Re: [ihc] head gasket advice?

[John Hofstetter <hofs@xxxxxxxxxxxx>]

On Tuesday, April 27, 2004, at 06:53 PM, John M. Adams wrote:

> What is meant by flattening? Are you actually lapping the valve cover? 
> Like
> on a large sheet of abrasive paper over thick glass on a flat bench? Or
> something else? I've never attempted this, always relied on the 
> sealant to
> compensate for any irregularities. Thanks, ~John A.
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.

John
John Hofstetter
www.goldrush.com/~hofs