RE: [ihc] head gasket advice?

["John M. Adams" <jma@xxxxxxxxxxx>]

> -----Original Message-----
> From: owner-ihc@domain.elided [mailto:owner-ihc@domain.elided]On Behalf Of
> John Hofstetter
> Sent: Tuesday, April 27, 2004 10:00 PM
> To: jma@domain.elided
> Cc: spamaddy@domain.elided; ihc@domain.elided
> Subject: Re: [ihc] head gasket advice?
>
> The valve cover is relatively thin metal. The rim that the bolts go
> through sit on a relatively soft gasket. Between the holes there is a
> rather large area sitting on gasket. What we want to happen when we
> tighten the bolts is for the entire rim to be sucked down on the gasket
> creating the seal. With excessive tightening, or more likely perhaps,
> with tightening some more to try and stop a leak, the area near the
> bolt gets pulled down from the plane of the rest of the rim. If the
> cover is not straightened before it is put on a fresh gasket, the area
> around the bolt holes has to be pulled down into the gasket before the
> flat areas of the cover even touch the gasket.
>
> Consequently, before putting the covers on the gasket lay the covers
> upside down with the rim contacting a flat surface and with a hammer
> (body hammer works very well)  pound the areas around the holes back
> down into the plane of the rest of the cover rim.
>
> Old Chevrolet covers had very elongated washer type things that went
> under the bolt and on top of the rim in order to spread out the down
> pull of the bolt. Worked well for that purpose too.
>

OK, now I get it. Thanks, John. I guess I've never encountered any covers
that were that far out of true, so I wasn't understanding. I've never had a
leak from the valve covers. And I actually used to change their gaskets as
part of every third "tune-up". (Don't ask me why - or why I have a half
dozen sets of slightly used, perfectly good, plugs, points, rotors,
condensers, caps... I'd have to admit that I used to have more time than
good information or common sense.) Anyway, the next time I pull them, I'll
be curious enough to put them on a machine table or something, see how much
daylight there is. On the Chevy design, that sounds like something that
could be fabbed up fairly easily. Has anyone ever tried that? Maybe some
slightly bent spring steel rectangles with a bolt hole at the apex? Like an
elongated fender washer with legs... Last question (yeah, right): why is the
rear of the valley plate so problematic? Was / is there a fitment problem at
that location? Thanks again, ~John A.
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