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Re: camshafts

To: "Erik V. Berg" <erikb@elrond.sp.TRW.COM>
Subject: Re: camshafts
From: Tor Hval <torhv@ifi.uio.no>
Date: Mon, 3 Aug 1998 22:42:20 +0200 (MET DST)
> I wonder if a 1558cc engine delivering 150 hp may be a bit too 
> camy for a mainly road driven car.  Not that it wouldn't be 
> driveable, but whether you would really like it, might depend on 
> how often you get stuck in slow traffic...  (If you *never* get 
> stuck in slow traffic, I'm JEALOUS!  ;-)
Well we live out in the country  and do most of our driving there.
And we do not very often get stuck in slow traffic unless we travel in to
cities (like Oslo), or get stuck behind a tractor ;). However we do not
want to "ruin" the car by removing all the power at low rpm. We actually
sometimes "cruises" with the elan( Thats when we are not breaking the
speed limits by too much;) )
 > 
> Have you considered a displacement increase?  Would the rules
> for the hillclimbing class you would run in, allow this?
I must say that I/we have not investigated the hillclimb thing to much
yet, so I can not say. But I do not think they are very strickt.
> 
> You wouldn't get a proportionate bhp increase from a displacement 
> increase, but what you *would* get is a more flexible engine, for
> a given camshaft combination.  A 1700cc engine with L1 cams will
> be a lot easier to tune for 150hp than will be a 1558cc engine
> with L1 cams, and it will also be more flexible.  A displacement 
> increase tends to "soften up" a radical cam profile, by increasing
> the port velocity at any given RPM, which will have the effect of
> broadening the torque curve... a very good thing for a road and 
> hillclimb driven car!
We have at first been thinking of taking the engine out to 1700cc by 
using a 83.5 mm bore and stroking it by using a corina gt crankshaft.
But we are now thinking of only using 83.5 mm bore, that would give us
approx 1650cc(I think). Because stroking  the engine would be expensive
with "custom" pistons and/or con-rods. My father called QED in the UK, and
talked to a bloke there. He said it would be cheaper to use a Ford Kent
bottom end instead of the original one.(One would have to shave of some
metal on top of the block though)


Tor Hval <torhv@ifi.uio.no>


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