In the case of an engine that’s been heavily modified for performance, as in the case of our Project BlownZ’s Late Model Engines-built LS platform, finding the proper head gasket can be a challenge. The LSX that’s between the framerails of BlownZ has been modified to use a dry-deck design, where the water jackets have been welded closed to prevent the potential for a head gasket failure.
Closing off the water ports in the cylinder head requires the use of a gasket that’s been designed specifically for the application, and as the LS engine never came with this configuration, we turned to SCE Gaskets for the solution – copper cylinder head gaskets with no water ports cut into the gasket body.
SCE starts with a clean sheet of copper in a range of thicknesses. They can make a custom dry-deck head gasket to the customer’s specifications.
Dry-decking will not prevent the head gasket from blowing out, but it will provide a measure of safety for the driver as the problem of a blown head gasket will not put water under the tires in a worst-case scenario.
An engine is an air pump that relies on the heat of expansion to push the piston down, and in the perfect internal combustion engine everything would be insulated – cooling it actually throws away much of this heat and is required in a production engine for longevity reasons. In a race car, the only reason for cooling the engine is to avoid melting it down, and the use of dry-decking can keep more heat in the engine and also produce more horsepower in the process. The added strength in the deck also allows for the placement of thicker head studs to provide more clamping strength.
The waterjet can do amazing things once it's programmed with the required dimensions of the gasket.
Engines are prone to lifting the cylinder head slightly under immense pressure, and with the LS engine’s four-bolt-per-cylinder arrangement, this can crop up – especially when the engine is pumped by by 30-plus pounds of ProCharger F-1X boost like the bullet in BlownZ. Eliminating the coolant from the cylinder head can make the head run hotter, but we’ve already solved that problem using a water pump from Davies Craig that’s been plumbed into each cylinder head thanks to an assortment of fittings and hose from Peterson Fluid Systems and Russell Performance, which was covered in this recent article.
The ProCharged LS engine that’s in BlownZ was put together by Late Model Engines with a dry-deck configuration. This offers many benefits, not the least of which is no worry about dumping water under the tires in the event of a blown head gasket.
In turning to SCE for the solution to our needs, we spoke with SCE’s Caleb Hunter to learn what’s involved in producing gaskets for a dry-deck engine. The company produces three lines of head gaskets – the Pro Copper, Titan, and Titan ICS – that can all be modified in some way to work on a dry-deck engine like ours.
Once SCE has set forth the design parameters of the gasket, the waterjet gets to work cutting out the requisite copper.
“We have over 2000 designs for head gaskets alone, and that is not including all the different part numbers that are associated with the different bores and thicknesses,” says Hunter.
The Pro Copper option is the most customizable, and the one we chose for our application. The gaskets can be further modified; for example, in the case where an engine builder has chosen to move the cylinder head around on the deck for better combustion, and the overall dimensions need to be adjusted, the outer profile requires trimming, and the bolt holes relocated from their OEM position.
The Pro Copper gasket typically relies on an O-ring to provide a positive seal, and the modifications that are possible with these gaskets are nearly unlimited – within reason, of course. The use of CAD software allows the company to make changes quickly and efficiently.
“In the case where we have the drawing and there is no real design needed, we have a $45.00 custom charge to make modifications outside of the standard closed-off water ports and different bore sizes that we offer,” Hunter explains.
The company can also make modifications to their Titan and Titan ICS gasket designs, although these are more limited in scope. The Titan gasket uses essentially the same base as the Pro Copper gasket, but includes silicone bed seals on both top and bottom. These can have the bore and bolt holes modified slightly, but Hunter recommends contacting the company to find out the design limitations with these before making a decision.
The Titan ICS gasket also includes the silicone bed seals, and adds an internal O-ring around the cylinder bore. These also have the ability to be modified for dry-decking, but there are also challenges using this gasket design. The integral combustion seal (ICS) must remain round and is compressed by both the cylinder head and the block all the way around the gasket to provide the combustion seal; in some engines the valve reliefs in the cylinder head are larger than the bore in the block, and the resultant bore in the gasket is not necessarily the same as what’s in the engine block.
BlownZ’s engine has been drilled and tapped to include the use of half-inch head studs to take further advantage of the improved deck strength with the water jackets filled.
There are also some limitations to what can be achieved by the machinery.
“We are limited to thickness provided by the mills – .021, .032, .043, .050, .062, .072, .080, .093, .100, and .110-inch. In all cases where the customer is looking for something that is not in the catalog they need to call first and discuss what it is that they are looking to achieve. We have been doing this for some time now and have seen a few different approaches to almost every combination out there,” says Hunter.
He’s big on the capabilities of the LS platform, and says that SCE has been involved in a number of custom builds to date – such as ours. They have many designs already available, and he stresses that the company can make most anything needed for the platform. Most importantly, he says that the company’s custom capabilities are only a phone call away, as the goal is to provide the best product possible to the customer.