There are many gaskets and...
There are many gaskets and seals in an engine kit and many differentkinds available. Are they all really necessary? Yes, differentapplications require different types of seals. Finding what works bestfor your specific needs is simply a matter of talking with your enginebuilder or the manufacturers.
Few things are more aggravating on a race car than an engine that'salways leaking water or oil. Oil leaks make it difficult to spot cracksand other problems and generally make the car no fun to work on. And itgets worse: Head gasket failures or leaks can cause engine problems andcost you money. Fortunately, it is easy to seal up an engine nice andtight if you employ your gaskets and seals properly. Here are a few tipsto make your life easier and leak-free.
Some seals, like the timing...
Some seals, like the timing cover seal or one-piece main seals on someChevrolets, must be pressed into place. Use a flat piece of wood ormetal over the seal instead of hammering directly on the seal. Also,don't use any lubricant between the seal and the cover. The onlylubricant should be on the lip of the seal.
Limit the Silicone
Silicone sealer is useful in certain places to help a gasket get a tightseal, but using too much will cause problems. If too much silicone isused it will come loose and float around inside the engine. Invariably,it will find its way inside oil galleries or clog the oil screen to theoil pump and harm oil flow. Excessive silicone used on both sides of agasket will also make it easier for that gasket to move and leak. Mostengine builders only use small dabs of silicone on the corners of theoil pan rails and the intake rails at the front and back of the block.
The valve covers on wet sump engines have vent holes for a reason. Ifthe engine isn't properly ventilated, the crank pressure will builduntil an engine seal gives way in order to vent the air pressure. Whenthat happens that particular seal is going to leak from there on out.For circle-track engines you need at least one large air breather (coverit with a filter to keep dirt from getting in) on the left valve cover.
Ken Troutman of KT Engine Development says most head gasket failureshe's seen aren't because of poor quality gaskets. They come from outsidesources. One of the biggest culprits is poor block prep at the machiningstage. If the deck of either the block or head isn't square with asmooth surface, you are going to have sealing problems. Machine marks inthe deck from the cutting operation is OK, but in Troutman's words, "Ifthe deck looks like it has been cut with a file, you know you are goingto have problems." Another common reason for head gasket failure is poorclamping. Head gaskets require proper clamping pressure, applied fromthe head bolts or studs, in order to seal properly. If you are usingpoor quality head bolts or are reusing torque-to-yield bolts youprobably aren't providing the head gaskets enough clamping force to sealproperly. Quality hardware designed specifically for racing, like thehead bolts sold by ARP, are necessary because there is a tremendouslifting force every time the fuel/air mixture is detonated in amedium-to-high compression racing engine.
This is a multi-layered steel...
This is a multi-layered steel (MLS) gasket from Cometic. MLS gaskets useat least three layers of steel to provide the seal between the block andhead. The outer layers have a stamped embossing that essentiallyperforms the same job as a grooved O-ring. These types of gaskets areextremely reliable and are becoming very popular in the Nextel CupSeries.
This is a more traditional...
This is a more traditional style head gasket from Corteco. It usesmultiple layers of different materials bonded together. Corteco uses aproprietary coating on the gasket which helps keep the gasket fromsticking to the head and block, which makes it reusable.
Fel-Pro also makes an MLS...
Fel-Pro also makes an MLS head gasket. It uses a coating on the outsidelayers that improves sealing on deck surfaces as rough as 65 ra. (Justconsider it a safety margin.) This gasket is also made for Ford. Fordblocks use water passages just in the back of the block. If you installthe gasket backwards, with the water-passage holes in the front, youblock the flow of coolant, which will cause severe heating problems.
Some intake manifold bolts on Chevrolets extend into the lifter valley.Use a good Teflon sealer--not silicone--on the threads to keep oil fromwicking up the bolt and puddling on top of the manifold.
Some head bolt holes on some Ford blocks are blind holes, meaning theydead-end into metal. If you try to use a head bolt that is too long thebolt will just butt into the end of the hole and go no farther. You willget the torque reading you are looking for, but the bolt will not applythe proper clamping load between the head and the block. When usingbolts in blind holes, check to make sure the bolt cannot reach the endof the hole or use studs instead.
One-piece oil pan gaskets...
One-piece oil pan gaskets are a great idea and work well. But they won'twork in every application. If you are using multi-piece gaskets for thepan, put a small (and we do mean small) bead of silicone where the corkgasket meets the rubber seal that goes over the caps.
Two-piece main seals are commonly...
Two-piece main seals are commonly used in racing. They fit in a groovearound the main journal at the back of the block. Seals designed forwet-sump engines have a directional lip, which should always pointtoward the inside of the engine. Get it backwards and you will have oilweeping out. Also, put the seal in so that one side extends beyond theparting line. Do the same thing with the other half of the seal in thecap. This way the parting lines between the two halves of the seal donot line up with the line between the cap and block, which helps reduceleaks. Lightly lubricate the lip of the seal only.