Building an oil tight Lotus Twin Cam engine is only possible by carefully selecting the correct components and sealants.
With the passage of time and machining the top of the cylinder block, every engine is now dimensionally different.
It is important to select the correct thickness of timing chest gasket to ensure an oil tight joint.
Failure to do this often results in the standard thickness gasket being over compressed and then rupturing.
The components that influence the correct timing chest gasket thickness are:-
a) The height of the cylinder block
b) The installed height of the timing chest
c) The head gasket thickness
Dummy installing the cylinder head with the head gasket on top of the cylinder block allows the critical measurement to be made between the cylinder head and the top of the timing chest.
Once this measurement is known then the correct cork gasket may be selected so as to guarantee an oil tight joint.
The following examples are intended to illustrate how to carry out the necessary checks to select the correct thickness gasket.
Example 1
The following example would be for a Lotus Twin Cam big valve engine where the cylinder head and cylinder block have not been excessively machined.
Cylinder head thickness = 4.600" (116.84mm)
Compressed head gasket thickness = 0.040" (1mm)
Step from top of cylinder block to timing chest top surface = 0.030" (0.75mm)
By adding the head gasket thickness to the step measurement we arrive at 0.070" (1.75mm)
To select the correct timing chest top gasket, there needs to be approximately 33% compression of the gasket material
Therefore an ideal thickness gasket would be 0.105" (2.6mm)
Example 2
The following example would be for a non-standard engine where the cylinder head and cylinder block have been machined.
Cylinder head thickness = 4.550" (115.57mm) - excessively machined
For a road going engine it would be necessary to use a 0.080" (2.00mm) head gasket to reduce the compression ratio
Step from top of cylinder block to timing chest top surface = 0.010" (0.25mm)
Compressed head gasket thickness = 0.080" (2.00mm)
By adding the head gasket thickness to the step measurement we arrive at 0.090" (2.25mm)
To select the correct timing chest top gasket, there needs to be approximately 33% compression of the gasket material
Therefore an ideal thickness gasket would be 0.135" (3.375mm)
Lotus twin cam timing chest gasket
Lotus Marques manufactures a range of different thickness timing chest gaskets to assist in building an oil tight Lotus Twin Cam engine.
Timing chest gaskets are available in the following sizes - 1.1mm, 1.6mm, 2.4mm, 3.0mm, 3.4mm
With the passage of time and machining the top of the cylinder block, every engine is now dimensionally different.
It is important to select the correct thickness of timing chest gasket to ensure an oil tight joint.
Failure to do this often results in the standard thickness gasket being over compressed and then rupturing.
The components that influence the correct timing chest gasket thickness are:-
a) The height of the cylinder block
b) The installed height of the timing chest
c) The head gasket thickness
Dummy installing the cylinder head with the head gasket on top of the cylinder block allows the critical measurement to be made between the cylinder head and the top of the timing chest.
Once this measurement is known then the correct cork gasket may be selected so as to guarantee an oil tight joint.
The following examples are intended to illustrate how to carry out the necessary checks to select the correct thickness gasket.
Example 1
The following example would be for a Lotus Twin Cam big valve engine where the cylinder head and cylinder block have not been excessively machined.
Cylinder head thickness = 4.600" (116.84mm)
Compressed head gasket thickness = 0.040" (1mm)
Step from top of cylinder block to timing chest top surface = 0.030" (0.75mm)
By adding the head gasket thickness to the step measurement we arrive at 0.070" (1.75mm)
To select the correct timing chest top gasket, there needs to be approximately 33% compression of the gasket material
Therefore an ideal thickness gasket would be 0.105" (2.6mm)
Example 2
The following example would be for a non-standard engine where the cylinder head and cylinder block have been machined.
Cylinder head thickness = 4.550" (115.57mm) - excessively machined
For a road going engine it would be necessary to use a 0.080" (2.00mm) head gasket to reduce the compression ratio
Step from top of cylinder block to timing chest top surface = 0.010" (0.25mm)
Compressed head gasket thickness = 0.080" (2.00mm)
By adding the head gasket thickness to the step measurement we arrive at 0.090" (2.25mm)
To select the correct timing chest top gasket, there needs to be approximately 33% compression of the gasket material
Therefore an ideal thickness gasket would be 0.135" (3.375mm)
Lotus twin cam timing chest gasketLotus Marques manufactures a range of different thickness timing chest gaskets to assist in building an oil tight Lotus Twin Cam engine.
Timing chest gaskets are available in the following sizes - 1.1mm, 1.6mm, 2.4mm, 3.0mm, 3.4mm