Rocker Cover Clearance..and more!

[cheezer60]

I'm reassembling my top end after much needed repairs to the stock heads (valve job, new exhaust ports, and fixed o-ring intake cracks). .020 on the cylinders, new pistons, rings...yada yada.

While surfacing the rocker covers and prepping for new felts, I noticed I've got the dreaded deep crescent marks inside both sides on both covers from the spring collars. Aftermarket collars and definitely aftermarket covers came with the bike; both of which I understand will cause this. Rough combination, huh? I'm sure surprised I never heard any banging before I pulled the heads.

Machinist that did the valve work, said guides and seats are stock, and in decent shape. The valves have a fresh reassembly with correct specs. That along with the rest of the work- means I'd like to prolong the life of these heads. The old covers are crusty chromes anyway, and I want some aluminum replacements I can polish up. What's my next step?

1) Are any aftermarket aluminum covers a correct fit to the stock heads? (V-Twin? Paughco? Someone else?)
2) Use a dremel inside the covers to make clearance for the collars?
3) Be ignorant, run the steel covers, beat the seats into oblivion, and go on rants about how unreliable panheads are?

[Panacea]

Or search for some OE pan covers...

[58flh]

Well Said!---I have seen stock collars banged also with aftermarkets.As long as the valve height is correct --you can raise the tin using thick corks & it will do the job!---But a OEM cover is truly a good thing.----Richie

[kitabel]

If you have nerves of steel, there's more you can do.
Imagine the top spring coil pushing up against the collar's large diameter flat surface. The actual line contact is between the flat and the highest radius of that coil (at 12:00 o'clock).
If the spring wire is (example only) .150" thick, and its OD matches the collar exactly, what does this tell us?
That a bit less than .075" (half the wire thickness) can be safely removed from the collar OD without disturbing how either component works.
Wire thickness = (spring OD - spring ID) ÷ 2
Example:
If OD is 1.500" and ID is 1.200":
1.500 - 1.200 = .300; .300 ÷ 2 = .150"
Minimum safe OD = OD - wire thickness + .060" safety margin
1.500 - .150" = 1.350 + .060 = 1.410"
That's .045" extra room between the collar and the point of tangency inside the cover.

Need even more?
Beehive springs.

[Panacea]

Somebody mentioned smaller collars being available on a simmilar thread recently as well...