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head gasket

Posted: 16 Aug 2008, 04:23
by Aleksd82
hey just a quick possibly stupid question.
with the head gasket you get frmo Leisure trail i noticed that the holes where the the water should flow through from the cylinder to the head are eaither partially blocked or completely blocked.
should it be left this way or should holes be cut into the gasket to match the water ports?

cheers.

Re: head gasket

Posted: 16 Aug 2008, 08:38
by fallenmikethebike
There should be a small "tang " on the side of the gasket that says "up" if not try the other 3 possible ways to obtain the best looking fit .From memory its generally green side up .
Regards Mike

Re: head gasket

Posted: 16 Aug 2008, 09:07
by knackeredMk1
The tag that says 'up' goes to the back (carb side) of the cylinder.

Re: head gasket

Posted: 16 Aug 2008, 10:43
by Aleksd82
i know which way the gasket goes, its just the ports arent completely open and smooth to allow free flowing water from the cylinder and the head.
should these holes be widened to match is what i want to know

Re: head gasket

Posted: 16 Aug 2008, 10:45
by knackeredMk1
Don't enlarge the holes in the gasket.

Re: head gasket

Posted: 16 Aug 2008, 11:42
by Aleksd82
but wouldnt it be better for the engine?
smoother flowing water meaning a cooler engine and less strain on the engine as the water pump wouldnt have to work as hard?

Re: head gasket

Posted: 16 Aug 2008, 12:12
by knackeredMk1
BUT -

The barrel and head are designed to allow the flow of coolant around giving access to all of the heat generated. However the heat generated by an engine is far from uniform so the the head gasket is designed to allow the flow in a 'tuned' manner so that those areas that get very hot have more coolant and those that don't have less.

You will notice that the 'holes' on the exhaust side are much bigger than those on the intake side. This is because although inside the combustion chamber all sides are heated the same during combustion, the hot gases produced are in contact with the exhaust side for much longer and thus the exhaust side gets much hotter. There is also a cooling element on the intake side from the air/fuel mix.

If you enlarge all the holes two things happen:

1. There is slightly less pressure in the system so the 'hot' places don't get as much cooling as they would have.
2. Much more cooling takes place on the intake side so you end up with a greater temp diferential across the cylinder and thus a greater expansion differential - which leads to uneven pressures/contact and seizure at worst.

Re: head gasket

Posted: 16 Aug 2008, 15:12
by Aleksd82
didnt think of it that way!
cheers for that mate =)