From: Dave Baker
Date: 29 Jun 2001 13:28:57 GMT
Subject: Re: Head gasket passageways
>firstname.lastname@example.org (MKoine) wrote in message
>> I recently replaced a head gasket in a 87 Tempo (2.3L). The gasket was
>> a Fel-Pro and I'm sure it was the correct gasket. When installing it,
>> I noticed that the coolant passageways in the gasket were smaller than
>> the openings in the head, and that there were markings on the gasket
>> that matched the openings in the head. However, there were no
>> instructions to cut the gasket to these marks so as to make the gasket
>> passageways larger to match the head, so I installed the gasket as it
>> came out of the package.
Waterways in a gasket are not necessarily the same size as the ones in the head
and block. When an engine is being designed the holes in the head and block are
usually cast bigger than necessary. The gasket is then modified during testing
to balance the water flow so all cylinders get cooled properly. This usually
results in the holes near the water pump being smaller than the ones at the
back of the block so that all the water doesn't just circulate near the front
Why ? Because it's a lot easier to keep changing the gasket than remachining
the engine. It also makes it possible to produce different gaskets for hot and
cold climates if necessary.
If you mess with the gasket you'll severely disrupt the intended flow pattern
and possibly end up with a piston seizing.
It does NOT mean you have the wrong gasket.
It might look like I'm doing nothing but I'm really actively waiting for things
to sort themselves out.