--- Scott Ruffner <jpr9c@cs.virginia.edu> wrote:
>
> I would've expected the valves to make a more substantial difference.
> Most of the more "modern" small engines I've seen that produce more power
> typically do so by increasing the head's ability to breathe (4-5 valves,
> better valve timing with OHC). I realize that there are other important
> things as well - ability to rev - such as a shorter stroke, lighter rods,
> but aside from balancing the engine (which I'm planning to do), I can't
> alter these nearly as easily.
>
> I'm interested in street power, not a high-revving race engine which runs
> poorly at a normal idle, and I like the idea of having reasonable low-end
> torque. However, I'm also wondering if my energies wouldn't be better
> spent extracting more power from a 1300 with the small rods?
>
>
first, i think you are mistaken with the 1300 engine. the difference between
the 1500 and 1300 engines are the pistons have a shorter pin to deck height,
and the crank has a longer stroke. other than that, they are very similar.
the early 1300 engines had the smaller diameter main bearings, but the later
1300 had the larger ones found in the 1500 engines.
just an opinion, i have a later 1300 engine, with a fast road cam, single 150ZS
carb, and a 4.11 rear end and i think it has quite good idle manners and
acceleration, and it also revs like and SOB. i am thinking of going to dual
carbs if i don't sell it come spring, and i think it will be quite a thrill to
drive then.
so, if you have the 1300 engine, put your efforts into that. if you have the
1500, put your efforts into that. i doubt you'll be unsatisfied with either.
=====
nikolai jaremka
72 spitfire mkIV
east aurora, new york
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