the factory rods are too heavy for high RPM use ...
corrillo H beam rods are a good choice but cost 600.00 + for a set of
four.
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: Jim Tyler <toplessdatsun@ga.prestige.net>;
datsun-roadsters@autox.team.net <datsun-roadsters@autox.team.net>
Date: Tuesday, May 23, 2000 4:12 PM
Subject: Re: U20 Compression
>I agree with the cast pistons verses forged pistons. I would never put a
>cast piston in a racing or any high compression engine.
>
>What about the factory connecting rods? Are they strong enough to
>handle around 200 horsepower? This around what a U20 is capable
>of normally aspirated. Plus or minus 20 horsepower.
>
>I was just brainstorming about competition U20's. I was trying to see if it
>was
>feasible to build a high compression engine using flat tops. It would be
>much
>cheaper I guess to go to the mod class and use a VG or SR then try to
>build horsepower into a U20.
>
>Thanks,
>Mike
>No money, so I am doing some leg work and taking notes for a race car.
>
>Jim Tyler wrote:
>
>> For a real competition engine, any of the OE cast pistons are totally
>> unacceptable. Decking the block with flat tops doesn't help much,
>> if you run at the piston at zero deck height that only allows
>> about .050 (gasket) of clearance which you must have. To get
>> 11.5 or more you must have a dome. The R16 piston is way to wimpy
>> for sustained revs over 7k.
>>
>> Probably the best choices for custom pistons are Venolia or JE.
>> Even after you get a set from them, consider that a starting point
>> since you will usually have to machine various portions for optimal
>> performance and clearance.
>>
>> If you want to get really serious about it, I have a set of Cosworths
>> around here some where I'll sell at a good price. They came out
>> of Studdards program. They are the lightest/strongest.
>> They can't be used for street since the under side of the dome is
>> relieved (meaning you can't cut some of it off to lower the
>> compression. They are all out racing pistons.
>>
>> Jim
>>
>> Mike Poorboy wrote:
>> >
>> > 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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