Also if a 1500 block is milled, the recesses around the cylinders for the
headgasket need to be recut.
MikeC
>
> I've used all the methods mentioned, with good
> results.
> Be aware that planing the block will 'pop-up' the top
> of the piston above the deck. This will require either
> machine work to the head (flycutting at the Combustion
> Chambers) or the pistons (milling to clear the flat
> portion of the CC). And will still probably require
> pushrod or rocker pedestal attention.
> As for pushrods, the aluminum tubes with steel ends
> are very easy to shorten to length. Are these still
> available though?
> The problem with putting spacers under the rocker
> pedestals is that the geometry of the rocker arms will
> change with respect to the top of the valve stems.
> This area is radiused, such that the tip of the rocker
> arm both rotates and slides accross the valve stem
> tip. I have used the spacers, and experienced abnormal
> wear at the rocker tips and valve stem tips. This may
> not be such a problem with stock springs, but if you
> fit a higher lift cam, and double springs, both the
> amount of motion of the parts, and pressure where they
> meet is increased. In a racer which gets very frequent
> inspection and maintenance, that may be OK. But for a
> street car/daily driver, do you want to be doing
> monthly teardowns?
> Changing the camshaft and lifters, once the head is
> off anyway, is not too bad (yes, you should change the
> lifters when you change the cam).
> I'd go with the flat top pistons, and only mill the
> head if compression is still too low. A 'mild' cam
> (Kastner 'B' ?) ought to allow you to keep the stock
> springs, pushrods, etc. which eliminates a whole slew
> of other changes.
>
> --- "Bowen, Patrick" <pbowen@intellinetics.com> wrote:
> >
> > Another option to planing the head and having to
> > argue with the difference
> > in height with the pushrods, is to plane the block.
> > The benefit of this is
> > you take less off to raise the compression more.
> > Since you are removing
> > less the actual height difference will be less for
> > the pushrods. This has
> > been recommended to me many times by spit Racers.
> > Another option to combat
> > the taller pushrods, is to make shims out of
> > aluminum cans or such and put
> > them underneath the rocker shaft pedestals --
> > important make sure you create
> > oil holes in the shims where required!!!
> >
> > Patrick
> > as for the octane/compression issue that is all up
> > to you and what you want
> > to do.
>
>
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