At 02:08 PM 3/7/99 EST, LRoth66627@aol.com wrote:
>How many different cams were available for the U20, how do you tell them
apart
>and what are the performance considerations.
Officially, there were two cams, designated "A" and "B." The specs are:
Lift Duration
A .440 256
B .460 280
The B cam was part of the "Solex kit" which also included a 7 1/2 qt finned
aluminum oil pan and a different distributor advance curve (along with the
44mm Solexes, of course). The cams can be distinguished by an "A" or "B"
stamped on the back end of the cam.
There have been persistent rumors of a "C" cam, but I have never seen one,
I've never heard any specs posted for it, nor have I ever seen any
reference to it in any Datsun literature. I like to think of it as the
"Sasquatch" cam.
Arguments will probably rage forever about which cam/carb combination is
better, but basically the bigger cam gives more top end and less bottom
end. If you really want to understand cams, find a copy of the old "How To
Modify Datsun Engines and Chassis" by Bill Fisher and Bob Waar. It's been
out of print forever but turns up occasionally at swap meets and on eBay.
The camshaft chapter was written by Racer Brown and is without a doubt the
most readable explanation of cam and valve timing technology I have ever read.
Gordon Glasgow
Renton, WA
http://www.gordon-glasgow.org
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