John,
.020 removed from the head and block shouldn't cause much of a problem with
the chain slack. It also depends on the condition of the chain and the 24
tooth sprockets.
The need to change the location of the cam lobe wipe pattern depends on
what you find. Grinding the valve faces and seats will compensate for some
of the material removed from the cam and rockers. Roadster lash pads only
came in one thickness (2mm). There is a place in San Diego called
Schneider Racing Cams that had some spring retainers that would accept "L"
series lash pads but they said that they were all out about 2 months back
and didn't plan to have more made. There are lash pads for the 230SL
Mercedes that have the correct 15mm OD and the same 10mm wide slot as the
originals. They came in three thicknesses, 2.5mm, 3.5mm and 4.5mm.
Strangely the prices were set inversely to the thickness. The 4.5mm ones
that I saw had a fairly large chamfer on the bottom corner that would
probably need to be ground off. I have the part numbers somewhere. What
you have will probably work fine for regular driving but may not be optimum
for competition.
Stan
=====
At 12:18 PM 8/14/03 -0400, JOver4X4@aol.com wrote:
>List,
>
>We have been discussing cam profiles recently. I am preparing to assemble
my U20 engine and have questions regarding rocker arm geometry. My head
has been milled about .010. The deck was milled about .005. My B cam was
reground to remove surface rust but only .003 was removed off of the
profile. The rockers were also resurfaced. This puts the cam .015 closer to
the crank and also leaves a few thousandths extra clearance between the
rockers and cam. To keep everything correct I have read I should shim the
towers by the amount milled and add thickness to the rocker arm buttons by
the amount milled, plus the thickness removed from the cam and rockers,
plus an extra .025-.040 to help center the pattern on the rocker surface.
>
>Does this sound like I am on the right track? If I have milled less than
.020 total do I really need to shim the towers? I have not checked the
pattern on the rocker surfaces yet but am under the impression that I
should at least buy thicker buttons to center the pattern on the pad.
>
>Are buttons available in thicker increments or will I have to have some
made?? Also, does anyone offer an adjustable cam gear to advance the cam
timing as things wear? Is this worth the expense? Any comments or
suggestions would be appreciated.
>
>John Over
>68 2000
>rebuild with old Solex underway
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