Shop STEAM VENT KIT
CYLINDER HEAD STEAM VENT KIT 944 8v / 944T
The 8 valve cylinder head has an air pocket or cavity in the rear of the head that traps the air and cannot remove this air on it's own. This air pocket is located on the number 4 combustion chamber and since the engine coolant cannot enter the pocket because of the trapped air, the aluminum overheats, causing it to expand and over crush the head gasket.
In a survey we did of blown head gaskets, in a high percentage of cases, the gasket was pushing out on #4 cylinder adjacent to this air pocket.
Think of it as an under water cave. A cave full of air and no water. In order to fill this area with engine coolant, it is necessary to vent the air out the top of this cave. We achieve this by tapping a hole in the back on the cylinder head and attaching our "Steam Vent Kit". This continuously flows coolant from the back of the head where the trapped air "was" and dumps it into the coolant expansion tank.
Time will tell, but we have sold dozens of these kits and have yet to hear from anybody reporting a blown head gasket since. We're not claiming this as a "fix all"... yet... but it may just be the best preventative measure we have seen.
In addition, if you're pulling your head, you would want Wide Fire or Cometic head gaskets with our Exhaust Port coolant holes. This, combined with our Steam Vent Kit, should give you that added protection you're seeking.
Above you see the steam vent from the back of the head to the coolant expansion tank.
Above you see the steam vent kit plumbed back into our aluminum expansion tank. If you have one of those, then you don't need the "T" and Nipples. If not, and you're using your stock coolant tank, then you use our fittings to deliver the coolant back to the expansion tank through the radiator vent hose.
Our steam vent hose will handle 550 degrees and is chemical resistant.
All cylinder heads having left our shop since early spring '05 have provisions for this Steam Vent Kit. It requires you to drill and tap a hole in the back of the head which would be difficult to do with the head installed on the engine. A right angle drill may allow this to be done, but you will also get metal chips in your coolant system. We recommend installing this kit when the head is off your engine.