gaskets fixings

0 1 2 4 0 1 2 5FAST FORD SUMMER 2010

THE LOWDOWN GASKETS AND FIXINGS

n previous Lowdown features we have looked

in-depth at various engine components, what they do, and why you need them to enhance your car. But we havent looked at what physically holds all of those components together.

The simple fact is that without gaskets and fi xings an engine wouldnt

run, in fact it would be a mere pile of very expensive bits.

As with different engine parts there are many different types of gaskets and fi xings available for your engine. Uprating these will add reliability, allow your engine to work harder, and in some cases are just needed to support some of the performance

components that we have already covered.

So, to fi nd out exactly whats what in the world of performance gaskets and uprated fi xings we headed over to see the guys at Burton Power in Essex to raid through their extensive range of Cometic gaskets and ARP fi xings, and pick their brains on how they all go together

I

The components that hold your engine together are just as

important as the bits in it. We went to Burton Power to fi nd out why.

Words: Jamie Photos: Jon Hill

GASKETS AND FIXINGS

0 1 2 50 1 2 50 1 2 50 1 2 50 1 2 50 1 2 50 1 2 50 1 2 50 1 2 50 1 2 50 1 2 50 1 2 50 1 2 5FAST FORD SUMMER 2010

n previous Lowdown features we have looked

in-depth at various engine components, what they do, and why you need them to enhance your car. But we havent looked at what physically holds all of those components together.

The simple fact is that without gaskets and fi xings an engine wouldnt

run, in fact it would be a mere pile of very expensive bits.

As with different engine parts there are many different types of gaskets and fi xings available for your engine. Uprating these will add reliability, allow your engine to work harder, and in some cases are just needed to support some of the performance

components that we have already covered.

So, to fi nd out exactly whats what in the world of performance gaskets and uprated fi xings we headed over to see the guys at Burton Power in Essex to raid through their extensive range of Cometic gaskets and ARP fi xings, and pick their brains on how they all go together

I



The components that hold your

important as the bits in it. We went engine together are just as

important as the bits in it. We went engine together are just as

to Burton Power to fi nd out why.important as the bits in it. We went

to Burton Power to fi nd out why.important as the bits in it. We went

Words: Jamie Photos: Jon Hill

SUMMER 2010 FAST FORD

GASKETS AND

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GASKETS AND FIXINGS


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TYPES OF GASKETBefore we start looking at the many different types of gasket available we need to understand what a gasket is and why it is needed. In short a gasket simply creates a seal between two mating surfaces. It does this by taking up the space caused by the imperfections of the two mating surfaces. Therefore most gaskets are effectively crushed to create the seal when the two objects are bolted together. Because of this most can only be used once, and need to be replaced for new when removed.

In an engine gaskets are needed to create seals for components dealing with oil, fuel, water and sometimes air. Therefore different gaskets need to be made from different materials depending upon their use.

The most common types of gasket material include:

CORK Cork gaskets are commonly used to create a seal between two steel surfaces when oil is present, for example rocker cover-to-head, and sump-to-block. Cork is the best material to use for this

as it is absorbent, has excellent crush

capabilities, and is cheap and

easy to produce.

PAPER This is often used to

prevent water leaks. Most commonly found in water pumps and thermostats, thin water-resistant paper gaskets are ideal for sealing between two machined surfaces when water is present.

FIBRE Fibre gaskets and in particular washers are often used to create seals in fuel systems. They are impermeable to fuel, yet have excellent crush capabilities, which makes them ideal for use in conjunction

with banjo bolts

for components such as fuel pumps, fuel rails etc.

RUBBER SEALS Rubber seals are often used to seal between a rotating assembly and a fi xed object, such as crankshafts-in-block and camshafts-in-head. The outer casing of a rubber seal is usually rubber-coated steel which presses into the fi xed component to create a seal around the outer edge. The inner part of the seal is typically a rubber fl ange with a spring in it, which holds the inner edge of the seal onto the component running through it. This allows the inner component such as a crankshaft to rotate freely, while still retaining an oil-tight seal.


THE LOWDOWNGASKETS AND FIXINGS

HEAD GASKETSSTANDARD HEAD GASKETSThe head gasket is probably the most stressed gasket in the whole engine as it has to seal oil ways, water ways, fuel/air mixture and exhaust gases, and has to operate under the extreme temperatures and pressures of mating the cylinder head to the block. This is why the head gasket is amongst the most common gaskets to fail in a high-performance engine.

Older head gaskets like those used in the original Lotus twin-cam engine were actually made from copper and

PERFORMANCE GASKETS

the rings will crush and deform to create a seal between the cylinder head and block. The resulting seal is much stronger than with a traditional head gasket, enabling far greater cylinder pressures to be reached without the head gasket failing. This type

of system was commonly used on race engines, and in particular high-boosting turbo engines. To accompany the Coopers rings a Group A-style head gasket without

any fi re rings can be used to seal the oil and water ways. Alternatively some top-end motorsport engines didnt use a head gasket as wed know it at all. Instead they used Coopers rings to seal against combustion, and the block was also machined to accept

rubber O-rings around the oil and water galleries, therefore not needing a single-piece head gasket. However, Coopers rings are now seen as old technology,

and many engine builders,

including the guys at Burton Power, agree that for most engines a good multi-layer steel (MLS) head gasket will offer the same level of performance as Coopers rings, but without having to machine the block.

A MLS gasket is made up of multiple steel layers joined together to form a gasket. Burton Power stocks a complete range of Cometic MLS gaskets, so we were able to pull one apart to see exactly how they work.

The outer two layers of an MLS head gasket are embossed and on Cometic gaskets are covered in a

fl ouroelastomer rubber-based material called Viton. These outer layers are what give the gasket its sealing properties. When the gasket is installed the embossed edges deform slightly to create a seal. The gaskets strength comes from the centre layer, which is made from untreated stainless steel. The centre layer is also what gives the gasket its thickness, as this centre shim is available in a

gasket available. In the Ford tuning world Group A uprated head gaskets are often seen as the fi rst available upgrade. These are based heavily on the standard design, but are made from a more durable and more resistant composite material. They can therefore cope with the increased strains of a higher performance engine than the standard gasket, but are also a direct swap and operate in exactly the same way. Another method of uprating the head gasket, which was particularly common in the mid-80s, is to fi t a set of Coopers rings. These replace the fi re rings on a traditional head gasket with a much heavier-duty set of O-rings. The block needs to have a lip machined around the top of each cylinder to allow the Coopers rings to be fi tted, and as the head is torqued down

range of different sizes. Four layer gaskets feature two centre shims as well as the two outer layers, with the extra centre layer offering even greater clamping pressure.

According to Burton Power, Cometic gaskets are available off-the-shelf in sizes ranging from 1mm to 2.5mm thick, and can even be custom made to any thickness required. Thicker gaskets are not necessarily stronger, but do offer the engine builder the chance to tweak the compression ratio easily after the head has been skimmed, or if a slightly lower comp

ratio is required.

One downside to MLS gaskets is that because they do not crush and therefore move about in the same fashion as a composite gasket, they are best used when the two mating surfaces have been machined totally fl at. Fitting a steel gasket to a slightly uneven block or head surface could result in failure, whereas a composite gasket has more give in it to accommodate these irregularities.

A three-layer MLS features two thin Viton-covered outer layers and a stainless steel centre shim

Coopers rings replace the fi re rings on a standard-style head gasket

Fitting a steel gasket to an uneven block could result in failure.

MLS head gaskets are available in different

thicknesses

Its not just head gaskets that are available as uprated items. In a highly tuned engine all the gaskets are subjected to higher pressures and temps and so could potentially fail.

As we have mentioned, different gaskets need to be made of different materials dependant upon what they are designed to seal. It is the same story with performance gaskets too, as one material may have excellent properties for coping with a particular task, but may be utterly useless in another area.

Cometic offers a range of performance gaskets

designed to suit almost every application where a gasket could be required. The main types of performance gasket available include:

ALUMINIUM FOAM MATERIAL (AFM) A synthetic foam rubber bonded to an aluminium core. These are ideal for sealing many components such as inlet manifolds and rocker covers, as the foam rubber compresses to create a seal.

CFM 20 This is ideal for areas subjected to high temperatures as the steel perforated core allows heat to be drawn across the

gasket in a uniform fashion. It is also coated with an elastomer fi nish to help seal the two surfaces together.

SPRING STEEL Very similar to the outer layers of a MLS head gasket, and work in the same way. They are ideal for sealing many component surfaces, especially those with high clamp loads.

ARAMID FIBRE Gaskets are suited to high temperature areas and the high density of the woven fabric offers great resistance to tearing. Also as the aramid is fuel resistant this material is perfect for inlet manifold gaskets.

ARMOUR CLAD A combination of fi brous material coated in a steel casing. They are capable of dealing with temperatures up to 2000degrees F, and are easily compressed, making them ideal for sealing very uneven surfaces such as exhaust manifolds.

Paper gaskets arevery common in standard engines

Cork is a good material for sealing against oil leaks

AFM gaskets have a foam rubber bonded to an aluminium core

Armour clad gaskets are ideal for exhaust manifolds

AFM gaskets can be used in many applications

head gaskets are often seen as the fi rst available upgrade.

need to be made from different materials depending upon their use.

The most common types of

Fibre gaskets and in particular washers are often used to create seals in fuel systems.

HEAD GASKETSSTANDARD HEAD GASKETS

the block. This is why the head


The most common types of gasket material include:

washers are often used to create seals in fuel systems. They are impermeable to fuel, yet have excellent crush capabilities, which makes them ideal for use in conjunction

with banjo bolts

HEAD GASKETSSTANDARD HEAD GASKETS

the block. This is why the head

gasket available. In the Ford tuning world Group A uprated head gaskets are often seen as the fi rst available upgrade.

Coopers rings replace the fi re rings on a standard-style head gasket


a gasket simply creates a seal between two mating surfaces. It does this by taking up the space caused by the imperfections of the two mating surfaces. Therefore most gaskets are effectively crushed to create the seal when the two objects are bolted together. Because of this most can only be used once, and need to be replaced

rocker cover-to-head, and sump-to-block. Cork is the best material to use for this

as it is absorbent, has excellent crush

capabilities, and is cheap and

PAPER This is often used to

prevent water leaks. Most commonly found in water pumps and thermostats, thin

gasket in a uniform fashion.

elastomer fi nish to help seal

layers of a MLS head gasket, and work in the same way.

many component surfaces, especially those with high many component surfaces,

Gaskets are suited to high

woven fabric offers great resistance to tearing. Also as the aramid is fuel resistant this material is perfect for

material coated in a steel casing. They are capable of dealing with temperatures up to 2000degrees F, and are easily compressed, making them ideal for sealing very

Armour clad gaskets are ideal for exhaust manifolds

AFM gaskets can be used in many applications

Gaskets are suited to high

resistance to tearing. Also as the aramid is fuel resistant AFM gaskets can

in particular high-boosting turbo engines. To accompany

not needing a single-piece head gasket.

made from a more durable and more resistant composite material. They can therefore cope with the increased strains of a higher performance engine than the standard gasket, but are also a direct swap and operate in exactly

Another method of uprating the head gasket, which was particularly common in the mid-80s, is to fi t a set of Coopers rings. These replace the fi re rings on a traditional head gasket with a much heavier-duty set of O-rings. The block needs to have a lip machined around the top of each cylinder to allow the Coopers rings to be fi tted, and as the head is torqued down

the Coopers rings a Group A-style head gasket without

However, Coopers rings are now seen as old technology,


material. They can therefore cope with the increased strains

gasket, but are also a direct swap and operate in exactly

Another method of uprating the head gasket, which was particularly common in the

Coopers rings. These replace the fi re rings on a traditional

heavier-duty set of O-rings.

lip machined around the top of each cylinder to allow the Coopers rings to be fi tted, and as the head is torqued down

to help create a better seal. The way a head gasket seals the oil and water ways is pretty conventional, but the most diffi cult job a head gasket has to do is create a seal between the cylinder head and block

asbestos, but modern-day standard gaskets are made from a composite material (which incidentally is often incorrectly referred to as a fi bre gasket). The composite material is coated in a wax-like fi nish, and the head gasket will usually feature a bead of silicone around the oil and water ways

around the combustion chamber. The immense pressures and heat which are generated here make it an intrinsically diffi cult joint to seal. To overcome this, a head gasket features steel rings known as fi re rings that seal around the top of the cylinder. The fi re rings are crushed when the head is tightened onto the block (which is why torque settings are critical to ensure optimum gasket thickness is achieved) and creates a seal capable of dealing with the pressures and temperatures involved. However, when you start tuning your engine these pressures and temperatures are dramatically increased and frequently lead to failure of the standard head gasket. Therefore performance upgrades are needed.

PERFORMANCE HEAD GASKETSThere are quite a few different types of performance head

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motorsport engines didnt use a head gasket as wed know it at all. Instead they used Coopers rings to seal against combustion, and the block was also machined to accept

rubber O-rings around the oil and water galleries, therefore not needing a single-piece

steel (MLS) head gasket will offer the same level of performance as Coopers rings, but without having to machine the block.

A MLS gasket is made up of multiple steel layers joined together to form a gasket. Burton Power stocks a complete range of Cometic MLS gaskets, so we were able to pull one apart to see exactly how they work.

The outer

MLS head gasket are embossed and on Cometic gaskets are covered in a


two outer layers, with the extra centre layer offering even greater clamping pressure.

According to Burton Power, Cometic gaskets are available off-the-shelf in sizes ranging from 1mm to 2.5mm thick, and can even be custom made to any thickness required. Thicker gaskets are not necessarily stronger, but do offer the engine builder the chance to tweak the compression ratio easily after the head has been skimmed, or if a slightly lower comp

ratio is required.

therefore move about in the same fashion as a composite gasket, they are best used when the two mating surfaces have been machined totally fl at. Fitting a steel gasket to a slightly uneven block or head surface could result in failure, whereas a composite gasket has more give in it to accommodate these irregularities.

Fitting a steel gasket

could result in failure.

MLS head gaskets are available in different

thicknesses

not needing a single-piece The outer two layers of an MLS head gasket are embossed and on Cometic gaskets are covered in a


However, Coopers rings are now seen as old technology,


MLS head gasket are embossed and on Cometic gaskets are covered in a


FAST FORD SUMMER 2010

0 1 2 8 SUMMER 2010 FAST FORD

THE LOWDOWNGASKETS AND FIXINGS

FIXINGSAs well as the gaskets that fi t in between engine components, the bolts that hold everything in place are also a critical part of a high-performance engine. Whats more, they are probably the most overlooked and underrated areas of an engine build.

Its all well and good fi tting performance engine components which allow you to extract more power

and revs, but it all becomes worthless if the nuts and bolts that hold everything together fail.

That is why performance fi xings from the likes of ARP are needed in highly tuned motors that are subjected to increased stresses and forces. Thankfully Burton Power has a host of various standard and ARP fi xings in stock for us to have a good nosey at and fi nd out what theyre all about.

SILICONE HOSES

THANKS Burton Power 617-631 Eastern AvenueIlford, EssexIG2 6PN020 8518 9136www.burtonpower.com

NEXT MONTH

STUD AND NUT KITS

BOLT HEAD DESIGNYou may have noticed there are many different types of bolt, and the head design differs quite dramatically. This is not by coincidence and is done for a reason. Sometimes its due to the available space, for example some head bolts have an Allen key-style bolt which offers easier access compared to a hex-head bolt.

However, with most performance fi xings the

two most common types are known as six-point and twelve-point. A six-point bolt has a traditional hexagon bolt head, whereas a twelve-point head-style features, as the name suggests, twelve points rather than six.

Most ARP bolts now feature twelve-point heads as they offer twice the surface area for a socket to gain purchase from and therefore are less at risk of being rounded-off when you tighten them up.

STRETCH BOLTSMost standard head bolts are of a stretch bolt design. Unsurprisingly they are given their name because they actually stretch slightly when they are fully tightened. This is why they need to be tightened in stages to a specifi c torque load, and then rotated a further 90 or 180degrees to ensure they stretch the required amount. The main benefi t of this is that the bolt doesnt always require re-torquing after time, meaning it is more or less a fi t-and-forget item.

In some applications replacing the standard, or even uprated, bolt with a stud-and-nut set-up offers greater clamping force and improved performance.

Typically stud-and-nut kits are used where the torque required is very high, such as main cap bearings and clamping the cylinder head to the block. The original bolt is replaced by a stud which is threaded into the bolt hole and torqued-up accordingly. The stud is also threaded on the other end, and a nut secures the component to be fi xed. By doing this the torque load is spread more evenly, and subsequently a greater clamping force can be achieved.

It is also possible to fi t what are known as long studs, which is a common upgrade on the Cossie YB engine. This involves machining the block to accept even longer studs

than the original head bolts, and means the studs can be threaded into a much stronger area of the block. This then ties the whole engine together much better and therefore offers a far superior clamping force than the standard head bolt design.

Different forms of stud and nut kit are often used as standard fi xings, for example fi tting an exhaust manifold to an aluminium head. The reason for this is again due to the way a stud and nut spreads the torque load compared to a standard bolt. If the manifold was bolted directly to the head the torque loads required, and the movement it would encounter when the manifold expands due to heat, would rip the threads out of the head. A stud and nut spreads this load much better, and keeps everything in one piece.

Stud and nut kits spread the torque load better than a conventional bolt

Stud and nut kits are often used to secure main cap bearings

STRETCH BOLTSMost standard head bolts are of a stretch bolt design. Unsurprisingly they are given their name because they actually stretch slightly when they are fully tightened. This is why they need to be tightened in stages to a specifi c torque load, and then rotated a further 90 or 180degrees to ensure they stretch the required amount. The main benefi t of this is that the bolt doesnt always require re-torquing after time, meaning it is more or less a fi t-and-forget item.

In some applications replacing the standard, or

STRETCH BOLTSMost standard head bolts are of a stretch bolt design. Unsurprisingly they are given their name because they actually stretch slightly when they are fully tightened. This is why they need to be tightened in stages to a specifi c torque load, and then rotated a further 90 or 180degrees to ensure they stretch the required amount.

re-torquing after time, meaning it is

In some applications

Stretch bolts are commonly used as standard head bolts

THANKS THANKS

Performance bolts are available with different head designs depending on the application

SILICONE HOSES


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