Mis-Matched head and valve covers?

thuban

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Anyone ever used a mismatched valve cover with another serial number head? I have a good valve cover and good head but they are not matched. Fit is good as far as I can determine. Hate to throw good spares away because they might come in handy, in the future, in a tight.
Thu
 
If everything lines up, I don't see why not. It's probably hit and miss but I have a mismatched set also.... same as you, just in case.
 
Even though there are alignment dowels between the two parts, to insure proper valve cover fitment, I loosely install them before tightening the head bolts down.
 
5Twins, You've got some good riding mileage out of your XS. With what riding time I got left, I hope parts availability remains high and we don't have to resort to making mismatches work but nice insurance.
Thu
 
I have a couple of mismatches, early XS1 heads/camcovers, and will be facing the same challenge. Kinda cooked up a scheme.

Primary importance is the cam bearings (fore/aft) alignment,
Followed by flush (side/side) alignment at the cam bearing ends,
Followed by flush alignment of the valve cover openings.
Alignment of the rockers and valves is a given, they're aligned with the cam bearing openings.

I'd fit the dowels, and a cam with bearings. Lower the camcover onto the head, check for interference with the cam bearings.

If no interference, check the remaining 2 alignments.

If no fit, try again with just 1 dowel.

Else, remove the dowels, lower the camcover onto the head, align the cam bearing ends, check the valvecover openings.

I feel that the dowels may be considered unnecessary, since the bearings will establish alignment in the fore/aft direction. Use the cam endcovers to establish alignment in the side/side direction. Bolt it all down. Valvecover openings are on their own. Within limits, use gggGary's goober and/or o-rings trick. Else, remove valvecover studs, resurface the openings...
 
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I HeliCoil repaired a valve cover stud hole for a guy. It didn't come out exactly straight and the valve cover was a bit difficult to get on and off. A few months later, we tore the topend down. On re-assembly, I did my loose fitting of the valve covers trick before final tightening of the head bolts.This fixed that slightly out of line valve cover stud. So, it seems there is a little room for realignment even with the dowels in there.
 
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