QUESTION
In an earlier email you mentioned using Loctite 7471 as the primer on the cam housing to head surfaces.
You also mentioned using it on all surfaces?
Does that include the cylinder head, deck and head gasket?
What is the purpose of doing this given it's an activator but the head gasket is installed dry?
G.H. - Brisbane, Queensland
ANSWER
For engine assembly purposes Loctite 7471 is recommended to ensure that all mating surfaces are free of oil.
7471 should be used on the cylinder block top face, upper and lower faces of the cylinder head and the cam housing faces.
Aluminium castings by their nature tend to have a porous structure and micro-crevasses (retains traces of oil).
To obtain an oil tight engine it is necessary to remove all traces of oil from the mating surfaces.
As a general purpose solvent, Lotus Marques uses Shell X55 to clean dirty engine parts.
However, all alloy parts are cleaned again with soft cloth and 7471.
This secondary cleaning action always removes a small amount of residual oil that has been left behind from the initial cleaning operation.
Under NO circumstances should 7471 be applied to the cylinder head gasket.
The block and the cylinder head surfaces need to be completely free of oil contaminants for the head gasket to seal effectively.
Loctite 7471 should also be applied to all mating surfaces just prior to final assembly as it assists in the curing process of anaerobic sealants.
Loctite 510 is a high temperature resistant anaerobic sealant which recommended for installing the cam housings to the cylinder head on Lotus 907, 910, 911, 912 and 920 engines.
For reference purposes a copy of the Loctite 7471 data sheet is shown below.
In an earlier email you mentioned using Loctite 7471 as the primer on the cam housing to head surfaces.
You also mentioned using it on all surfaces?
Does that include the cylinder head, deck and head gasket?
What is the purpose of doing this given it's an activator but the head gasket is installed dry?
G.H. - Brisbane, Queensland
ANSWER
For engine assembly purposes Loctite 7471 is recommended to ensure that all mating surfaces are free of oil.
7471 should be used on the cylinder block top face, upper and lower faces of the cylinder head and the cam housing faces.
Aluminium castings by their nature tend to have a porous structure and micro-crevasses (retains traces of oil).
To obtain an oil tight engine it is necessary to remove all traces of oil from the mating surfaces.
As a general purpose solvent, Lotus Marques uses Shell X55 to clean dirty engine parts.
However, all alloy parts are cleaned again with soft cloth and 7471.
This secondary cleaning action always removes a small amount of residual oil that has been left behind from the initial cleaning operation.
Under NO circumstances should 7471 be applied to the cylinder head gasket.
The block and the cylinder head surfaces need to be completely free of oil contaminants for the head gasket to seal effectively.
Loctite 7471 should also be applied to all mating surfaces just prior to final assembly as it assists in the curing process of anaerobic sealants.
Loctite 510 is a high temperature resistant anaerobic sealant which recommended for installing the cam housings to the cylinder head on Lotus 907, 910, 911, 912 and 920 engines.
For reference purposes a copy of the Loctite 7471 data sheet is shown below.