Fax# 530-644-6777
E-mail mikekerr@innercite.com
Web; innercite.com/~wolfgang
-----Original Message-----
From: Mike Poorboy <bitterrootprop@nidlink.com>
To: datsun-roadsters@autox.team.net <datsun-roadsters@autox.team.net>
Date: Tuesday, May 23, 2000 8:18 AM
Subject: U20 Compression
>List,
>After Stephan's use of 1600 domed pistons in his U20 it
>had me wondering what the race car engines that are running
>11.5 to 1 or higher compression ratio's are using for pistons.
>
>NISMO catalog shows an Arias .40 over piston, but it doesn't
>mention if it is domed or not. The standard U20 piston is a flat
>top cast piston. I am thinking there are at least two ways to increase
>compression in the U20 one is use the flat top style piston and deck
>the block. the other is using dome top or pop up type pistons.
>I realize that the engine would have to be run on racing fuel.
>
>I am just trying to get an idea what has been done out there to
>accomplish
>this on the U20 race cars.
>
>Thanks,
>Mike
>2 69 SRL's part cars.
>
>
>
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